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Publisher: Elsevier   (Total: 3043 journals)

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Showing 1 - 200 of 3043 Journals sorted alphabetically
AASRI Procedia     Open Access   (Followers: 15)
Academic Pediatrics     Hybrid Journal   (Followers: 20, SJR: 1.402, h-index: 51)
Academic Radiology     Hybrid Journal   (Followers: 18, SJR: 1.008, h-index: 75)
Accident Analysis & Prevention     Partially Free   (Followers: 83, SJR: 1.109, h-index: 94)
Accounting Forum     Hybrid Journal   (Followers: 23, SJR: 0.612, h-index: 27)
Accounting, Organizations and Society     Hybrid Journal   (Followers: 27, SJR: 2.515, h-index: 90)
Achievements in the Life Sciences     Open Access   (Followers: 4)
Acta Anaesthesiologica Taiwanica     Open Access   (Followers: 5, SJR: 0.338, h-index: 19)
Acta Astronautica     Hybrid Journal   (Followers: 333, SJR: 0.726, h-index: 43)
Acta Automatica Sinica     Full-text available via subscription   (Followers: 3)
Acta Biomaterialia     Hybrid Journal   (Followers: 25, SJR: 2.02, h-index: 104)
Acta Colombiana de Cuidado Intensivo     Full-text available via subscription   (Followers: 1)
Acta de Investigación Psicológica     Open Access   (Followers: 2)
Acta Ecologica Sinica     Open Access   (Followers: 8, SJR: 0.172, h-index: 29)
Acta Haematologica Polonica     Free   (SJR: 0.123, h-index: 8)
Acta Histochemica     Hybrid Journal   (Followers: 3, SJR: 0.604, h-index: 38)
Acta Materialia     Hybrid Journal   (Followers: 225, SJR: 3.683, h-index: 202)
Acta Mathematica Scientia     Full-text available via subscription   (Followers: 5, SJR: 0.615, h-index: 21)
Acta Mechanica Solida Sinica     Full-text available via subscription   (Followers: 9, SJR: 0.442, h-index: 21)
Acta Oecologica     Hybrid Journal   (Followers: 9, SJR: 0.915, h-index: 53)
Acta Otorrinolaringologica (English Edition)     Full-text available via subscription   (Followers: 1)
Acta Otorrinolaringológica Española     Full-text available via subscription   (Followers: 3, SJR: 0.311, h-index: 16)
Acta Pharmaceutica Sinica B     Open Access   (Followers: 2)
Acta Poética     Open Access   (Followers: 4)
Acta Psychologica     Hybrid Journal   (Followers: 23, SJR: 1.365, h-index: 73)
Acta Sociológica     Open Access  
Acta Tropica     Hybrid Journal   (Followers: 6, SJR: 1.059, h-index: 77)
Acta Urológica Portuguesa     Open Access  
Actas Dermo-Sifiliograficas     Full-text available via subscription   (Followers: 4)
Actas Dermo-Sifiliográficas (English Edition)     Full-text available via subscription   (Followers: 3)
Actas Urológicas Españolas     Full-text available via subscription   (Followers: 4, SJR: 0.383, h-index: 19)
Actas Urológicas Españolas (English Edition)     Full-text available via subscription   (Followers: 2)
Actualites Pharmaceutiques     Full-text available via subscription   (Followers: 5, SJR: 0.141, h-index: 3)
Actualites Pharmaceutiques Hospitalieres     Full-text available via subscription   (Followers: 4, SJR: 0.112, h-index: 2)
Acupuncture and Related Therapies     Hybrid Journal   (Followers: 3)
Ad Hoc Networks     Hybrid Journal   (Followers: 11, SJR: 0.967, h-index: 57)
Addictive Behaviors     Hybrid Journal   (Followers: 15, SJR: 1.514, h-index: 92)
Addictive Behaviors Reports     Open Access   (Followers: 5)
Additive Manufacturing     Hybrid Journal   (Followers: 8, SJR: 1.039, h-index: 5)
Additives for Polymers     Full-text available via subscription   (Followers: 20)
Advanced Drug Delivery Reviews     Hybrid Journal   (Followers: 134, SJR: 5.2, h-index: 222)
Advanced Engineering Informatics     Hybrid Journal   (Followers: 11, SJR: 1.265, h-index: 53)
Advanced Powder Technology     Hybrid Journal   (Followers: 16, SJR: 0.739, h-index: 33)
Advances in Accounting     Hybrid Journal   (Followers: 9, SJR: 0.299, h-index: 15)
Advances in Agronomy     Full-text available via subscription   (Followers: 15, SJR: 2.071, h-index: 82)
Advances in Anesthesia     Full-text available via subscription   (Followers: 25, SJR: 0.169, h-index: 4)
Advances in Antiviral Drug Design     Full-text available via subscription   (Followers: 3)
Advances in Applied Mathematics     Full-text available via subscription   (Followers: 6, SJR: 1.054, h-index: 35)
Advances in Applied Mechanics     Full-text available via subscription   (Followers: 10, SJR: 0.801, h-index: 26)
Advances in Applied Microbiology     Full-text available via subscription   (Followers: 22, SJR: 1.286, h-index: 49)
Advances In Atomic, Molecular, and Optical Physics     Full-text available via subscription   (Followers: 16, SJR: 3.31, h-index: 42)
Advances in Biological Regulation     Hybrid Journal   (Followers: 4, SJR: 2.277, h-index: 43)
Advances in Botanical Research     Full-text available via subscription   (Followers: 3, SJR: 0.619, h-index: 48)
Advances in Cancer Research     Full-text available via subscription   (Followers: 25, SJR: 2.215, h-index: 78)
Advances in Carbohydrate Chemistry and Biochemistry     Full-text available via subscription   (Followers: 9, SJR: 0.9, h-index: 30)
Advances in Catalysis     Full-text available via subscription   (Followers: 5, SJR: 2.139, h-index: 42)
Advances in Cellular and Molecular Biology of Membranes and Organelles     Full-text available via subscription   (Followers: 12)
Advances in Chemical Engineering     Full-text available via subscription   (Followers: 24, SJR: 0.183, h-index: 23)
Advances in Child Development and Behavior     Full-text available via subscription   (Followers: 10, SJR: 0.665, h-index: 29)
Advances in Chronic Kidney Disease     Full-text available via subscription   (Followers: 10, SJR: 1.268, h-index: 45)
Advances in Clinical Chemistry     Full-text available via subscription   (Followers: 28, SJR: 0.938, h-index: 33)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 18, SJR: 2.314, h-index: 130)
Advances in Computers     Full-text available via subscription   (Followers: 16, SJR: 0.223, h-index: 22)
Advances in Developmental Biology     Full-text available via subscription   (Followers: 11)
Advances in Digestive Medicine     Open Access   (Followers: 4)
Advances in DNA Sequence-Specific Agents     Full-text available via subscription   (Followers: 5)
Advances in Drug Research     Full-text available via subscription   (Followers: 22)
Advances in Ecological Research     Full-text available via subscription   (Followers: 42, SJR: 3.25, h-index: 43)
Advances in Engineering Software     Hybrid Journal   (Followers: 25, SJR: 0.486, h-index: 10)
Advances in Experimental Biology     Full-text available via subscription   (Followers: 7)
Advances in Experimental Social Psychology     Full-text available via subscription   (Followers: 40, SJR: 5.465, h-index: 64)
Advances in Exploration Geophysics     Full-text available via subscription   (Followers: 3)
Advances in Fluorine Science     Full-text available via subscription   (Followers: 8)
Advances in Food and Nutrition Research     Full-text available via subscription   (Followers: 47, SJR: 0.674, h-index: 38)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 15)
Advances in Genetics     Full-text available via subscription   (Followers: 15, SJR: 2.558, h-index: 54)
Advances in Genome Biology     Full-text available via subscription   (Followers: 11)
Advances in Geophysics     Full-text available via subscription   (Followers: 6, SJR: 2.325, h-index: 20)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 21, SJR: 0.906, h-index: 24)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 8, SJR: 0.497, h-index: 31)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 26)
Advances in Imaging and Electron Physics     Full-text available via subscription   (Followers: 2, SJR: 0.396, h-index: 27)
Advances in Immunology     Full-text available via subscription   (Followers: 35, SJR: 4.152, h-index: 85)
Advances in Inorganic Chemistry     Full-text available via subscription   (Followers: 9, SJR: 1.132, h-index: 42)
Advances in Insect Physiology     Full-text available via subscription   (Followers: 3, SJR: 1.274, h-index: 27)
Advances in Integrative Medicine     Hybrid Journal   (Followers: 5)
Advances in Intl. Accounting     Full-text available via subscription   (Followers: 4)
Advances in Life Course Research     Hybrid Journal   (Followers: 8, SJR: 0.764, h-index: 15)
Advances in Lipobiology     Full-text available via subscription   (Followers: 2)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 9)
Advances in Marine Biology     Full-text available via subscription   (Followers: 16, SJR: 1.645, h-index: 45)
Advances in Mathematics     Full-text available via subscription   (Followers: 10, SJR: 3.261, h-index: 65)
Advances in Medical Sciences     Hybrid Journal   (Followers: 6, SJR: 0.489, h-index: 25)
Advances in Medicinal Chemistry     Full-text available via subscription   (Followers: 5)
Advances in Microbial Physiology     Full-text available via subscription   (Followers: 4, SJR: 1.44, h-index: 51)
Advances in Molecular and Cell Biology     Full-text available via subscription   (Followers: 22)
Advances in Molecular and Cellular Endocrinology     Full-text available via subscription   (Followers: 10)
Advances in Molecular Toxicology     Full-text available via subscription   (Followers: 7, SJR: 0.324, h-index: 8)
Advances in Nanoporous Materials     Full-text available via subscription   (Followers: 4)
Advances in Oncobiology     Full-text available via subscription   (Followers: 3)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 15, SJR: 2.885, h-index: 45)
Advances in Parallel Computing     Full-text available via subscription   (Followers: 7, SJR: 0.148, h-index: 11)
Advances in Parasitology     Full-text available via subscription   (Followers: 7, SJR: 2.37, h-index: 73)
Advances in Pediatrics     Full-text available via subscription   (Followers: 24, SJR: 0.4, h-index: 28)
Advances in Pharmaceutical Sciences     Full-text available via subscription   (Followers: 13)
Advances in Pharmacology     Full-text available via subscription   (Followers: 15, SJR: 1.718, h-index: 58)
Advances in Physical Organic Chemistry     Full-text available via subscription   (Followers: 7, SJR: 0.384, h-index: 26)
Advances in Phytomedicine     Full-text available via subscription  
Advances in Planar Lipid Bilayers and Liposomes     Full-text available via subscription   (Followers: 3, SJR: 0.248, h-index: 11)
Advances in Plant Biochemistry and Molecular Biology     Full-text available via subscription   (Followers: 8)
Advances in Plant Pathology     Full-text available via subscription   (Followers: 5)
Advances in Porous Media     Full-text available via subscription   (Followers: 4)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 18)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 19, SJR: 1.5, h-index: 62)
Advances in Psychology     Full-text available via subscription   (Followers: 60)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 5, SJR: 0.478, h-index: 32)
Advances in Radiation Oncology     Open Access  
Advances in Small Animal Medicine and Surgery     Hybrid Journal   (Followers: 2, SJR: 0.1, h-index: 2)
Advances in Space Research     Full-text available via subscription   (Followers: 345, SJR: 0.606, h-index: 65)
Advances in Structural Biology     Full-text available via subscription   (Followers: 8)
Advances in Surgery     Full-text available via subscription   (Followers: 7, SJR: 0.823, h-index: 27)
Advances in the Study of Behavior     Full-text available via subscription   (Followers: 30, SJR: 1.321, h-index: 56)
Advances in Veterinary Medicine     Full-text available via subscription   (Followers: 16)
Advances in Veterinary Science and Comparative Medicine     Full-text available via subscription   (Followers: 13)
Advances in Virus Research     Full-text available via subscription   (Followers: 5, SJR: 1.878, h-index: 68)
Advances in Water Resources     Hybrid Journal   (Followers: 43, SJR: 2.408, h-index: 94)
Aeolian Research     Hybrid Journal   (Followers: 5, SJR: 0.973, h-index: 22)
Aerospace Science and Technology     Hybrid Journal   (Followers: 310, SJR: 0.816, h-index: 49)
AEU - Intl. J. of Electronics and Communications     Hybrid Journal   (Followers: 8, SJR: 0.318, h-index: 36)
African J. of Emergency Medicine     Open Access   (Followers: 5, SJR: 0.344, h-index: 6)
Ageing Research Reviews     Hybrid Journal   (Followers: 8, SJR: 3.289, h-index: 78)
Aggression and Violent Behavior     Hybrid Journal   (Followers: 408, SJR: 1.385, h-index: 72)
Agri Gene     Hybrid Journal  
Agricultural and Forest Meteorology     Hybrid Journal   (Followers: 15, SJR: 2.18, h-index: 116)
Agricultural Systems     Hybrid Journal   (Followers: 30, SJR: 1.275, h-index: 74)
Agricultural Water Management     Hybrid Journal   (Followers: 38, SJR: 1.546, h-index: 79)
Agriculture and Agricultural Science Procedia     Open Access  
Agriculture and Natural Resources     Open Access   (Followers: 1)
Agriculture, Ecosystems & Environment     Hybrid Journal   (Followers: 53, SJR: 1.879, h-index: 120)
Ain Shams Engineering J.     Open Access   (Followers: 5, SJR: 0.434, h-index: 14)
Air Medical J.     Hybrid Journal   (Followers: 5, SJR: 0.234, h-index: 18)
AKCE Intl. J. of Graphs and Combinatorics     Open Access   (SJR: 0.285, h-index: 3)
Alcohol     Hybrid Journal   (Followers: 9, SJR: 0.922, h-index: 66)
Alcoholism and Drug Addiction     Open Access   (Followers: 6)
Alergologia Polska : Polish J. of Allergology     Full-text available via subscription   (Followers: 1)
Alexandria Engineering J.     Open Access   (Followers: 1, SJR: 0.436, h-index: 12)
Alexandria J. of Medicine     Open Access  
Algal Research     Partially Free   (Followers: 8, SJR: 2.05, h-index: 20)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 3)
Allergologia et Immunopathologia     Full-text available via subscription   (Followers: 1, SJR: 0.46, h-index: 29)
Allergology Intl.     Open Access   (Followers: 4, SJR: 0.776, h-index: 35)
ALTER - European J. of Disability Research / Revue Européenne de Recherche sur le Handicap     Full-text available via subscription   (Followers: 7, SJR: 0.158, h-index: 9)
Alzheimer's & Dementia     Hybrid Journal   (Followers: 48, SJR: 4.289, h-index: 64)
Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring     Open Access   (Followers: 5)
Alzheimer's & Dementia: Translational Research & Clinical Interventions     Open Access   (Followers: 3)
American Heart J.     Hybrid Journal   (Followers: 48, SJR: 3.157, h-index: 153)
American J. of Cardiology     Hybrid Journal   (Followers: 45, SJR: 2.063, h-index: 186)
American J. of Emergency Medicine     Hybrid Journal   (Followers: 38, SJR: 0.574, h-index: 65)
American J. of Geriatric Pharmacotherapy     Full-text available via subscription   (Followers: 6, SJR: 1.091, h-index: 45)
American J. of Geriatric Psychiatry     Hybrid Journal   (Followers: 16, SJR: 1.653, h-index: 93)
American J. of Human Genetics     Hybrid Journal   (Followers: 31, SJR: 8.769, h-index: 256)
American J. of Infection Control     Hybrid Journal   (Followers: 24, SJR: 1.259, h-index: 81)
American J. of Kidney Diseases     Hybrid Journal   (Followers: 33, SJR: 2.313, h-index: 172)
American J. of Medicine     Hybrid Journal   (Followers: 46, SJR: 2.023, h-index: 189)
American J. of Medicine Supplements     Full-text available via subscription   (Followers: 3)
American J. of Obstetrics and Gynecology     Hybrid Journal   (Followers: 187, SJR: 2.255, h-index: 171)
American J. of Ophthalmology     Hybrid Journal   (Followers: 54, SJR: 2.803, h-index: 148)
American J. of Ophthalmology Case Reports     Open Access   (Followers: 3)
American J. of Orthodontics and Dentofacial Orthopedics     Full-text available via subscription   (Followers: 6, SJR: 1.249, h-index: 88)
American J. of Otolaryngology     Hybrid Journal   (Followers: 23, SJR: 0.59, h-index: 45)
American J. of Pathology     Hybrid Journal   (Followers: 26, SJR: 2.653, h-index: 228)
American J. of Preventive Medicine     Hybrid Journal   (Followers: 21, SJR: 2.764, h-index: 154)
American J. of Surgery     Hybrid Journal   (Followers: 34, SJR: 1.286, h-index: 125)
American J. of the Medical Sciences     Hybrid Journal   (Followers: 12, SJR: 0.653, h-index: 70)
Ampersand : An Intl. J. of General and Applied Linguistics     Open Access   (Followers: 5)
Anaerobe     Hybrid Journal   (Followers: 4, SJR: 1.066, h-index: 51)
Anaesthesia & Intensive Care Medicine     Full-text available via subscription   (Followers: 55, SJR: 0.124, h-index: 9)
Anaesthesia Critical Care & Pain Medicine     Full-text available via subscription   (Followers: 9)
Anales de Cirugia Vascular     Full-text available via subscription  
Anales de Pediatría     Full-text available via subscription   (Followers: 2, SJR: 0.209, h-index: 27)
Anales de Pediatría (English Edition)     Full-text available via subscription  
Anales de Pediatría Continuada     Full-text available via subscription   (SJR: 0.104, h-index: 3)
Analytic Methods in Accident Research     Hybrid Journal   (Followers: 2, SJR: 2.577, h-index: 7)
Analytica Chimica Acta     Hybrid Journal   (Followers: 38, SJR: 1.548, h-index: 152)
Analytical Biochemistry     Hybrid Journal   (Followers: 164, SJR: 0.725, h-index: 154)
Analytical Chemistry Research     Open Access   (Followers: 8, SJR: 0.18, h-index: 2)
Analytical Spectroscopy Library     Full-text available via subscription   (Followers: 11)
Anesthésie & Réanimation     Full-text available via subscription   (Followers: 1)
Anesthesiology Clinics     Full-text available via subscription   (Followers: 22, SJR: 0.421, h-index: 40)
Angiología     Full-text available via subscription   (SJR: 0.124, h-index: 9)
Angiologia e Cirurgia Vascular     Open Access  
Animal Behaviour     Hybrid Journal   (Followers: 158, SJR: 1.907, h-index: 126)
Animal Feed Science and Technology     Hybrid Journal   (Followers: 5, SJR: 1.151, h-index: 83)
Animal Reproduction Science     Hybrid Journal   (Followers: 5, SJR: 0.711, h-index: 78)
Annales d'Endocrinologie     Full-text available via subscription   (Followers: 1, SJR: 0.394, h-index: 30)
Annales d'Urologie     Full-text available via subscription  
Annales de Cardiologie et d'Angéiologie     Full-text available via subscription   (SJR: 0.177, h-index: 13)
Annales de Chirurgie de la Main et du Membre Supérieur     Full-text available via subscription  
Annales de Chirurgie Plastique Esthétique     Full-text available via subscription   (Followers: 2, SJR: 0.354, h-index: 22)
Annales de Chirurgie Vasculaire     Full-text available via subscription   (Followers: 1)

