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Publisher: Elsevier   (Total: 3042 journals)

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Showing 1 - 200 of 3042 Journals sorted alphabetically
AASRI Procedia     Open Access   (Followers: 15)
Academic Pediatrics     Hybrid Journal   (Followers: 19, SJR: 1.402, h-index: 51)
Academic Radiology     Hybrid Journal   (Followers: 16, SJR: 1.008, h-index: 75)
Accident Analysis & Prevention     Partially Free   (Followers: 81, 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: 325, 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  
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: 204, 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: 22, SJR: 1.365, h-index: 73)
Acta Sociológica     Open Access  
Acta Tropica     Hybrid Journal   (Followers: 5, 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)
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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: 7, SJR: 1.039, h-index: 5)
Additives for Polymers     Full-text available via subscription   (Followers: 20)
Advanced Drug Delivery Reviews     Hybrid Journal   (Followers: 123, 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: 21, 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: 8, 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: 39, 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: 45, SJR: 0.674, h-index: 38)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 14)
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: 12)
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: 20, 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: 24)
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: 34, 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: 4)
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: 5, 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: 21, 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: 58)
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: 338, 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: 6, SJR: 0.823, h-index: 27)
Advances in the Study of Behavior     Full-text available via subscription   (Followers: 29, SJR: 1.321, h-index: 56)
Advances in Veterinary Medicine     Full-text available via subscription   (Followers: 15)
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: 307, 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: 7, SJR: 3.289, h-index: 78)
Aggression and Violent Behavior     Hybrid Journal   (Followers: 422, 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: 50, 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: 10, 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: 5, 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: 6, SJR: 0.158, h-index: 9)
Alzheimer's & Dementia     Hybrid Journal   (Followers: 46, 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: 47, SJR: 3.157, h-index: 153)
American J. of Cardiology     Hybrid Journal   (Followers: 44, SJR: 2.063, h-index: 186)
American J. of Emergency Medicine     Hybrid Journal   (Followers: 34, 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: 15, SJR: 1.653, h-index: 93)
American J. of Human Genetics     Hybrid Journal   (Followers: 30, 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: 32, SJR: 2.313, h-index: 172)
American J. of Medicine     Hybrid Journal   (Followers: 44, 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: 179, 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: 2)
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: 23, 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: 33, 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: 53, SJR: 0.124, h-index: 9)
Anaesthesia Critical Care & Pain Medicine     Full-text available via subscription   (Followers: 5)
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: 160, 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: 10)
Anesthésie & Réanimation     Full-text available via subscription  
Anesthesiology Clinics     Full-text available via subscription   (Followers: 21, 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: 152, 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   (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  [3042 journals]
  • Harvesting of microalgae Chlorella vulgaris using
           electro-coagulation-flocculation in the batch mode
    • Authors: Nidal Fayad; Tania Yehya; Fabrice Audonnet; Christophe Vial
      Pages: 1 - 11
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Nidal Fayad, Tania Yehya, Fabrice Audonnet, Christophe Vial
      The aim of this study was to evaluate the harvesting of microalgae Chlorella vulgaris by electro-coagulation-flocculation (ECF) using aluminum and iron electrodes, assess the mechanisms responsible for microalgae recovery, quantify the metal contamination in the effluent and biomass, analyze power requirements, and investigate the effect of ECF on lipid and pigment content in the biomass. The influence of six operating parameters (electrode material, sedimentation time, current density, stirring speed, initial pH (pHi) and inter-electrode distance) on the harvesting efficiency was tested. A specific strategy involving flotation and pH-controlled ECF experiments was developed to identify the prevailing mechanism of harvesting: adhesion on flocs was shown to be negligible; flotation contributed to a maximum of 36.6% of microalgae recovery; zeta potential highlighted that the main mechanism responsible for microalgae recovery was charge neutralization at pHi 4 and 6, and sweep flocculation at pHi 8. The most energy saving conditions for the harvesting of Chlorella vulgaris involved aluminum electrodes, and 60min electrolysis with a current density of 2.9mA/cm2, pHi 4, stirring speed 250rpm and an inter-electrode distance of 1cm. Economic and competitive energy input (1kWh/kg microalgae) could be achieved by adding 1.5g/L NaCl. In addition, ECF did not affect significantly the amount of microalgal lipids and pigments.

      PubDate: 2017-04-09T10:44:46Z
      DOI: 10.1016/j.algal.2017.03.015
      Issue No: Vol. 25 (2017)
       
  • Evaluating Marinichlorella kaistiae KAS603 cell size variation, growth and
           TAG accumulation resulting from rapid adaptation to highly diverse trophic
           and salinity cultivation regimes
    • Authors: Eva L. Sánchez-Alvarez; Grisele González-Ledezma; José A. Bolaños Prats; José L. Stephano-Hornedo; Mark Hildebrand
      Pages: 12 - 24
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Eva L. Sánchez-Alvarez, Grisele González-Ledezma, José A. Bolaños Prats, José L. Stephano-Hornedo, Mark Hildebrand
      The ability of a microalgal species to adapt to changes in cultivation environment is likely to be beneficial for a successful biofuel/bioproduct production system, because the species could maintain high yields under diverse seasonal or cultivation conditions. Examining factors that enable culturing flexibility in a single species could provide clearer insights than when comparing different species because it will reduce interspecies variability. Marinichlorella kaistiae KAS603 is an excellent model to evaluate mechanisms involved in adaptation to different cultivation regimes. We have studied cell growth, size, triacylglycerol (TAG) accumulation and life cycle stages in this multiple fission dividing strain under a wide variety of conditions, ranging from autotrophic growth in freshwater to mixotrophic growth in fresh and seawater, and to autotrophic growth under saline and hypersaline conditions. Such conditions influence the division mode of the strain, which is linked to biomass and TAG yield. Based on lab and pilot plant experiments, we have discovered that the fastest TAG accumulation takes place under mixotrophy in freshwater, highest yield (culture density plus TAG) condition occurs under mixotrophy in sea water, and the best outdoor culture condition to achieve growth with fewer invasive species is hypersaline natural seawater. In addition to characterizing growth and TAG accumulation characteristics under a wide variety of cultivation conditions, this work sets the stage for investigation into the mechanisms that enable diverse cultivation adaptations, and contribute to the development of this environmentally flexible microalga as a production feedstock.

      PubDate: 2017-04-09T10:44:46Z
      DOI: 10.1016/j.algal.2017.03.027
      Issue No: Vol. 25 (2017)
       
  • Flow cytometry to estimate the cell disruption yield and biomass release
           of Chlorella sp. during bead milling
    • Authors: Emre Günerken; Els D'Hondt; Michel Eppink; Kathy Elst; Rene Wijffels
      Pages: 25 - 31
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Emre Günerken, Els D'Hondt, Michel Eppink, Kathy Elst, Rene Wijffels
      A number of visual, chemical and fluorescence-based methods are generally employed for monitoring of algae cell growth, culture health and biomass concentration. These methods are often time-consuming, demand destructive and high volume sampling. Rapid, efficient, cost-effective and automated methods which facilitate high-throughput and non-destructive sampling would highly benefit microalgae biotechnology. It is known in literature that with flow cytometry it is possible to monitor microalgae growth and microalgae culture health. Flow cytometry, however, has not been used to estimate biomass release and cell disruption yield. In this study with representative cultures of Chlorella sp., flow cytometry data were generated by a long pass filter (>670nm) and proved to be a promising technique to rapidly evaluate these parameters during cell disruption by bead milling. Both a laboratory and a commercial culture of Chlorella were bead milled. Prior to and during bead milling, biomass release was evaluated gravimetrically and the cell count was determined via hemocytometer manual counting and 3 flow cytometry methods: 1) direct event count of a certain population, 2) quadrant-upper right event count of a long pass filter (>670nm) and 3) a calculation based on the long pass filter data. The data of all methods were compared and correlated to gravimetric biomass release data. Manual counting resulted in an underestimation of the cell disruption yield as one of the Chlorella cultures manual counts did not agree with biomass release data. Good correlations for both cultures were found for cell disruption yield calculations based on flow cytometry data and gravimetric biomass release data. Flow cytometry is therefore an efficient analytical method to rapidly screen disruption yields during cell disruption in microalgae and can be a substitute for the time-consuming direct methods (e.g. gravimetric, manual counting) for estimating biomass release and cell disruption yield.