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Journal Cover Algal Research
  [SJR: 2.05]   [H-I: 20]   [8 followers]  Follow
    
   Partially Free Journal Partially Free Journal
   ISSN (Online) 2211-9264
   Published by Elsevier Homepage  [3043 journals]
  • Facile production of seaweed-based biomaterials with antioxidant and
           anti-inflammatory activities
    • Authors: Susana Guzman-Puyol; Debora Russo; Ilaria Penna; Luca Ceseracciu; Francisco Palazon; Alice Scarpellini; Roberto Cingolani; Rosalia Bertorelli; Ilker S. Bayer; José A. Heredia-Guerrero; Athanassia Athanassiou
      Pages: 1 - 11
      Abstract: Publication date: November 2017
      Source:Algal Research, Volume 27
      Author(s): Susana Guzman-Puyol, Debora Russo, Ilaria Penna, Luca Ceseracciu, Francisco Palazon, Alice Scarpellini, Roberto Cingolani, Rosalia Bertorelli, Ilker S. Bayer, José A. Heredia-Guerrero, Athanassia Athanassiou
      New seaweed-based biomaterials have been prepared using a simple method based on the selective dissolution in trifluoroacetic acid (TFA) of specific polymers and bioactive substances from red, green, and brown seaweeds. Depending on the seaweed's origin, the properties were found to be different, especially the mechanical ones. Furthermore, the samples were fully biodegradable in seawater in one month. Moreover, the antioxidant capacity of the biomaterials was highly increased respect to the pristine materials, demonstrating a selective extraction during the process of solubilization. Finally, biocompatibility and anti-inflammatory experiments demonstrated the non-toxicity of the biomaterials prepared from brown seaweed and a similar anti-inflammatory effect to commercial available drugs, confirming the potential application of the prepared biomaterials for the fabrication of biomedical devices.
      Graphical abstract image

      PubDate: 2017-08-21T16:47:00Z
      DOI: 10.1016/j.algal.2017.08.015
      Issue No: Vol. 27 (2017)
       
  • Process intensification of biodiesel production from Chlorella sp. MJ
           11/11 by single step transesterification
    • Authors: Supratim Ghosh; Srijoni Banerjee; Debabrata Das
      Pages: 12 - 20
      Abstract: Publication date: November 2017
      Source:Algal Research, Volume 27
      Author(s): Supratim Ghosh, Srijoni Banerjee, Debabrata Das
      The present study investigates the effect of single step transesterification method for the improvement of biodiesel yield using algal biomass. Different photobioreactor configurations were studied to find out the most suitable reactor for biomass production. Suitable conditions for HCl catalyzed transesterification were determined for the improvement of biodiesel production. Maximum lipid conversion (95%) was observed under catalyst concentration, algal biomass/methanol ratio, reaction temperature, reaction time and biomass drying duration of 4M, 1:5, 65°C, 7h and 90min, respectively. Single step transesterification showed significant improvement in lipid conversion as compared to conventional two steps transesterification. The kinetics and thermodynamics of the reaction was also determined. The results could help in development of sustainable technology with improved biodiesel quality.
      Graphical abstract image

      PubDate: 2017-08-21T16:47:00Z
      DOI: 10.1016/j.algal.2017.08.021
      Issue No: Vol. 27 (2017)
       
  • The freshwater macroalga Oedogonium intermedium can meet the nutritional
           requirements of the herbivorous fish Ancistrus cirrhosus
    • Authors: Matthew J. Vucko; Andrew J. Cole; Jonathan A. Moorhead; Josiah Pit; Rocky de Nys
      Pages: 21 - 31
      Abstract: Publication date: November 2017
      Source:Algal Research, Volume 27
      Author(s): Matthew J. Vucko, Andrew J. Cole, Jonathan A. Moorhead, Josiah Pit, Rocky de Nys
      The macroalga Oedogonium intermedium has a diverse elemental profile, high energy potential, high lipid content, a high proportion of essential amino acids and a total concentration of protein with the potential to meet the nutritional requirements of herbivorous fishes. The aim of this study was to assess growth, condition, colouration and reproductive output in an herbivorous ornamental fish. The catfish Ancistrus cirrhosus was fed one of three pelletised experimental feeds, Oedogonium, a formulated commercial feed and a 50:50 mix of the two, over a 10month trial. After 10months, fish that were fed exclusively on Oedogonium had equivalent growth rates, body condition, colouration, fecundity and fertilisation rates compared to those fed the commercial and mixed feeds. The absence of any major differences of these characteristics between feeds, especially between Oedogonium and the commercial feed, demonstrates the viability of Oedogonium as a feed, or significant feed ingredient, for this herbivorous fish. As such, linking the cultivation of Oedogonium with the production of herbivorous fish may provide an ideal application for Oedogonium.

      PubDate: 2017-08-21T16:47:00Z
      DOI: 10.1016/j.algal.2017.08.020
      Issue No: Vol. 27 (2017)
       
  • Improving performance in algal organic matter filtration using
           polyvinylidene fluoride–graphene oxide nanohybrid membranes
    • Authors: Woon Chan Chong; Ebrahim Mahmoudi; Ying Tao Chung; Chai Hoon Koo; Abdul Wahab Mohammad; Kamrul Fakir Kamarudin
      Pages: 32 - 42
      Abstract: Publication date: November 2017
      Source:Algal Research, Volume 27
      Author(s): Woon Chan Chong, Ebrahim Mahmoudi, Ying Tao Chung, Chai Hoon Koo, Abdul Wahab Mohammad, Kamrul Fakir Kamarudin
      This study investigated the characteristics of various graphene oxide (GO) nanohybrid membranes and their performance in algal organic matter (AOM) filtration. The membranes were fabricated by phase inversion method. The effect of GO and its nanohybrids embedded in membranes was investigated in terms of wettability, porosity, pore size, surface charge, composition, morphology, permeability, fouling resistance and antimicrobial ability. In addition, the rejection of protein and carbohydrate as critical foulants in AOM was studied. Based on the findings, all the composite membranes showed lower flux decline than PVDF membrane. Composite membranes maintained higher protein (81–86%) and carbohydrate (77–83%) rejection compared with PVDF membrane (64% for protein and 63% for carbohydrate). However, the reversible to irreversible fouling ratio of PVDF, ZnO/GO-PVDF, Ag/GO-PVDF and GO-PVDF membranes was 3.07, 1.53, 0.86 and 1.09, respectively. This scenario implied that more hydrophilic substances in small molecular weight (MW) contained in AOM had plugged the composite membranes' pores and resulted in irreversible fouling. On the other hand, ZnO/GO-PVDF and Ag/GO-PVDF membranes exhibited superior antimicrobial ability and showed great potential in anti-biofouling mitigation.
      Graphical abstract image

      PubDate: 2017-08-21T16:47:00Z
      DOI: 10.1016/j.algal.2017.08.023
      Issue No: Vol. 27 (2017)
       
  • Explorative environmental life cycle assessment for system design of
           seaweed cultivation and drying
    • Authors: Roel van Oirschot; Jean-Baptiste E. Thomas; Fredrik Gröndahl; Karen P.J. Fortuin; Willem Brandenburg; José Potting
      Pages: 43 - 54
      Abstract: Publication date: November 2017
      Source:Algal Research, Volume 27
      Author(s): Roel van Oirschot, Jean-Baptiste E. Thomas, Fredrik Gröndahl, Karen P.J. Fortuin, Willem Brandenburg, José Potting
      Seaweeds are presently explored as an alternative source to meet the future protein demand from a growing world population with an increasing welfare level. Present seaweed research largely focuses on agri-technical and economic aspects. This paper explores directions for optimizing the cultivation, harvesting, transport and drying of seaweed from an environmental point of view. An environmental life cycle assessment (LCA) and detailed sensitivity analysis was made for two different system designs. One system design is featuring one layer of cultivation strips (four longlines side by side) interspaced with access corridors. The other system design is featuring a doubling of cultivation strips by dual layers in the water column. Impact profiles and sensitivity analysis showed that the most important impacts came from drying the harvested seaweed, and from the production of the chromium steel chains and polypropylene rope in the infrastructure. This indicates that caution should be used when designing cultivation systems featuring such materials and processes. Furthermore, the high-density productivity of the dual layer system decreases absolute environmental impacts and so found to be a little more environmentally friendly from a life cycle perspective.