      PubDate: 2017-05-07T06:56:49Z
      DOI: 10.1016/j.algal.2017.04.033
      Issue No: Vol. 25 (2017)
       
  • Hydrolysis of Golenkinia sp. biomass using Amberlyst 36 and nitric acid as
           catalysts
    • Authors: Hyun Woo Joo; Yong Jae Kim; Juyi Park; Yong Keun Chang
      Pages: 32 - 38
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Hyun Woo Joo, Yong Jae Kim, Juyi Park, Yong Keun Chang
      Golenkinia sp. is a microalga with potential commercial value because of its high carbohydrate content (more than 40%). The major challenge is to find hydrolytic processes that can efficiently convert these carbohydrates into fermentable sugars. Hydrolysis of microalgal biomass generally uses a dilute liquid acid catalyst, such as hydrochloric acid, sulfuric acid, or nitric acid. However, neutralization and desalting processes are needed after this procedure for production of a hydrolysate that is suitable for use as a fermentable broth. These processes require large amounts of energy and are, therefore, very expensive. In this work, we hydrolyzed 10g/L of Golenkinia sp. using 9.2g/L of Amberlyst 36 with 0.01N of nitric acid at 150°C for 160min, a process that required no desalting. 88% of total sugar yield mainly glucose and galactose was obtained after a 120min reaction. Our results also showed that these 2 catalysts had a prominent synergistic effect, in that the yield when both catalysts were used together was much greater than the sum of the yields of the individual catalysts. The small amount of nitric acid reduced the particle size of the Golenkinia substrate, and this led to a greater total surface area and 135% increase in the hydrolysis efficiency of Amberlyst 36. The Golenkinia sp. hydrolysate (3.7g/L sugars) was used as a carbon source for 2,3-butanediol fermentation by Klebsiella oxytoca, with no need for further detoxification or deionization processes. The yield was 0.19g of 2,3-butanediol per g of sugar.

      PubDate: 2017-05-07T06:56:49Z
      DOI: 10.1016/j.algal.2017.04.031
      Issue No: Vol. 25 (2017)
       
  • Functional characterization of a novel “ulvan utilization loci” found
           in Alteromonas sp. LOR genome
    • Authors: Elizabeth Foran; Vitaliy Buravenkov; Moran Kopel; Naama Mizrahi; Sivan Shoshani; William Helbert; Ehud Banin
      Pages: 39 - 46
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Elizabeth Foran, Vitaliy Buravenkov, Moran Kopel, Naama Mizrahi, Sivan Shoshani, William Helbert, Ehud Banin
      Green algae belonging to the genus Ulvales are known to produce ulvan which is one of the main polysaccharide components of their cell wall. Ulvan is composed of 3O-sulfate-rhamnose (Rha3S), glucuronic acid (GlcA), iduronic acid (IduA) and xylose (Xyl) distributed in three disaccharide repetition moieties: [→4)-β-D-GlcA-(1→4)-α-L-Rha3S-(1→], [→4)-α-L-IdoA-(1→4)-α-L-Rha3S(1→] and [→4)-β-D-Xyl-(1→4)-α-L-Rha3S(1→]. The ability of bacteria to degrade complex algal polysaccharides such as ulvan is usually encoded in clusters of genes referred to as polysaccharide utilization loci (PUL). Full saccharification of ulvan is expected to require an ulvan lyase, which cleaves the β-(1→4)-glycosidic bond between Rha3S and GluA or IduA through a β-elimination mechanism. In addition, enzymes with β-glucuronyl hydrolase, rhamnosidase, xylosidase and sulfatase activity are also expected. Recently, the genomes of several ulvan degrading bacteria were sequenced, which led to the identification of a new family of polysaccharide lyases family 24 (PL24). In this work, we have continued to mine the genomic data of one of the sequenced strains, Alteromonas sp. LOR. Here we report the identification of an ulvan associated PUL residing between open reading frames (lor_19 – lor_34). This PUL contains a TonB dependent receptor, along with an experimentally verified rhamnosidase, a β-glucuronyl hydrolase and predicted sulfatases. Interestingly, we also identified in the PUL a new ulvan lyase (LOR_29) which showed no homology to previously reported ulvan lyases making it a founding member of yet another new family of polysaccharide lyases (PL25). Finally, this enzyme prompted us to mine other genomes where we identified additional potential ulvan PULs harboring this gene in other bacterial species. Taken together our report provides further insight into ulvan degradation mechanisms in bacteria and reveals a new family of polysaccharide lyases.
      Graphical abstract image