      PubDate: 2017-08-21T16:47:00Z
      DOI: 10.1016/j.algal.2017.07.025
      Issue No: Vol. 27 (2017)
       
  • Outdoor performance of Chlorococcum littorale at different locations
    • Authors: Iago Teles Dominguez Cabanelas; Petronella M. Slegers; Hanna Böpple; Dorinde M.M. Kleinegris; René H. Wijffels; Maria J. Barbosa
      Pages: 55 - 64
      Abstract: Publication date: November 2017
      Source:Algal Research, Volume 27
      Author(s): Iago Teles Dominguez Cabanelas, Petronella M. Slegers, Hanna Böpple, Dorinde M.M. Kleinegris, René H. Wijffels, Maria J. Barbosa
      Our goal in the present study was to evaluate the potential for lipid production of two cell populations of the marine microalgae Chlorococcum littorale under different climate conditions. We selected, in a previous study and via fluorescence activated cell sorting (FACS), a new cell population of Chlorococcum littorale, namely S5. S5 showed a stable doubled triacylglycerol (TAG) productivity in comparison with the original population. A previously developed model was expanded to include day:night cycles and validated to predict biomass and outdoor TAG productivities at different locations. Four different locations were chosen to simulate the response of C. littorale to different day lengths and light intensities (the Netherlands, Norway, Brazil and Spain). Indoor experiments (simulated summer) were carried out with Original and S5, showing that S5 had a doubled TAG productivity under N-starvation. Finally, simulations of biomass and TAG productivities of Original and S5 at different locations were performed. At locations with lower light intensities, Norway and the Netherlands, biomass productivities were higher than at locations with higher light intensities, Brazil/Spain. Such results might be associated with light-saturation effects. TAG productivities, however, showed no effect of local light intensity. Locations at higher latitudes, Norway/Netherlands, cannot sustain phototrophic year-round production, hence, the yearly average TAG productivities were doubled in Brazil/Spain (from 1.4–1.6 to 3.0–3.2gm−2 d−1). Likewise, C. littorale S5 was simulated with doubled TAG productivities when compared with Original, at all locations (2.5–2.7 (low light) to 4.7–5.2gm−2 d−1 (high light)). The present results confirm the industrial potential of Chlorococcum littorale, both Original and S5, as a source of TAG. Furthermore, our results can be used for comparison and to estimate future production scenarios.

      PubDate: 2017-08-21T16:47:00Z
      DOI: 10.1016/j.algal.2017.08.010
      Issue No: Vol. 27 (2017)
       
  • Twisted tubular photobioreactor fluid dynamics evaluation for energy
           consumption minimization
    • Authors: C.A. Gómez-Pérez; J.J. Espinosa Oviedo; L.C. Montenegro Ruiz; A.J.B. van Boxtel
      Pages: 65 - 72
      Abstract: Publication date: November 2017
      Source:Algal Research, Volume 27
      Author(s): C.A. Gómez-Pérez, J.J. Espinosa Oviedo, L.C. Montenegro Ruiz, A.J.B. van Boxtel
      This paper discusses a new tubular PhotoBioReactor (PBR) called twisted tubular PBR. The geometry of a twisted tubular PBR induces swirl mixing to guarantee good exposure of microalgae to Light-Dark (LD) cycles and to the nutrients and dissolved CO2. The paper analyses the energy uptake for fluid transport through the twisted tubular PBR. The analysis is based on a comparison between the twisted tubular PBR and other tubular PBRs that have swirl mixing generation. Four types of tubular PBRs are simulated using Computational Fluid Dynamics (CFD); these results are used to evaluate energy consumption and mixing conditions. Swirl number is used to evaluate mixing conditions and swirl flow. On the other hand, microalgae particles performing undulatory motion are evaluated with Discrete Fourier Transform (DFT). Characteristics of the microalgae frequency in the swirl mixing depend on average flow velocity. Results show that the new twisted tubular PBR demands less energy for pumping than the other tubular PBRs that have swirl motion; providing an important step towards the construction of a highly efficient tubular PBR.

      PubDate: 2017-08-21T16:47:00Z
      DOI: 10.1016/j.algal.2017.08.019
      Issue No: Vol. 27 (2017)
       
  • Feasibility of posthydrolysis processing of hydrothermal extracts from
           Sargassum muticum
    • Authors: Noelia Flórez-Fernández; María Jesús González-Muñoz; Herminia Domínguez
      Pages: 73 - 81
      Abstract: Publication date: November 2017
      Source:Algal Research, Volume 27
      Author(s): Noelia Flórez-Fernández, María Jesús González-Muñoz, Herminia Domínguez
      The posthydrolysis of the crude fucoidan extracted during hydrothermal treatment of Sargassum muticum was carried out with mineral acid or without added acid and aided by microwave or by ultrasound processing during short periods. The liquors produced under non-isothermal treatments at 150 and 170°C were subjected to alginate precipitation and the soluble crude fucoidan to posthydrolysis. Acid posthydrolysis caused a steady increase in the monosaccharide content. Ultrasound (US) was the intensified process selected for assisting short term posthydrolysis, which caused depolymerization of crude fucoidan, but did not significantly change the saccharide or sulfate content. The antiradical and cytotoxic properties against lung and colon cancer cells were significantly enhanced by US assisted posthydrolysis.

      PubDate: 2017-08-21T16:47:00Z
      DOI: 10.1016/j.algal.2017.08.002
      Issue No: Vol. 27 (2017)
       
  • Contribution of microalgae-enriched fodder for the Nile tilapia to growth
           and resistance to infection with Aeromonas hydrophila
    • Authors: Sabreen E. Fadl; M.S. ElGohary; Abdelgawad Y. Elsadany; Doaa M. Gad; Farag F. Hanaa; Nagwan M. El-Habashi
      Pages: 82 - 88
      Abstract: Publication date: November 2017
      Source:Algal Research, Volume 27
      Author(s): Sabreen E. Fadl, M.S. ElGohary, Abdelgawad Y. Elsadany, Doaa M. Gad, Farag F. Hanaa, Nagwan M. El-Habashi
      We studied the impact of using fodder enriched with the cyanobacterium Spirulina platensis or the green alga Chlorella vulgaris or a consortium containing both of them on growth, biochemistry profile and immune status of the Nile tilapia (Oreochromis niloticus) fish. A set of 240 males challenged with Aeromonas hydrophila one week before the end of 9weeks experimental period. The fodder supplemented with 15% (w/w) of Spirulina platensis, 15% of Chlorella vulgaris or 15% of their (1/1) mixture. Growth performance was measured all over 9weeks. Challenge test was performed by infection with the pathogen after 8weeks of growth. The serum total contents of protein, albumin, globulin, urea, creatinine and activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALK) and lactate dehydrogenase (LDH) were measured at 7days before and after the infection. The results revealed significant increases in body weight of the Chlorella and their mixture (Chlorella and Spirulina) treated groups compared with the untreated control and the only Spirulina treated ones (p≤0.05). Without infection, the serum total protein and serum globulin significantly increased by supplementation with the Spirulina, Chlorella and both compared to the uninfected control group. The serum albumin significantly decreased with Chlorella and the mixture supplementations. Lactate dehydrogenase (LDH) in the fish serum generally decreased with application of the enriched feed compared with the control. After infection, serum total protein and globulin significantly increased by the feed supplementations compared with the control group while the serum albumin insignificantly increased by supplementation with Chlorella and Spirulina. ALT, AST, ALK, LDH, urea and creatinine in the fish serum decreased with the microalgae additives compared with the control.

      PubDate: 2017-08-21T16:47:00Z
      DOI: 10.1016/j.algal.2017.08.022
      Issue No: Vol. 27 (2017)
       
  • Laminaria digitata as potential carbon source in heterotrophic microalgae
           cultivation for the production of fish feed supplement
    • Authors: Martina D'Este; Merlin Alvarado-Morales; Irini Angelidaki
      Pages: 1 - 7
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): Martina D'Este, Merlin Alvarado-Morales, Irini Angelidaki
      A novel concept using the macroalgae Laminaria digitata as substrate to grow heterotrophically microalgae species to be used as fish feed supplement is investigated in the present study. Enzymatic hydrolysis of the macroalgae was performed to release the sugars present in the biomass. The hydrolysate was then used as culture medium and nutrient source to grow heterotrophically three different microalgae species, namely Chlorella protothecoides, Chlorella vulgaris and Chlorella sorokiniana, identified as valuable sources of proteins. Due to its faster growth rates, C. protothecoides was selected for further cultivation in batch reactors and its protein content and amino acid composition were measured. At the end of the process the biomass production reached 10.68±1.33gL−1 with a total protein accumulation of 41.77±1.82% (dry weight basis) and a protein yield of 0.17±0.06. Moreover, the essential amino acids score at the end of the experiment was 6 times greater than for the original content of the macroalgae hydrolysate which was used as substrate for the microalgae cultivation. Therefore, this study reveals the potential of macroalgae hydrolysate as culture medium for microalgae cultivation and it opens possibilities for the development of future strategies to optimize the microalgae production processes.
      Graphical abstract image

      PubDate: 2017-07-06T04:46:50Z
      DOI: 10.1016/j.algal.2017.06.025
      Issue No: Vol. 26 (2017)
       
  • Nutritional characterization of the microalga Ruttnera lamellosa compared
           to Porphyridium purpureum
    • Authors: Mariana F.G. Assunção; Jorge M.T.B. Varejão; Lília M.A. Santos
      Pages: 8 - 14
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): Mariana F.G. Assunção, Jorge M.T.B. Varejão, Lília M.A. Santos
      Sustainable food and human health are the major concerns of the society in the last decades. Functional foods and nutraceuticals from natural sources such as microalgae are regarded as a solution. In this study the nutritional composition of Ruttnera lamellosa ACOI 339 has been evaluated and compared to the widely studied Porphyridium purpureum. R. lamellosa showed a proximate composition with 8.81% of protein and 43.88% of carbohydrate and also a convenient lack of fiber (0.94%). The strain revealed a lipid content of 2.68% with substantial amount of long chain polyunsaturated fatty acids, especially docosahexaenoic fatty acid (C22:6ω3 – DHA) representing 6.36% of total fatty acids. The intracellular polysaccharide is rich in xylose, and also a promising antioxidant capacity of 12.02mg/L equivalent to ascorbic acid was detected as an additional feature of the valuable biomass.
      Graphical abstract image

      PubDate: 2017-07-06T04:46:50Z
      DOI: 10.1016/j.algal.2017.06.028
      Issue No: Vol. 26 (2017)
       
  • Astaxanthin from Haematococcus pluvialis as a natural photosensitizer for
           dye-sensitized solar cell
    • Authors: A. Orona-Navar; I. Aguilar-Hernández; A. Cerdán-Pasarán; T. López-Luke; M. Rodríguez-Delgado; D.L. Cárdenas-Chávez; E. Cepeda-Pérez; N. Ornelas-Soto
      Pages: 15 - 24
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): A. Orona-Navar, I. Aguilar-Hernández, A. Cerdán-Pasarán, T. López-Luke, M. Rodríguez-Delgado, D.L. Cárdenas-Chávez, E. Cepeda-Pérez, N. Ornelas-Soto
      An extract of photosynthetic pigments from Haematococcus pluvialis was evaluated as sensitizer for solar cells. Nutrient-stressed H. pluvialis was cultured in a modified WC medium and harvested in the mature aplanospore stage. A crude extract was obtained and purified by column chromatography, rendering a primary purified extract (PPE). A comparison between PPE and a pure astaxanthin standard (AS), applied as sensitizers to TiO2 film photoelectrodes, was carried out. The dye-sensitized solar cell (DSSC) was assembled under a sandwich scheme, where the photoelectrode faced the platinum counter electrode and an iodide electrolyte solution was between them. Photoelectric conversion efficiency was measured using a solar simulator under a single sunlight intensity (100mWcm−2). The photoelectrode sensitized with PPE showed higher efficiency (0.1%), fill factor (0.72), open circuit voltage (0.449V) and short circuit current density (0.313mA/cm2) than those with AS. The increased efficiency obtained using a PPE was attributed to a broader absorption range in the visible region, as well as the thorough internalization and distribution of the molecules in the mesoporous semiconductor (TiO2). Results indicated that the use of semi-purified extracts allows time and costs reduction of the production process for dye-sensitized solar cells applications.
      Graphical abstract image

      PubDate: 2017-07-06T04:46:50Z
      DOI: 10.1016/j.algal.2017.06.027
      Issue No: Vol. 26 (2017)
       
  • Improved productivity and oxidative stress tolerance under nitrogen
           starvation is associated with the ablated Δ5 desaturation in the green
           microalga Lobosphaera incisa
    • Authors: Dipasmita Pal-Nath; Shoshana Didi-Cohen; Nastassia Shtaida; Pulak Ranjan Nath; Talya Samani; Sammy Boussiba; Inna Khozin-Goldberg
      Pages: 25 - 38
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): Dipasmita Pal-Nath, Shoshana Didi-Cohen, Nastassia Shtaida, Pulak Ranjan Nath, Talya Samani, Sammy Boussiba, Inna Khozin-Goldberg
      The green microalga Lobosphaera incisa deposits exceptional amounts of arachidonic acid (ARA, 20:4 n-6) in the storage lipid triacylglycerol (TAG) under nitrogen (N) starvation. The mutant P127, impaired in Δ5 desaturation, is devoid of ARA and produces dihomo γ-linolenic acid (DGLA, 20:3 n-6). Here, we performed a comparative assessment of the effects of N starvation in the mutant and wild type (WT) to elucidate the consequences of mutation on biomass and long-chain polyunsaturated fatty acid (LC-PUFA) productivity. The initial cell density and external light intensities were used as variables for altering incident light availability in the N-depleted cultures. The majority of examined parameters were impaired in the WT, in particular, upon increasing the magnitude of stress applied. Under high light, the highest biomass and LC-PUFA productivities were documented in the cultures of higher cell density in both strains, with maximal productivities attained by the mutant. We surmised that the high content of ARA in N-starved WT cells renders cellular lipids susceptible to reactive oxygen species (ROS), produced under such stress conditions and thus aggravates photosynthetic parameters and biomass production. This assumption was corroborated by the higher lipid peroxidation level during starvation and the lower glutathione content in the WT in the N-replete cells. The mutant also appeared to be more resistant to administration of oxidative stress-generators, methyl viologen and H2O2, than the WT. Furthermore, the expression of selected examined genes functioning in the redox status maintenance in the chloroplast was downregulated in the WT under N starvation. We conclude that the characteristically augmented oleic acid (18:1 n-9) accumulation in the TAG of P127, is associated with the decreased expression of LC-PUFA biosynthesis genes, leading in turn to alleviation of oxidative stress and improved DGLA productivity under N starvation. Hence, from the biotechnological stand-point, strategies avoiding oxidative damage are critically important for the WT L. incisa cultivation.

      PubDate: 2017-07-15T02:44:15Z
      DOI: 10.1016/j.algal.2017.06.026
      Issue No: Vol. 26 (2017)
       
  • The laboratory environmental algae pond simulator (LEAPS) photobioreactor:
           Validation using outdoor pond cultures of Chlorella sorokiniana and
           Nannochloropsis salina
    • Authors: M. Huesemann; P. Williams; S. Edmundson; P. Chen; R. Kruk; V. Cullinan; B. Crowe; T. Lundquist
      Pages: 39 - 46
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): M. Huesemann, P. Williams, S. Edmundson, P. Chen, R. Kruk, V. Cullinan, B. Crowe, T. Lundquist
      A bench-scale photobioreactor system, the Laboratory Environmental Algae Pond Simulator (LEAPS), was designed and constructed to simulate outdoor pond cultivation for a wide range of geographical locations and seasons. The LEAPS consists of six well-mixed glass column photobioreactors submerged in a temperature controlled waterbath (−2°C to >60°C) and illuminated from above by a programmable multicolor LED lighting system (0 to 2500μmol/m2-s). Measured incident light intensities and water temperatures deviated from the respective light and temperature setpoints on average only 2.3% and 0.9%, demonstrating accurate simulation of light and temperature conditions measured in outdoor ponds. In order to determine whether microalgae strains cultured in the LEAPS exhibit the same linear phase biomass productivity as in outdoor ponds, Chlorella sorokiniana and Nannochloropsis salina were cultured in the LEAPS bioreactors using light and temperature scripts measured previously in the respective outdoor pond studies. For Chlorella sorokiniana, the summer season biomass productivity in the LEAPS was 6.6% and 11.3% lower than in the respective outdoor ponds in Rimrock, Arizona, and Delhi, California; however, these differences were not statistically significant. For Nannochloropsis salina, the winter season biomass productivity in the LEAPS was 9.2% higher than in the respective outdoor ponds in Tucson, Arizona, a difference shown to be not statistically significant. Potential reasons for the positive or negative divergence in LEAPS performance, relative to outdoor ponds, are discussed. To demonstrate the utility of the LEAPS in predicting productivity, two other strains – Scenedesmus obliquus and Stichococcus minor – were evaluated using the summer season script for Rimrock, Arizona. For both strains, the productivity was around 11.6g/m2-day at 25cm culture depth. In conclusion, the LEAPS is an accurate pond simulator and thus offers a reliable, fast, and cost-effective way to screen microalgae strains and operating conditions for high biomass productivity and co-product yields.
      Graphical abstract image

      PubDate: 2017-07-15T02:44:15Z
      DOI: 10.1016/j.algal.2017.06.017
      Issue No: Vol. 26 (2017)
       
  • Modeling of microfluidic bio-solar cell using microalgae through
           multiphysics platform: A greener approach en route for energy production
    • Authors: Liyakath Reshma; Amballa Chaitanyakumar; A.L.G.N. Aditya; Boopathy Ramaraj; Kannappan Santhakumar
      Pages: 47 - 55
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): Liyakath Reshma, Amballa Chaitanyakumar, A.L.G.N. Aditya, Boopathy Ramaraj, Kannappan Santhakumar
      Due to the growing energy demands and increased concern over environmental deterioration and energy climate catastrophe, bio-energy based mechanisms had gained interest over recent years and had attained acknowledgment as the “greener” energy self-sustainable technologies of the future. A new micro-fluidic bio-solar cell modeling and their integration using COMSOL multi-physics have been proposed in order to convert solar energy into bioelectricity. Synechocystis PCC6803 is used as the microbial source due to its electrical property for generating electrons through an anodic chamber. Using COMSOL multi-physics platform, the microfluidic bio-solar cell was designed with five functioning layers. Each layer is been assigned with the suitable electrical/electrode properties of the polymer and the anodic chamber layer been assigned with the properties of the microalgae. Finally, the microfluidic bio-solar cell was modeled to create interfaces between optical and electrical physics in order to determine their material transport, heat transfer, electrochemical behavior, current density and voltage distribution behavior of the microfluidic bio-solar cell. The open circuit voltage of about 0.42V is been obtained with 80% of absorption capacity. This modeling can be further developed into an extensible bio-solar panel by fabricating it using a microfluidic chamber for further application enhancement, which can replace inorganic solar cells with bio-solar cells for an eco-friendly environment with less production cost.
      Graphical abstract image

      PubDate: 2017-07-15T02:44:15Z
      DOI: 10.1016/j.algal.2017.07.002
      Issue No: Vol. 26 (2017)
       
  • Phytohormones and free volatile fatty acids from cyanobacterial biomass
           wet extract (BWE) elicit plant growth promotion
    • Authors: Manickam Gayathri; Sumathy Shunmugam; Nooruddin Thajuddin; Gangatharan Muralitharan
      Pages: 56 - 64
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): Manickam Gayathri, Sumathy Shunmugam, Nooruddin Thajuddin, Gangatharan Muralitharan
      The present study highlights the importance of cyanobacteria in plant growth promotion and screened the effect of biomass wet extract (BWE 1% and BWE 10%) of twenty cyanobacterial strains on the morphometric parameters of Pisum sativum L. seedlings after germination. Cyanobacterial BWE treatment significantly increased the radicle, plumule and total seedling length along with percentage of response than the control treatment with water. At BWE 1% treatment, Scytonema bohneri MBDU 104 showed 73.3% of the total seedling response, whereas Dolichospermum spiroides MBDU 903 showed increased total seedling length of 5.69cm among other strains tested. All the tested strains varied among themselves at different parameters. To identify the most potent isolate, all the tested morphometric parameters were evaluated using a multi – criteria decision analysis (MCDA) of PROMETHEE-GAIA software. The isolate Scytonema bohneri MBDU 104 was selected as the potent plant growth promoting cyanobacteria and its BWE was purified using preparative – HPLC and analysed by LC-MS/MS for identifying possible plant growth elicitors. Phytohormones like indole-3 acetic acid (IAA), indole-3 butyric acid (IBA) and cinnamic acid along with free volatile fatty acids were identified and implicated for plant growth promotion by cucumber seed germination bioassay.

      PubDate: 2017-07-15T02:44:15Z
      DOI: 10.1016/j.algal.2017.06.022
      Issue No: Vol. 26 (2017)
       
  • Nutrient removal and biodiesel feedstock potential of green alga UHCC00027
           grown in municipal wastewater under Nordic conditions
    • Authors: Mikael Jämsä; Fiona Lynch; Anita Santana-Sánchez; Petteri Laaksonen; Gennadi Zaitsev; Alexei Solovchenko; Yagut Allahverdiyeva
      Pages: 65 - 73
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): Mikael Jämsä, Fiona Lynch, Anita Santana-Sánchez, Petteri Laaksonen, Gennadi Zaitsev, Alexei Solovchenko, Yagut Allahverdiyeva
      Integrating cultivation with wastewater treatment improves the economics of microalgal based biofuel production and allows for the sustainable reuse of nitrogen (N) and phosphorus (P) from waste streams. Batch-cultivation of a locally isolated green microalga, UHCC00027, and an indigenous algal-bacterial consortium was undertaken on screened municipal wastewater in 24L pilot reactors. Evaluations of growth and of N and P removal were performed at different Chemical Oxygen Demand (COD) levels and N:P ratios. Lipid accumulation and fatty acid composition of the resulting biomass were also examined. Unique to the present study was the evaluation of wastewater treatment performance under cold temperatures (7–13°C) typical of a Nordic climate. While temperature exerted little influence on heterotrophic COD removal, vigorous (temperature dependent) growth of microalgae was important in the efficient removal of N and P, with the N:P ratio playing a central role. The studied cultivation regime and organisms achieved regulatory N and P removal levels with a hydraulic retention time (HRT) of 12days. However, biodiesel properties of the resulting biomass did not meet international standards due to a high proportion of polyunsaturated fatty acids. Possible workarounds for simultaneously increasing nutrient removal efficiency, biomass productivity, and improving biomass suitability for biodiesel under a Nordic climate are discussed.

      PubDate: 2017-07-15T02:44:15Z
      DOI: 10.1016/j.algal.2017.06.019
      Issue No: Vol. 26 (2017)
       
  • Effects of crosslinking modes on the film forming properties of kelp
           mulching films
    • Authors: Yun Zhao; Jie Qiu; Jiachao Xu; Xin Gao; Xiaoting Fu
      Pages: 74 - 83
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): Yun Zhao, Jie Qiu, Jiachao Xu, Xin Gao, Xiaoting Fu
      To solve the serious environmental pollution caused by traditional plastic mulching film, a biodegradable kelp mulching film (KMF) with excellent film forming properties was fabricated using kelp as the raw material. In this paper, the effects of different crosslinking modes with Ca2+ and H+ on the film formation of KMF were investigated. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) results indicated that the synergistic gelation of calcium alginate and alginic acid existed in Ca2+-H+-KMF, implying that the KMF simultaneously crosslinks with Ca2+ and H+. And the Ca2+-H+-KMF exhibited the best physical and mechanical properties among the five differently crosslinked KMFs. Studied results suggested that KMF simultaneously crosslinked by 2% Ca2+ and 1% H+ for 15min had the best overall performance. The maximum tensile strength (TS) and elongation at break (EB) were 66.72MPa and 7.68%, at the same time, the water vapour permeation (WVP) and water solubility (WS) were 8.05×10−11 g/(m·s·Pa) and 7.75%. Using kelp in agricultural mulching films reflects the ecological concept of making full use of resources, thus the KMF can be regarded as a sustainable ecological alternative to traditional plastic mulching films in agriculture.

      PubDate: 2017-07-15T02:44:15Z
      DOI: 10.1016/j.algal.2017.07.006
      Issue No: Vol. 26 (2017)
       
  • Low-molecular-mass organic acid and lipid responses of Isochrysis galbana
           Parke to high temperature stress during the entire growth stage
    • Authors: Juan Su; Mengwei Ye; Yamin Lou; Zhiming Yang; Tiancheng Sun; Runtao Zhang; Jilin Xu; Chengxu Zhou; Xiaojun Yan
      Pages: 93 - 103
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): Juan Su, Mengwei Ye, Yamin Lou, Zhiming Yang, Tiancheng Sun, Runtao Zhang, Jilin Xu, Chengxu Zhou, Xiaojun Yan
      Isochrysis galbana is an important food source in aquaculture especially in the rearing of bivalve mollusks and usually cultured in summer, when water temperatures in breeding pools may reach 35°C. However, the impact of high temperature stress on the growth and metabolism of I. galbana is poorly understood. In this study, the changes of total superoxide dismutase (T-SOD) activity, organic acid, and lipid levels were analyzed at different growth stages when I. galbana Parke was cultured under normal temperature (20°C) and extreme high temperature (35°C), respectively. The result showed that T-SOD activity reached the highest level at exponential phase at both temperatures but exhibited lower level during growth at 35°C. The lower content of citric acid and α-ketoglutaric acid during late stationary phase indicated that tricarboxylic acid (TCA) cycle, amino acid metabolism, and the synthesis of fatty acids may severely be damaged under high temperature stress. The upregulation of monogalactosyldiacylglycerol (MGDG), diacylglycerylcarboxyhydroxymethylcholine (DGCC), diacylglyceryl-N,N,N-trimethylhomoserine (DGTS), triacylglycerol (TAG), and lyso-lipids was observed from adaptation phase to early stationary phase. But downregulation of glyceroglycolipids (MGDG, DGDG, and SQDG), DGCC, and DGTS were found between early stationary phase and late stationary phase at high temperature. Besides, the level of DHA decreased under high temperature stress, revealing that the nutritional value of I. galbana Parke had been reduced. This is the first report addressing metabolic responses of I. galbana Parke to high temperature stress combining T-SOD activity, organic acid, and lipid analysis, and the results demonstrated that the extreme high temperature (35°C) will not only suppress the activity of T-SOD and the formation of organic acids in the TCA cycle and photorespiration, but also influence the lipid metabolism in I. galbana Parke. This study provided a useful reference value for the cultivation of I. galbana under high temperature condition.
      Graphical abstract image

      PubDate: 2017-07-15T02:44:15Z
      DOI: 10.1016/j.algal.2017.06.011
      Issue No: Vol. 26 (2017)
       
  • Plasticity and remodelling of lipids support acclimation potential in two
           species of low-intertidal macroalgae, Fucus serratus (Phaeophyceae) and
           Palmaria palmata (Rhodophyta)
    • Authors: Matthias Schmid; Freddy Guihéneuf; Dagmar B. Stengel
      Pages: 104 - 114
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): Matthias Schmid, Freddy Guihéneuf, Dagmar B. Stengel
      This study aimed to investigate the seasonal changes in the lipid and pigment profiles of two macroalgae, Fucus serratus (Phaeophyceae) and Palmaria palmata (Rhodophyta). The two species displayed distinct differential seasonal patterns of lipid partitioning when collected from their natural habitat at times when species-specific maxima and minima in total fatty acids (TFA) concentrations occurred. F. serratus contained highest levels of TFA (40.07mgg−1 DW) and triacylglycerols (TAG) (26.83mgg−1 DW) during summer (July), in association with lowest levels of polyunsaturated fatty acids (PUFA, 30.2% of TFA) and pigments (1.44mgg−1 DW chlorophyll a). In P. palmata, high levels of TFA (13.00mgg−1 DW) were observed during spring (May), with high levels of polar lipids (10.00mgg−1 DW) rich in PUFA (52.3% of TFA), and high levels of pigments (1.25mgg−1 DW chlorophyll a and 10.88mgg−1 DW phycoerythrin). The results suggest that summer-acclimated F. serratus diverted excess energy into storage lipids (TAG), while P. palmata was more sensitive and susceptible to degradation of its chloroplast membranes, resulting in a decrease in TFA, PUFA-rich polar lipids and pigments, and a release of FFA. The ability to accumulate TAG may be a key factor allowing acclimation to environmental stressors for F. serratus, a species with broader vertical distribution than P. palmata which is restricted to low-intertidal and upper subtidal shores in western Ireland.