      PubDate: 2017-05-11T07:00:06Z
      DOI: 10.1016/j.algal.2017.04.036
      Issue No: Vol. 25 (2017)
       
  • Development of microalgal bioassay based on the community level
           physiological profiling (CLPP)
    • Authors: Jun-Woo Kim; Lars Rehmann; Madhumita B. Ray
      Pages: 47 - 53
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Jun-Woo Kim, Lars Rehmann, Madhumita B. Ray
      Microalgal bioassay was developed based on community level physiological profiling (CLPP) to assess the effect of environmental stressors such as micropollutants. ECO Biolog plates were used to determine the changes in substrate utilization patterns caused by external disturbances such as the presence of antibiotics (a mixture of streptomycin sulfate and penicillin GT sodium), hexadecyl trimethyl ammonium chloride (CTAC), a micropollutant, and their combination (antibiotics and CTAC). The performance of the bioassay was assessed using artificially defined communities made up of five freshwater algae strains (Chlorella vulgaris, Chlamydomonas reinhardtii, Desmodesmus subspicatus, Selenastrum capricornutum, and Scenedesmus obliquus) at five different compositions with varying ratios of the test algae. Differences in the response as indicated by substrate utilization patterns to induced stressor by five defined microalgal communities were quantified using principal component analysis (PCA). The changes in substrate utilization patterns are probably due to the changes in metabolic potentials of the individual strains. The effects were more pronounced for the treatments than that obtained by varying the initial composition of the defined algal communities. The effects of the external factors were found to be consistent in the highest cell density of 300,000 cells per well to the lowest of 25 cells per well.
      Graphical abstract image

      PubDate: 2017-05-11T07:00:06Z
      DOI: 10.1016/j.algal.2017.04.037
      Issue No: Vol. 25 (2017)
       
  • Biodegradation and metabolic fate of levofloxacin via a freshwater green
           alga, Scenedesmus obliquus in synthetic saline wastewater
    • Authors: Jiu-Qiang Xiong; Mayur B. Kurade; Dilip V. Patil; Min Jang; Ki-Jung Paeng; Byong-Hun Jeon
      Pages: 54 - 61
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Jiu-Qiang Xiong, Mayur B. Kurade, Dilip V. Patil, Min Jang, Ki-Jung Paeng, Byong-Hun Jeon
      Levofloxacin (LEV), a fluoroquinolone antibiotic has been frequently observed in water resources imposing ecotoxicological effects on aquatic microbiota. The biodegradation and metabolic fate of LEV via a microalga, Scenedesmus obliquus in synthetic saline wastewater were investigated in this study. LEV removal (1mgL−1) by S. obliquus was relatively low in the synthetic wastewater without the addition of sodium chloride (NaCl); however, its removal increased significantly from 4.5 to 93.4% with increasing of its salinity from 0 to 171mM NaCl. Kinetic studies showed that the removal rate constant (k) increased from 0.005 to 0.289d−1 and degradation half-life decreased from 272 to 5d in the presence of NaCl (0–856mM). The removal mechanism analysis showed that the major mechanism of NaCl mediated enhancement of LEV removal was the bioaccumulation and subsequent intracellular biodegradation of LEV in microalgal cells. Six metabolites were identified via gas chromatography–mass spectrometry analysis after biodegradation of LEV. A metabolic pathway was postulated with regard to various cellular biocatalytic reactions in S. obliquus, including decarboxylation, demethylation, dehydroxylation, side chain breakdown, and ring cleavage.
      Graphical abstract image

      PubDate: 2017-05-11T07:00:06Z
      DOI: 10.1016/j.algal.2017.04.012
      Issue No: Vol. 25 (2017)
       
  • Evaluation of cell disruption method for lipase extraction from novel
           thraustochytrids
    • Authors: Avinesh R. Byreddy; Nalam Madhusudhana Rao; Colin J. Barrow; Munish Puri
      Pages: 62 - 67
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Avinesh R. Byreddy, Nalam Madhusudhana Rao, Colin J. Barrow, Munish Puri
      Marine microorganisms represent a rich source of enzymes with the potential industrial application. In this study, we screened novel thraustochytrids for a range of enzymatic activities. The similarity between isolates based on enzyme activities was investigated using cluster analysis. Thraustochytrids were observed to possess different enzymatic activities, however, we focused on lipase activity. Two strains AMCQ-4b27 (34IU/g) and AMCQS1-9 (36IU/g) exhibited highest intracellular lipase activity among the isolates. To extract lipase, four different cell disruption methods such as bead vortexing, grinding, sonication and homogenization, were evaluated for their efficiency on lipase extraction yields and quality. Sonication was found to be the best method for enhancing lipase extraction yields from Thraustochytrium sp. AMCQ-4b27 (0.903IU/μg) and Schizochytrium AMCQS1-9 (1.44IU/μg).

      PubDate: 2017-05-11T07:00:06Z
      DOI: 10.1016/j.algal.2017.04.025
      Issue No: Vol. 25 (2017)
       
  • Quantification of effects of flue gas derived inorganic contaminants on
           microalgae growth system and end fate of contaminants
    • Authors: Derek Hess; Katerine Napan; Brian T. McNeil; Eric M. Torres; Tessa Guy; Joan E. McLean; Jason C. Quinn
      Pages: 68 - 75
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Derek Hess, Katerine Napan, Brian T. McNeil, Eric M. Torres, Tessa Guy, Joan E. McLean, Jason C. Quinn
      Increasing demand for renewable fuels has researchers investigating the feasibility of alternative feedstocks, including microalgae. Inherent advantages of microalgae include high potential yield, use of non-arable land, and integration with waste streams. Large-scale production of biodiesel from microalgae will require the integration of growth platforms with point source carbon dioxide such as coal derived flue gas. The introduction of this waste stream into the growth system will inevitably introduce trace inorganic contaminants which have a high affinity to bind to microalgal cells, could be toxic to the cells, and if transferred to the microalgae could impact the end use of the derived products. Inorganic contaminants As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Sb, Se, Sn, V and Zn were added to microalgal growth medium at a base concentration estimated to be representative of concentrations expected from 7day growth periods where coal derived flue gas is used as the carbon source. Nannochloropsis salina was cultivated in photobioreactors at outdoor light levels, 984μmolm−2 s−1, with results for biomass, lipid yield, and fatty acid profiles evaluated. Results show trace inorganic contaminants negatively impacted growth and lipid yields with the average biomass productivity dropping from 1.13gL−1 d−1 ±0.12 (control) to 0.37gL−1 d−1 ±0.18, corresponding to a 67.5% decrease in biomass yield and a lipid decrease from 43.8±1.6 (control) to 29.8±5.7 (% dry biomass). Inorganic contaminant analysis performed using inductively coupled plasma mass spectrometry shows significant biomass sorption of the majority of the inorganic contaminants, which impacts the potential end uses of the biomass.
      Graphical abstract image

      PubDate: 2017-05-11T07:00:06Z
      DOI: 10.1016/j.algal.2017.04.007
      Issue No: Vol. 25 (2017)
       