      PubDate: 2017-08-02T02:18:12Z
      DOI: 10.1016/j.algal.2017.07.004
      Issue No: Vol. 26 (2017)
       
  • Copper-induced early responses involve the activation of Transient
           Receptor Potential (TRP) channels, release of amino acids, serotonin and
           adrenalin, and activation of homologs of glutamate, adrenalin and
           serotonin receptors in the marine alga Ulva compressa
    • Authors: M. Gómez; A. González; F. Moenne; C.A. Sáez; A. Moenne
      Pages: 115 - 122
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): M. Gómez, A. González, F. Moenne, C.A. Sáez, A. Moenne
      It has been previously shown that U. compressa cultivated with 10μM copper showed the activation of Transient Receptor Potential (TRP) channels at 4, 8 and 13min allowing copper ions entry and transient depolarizations. Here, the alga was incubated with copper and with inhibitors of human TRP channels that were incorporated just after copper addition (time 0), and after 1 and 2min of copper exposure, and membrane depolarizations were detected at 4, 8 and 13min. Copper induced the activation of a TRP A1/C5/M8 at time 0, a TRP A1/C4/M8/V1 after 1min, and a TRP A1/C5/M8, after 2min of copper exposure. In addition, EGTA, a specific calcium chelator, did not inhibit depolarization events when added at time 0, and after 1 and 2min, whereas bathocuproine, a specific copper chelator, inhibited transient depolarizations at 4, 8 and 13min. In addition, inhibitors of human GluR of NMDA type, added at time 0, and GluR of AMPA/KA types, added after 1 and 2min as well as inhibitors of serotonin and adrenalin receptors added after 2min inhibited depolarizations at 4, 8 and 13min. Furthermore, amino acids, serotonin and adrenalin were release to culture medium in response to copper excess. Thus, copper ions induces the activation of TRP channels allowing extracellular copper ions entry leading to transient depolarizations, release of aminoacids, serotonin, and adrenalin, and activation of homologs of glutamate, adrenalin and serotonin receptors which are involved in the activation of TRPs and depolarizations observed at 4, 8 and 12min of copper exposure.

      PubDate: 2017-07-24T11:50:58Z
      DOI: 10.1016/j.algal.2017.07.009
      Issue No: Vol. 26 (2017)
       
  • Optimization of yield and quality of agar polysaccharide isolated from the
           marine red macroalga Pyropia yezoensis
    • Authors: Keiji Sasuga; Tomoya Yamanashi; Sigeru Nakayama; Syuetsu Ono; Koji Mikami
      Pages: 123 - 130
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): Keiji Sasuga, Tomoya Yamanashi, Sigeru Nakayama, Syuetsu Ono, Koji Mikami
      The marine red seaweed Pyropia yezoensis is grown on a large scale in Japan using mariculture for production of nori sheets. Here, we optimized the isolation of agar from P. yezoensis and evaluated its yield, physical properties, and product applications. An alkali pre-treatment of seaweeds before agar extraction increased the weight-average molecular weight of the agar and promoted the conversion of L-galactose sulfate to 3,6-anhydrogalactose, which in turn reduced the sulfate contents, thus altering the gel strength of the agar. This ability to adjust agar quality by altering the alkali concentration during material pre-treatment allowed production of agar with properties similar to those of agar from the red seaweed Gelidium sp., which is widely used for industrial agar applications. We demonstrate the suitability of P. yezoensis agar in production of solid plates for bacterial growth. In addition, the P. yezoensis agar was particularly useful as a gel material, with the capacity for excellent size separation of DNA by electrophoresis even without agarose purification, because of quite low contents of sulfate. These findings support the applicability and usefulness of P. yezoensis for agar production. The established large-scale cultivation methods for P. yezoensis can generate sufficient biomass to produce agar to support medical and biological studies.

      PubDate: 2017-07-24T11:50:58Z
      DOI: 10.1016/j.algal.2017.07.010
      Issue No: Vol. 26 (2017)
       
  • Influence of process conditions and interventions on metals content in
           biocrude from hydrothermal liquefaction of microalgae
    • Authors: Jimeng Jiang; Phillip E. Savage
      Pages: 131 - 134
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): Jimeng Jiang, Phillip E. Savage
      We determined how different reaction conditions influence the metals contents in biocrude oil and other product fractions from hydrothermal liquefaction (HTL) of microalgae. We then assessed the effect of using different solvents for biocrude recovery and adding catalysts on the metal content in the biocrude. The Fe content was lower and the Na content higher in biocrude produced at higher temperature (400 vs 350°C) and longer holding time (60 vs 3min). The Fe and Na contents were reduced over 50% and 95%, respectively, by use of methyl tert-butyl ether (MTBE) rather than dichloromethane as the organic solvent for biocrude recovery and they were reduced over 98% via additional application of a supported Ni catalyst during HTL. This work demonstrates that the hydrothermal treatment conditions influence the metal content in biocrude and that judicious selection of solvent and catalyst can lead to significant reduction in the metal content in biocrude.
      Graphical abstract image

      PubDate: 2017-07-24T11:50:58Z
      DOI: 10.1016/j.algal.2017.07.012
      Issue No: Vol. 26 (2017)
       
  • Polymer chitosan nanoparticles functionalized with Ulva ohnoi extracts
           boost in vitro ulvan immunostimulant effect in Solea senegalensis
           macrophages
    • Authors: Catalina Fernández-Díaz; Olivier Coste; Erik-jan Malta
      Pages: 135 - 142
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): Catalina Fernández-Díaz, Olivier Coste, Erik-jan Malta
      The potential of chitosan-based nanoparticles to incorporate ulvan was investigated and the immunostimulant properties of ulvan polysaccharide as nanocarrier in Solea senegalensis macrophage were evaluated. Ulvan native extract (UL) and ulvan fractionated by chemical (ULQ) or enzymatic (ULE) methods were obtained from Ulva ohnoi macroalgae in culture. These different ulvan types were tested for their ability to form polymeric nanoparticles. Nanoparticles including either unaltered or fractionated ulvan were prepared by ionotropic gelation and characterized. Activity of the ulvan-loaded nanoparticles was tested in vitro on fish macrophages against free unaltered or fractioned ulvan extract. Intracellular and extracellular reactive oxygen species (ROS) production from the different ulvan products was determined in S. senegalensis macrophages using oxidative burst assay. The native ulvan extract (UL) as well as the fractioned form (ULQ and ULE) successfully yielded nanoparticles with a size of 250–300nm and with a Z-potential of 30–40mV. Highest nanoparticle production was achieved using ulvan native extract (NPsUL). Our results indicate that the configuration of the structure of ulvan molecules influence the immune response; in this way, unaltered ulvan is required for successful stimulation of Solea macrophages by Ulva ohnoi polysaccharides. This immune response significantly increases when unaltered ulvan is nanoencapsulated. We conclude that the here developed hybrid polysaccharide nanoparticles composed of chitosan and ulvan are functional. This might open the way for production of nanocarriers that can be used for oral administration of active compounds in aquaculture.

      PubDate: 2017-07-24T11:50:58Z
      DOI: 10.1016/j.algal.2017.07.008
      Issue No: Vol. 26 (2017)
       
  • Effects of disrupted omega-3 desaturase gene construct on fatty acid
           composition and expression of four fatty acid biosynthetic genes in
           transgenic Chlorella vulgaris
    • Authors: Cher Chien Lau; Saw Hong Loh; Ahmad Aziz; Thye San Cha
      Pages: 143 - 152
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): Cher Chien Lau, Saw Hong Loh, Ahmad Aziz, Thye San Cha
      This study demonstrated the genetic modification of Chlorella vulgaris by introducing a copy of disrupted omega-3 desaturase (ω-3 FAD) gene into its genome to study the effect on fatty acid biosynthesis pathway. Results revealed that the expression of endogenous ω-3 FAD gene in transgenic lines (C28 and C30) was temporarily suppressed during the early stage of sub-culture and then reactivated subsequently after six months of alternate sub-culturing. Furthermore, the endogenous ω-3 FAD expression was found to be upregulated to >3-fold without any notable changes in C18:3n3 composition when cultured under nitrate-deficient medium. Interestingly, a significant shift in fatty acid saturation profile towards the production of higher C16:0 was observed along with a reduction in C18:1 composition in transgenic lines. In addition, PCR walking experiment confirmed that the entire T-DNA region and vector backbone were co-transferred and randomly integrated into the host genome. These findings provide valuable insight in understanding the regulation of fatty acid biosynthesis pathway in C. vulgaris and could pave the way for further genetic improvement of the species for various downstream applications.

      PubDate: 2017-07-24T11:50:58Z
      DOI: 10.1016/j.algal.2017.07.011
      Issue No: Vol. 26 (2017)
       
  • Biomass production in Chlorella vulgaris biofilm cultivated under
           mixotrophic growth conditions
    • Authors: Sandra Milena Rincon; Hernan Mauricio Romero; Wrya Moh Aframehr; Haluk Beyenal
      Pages: 153 - 160
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): Sandra Milena Rincon, Hernan Mauricio Romero, Wrya Moh Aframehr, Haluk Beyenal
      The microalga Chlorella vulgaris can produce carbohydrates and lipids within short periods with high lipid productivity. Biofilm reactors can be used for microalga cultivation; however, the research on the use of biofilm reactors as a platform for algal biomass and oil production under mixotrophic conditions is limited. The goals of our work were 1) to develop a mixotrophic algal biofilm reactor using glycerol and urea as carbon and nitrogen sources; 2) to quantify biomass, total lipid, glycerol and urea consumption rates and estimate fatty acid profiles; and 3) to measure dissolved oxygen and pH depth profiles using microelectrodes under dark and light conditions. A membrane bioreactor in continuous mode with recycle under 50μmolphotons m−2 s−1 light irradiance was used to grow the algae. No exogenous CO2 was supplied. The productivities were 9.27±0.47gDWm−2 d−1 and 12.64±0.94gDWm−2 d−1 when 2 and 5gL−1 initial glycerol concentrations were used. The total lipid contents were 13±0.02% and 23.91±0.03%, respectively. Depth profile measurements showed a maximum dissolved oxygen concentration of 3.5mgL−1 near the surface and a minimum of 1.4mgL−1 at the bottom of the biofilm. The pH in the biofilms did not vary with the depth, and it was around 6.8 in the dark and 7.5 in the light. The main fatty acids produced were C18:1, C18:2 and C16:0, and there was a low saturated fatty acid content of 23.37%. The designed biofilm reactor allowed C. vulgaris growth using very low light with a lower water demand. The composition of fatty acids detected in Chlorella vulgaris oil was significantly polyunsaturated. The biofilm growth mode affected C. vulgaris metabolism such that the cell met its CO2 requirements internally and a high oil yield was obtained without nitrogen starvation.

      PubDate: 2017-07-24T11:50:58Z
      DOI: 10.1016/j.algal.2017.07.014
      Issue No: Vol. 26 (2017)
       
  • Microalgae biomass as an alternative ingredient in cookies: Sensory,
           physical and chemical properties, antioxidant activity and in vitro
           digestibility
    • Authors: Ana Paula Batista; Alberto Niccolai; Patrícia Fradinho; Solange Fragoso; Ivana Bursic; Liliana Rodolfi; Natascia Biondi; Mario R. Tredici; Isabel Sousa; Anabela Raymundo
      Pages: 161 - 171
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): Ana Paula Batista, Alberto Niccolai, Patrícia Fradinho, Solange Fragoso, Ivana Bursic, Liliana Rodolfi, Natascia Biondi, Mario R. Tredici, Isabel Sousa, Anabela Raymundo
      Microalgae can be regarded as an alternative and promising food ingredient due to their nutritional composition, richness in bioactive compounds, and because they are considered a sustainable protein source for the future. The aim of this work was to evaluate microalgae (Arthrospira platensis F&M-C256, Chlorella vulgaris Allma, Tetraselmis suecica F&M-M33 and Phaeodactylum tricornutum F&M-M40) as innovative ingredients to enhance functional properties of cookies. Two biomass levels were tested and compared to control: 2% (w/w) and 6% (w/w), to provide high levels of algae-bioactives. The cookies sensory and physical properties were evaluated during eight weeks showing high color and texture stability. Cookies prepared with A. platensis and C. vulgaris presented significantly (p <0.05) higher protein content compared to the control, and by sensory analysis A. platensis cookies were preferred. Besides, A. platensis also provided a structuring effect in terms of cookies texture. All microalgae-based cookies showed significantly higher (p <0.05) total phenolic content and in vitro antioxidant capacity compared to the control. No significant difference (p <0.05) in in vitro digestibility between microalgae cookies and the control was found.
      Graphical abstract image

      PubDate: 2017-08-02T02:18:12Z
      DOI: 10.1016/j.algal.2017.07.017
      Issue No: Vol. 26 (2017)
       
  • New structural insights into the cell-wall polysaccharide of the diatom
           Phaeodactylum tricornutum
    • Authors: Tinaïg Le Costaouëc; Carlos Unamunzaga; Lalia Mantecon; William Helbert
      Pages: 172 - 179
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): Tinaïg Le Costaouëc, Carlos Unamunzaga, Lalia Mantecon, William Helbert
      The cell wall of diatoms is composed of silica and organic matter, including protein, long-chain polyamines and polysaccharides. The main polysaccharide, a sulphated glucuronomannan, has been observed in many diatoms suggesting that it plays an important role in cell-wall biogenesis. We extracted and purified the polysaccharide, prepared oligosaccharide series and analysed the structure of poly- and oligosaccharides using chromatography and NMR spectroscopy methods. Our results show that the backbone of the polysaccharide is predominantly a linear poly-α-(1→3) mannan decorated with sulphate ester groups and β-D-glucuronic residues.