  • Microalgae and cyanobacteria as enzyme biofactories
    • Authors: Bruno dos Santos Alves Figueiredo Brasil; Félix Gonçalves de Siqueira; Thaís Fabiana Chan Salum; Cristina Maria Zanette; Michele Rigon Spier
      Pages: 76 - 89
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Bruno dos Santos Alves Figueiredo Brasil, Félix Gonçalves de Siqueira, Thaís Fabiana Chan Salum, Cristina Maria Zanette, Michele Rigon Spier
      Microalgae consist of a diverse group that includes prokaryotic cyanobacteria and eukaryotic photosynthetic microorganisms that inhabit freshwater and marine habitats. Microalgae can be used in different industries, including as food for human consumption, as animal feed, in aquaculture, in cosmetics and as biofuels. Because they are photoautotrophs, with minimal nutritional requirements, microalgae have advantages compared to other microbial cells. An overview of the great potential of these cells to synthesize enzymes for several industrial applications is provided. Photosynthetic microorganism-derived enzymes include cellulases, galactosidases, proteases, lipases, phytases, laccases, amylases, antioxidant enzymes and enzyme associated with carbohydrate accumulation and the carbon concentration. Furthermore, recent reports on microalgae genomics are revealing a variety of novel genes that should be investigated for biotechnological applications. Exploring algal genetic diversity will also enable the efficient use of photosynthetic microorganisms as recombinant enzyme biofactories that will be useful to industry.
      Graphical abstract image

      PubDate: 2017-05-11T07:00:06Z
      DOI: 10.1016/j.algal.2017.04.035
      Issue No: Vol. 25 (2017)
       
  • Large scale cultivation of genetically modified microalgae: A new era for
           environmental risk assessment
    • Authors: Tracey A. Beacham; Jeremy B. Sweet; Michael J. Allen
      Pages: 90 - 100
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Tracey A. Beacham, Jeremy B. Sweet, Michael J. Allen
      The genetic modification of microalgal strains for enhanced or modified metabolic activity shows great promise for biotechnological exploitation. However, of key concern for many is the safety of genetic modification technology and genetically modified organisms with regard to both the environment and human health, and how these concerns are met will play a key role in ensuring how successful commercialisation of genetically modified (GM) algae is achieved. Commercialisation opportunities for GM microalgae will inevitably require translation from laboratory to industrial settings, on scales beyond those typically associated with the current biotechnology sector. Here we provide an overview of the current situation with regards to genetic modification techniques and legislation, and the implications of large-scale cultivation with regards to developing a safe and effective risk assessment system for contained and uncontained activities. We discuss the rationale and options for modification and the implications for risks associated with scale up to human health and the environment, current grey areas in political/technical legislation, the use of contained/uncontained production systems, deliberate release and monitoring strategies. We conclude that while existing procedures are not entirely sufficient for accurate and exhaustive risk assessment, there exists a substantial knowledge base and expertise within the existing aquaculture, fermentation and (algal) biotechnology industries that can be combined and applied to ensure safe use in the future.

      PubDate: 2017-05-16T15:05:06Z
      DOI: 10.1016/j.algal.2017.04.028
      Issue No: Vol. 25 (2017)
       
  • Detailing the start-up and microalgal growth performance of a full-scale
           photobioreactor operated with bioindustrial wastewater
    • Authors: Michael Podevin; Ioannis A. Fotidis; Davide De Francisci; Per Møller; Irini Angelidaki
      Pages: 101 - 108
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Michael Podevin, Ioannis A. Fotidis, Davide De Francisci, Per Møller, Irini Angelidaki
      In this study, a full-scale enclosed microalgal air-lift photobioreactor (PBR) module was operated using both defined and industrial wastewater (WW) media. In the effort to establish full-scale operation: a WW ultrafiltration system, two algal productions, and a harvesting microfiltration system were tested. Bioindustrial WW medium was treated with ultrafiltration and was demonstrated to be a viable microalgal growth medium at large scale; however, further treatment is needed for the removal of fecal coliform to meet drinking water standards. The fresh water mesophilic algae Chlorella sorokiniana was successfully grown on bioindustrial WW medium at suboptimal temperatures (<25°C) and natural lighting with peak specific growth rate (SGR) of 0.48day−1, consistent with lab-scale results from literature. Optical densities (OD) of the algae at 665, 680, and 735nm were found to be viable proxies for cell number of C. sorokiniana grown outdoors with daily fluctuations, despite inherent differences in chlorophyll sensitivity at each absorbance wavelength. However, OD measurements at different reactor locations shown to diverge at the onset of growth. Greenhouse temperature and solar insolation were measured, where it was observed that the SGR did not considerably improve from higher solar irradiance during periods of lower temperatures. Finally, the viability of harvested cells after microfiltration was also examined, with a negative exponential correlation between cell death and the volume of remaining filter condensate (R2 =0.9247).
      Graphical abstract image

      PubDate: 2017-05-16T15:05:06Z
      DOI: 10.1016/j.algal.2017.04.030
      Issue No: Vol. 25 (2017)
       
  • The synergistic energy and carbon metabolism under mixotrophic cultivation
           reveals the coordination between photosynthesis and aerobic respiration in
           Chlorella zofingiensis
    • Authors: Zhao Zhang; Dongzhe Sun; Tao Wu; Yuelian Li; Yuankun Lee; Jin Liu; Feng Chen
      Pages: 109 - 116
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Zhao Zhang, Dongzhe Sun, Tao Wu, Yuelian Li, Yuankun Lee, Jin Liu, Feng Chen
      Microalgal biofuels have attracted much attention in recent years. Nevertheless, the relatively low growth rate and low cell density limits its industrial application. Mixotrophic cultivation has been considered as a good strategy to increase the specific growth rate and biomass yield in some microalgal species. However, the metabolic mechanism has not been well elucidated. To address it, Chlorella zofingiensis was employed in the present study. The biomass productivity and maximum dry weight achieved under mixotrophic condition were greater than the sum of those under photoautotrophic and heterotrophic conditions. Interestingly, compared with photoautotrophic cultures, the RuBisCO activity was reduced for mixotrophic cultures, indicative of the down-regulation of the Calvin cycle. When compared with heterotrophic cultures, the citrate synthase activity was attenuated for mixotrophic cultures, indicative of the down-regulation of Tricarboxylic Acid cycle. Biochemical analysis showed that mixotrophic cells contained more starch but less total fatty acid content than heterotrophic cells. Besides, the biomass yield on glucose was 0.789gg−1 for mixotrophic cultures, 63.7% higher than that for heterotrophic cultures, and the enhancement effect of light under mixotrophic cultivation was 7.35-fold. Based on these results, a novel mechanism for the synergistic effects in mixotrophic cultivation was proposed, in which glucose was more efficiently utilized for biomass production by the possible coordination of energy and carbon metabolism between photosynthesis and aerobic respiration.

      PubDate: 2017-05-21T15:08:30Z
      DOI: 10.1016/j.algal.2017.05.007
      Issue No: Vol. 25 (2017)
       
  • Genetic engineering of Synechocystis sp. PCC6803 for
           poly-β-hydroxybutyrate overproduction
    • Authors: Roberta Carpine; Wei Du; Giuseppe Olivieri; Antonino Pollio; Klaas J. Hellingwerf; Antonio Marzocchella; Filipe Branco dos Santos
      Pages: 117 - 127
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Roberta Carpine, Wei Du, Giuseppe Olivieri, Antonino Pollio, Klaas J. Hellingwerf, Antonio Marzocchella, Filipe Branco dos Santos
      The biosynthesis of poly-β-hydroxybutyrate (PHB) directly from carbon dioxide is a sustainable alternative for non-renewable, petroleum-based polymer production. Synechocystis sp. PCC6803 can naturally accumulate PHB using CO2 as the sole carbon source, particularly when major nutrients such as nitrogen become limiting. Many previous studies have tried to genetically engineer PHB overproduction; mostly by increasing the expression of enzymes directly involved in its biosynthesis pathway. Here, we have instead concentrated on engineering the central carbon metabolism of Synechocystis such that (i) the PHB synthesis pathway becomes deregulated, and/or (ii) the levels of its substrate, acetyl-CoA, were increased. Seven different mutants were constructed harboring, separately or in combination, three different genetic modifications to Synechocystis' metabolic network. These were the deletions of phosphotransacetylase (Pta) and acetyl-CoA hydrolase (Ach), and the expression of a heterologous phosphoketolase (XfpK) from Bifidobacterium breve. The wild type Synechocystis and the derivative strains were compared in terms of biomass and the PHB production capability during photoautotrophic growth. This was performed in a photobioreactor exposed to a diel light/dark rhythm and using standard BG11 as the growth medium. We found that the strain that combined all three genetic modifications, i.e. xfpk overexpression in a double pta and ach deletion background, showed the highest levels of PHB production from all the strains tested here. Encouragingly, the production levels obtained: 232mgL−1, ~12% (w/w) of the dry biomass weight, and a productivity of 7.3mgL−1 d−1; are to the best of our knowledge, the highest ever reported for PHB production directly from CO2.
      Graphical abstract image