      PubDate: 2017-08-02T02:18:12Z
      DOI: 10.1016/j.algal.2017.07.021
      Issue No: Vol. 26 (2017)
       
  • Improvement of biomass and lipid yield under stress conditions by using
           diploid strains of Chlamydomonas reinhardtii
    • Authors: Minsoo Kwak; Won-Kun Park; Sung-Eun Shin; Hyun-Gi Koh; Bongsoo Lee; Byeong-ryool Jeong; Yong Keun Chang
      Pages: 180 - 189
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): Minsoo Kwak, Won-Kun Park, Sung-Eun Shin, Hyun-Gi Koh, Bongsoo Lee, Byeong-ryool Jeong, Yong Keun Chang
      Algal biofuel feedstocks are excellent candidates for sustainable and eco-friendly fuels for the next generation, which can be improved by genetic modifications for their maximal production of biomaterials. However, currently available genetic modifications involve the introduction of foreign DNA into the algal genome, and this may face legal and public conflicts due to the risk of environmental, economic, and/or health problems. In this regard, we employed an old concept of crop improvement that has been accepted in the long history of agriculture, i.e. polyploidization. Polyploidization of crop plants has been selected fortuitously or intentionally not only for increased quality and/or quantity of products, but also for enhanced stress tolerance. We induced diploidy in the model algae Chlamydomonas by treating haploid cells with the microtubule inhibitor colcemid, and the resulting diploids were selected for increased colony size and neutral lipid contents. Two of the isolated diploid strains containing doubled DNA contents, named CMD ex1 and CMD ex4, were increased in their cell size and cellular weight. These diploids were excellent in coping with abiotic stresses, including nutritional, oxidative, and cold stresses. Under these conditions, the diploids accumulated two times more biomass and FAME yield compared to the control. To understand underlying mechanisms, we performed RNA-Seq analyses for the diploid under the cold stress. Transcriptomic analyses revealed that the diploids showed enhanced expression of genes involved in photosynthesis, energy metabolism, and translation as well as reduced starch metabolism. Overall, diploids of Chlamydomonas showed improvements including increased yields of biomass and FAME and enhanced stress tolerance compared to wild-type organisms. The results demonstrate that polyploidization can be utilized in industrial microalgae for the production of biofuels and other biomaterials not only on a laboratory scale but also in outdoor cultivation, where stress conditions are inevitable.
      Graphical abstract image

      PubDate: 2017-08-02T02:18:12Z
      DOI: 10.1016/j.algal.2017.07.027
      Issue No: Vol. 26 (2017)
       
  • Combined effects of UVR and nutrients on cell ultrastructure,
           photosynthesis and biochemistry in Gracilariopsis longissima
           (Gracilariales, Rhodophyta)
    • Authors: F. Álvarez-Gómez; Z.L. Bouzon; N. Korbee; P. Celis-Plá; É.C. Schmidt; F.L. Figueroa
      Pages: 190 - 202
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): F. Álvarez-Gómez, Z.L. Bouzon, N. Korbee, P. Celis-Plá, É.C. Schmidt, F.L. Figueroa
      The combined effects of ultraviolet radiation (UVR) and nutrients on the red macroalga Gracilariopsis longissima were analyzed for 14days in a 2×2 factorial experiment design. Cell ultrastructure, photosynthetic activity as in vivo chlorophyll a fluorescence and the accumulation of bioactive compounds as soluble proteins, starch, lipids, polyphenols and mycosporine-like amino acids (MAAs) were evaluated. Three main morphological alterations as defense mechanisms against UVR were observed, i.e., an increase in cell wall thickness, accumulation of floridean starch grains and multiplication of the number of layers of cortical cells. Interaction of light and nutrients affected photosynthetic variables, such as electron transport rate (estimator of photosynthetic capacity) and photoinhibition irradiance (Eopt), and also the level of N compounds (i.e., proteins and MAAs) and total carbon and polyphenol content. Other variables such as chlorophyll a, carotenoids, starch, lipids, antioxidant activity and cell viability were influenced by both factors, or only by light, but without interactive effects. G. longissima showed a high acclimation to elevated UVR and nutrients by the decrease of the photosynthetic rate and the increase in the accumulation of N compounds with photoprotection and antioxidant capacities. On the other hand, starch, lipid and polyphenols increased mainly in the presence of UVR under low nutrient availability. The biotechnological implications of the metabolic changes due to N availability and UVR in this species are discussed.

      PubDate: 2017-08-02T02:18:12Z
      DOI: 10.1016/j.algal.2017.07.022
      Issue No: Vol. 26 (2017)
       
  • Influence of biodiversity, biochemical composition, and species identity
           on the quality of biomass and biocrude oil produced via
           hydrothermal liquefaction
    • Authors: David C. Hietala; Cristina K. Koss; Anita Narwani; Aubrey R. Lashaway; Casey M. Godwin; Bradley J. Cardinale; Phillip E. Savage
      Pages: 203 - 214
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): David C. Hietala, Cristina K. Koss, Anita Narwani, Aubrey R. Lashaway, Casey M. Godwin, Bradley J. Cardinale, Phillip E. Savage
      We compared several measures of quality for biomass and biocrude oil produced via hydrothermal liquefaction for monocultures and polycultures of the freshwater microalgae Ankistrodesmus falcatus, Chlorella sorokiniana, Pediastrum duplex, Scenedesmus acuminatus, Scenedesmus ecornis, and Selenastrum capricornutum. On average, the 2-species cultures provided product quality comparable to that of the monocultures, while that of the average 4- and 6-species polycultures was lower. No single monoculture or polyculture performed the best with respect to all quality metrics considered, including biomass fatty acid content and biocrude elemental content and higher heating value. However, for each measure of quality, some polycultures did outperform or match the performance of the best monoculture for each respective metric. Numerous polycultures performed outside the range of product quality exhibited by their constituent species (transgressive overyielding), and polycultures with P. duplex did so to the greatest extent. Microalgal biochemical composition was correlated with biocrude properties, however including species identity as an additional correlation variable further explained the observed variation. Finally, we highlight several polycultures that offer potentially compelling trade-offs between product quantity and quality compared to the most productive monoculture.

      PubDate: 2017-08-02T02:18:12Z
      DOI: 10.1016/j.algal.2017.07.020
      Issue No: Vol. 26 (2017)
       
  • A lipid droplet-associated protein involved in lipid droplet biogenesis
           and triacylglycerol accumulation in the oleaginous microalga Phaeodactylum
           tricornutum
    • Authors: Xiang Wang; Ting-Bin Hao; Srinivasan Balamurugan; Wei-Dong Yang; Jie-Sheng Liu; Hong-Po Dong; Hong-Ye Li
      Pages: 215 - 224
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): Xiang Wang, Ting-Bin Hao, Srinivasan Balamurugan, Wei-Dong Yang, Jie-Sheng Liu, Hong-Po Dong, Hong-Ye Li
      Lipid droplets (LDs) are lipid monolayer-enclosed organelles comprising a lipid core and surface associated-proteins. However, the protein components and their regulatory functions in LDs have remained largely unknown in oleaginous diatoms. In this study, we identified a gene encoding lipid droplet (LD)-associated protein (PtLDP1) in Phaeodactylum tricornutum and examined its function. The PtLDP1 showed homology to the diatom-oleosome-associated protein 1 (DOAP1) from Fistulifera. Overexpression of the PtLDP1 gene elevated lipid content, enlarged LD size and increased relative expression levels of key genes involved in triacylglycerol (TAG) and fatty acid biosynthesis. In contrast, knockdown of PtLDP1 by RNAi decreased lipid and TAG content, and subsequently reduced LD size. In addition, LDs were isolated from P. tricornutum cells and the proteome of LDs was identified by mass spectrometry. We found that PtLDP1 was a significant protein in the LD proteome. Importantly, labeling of enhanced yellow fluorescent protein (EYFP) confirmed that the PtLDP1 was localized to the LDs. Altogether, our data suggest that the PtLDP1 could be an important LD-associated protein contributing to regulation of TAG synthesis and lipogenesis. The findings will provide new targets for genetic improvement of oleaginous microalgae.

      PubDate: 2017-08-02T02:18:12Z
      DOI: 10.1016/j.algal.2017.07.028
      Issue No: Vol. 26 (2017)
       
  • Metabolic acclimation mechanism in microalgae developed for CO2 capture
           from industrial flue gas
    • Authors: Ying Guo; Zhenhong Yuan; Jingliang Xu; Zhongming Wang; Tao Yuan; Weizheng Zhou; Jin Xu; Cuiyi Liang; Huijuan Xu; Shijie Liu
      Pages: 225 - 233
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): Ying Guo, Zhenhong Yuan, Jingliang Xu, Zhongming Wang, Tao Yuan, Weizheng Zhou, Jin Xu, Cuiyi Liang, Huijuan Xu, Shijie Liu
      Microalgae are the potential choice in diverting carbon emission from industrial plants. Owing to the high CO2 concentrations, industrial flue gas can constrain the growth of most microalgae. A continuous transfer procedure was developed to select a tolerant microalgae species to feed on CO2-rich industrial flue gas. The ability to capture CO2 by the developed microalgae species is verified in a closed gas bag system and the bubble column reactors. A total of 432 metabolic molecules were collected from the microalgae culture subject to the ambient (0.04% CO2) and the CO2-elevated (15%) treatments, 37 of which showed significantly different concentrations. These 37 metabolites were found to enhance the cellular physiology mechanisms of the microalgae to thrive in the high concentrations of CO2. The productivity of microalgae was shown to be improved for industrial applications.
      Graphical abstract image

      PubDate: 2017-08-11T08:52:55Z
      DOI: 10.1016/j.algal.2017.07.029
      Issue No: Vol. 26 (2017)
       
  • Ethylene stimulates growth and affects fatty acid content of Synechocystis
           sp. PCC 6803
    • Authors: Marion Le Henry; Michael Charton; Marion Alignan; Pierre Maury; Ana Luniov; Ingrid Pelletier; Pierre-Yves Pontalier; Brad Mark Binder; Carlos Vaca-Garcia; Christian Chervin
      Pages: 234 - 239
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): Marion Le Henry, Michael Charton, Marion Alignan, Pierre Maury, Ana Luniov, Ingrid Pelletier, Pierre-Yves Pontalier, Brad Mark Binder, Carlos Vaca-Garcia, Christian Chervin
      This set of results shows that the growth of wild type Synechocystis sp. PCC 6803 was enhanced by exogenous ethylene and inhibited by 1-methylcyclopropene (1-MCP), a specific inhibitor of ethylene receptors. The fact that the growth of a Synechocystis sp. PCC 6803 strain with the ethylene receptor deleted was unaffected by exogenous ethylene, brings additional proof that this is a specific effect of ethylene. The results also confirm previous observations regarding the positive impact of ethylene on the photochemical efficiency of PSII. Additionally, it was observed that exogenous ethylene enhanced accumulation of C16:0 and C18:0 and C18:1 in the wild type strain. Finally, observations were performed regarding the capacity of the wild type strain to biosynthesize ethylene in the culture medium in the presence of methionine. These results and the recent description of an ethylene receptor in Synechocystis should lead to new areas of research in the field of microalgae.

      PubDate: 2017-08-11T08:52:55Z
      DOI: 10.1016/j.algal.2017.07.032
      Issue No: Vol. 26 (2017)
       
  • In-depth metabolic profiling of marine macroalgae confirms strong
           biochemical differences between brown, red and green algae
    • Authors: Ikram Belghit; Josef D. Rasinger; Svenja Heesch; Irene Biancarosa; Nina Liland; Bente Torstensen; Rune Waagbø; Erik-Jan Lock; Christian G. Bruckner
      Pages: 240 - 249
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): Ikram Belghit, Josef D. Rasinger, Svenja Heesch, Irene Biancarosa, Nina Liland, Bente Torstensen, Rune Waagbø, Erik-Jan Lock, Christian G. Bruckner
      In-depth metabolic profiling, also termed metabolomics, provides detailed information about the biochemical phenotype of an organism. Besides improving our understanding of biochemical processes, metabolomics is used for environmental monitoring, natural product discovery, or even chemotaxonomy, among others. However, for marine macroalgae, comparative large-scale metabolomics studies are lacking, even though seaweeds belong to the most important aquatic primary producers. In this study, we present via a broad scale systematic metabolomics survey 391 metabolites from 21 seaweeds species, representing brown, red and green algae. We demonstrate clear differences in metabolite composition of these seaweeds, reflecting their taxonomic classification. We highlight these differences for amino acid, amino acid derivative and peptide metabolites, energy and carbohydrate metabolites, for lipid, fatty acid and sterol metabolites and for secondary metabolites, including selected metabolic pathways such as the urea cycle, the citrate cycle and the glyconeogenesis/glycolysis, besides others. Additionally, we link selected seaweed biochemical properties to potential pharmaceutical and nutraceutical applications.

      PubDate: 2017-08-11T08:52:55Z
      DOI: 10.1016/j.algal.2017.08.001
      Issue No: Vol. 26 (2017)
       
  • Control of zooplankton populations in a wastewater treatment High Rate
           Algal Pond using overnight CO2 asphyxiation
    • Authors: Valerio Montemezzani; Ian C. Duggan; Ian D. Hogg; Rupert J. Craggs
      Pages: 250 - 264
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): Valerio Montemezzani, Ian C. Duggan, Ian D. Hogg, Rupert J. Craggs
      High Rate Algal Ponds (HRAPs) with addition of CO2 are open pond wastewater treatment systems that recover nutrients as microalgal biomass. Such ponds are vulnerable to contamination by opportunistic zooplankton species able to survive the wastewater HRAP environment. The high food availability and a near neutral pH can promote the rapid development of high densities of zooplankton that can reduce treatment performance by consuming microalgae. Zooplankton control using night time CO2 asphyxiation was selected from promising zooplankton control methods previously screened at laboratory and mesocosm scales, and used to control zooplankton densities in an 8m3 HRAP over 14months. Increasingly higher flow rates (1 to 6L/min) of pure CO2 were tested by using 13 control treatment events. CO2 was injected during night time, and treatment events were repeated for a number of consecutive nights sufficient to control zooplankton density to ≤10% of that before treatment. Treatments with higher CO2 flow rates promoted more rapid reductions of zooplankton density (12 nights to 1), and were associated with higher maximum CO2 concentrations (100 to 420mg/L), and lower pH (~6 to ~5). Compared to the control HRAP, CO2 treatment decreased the average population densities of some zooplankton species over the experimental period: Moina tenuicornis (41.3%), Paracyclops fimbriatus (43.9%), Filinia longiseta (59.8%), but was associated with higher average population densities of others: Heterocypris incongruens (174.4%), Asplanchna sieboldi (177.8%), Cephalodella catellina (200.0%), and Brachionus calyciflorus (234.9%). However, the population densities of the rotifers B. calyciflorus and C. catellina were always reduced following CO2 treatments with flow rates ≥2L/min. The cladoceran Daphnia thomsoni and the rotifer Brachionus urceolaris established only in the control HRAP. Zooplankton control by CO2 asphyxiation improved the overall performance of the treated WW HRAP compared to the control in several ways, including increasing algal biomass (VSS) (150.8%), productivity (151.4%), chlorophyll-a concentration (161.8%), particle size (MCSA) (115.8%), and average settleability efficiency (189.2%). Overnight CO2 asphyxiation showed the potential to control zooplankton and to promote better WW HRAPs performance.

      PubDate: 2017-08-11T08:52:55Z
      DOI: 10.1016/j.algal.2017.08.004
      Issue No: Vol. 26 (2017)
       
  • Nutrients from anaerobic digestion effluents for cultivation of the
           microalga Nannochloropsis sp. — Impact on growth, biochemical
           composition and the potential for cost and environmental impact savings
    • Authors: Joshua J. Mayers; Anna Ekman Nilsson; Eva Albers; Kevin J. Flynn
      Pages: 275 - 286
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): Joshua J. Mayers, Anna Ekman Nilsson, Eva Albers, Kevin J. Flynn
      Microalgal biotechnology has yielded a range of products for different consumer markets, but large scale production for bulk commodities is limited by the cost and environmental impact of production. Nutrient requirements for large-scale production contribute significantly to the cost and environmental impact of microalgal biomass production and should subsequently be addressed by more careful sourcing of nutrients. This study assessed the use of nitrogen and phosphorus contained in effluents from anaerobic digestion of food waste to cultivate the marine microalga Nannochloropsis sp. With suitable dilution, effluent could replace 100% of nitrogen demands and 16% of required phosphorus, without significant impacts on growth or biomass productivity. Additional phosphorus requirements could be decreased by increasing the N:P molar ratio of the media from 16:1 to 32:1. Nannochloropsis sp. accumulated lipid up to 50% of dry weight under N-stress, with significant increases in the content of saturated and mono-unsaturated fatty acids. Using empirical data generated in this study, the cost and environmental impact of nitrogen and phosphorus supply was assessed versus the use of fertilizers for biomass and biodiesel production. Nutrient requirements predicted by the Redfield Ratio overestimating impacts by as much as 140% compared to empirical data. By utilising residual nutrients and optimising nutrient supply, the cost and environmental impact of nitrogen and phosphorus were decreased by >90% versus the use of artificial fertilizers. This study demonstrates the importance of using empirical data for process evaluation and how anaerobic digestate effluent derived nutrients can contribute to the sustainability of algal biomass production.
      Graphical abstract image

      PubDate: 2017-08-11T08:52:55Z
      DOI: 10.1016/j.algal.2017.08.007
      Issue No: Vol. 26 (2017)
       
  • The role of alginate lyases in the enzymatic saccharification of brown
           macroalgae, Macrocystis pyrifera and Saccharina latissima
    • Authors: María Cristina Ravanal; Sandeep Sharma; Javier Gimpel; Felipe E. Reveco-Urzua; Margareth Øverland; Svein Jarle Horn; María Elena Lienqueo
      Pages: 287 - 293
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): María Cristina Ravanal, Sandeep Sharma, Javier Gimpel, Felipe E. Reveco-Urzua, Margareth Øverland, Svein Jarle Horn, María Elena Lienqueo
      In this work, we have compared the carbohydrate content and the enzymatic saccharification of the brown algae Macrocystis pyrifera from Chile and Saccharina latissima from Norway. M. pyrifera contained 40% mannitol, 31% uronic acids and 15% glucose, while S. latissima contained 37% glucose, 30% uronic acids and 25% mannitol. Thus, the ratio between mannitol and glucose was much higher for M. pyrifera. Acid pre-treated and untreated algae were enzymatically saccharified in two steps; first at pH7.5, 25°C for 12h with a blend of recombinant alginate and oligoalginate lyases, then the pH was changed to 5.2, a commercial cellulase cocktail was added and saccharification continued at 50°C for 4h. These experiments showed that the use of recombinant alginate lyases and oligoalginate lyases in combination with cellulases increased the release of glucose from untreated seaweed. However, for saccharification of pretreated algae, only cellulases were needed to achieve high glucose yields. Finally, it was shown that brown algae hydrolysates could be used as a growth medium to produce microbial ingredients, such as Candida utilis yeast.

      PubDate: 2017-08-11T08:52:55Z
      DOI: 10.1016/j.algal.2017.08.012
      Issue No: Vol. 26 (2017)
       
  • A new approach to quantify system efficiency with dissolved oxygen
           isotopes during engineered growth of Galdieria sulphuraria
    • Authors: Michael Mader; Philipp Schwerna; Rainer Buchholz; Robert van Geldern; Johannes A.C. Barth
      Pages: 294 - 301
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): Michael Mader, Philipp Schwerna, Rainer Buchholz, Robert van Geldern, Johannes A.C. Barth
      The microalgae Galdieria sulphuraria was grown in a first technical approach in a closed system experiment for 29days. In this time period, 6 separate flasks were sampled for oxygen concentration and their stable isotope ratios (18O/16O) in dissolved and headspace phases. The oxygen isotope composition of the water was also analysed as an input for the transfer of its 18O/16O ratio to molecular oxygen via production by algae. This photosynthetic transfer of the isotope composition of water was counterbalanced by oxygen consumption that enriched both phases in 18O. For this reason, neither dissolved oxygen nor oxygen in the headspace reached the 18O-depleted oxygen isotope ratio of H2O despite excessive photosynthesis. Oxygen that was produced by photosynthesis accumulated with a yield of 13.96mmolL−1 in the headspace and with 0.5mmolL−1 in the fluid phase. This difference was due to rapid degassing of the solution. It was further amplified by preferential consumption of the dissolved O2 phase. In order to quantify oxygen production and its consumption we determined photosynthesis/respiration (P/R) ratios with a formula that combined O2 concentrations and its isotope ratios. It revealed a P/R ratio of 7.7 after 11days. After this it decreased again and moved towards dominance of respiration. With this work our results introduce a new method to monitor the growth and efficiency of algae in controlled experiments.

      PubDate: 2017-08-11T08:52:55Z
      DOI: 10.1016/j.algal.2017.07.026
      Issue No: Vol. 26 (2017)
       
  • Photosynthetic carbon uptake induces autoflocculation of the marine
           microalga Nannochloropsis oculata
    • Authors: Nhan-An T. Tran; Justin R. Seymour; Nachshon Siboni; Christian R. Evenhuis; Bojan Tamburic
      Pages: 302 - 311
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): Nhan-An T. Tran, Justin R. Seymour, Nachshon Siboni, Christian R. Evenhuis, Bojan Tamburic
      Microalgal biomass has been used to produce biofuels, aquaculture feed, high-value chemicals such as pigments and antioxidants, and even human food. This study addresses one of the key bottlenecks to the commercialisation of microalgal bioproducts: the high energy and environmental cost of harvesting microalgal cells out of suspension. An innovative and sustainable autoflocculation procedure was developed to pre-concentrate microalgal biomass for easier harvesting. Microalgal cell agglomeration by autoflocculation at high pH was induced for the first time, without the addition of a chemical flocculant, in the commercially-relevant microalga Nannochloropsis oculata. Photosynthetic inorganic carbon uptake, in the absence of carbon dioxide supply by mass transfer, was used to raise the culture pH. Autoflocculation started at pH9.5 and reached a maximum flocculation efficiency of 90% at pH10.4. Microalgal surface charge-neutralisation by calcium cations, and sweep flocculation by calcium carbonate and calcium phosphate precipitates were identified as the dominant flocculation mechanisms. This was also the first study to measure changes in bacterial community composition under autoflocculation. There was a clear shift from free-living bacteria in suspension to attached bacteria during autoflocculation, with Flavobacteriales becoming the dominant order of bacteria. This highlights the influential role of attached bacteria and bacteria-produced extracellular polymeric substances in microalgal flocculation. This study shows that regulating carbon dioxide supply is a promising green alternative to traditional microalgal flocculation processes as it alleviates the requirement for costly and harmful chemical flocculants and brings us closer to sustainable microalgal bioproducts.

      PubDate: 2017-08-11T08:52:55Z
      DOI: 10.1016/j.algal.2017.08.005
      Issue No: Vol. 26 (2017)
       
  • A chemical approach to manipulate the algal growth, lipid content and
           high-value alpha-linolenic acid for biodiesel production
    • Authors: Ali Parsaeimehr; Elena I. Mancera-Andrade; Felipe Robledo-Padilla; Hafiz M.N. Iqbal; Roberto Parra-Saldivar
      Pages: 312 - 322
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): Ali Parsaeimehr, Elena I. Mancera-Andrade, Felipe Robledo-Padilla, Hafiz M.N. Iqbal, Roberto Parra-Saldivar
      Microalgal cultivation systems for energy production are not yet economically viable due to the low yield of lipids and biomass. In this study, we propose a chemical approach, using exogenous bioactive molecules for improving algal growth, lipid content and the production of high-value alpha-linolenic acid (ALA), using Chlorella protothecoides as a model. Based on our findings, among the cytokinin and auxin classes, Kinetin increased the biosynthesis of ALA by 26.5% at 1ppm concentration, and indole-3-butyric acid at 2ppm improved the biomass and lipid productivity up to 29.15±2.02gm−2 day−1, and 6.69±0.56gm−2 day−1, respectively. Methyl jasmonate as a stress-related phytohormone also showed a positive stimulatory effect on growth of C. protothecoides, and the biomass productivity was increased up to 25.26±1.48gm−2 day−1 at the concentration of 5ppm (lipid content: 219.66±13.20mgg−1 dw; lipid productivity: 5.61±0.25gm−2 day−1; ALA: 0.81±0.16gm−2 day−1). A difference in the composition of fatty acids, due to the type and concentrations of stress-related phytohormones was observed, and under the influence of stress-related phytohormones, the biosynthesis of saturated fatty acids increased, and polyunsaturated fatty acids decreased in C. protothecoides. Butylated hydroxyanisole, at a concentration of 0.05ppm, increased the ALA content by 60.5%. Our study shows that the proposed bioactive molecules could increase the biomass productivity of C. protothecoides at a lower cost compared to the use of acetate as a carbon source.

      PubDate: 2017-08-11T08:52:55Z
      DOI: 10.1016/j.algal.2017.08.016
      Issue No: Vol. 26 (2017)
       
  • Chemical regulation of Fea1 driven transgene expression in Chlamydomonas
           reinhardtii
    • Authors: Paula Barjona do Nascimento Coutinho; Christine Friedl; Rainer Buchholz; Stephanie Christine Stute
      Pages: 323 - 329
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): Paula Barjona do Nascimento Coutinho, Christine Friedl, Rainer Buchholz, Stephanie Christine Stute
      Inducible promoters can provide regulated gene expression allowing the biosynthesis of gene products at most suitable moments of cultivation. In this study, parameters of induction and deactivation of the iron-responsive Fea1 promoter (Allen et al., 2007) were investigated in the green alga Chlamydomonas reinhardtii. Our results indicate that the construct used, ble-2A-mCherry, can be expressed successfully by the Fea1 promoter under iron-deficient conditions. The fluorescence signals of the fluorescent protein mCherry obtained via flow cytometry were detectable at different intensities in response to concentrations of iron ranging from 0μM to 20μM in media. We also demonstrate that the addition of the iron chelator deferroxamine (DFO) to iron-replete media leads to promoter activation, resulting in the increase of mCherry fluorescence. Reversibility of promoter induction is detected already within 3h after transferring the cells to iron-replete chelator-free media. In this case, the progressive decrease in mCherry fluorescence can reach, within 48h, as low as 5% of the fluorescence observed in a 40h – treatment with DFO. Cell viability after DFO treatment is not affected up to a concentration of 100μM of the chelator, which enables the establishment of a cyclic process of induction and repression for the production of recombinant proteins under the control of the Fea1 inducible promoter.

      PubDate: 2017-08-11T08:52:55Z
      DOI: 10.1016/j.algal.2017.08.006
      Issue No: Vol. 26 (2017)
       
  • Dynamic process model and economic analysis of microalgae cultivation in
           open raceway ponds
    • Authors: Sudhanya Banerjee; Shri Ramaswamy
      Pages: 330 - 340
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): Sudhanya Banerjee, Shri Ramaswamy
      Microalgae are a promising biomass feedstock for production of value-added chemicals and bioproducts. A first principle based bioreaction kinetics and bioprocess model of microalgae production was developed for an outdoor open raceway pond that takes into account year-round geospatial characteristics and variability. The primary factors that affect microalgae growth, such as solar irradiance, temperature, biological growth parameters, nutrients and carbon dioxide uptake rates, were considered in the bioreactor process model. Microalgae productivity varied between 2000 and 7200tkm−2 year−1 for the different geographical regions studied. For each location, techno-economic analysis was conducted to assess microalgae production price. The capital and operating expenses for microalgae cultivation systems were quantified based on the mass and energy balances of the process. Given the geospatial locations, cost of microalgae production varied between 1074$t−1 to 502$t−1. Results showed that cost of microalgae production depends heavily on the average areal productivity, price of nutrients, as well as design specifications of microalgae growth ponds.

      PubDate: 2017-08-11T08:52:55Z
      DOI: 10.1016/j.algal.2017.08.011
      Issue No: Vol. 26 (2017)
       
  • The hydrogen metabolism of sulfur deprived Chlamydomonas reinhardtii cells
           involves hydrogen uptake activities
    • Authors: Alberto Scoma; Anja Hemschemeier
      Pages: 341 - 347
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): Alberto Scoma, Anja Hemschemeier
      Several species of unicellular microalgae such as the model species Chlamydomonas reinhardtii possess plastid-localized [FeFe]-hydrogenases which, via ferredoxin, can accept electrons from photosynthetic electron transport. Thereby, under specific conditions, these algae light-dependently produce molecular hydrogen (H2), which offers a sustainable way to generate a “green” and efficient fuel. Until today, the most common way to induce sustained H2 production is to deprive Chlamydomonas of macronutrients such as sulfur (S) which results in a downregulation of photosynthetic production of molecular oxygen (O2) and of assimilatory processes. These acclimation responses allow the O2 sensitive algal [FeFe]-hydrogenases to become active and serve as an alternative electron sink of photosynthesis. Despite much progress in the field and a general understanding of the underlying mechanisms, many basic and applied aspects of the photosynthetic H2 metabolism of eukaryotic algae remain to be elucidated. One rarely investigated factor is that microalgae have also been reported to consume H2, especially as a response to high H2 concentrations. Here, we analyzed the H2 uptake activities of S-deprived Chlamydomonas cells incubated in different PBRs providing different gas phase volumes, either in continuous light or in the dark. We show that H2 uptake occurs after prolonged incubation in the light as well as in sudden darkness. Dark-induced H2 uptake can be delayed adding the phosphoribulose kinase inhibitor glycolaldehyde, suggesting a connection to carbohydrate metabolism. The results indicate that PBR setups as well as envisioned outdoor cultivation systems with natural light-dark cycles have to be carefully designed to prevent efficiency losses.

      PubDate: 2017-08-21T16:47:00Z
      DOI: 10.1016/j.algal.2017.08.018
      Issue No: Vol. 26 (2017)
       
  • N2O emissions during microalgae outdoor cultivation in 50L column
           photobioreactors
    • Authors: Maxence Plouviez; Andy Shilton; Michael A. Packer; Benoit Guieysse
      Pages: 348 - 353
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): Maxence Plouviez, Andy Shilton, Michael A. Packer, Benoit Guieysse
      This study investigated the potential environmental significance of nitrous oxide (N2O) emissions from outdoor microalgal cultivation. Chlorella vulgaris, Neochloris sp., and Arthrospira platensis were cultivated in 50L pilot scale photobioreactors (PBRs) operated in fed batch mode and fed with either nitrate (NO3 −) or ammonium (NH4 +) as the nitrogen (N) source. When NO3 − was supplied as N-source, Neochloris sp., and C. vulgaris cultures emitted 50.0–14,200nmol·N2O·m−2·h−1 (36days of cultivation, n =136, median=2220nmol·N2O·m−2·h−1) and 9.60–38,000nmol·N2O·m−2·h−1 (90days of cultivation, n =332, median=4050nmol·N2O·m−2·h−1), respectively. Based on the emissions representing 25–75% of the data recorded from C. vulgaris fed NO3 − (1500–8000nmol·N2O·m−2·h−1), N2O emissions factors were estimated as 0.1–0.4% of the N input load of 25g·N·d−1. Further monitoring of C. vulgaris cultures showed that N2O emissions were positively correlated to biomass concentration (R2 =0.77) and light intensity (R2 =0.57). Nitrous oxide emissions were not detected when C. vulgaris was cultivated using ammonium as N-source (32days of cultivation, n =84), or when A. platensis cultures were cultivated with NO3 − as N-source (36days of cultivation, n =90). The use of ammonium as N-source or the selection of appropriate algae species could therefore provide simple N2O mitigation strategies.
      Graphical abstract image

      PubDate: 2017-08-21T16:47:00Z
      DOI: 10.1016/j.algal.2017.08.008
      Issue No: Vol. 26 (2017)
       
  • A customized contamination controlling approach for culturing oleaginous
           Nannochloropsis oceanica
    • Authors: Qinhua Gan; Wenxu Zhou; Shifan Wang; Xianzhu Li; Zineng Xie; Jun Wang; Jinju Jiang; Yandu Lu
      Abstract: Publication date: Available online 18 August 2017
      Source:Algal Research
      Author(s): Qinhua Gan, Wenxu Zhou, Shifan Wang, Xianzhu Li, Zineng Xie, Jun Wang, Jinju Jiang, Yandu Lu
      Functional genomics of microalgae have undergone tremendous progress and have a huge impact for streamlining the algal cultivation technology; however, the rational utilization of algal genomes for discovering the strategies to combat algal culture contamination remain unexplored. Genome comparison of fungi and microalgae allowed us to find insights into the possible distinctions of key enzymes and genetic structural of sterol biosynthetic pathway, which are the targets for commercial fungicides. By further screening and characterizing chemical inhibitors targeting selected sterol biosynthetic enzymes, a species-specific contamination control method tailored to oleaginous Nannochloropsis oceanica has been developed. With a concentration of as low as 1μg/ml, triticonazole, a sterol 14-demethylase inhibitor, was capable of effectively eliminating contaminated fungi and potential invasive algal strains, and able to stimulate the growth of desired microalgal species. These findings suggest that the crossing kingdom genome comparison helps to identify genetic distinctions which can be utilized to select appropriate and customized microbial contamination control approach for culturing individual microalgal species with desired production traits.

      PubDate: 2017-08-21T16:47:00Z
      DOI: 10.1016/j.algal.2017.07.013
       
  • Reconstruction and analysis of a genome-scale metabolic model of
           Nannochloropsis gaditana
    • Authors: Ab Rauf Shah; Ahmad Ahmad; Shireesh Srivastava; B.M. Jaffar Ali
      Abstract: Publication date: Available online 16 August 2017
      Source:Algal Research
      Author(s): Ab Rauf Shah, Ahmad Ahmad, Shireesh Srivastava, B.M. Jaffar Ali
      Nannochloropsis gaditana is a promising marine microalga for biotechnological applications due to its capacity to accumulate large amounts of lipids and to synthesize valuable chemicals for the food industry. To identify the metabolic capabilities of this organism, a broad-level understanding of its metabolism is needed, which can be accomplished by a large-scale metabolic model. In this work, we present the first functional compartmentalized genome-scale metabolic model of this microalga, which we call iRJ1321. It includes 1321 genes, 1918 reactions, and 1862 metabolites and is thus the largest algal genome scale metabolic model to date in terms of number of genes and percentage gene coverage. The model-predicted growth rate matches reasonably well with the literature reported growth rate for photoautotrophic growth. The model was applied to capture the role of nitrogen limitation in remodeling N. gaditana metabolism. The flux distribution in iRJ1321 predicts C4-like carbon-concentrating co-existing with Calvin cycle. This model will be useful to researchers interested in understanding capabilities and limitations of N. gaditana metabolism and devising metabolic engineering strategies for synthetic pathway design for production of diverse molecules.

      PubDate: 2017-08-21T16:47:00Z
      DOI: 10.1016/j.algal.2017.08.014
       
  • De novo transcriptomic and metabolomic analysis of docosahexaenoic acid
           (DHA)-producing Crypthecodinium cohnii during fed-batch fermentation
    • Authors: Guangsheng Pei; Xingrui Li; Liangsen Liu; Jing Liu; Fangzhong Wang; Lei Chen; Weiwen Zhang
      Abstract: Publication date: Available online 12 August 2017
      Source:Algal Research
      Author(s): Guangsheng Pei, Xingrui Li, Liangsen Liu, Jing Liu, Fangzhong Wang, Lei Chen, Weiwen Zhang
      The heterotrophic microalga Crypthecodinium cohnii accumulates lipids with a high fraction of docosahexaenoic acid (DHA). However, lack of genomic information limits the understanding of its physiological metabolism for better DHA production. In this study, de novo assembly of the C. cohnii transcriptome from three growth stages (i.e., fast growth, fatty acid accumulation and DHA conversion stages) was conducted, leading to identification of a total of 82,106 unigenes with an N50 of 1822bp, among which 64.7% were annotated based on sequence similarity to known genes in the database. In addition, pathway enrichment analysis showed that transcripts related to fatty acid biosynthesis, starch and sucrose metabolism as well as biosynthesis of unsaturated fatty acids were significantly up-regulated during late-stage fermentation. Interestingly, several polyketide synthases (PKSs) and multiple fatty acid desaturases potentially involved in DHA biosynthesis were identified in the C. cohnii transcriptome, most of which were significantly up-regulated during lipid and DHA accumulation, implying that C. cohnii might utilize a combination of PKS systems and desaturase steps for DHA biosynthesis. The results were further confirmed by qRT-PCR and GC–MS-based metabolomic analyses. Overall, integrative analysis of de novo transcriptomic and metabolomic data provided important functional genomic information necessary for not only a better understanding of C. cohnii growth and DHA biosynthesis but also future genetic engineering of industry-important C. cohnii.
      Graphical abstract image

      PubDate: 2017-08-21T16:47:00Z
      DOI: 10.1016/j.algal.2017.07.031
       
  • Microalgal biomass productivity and dominant species transition in a
           Korean mass cultivation system
    • Authors: J.W. Hong; O.H. Kim; S.W. Jo; J.M. Do; H.S. Yoon
      Abstract: Publication date: Available online 10 August 2017
      Source:Algal Research
      Author(s): J.W. Hong, O.H. Kim, S.W. Jo, J.M. Do, H.S. Yoon
      Mass cultivation of microalgae was carried out at a large-scale outdoor raceway facility in Korea from June 2014 to January 2017 and we analyzed the transition of dominant microalgal species and influence of zooplankton predation. Concurrently the microalgae yield, biomass characterization, and resource consumption results were examined from two identical 675.0m2 raceways with or without a semitransparent film cover to determine which model is a better fit for Korean geoclimatic conditions. Year-round cultivation was possible in the covered raceway, but the average seasonal productivities were lower than those of the non-covered one, probably due to the reduced solar radiation. The addition of a cover did not confer advantages for the production of microalgae, even though the production period was extended over sub-zero temperature winter seasons. Species transitions were observed throughout the cultivation period, and the most dominant microalgal genera found year round were Acutodesmus and Pseudopediastrum. In addition, an algal predator, Vorticella, was present during most of the cultivation periods. The seasonal water temperature fluctuation and presence of predators greatly affected the dominant microalgae and biomass productivity. The maximal productivity, 29.3g dry weight (DW)/m2-day with 15.0% lipid and a calorific value (CV) of 20.1MJ/kg, was attained in the non-covered raceway during the summer of 2016. Overall, a yearly average productivity of 8.9g DW/m2-day was obtained from the raceways, and the biomass had an average lipid content of 12.8% and CV of 17.7MJ/kg. The grazer-resistant microalgae were allowed to dominate rather than maintaining target strains and the results demonstrated the potential of naturally occurring microalgae as a biofuel source since the CVs of the biomass were close to those of terrestrial energy crops. Also, the mass cultivation of the indigenous isolates could be applied to wastewater treatment due to their high capacity to assimilate nutrients.

      PubDate: 2017-08-11T08:52:55Z
      DOI: 10.1016/j.algal.2017.08.013
       
  • Influence of different degrees of N limitation on photosystem II
           performance and heterogeneity of Chlorella vulgaris
    • Authors: Giorgos Markou; H.T. Dao Koenraad Muylaert John Beardall
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): Giorgos Markou, Ly H.T. Dao, Koenraad Muylaert, John Beardall
      Nitrogen (N) limitation is considered as the most efficient strategy to induce the accumulation of lipids, carbohydrates or other target compounds in microalgal biomass. However, along with biomass biochemical composition, alterations in N limitation affect the photosynthetic apparatus and result in decreased growth. In this study, Chlorella vulgaris was cultivated in semi-continuous mode with different degrees of N limitation and chlorophyll (Chl) fluorescence analyses were used to investigate the effect of N limitation on photosystem II (PSII) performance, in terms of structural and functional heterogeneity. As expected, N limitation resulted in the decrease of quantum yield and calculated OJIP parameters related to PSII performance. N limitation resulted in a significant increase of trapped energy per reaction center (RC) and subsequently to higher dissipation of excess energy. However, despite the negative effect of N limitation on the number of RCs, the electron transport beyond QA as well the capacity of reducing/re-oxidation of plastiquinone were not negatively affected, implying that performance of RCs was not affected by N limitation. Photochemical quenching (qp) increased of as N limitation increased while the curve of non-photochemical quenching (NPQ) was unimodal, i.e. increased up to a level of N limitation and then decreased as N limitation degree increased further. The overall results of the present study suggest that the decrease of PSII performance was due to a reduction of the number of RCs accompanied with higher energy dissipation a probable outcome of the decreased need for reductant by cells due to lower metabolic activity under N limitation.

      PubDate: 2017-07-15T02:44:15Z
       
 
 
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