      PubDate: 2017-05-21T15:08:30Z
      DOI: 10.1016/j.algal.2017.05.013
      Issue No: Vol. 25 (2017)
       
  • The regulation of photosynthetic pigments in terrestrial Nostoc
           flagelliforme in response to different light colors
    • Authors: Pei-pei Han; Shi-gang Shen; Rong-jun Guo; Shun-yu Yao; Ying Sun; Zhi-lei Tan; Shi-ru Jia
      Pages: 128 - 135
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Pei-pei Han, Shi-gang Shen, Rong-jun Guo, Shun-yu Yao, Ying Sun, Zhi-lei Tan, Shi-ru Jia
      Cyanobacteria have evolved a number of photosynthetic strategies by adjusting the properties of the light-harvesting pigments to cope with changes in the light environment. Nostoc flagelliforme is a terrestrial filamentous cyanobacterium that has distinct phycobilisome composition consisting of phycocyanin (PC) and allophycocyanin (APC). The photoregulation process of N. flagelliforme was explored by investigating the effects of different light colors on photosynthetic pigments, which were determined after photoautotrophic growth with red (RL), yellow (YL), green (GL), blue (BL), purple (PL) and white (WL) light of same photosynthetically active photon flux density. Compared with WL, YL, GL, BL and PL changed the amounts of pigments but did not alter the cellular ratio of PC/APC; while RL altered both the amounts and proportions of PC and APC. The observations by confocal laser scanning microscope and transmission electron microscope showed that PC, APC and chlorophyll a were distributed throughout the cells under GL, BL, PL, and WL illumination but located in the outermost layer in RL and YL-grown cells. Further study revealed that changing RL intensity would not influence the ratio of PC/APC but the distribution of pigments shifted from central cytoplasmic region to the periphery of the cells with the increase of intensity. These results implied that N. flagelliforme responded to RL by regulating the composition and location of phycobilisomes and these findings would be of importance to develop the high-efficient process of N. flagelliforme culture.

      PubDate: 2017-05-21T15:08:30Z
      DOI: 10.1016/j.algal.2017.04.009
      Issue No: Vol. 25 (2017)
       
  • Cultivation of Dunaliella tertiolecta intervened by triethylamine enhances
           the lipid content
    • Authors: Lu-Lu Xue; Jian-Guo Jiang
      Pages: 136 - 141
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Lu-Lu Xue, Jian-Guo Jiang
      Microalgae have become increasingly attractive as feedstocks for biodiesel production since they have many advantages over traditional raw materials, such as strong carbon fixation ability, high growth rate, not competing with arable land etc. In this study, different concentrations of triethylamine were added into the culture medium to test their effects on biomass, chlorophyll content, fatty acid profile and neutral lipid content of Dunaliella tertiolecta. The results showed that biomass production and chlorophyll content were notably reduced by the addition of triethylamine. However, total lipid production and lipid content per cell were significantly enhanced. One hundred ppm showed the greatest boosting effect and elevated the lipid production and lipid content per cell by 20% and 80%, respectively, compared to the control group. Fatty acid profile was also affected, where C16:0 was increased while C18:2 and C18:3 were decreased. The content of C18:1 decreased from 0 to 100ppm and then elevated as the addition of triethylamine increased from 100ppm to 200ppm. Intracellular stress was suspected to have occurred. It can be concluded that triethylamine is an effective inducer of lipid accumulation in D. tertiolecta.

      PubDate: 2017-05-21T15:08:30Z
      DOI: 10.1016/j.algal.2017.04.019
      Issue No: Vol. 25 (2017)
       
  • Isolation and identification of Choricystis minor Fott and mass
           cultivation for oil production
    • Authors: Yong Chen; Xiao-yang Li; Zheng Sun; Zhi-gang Zhou
      Pages: 142 - 148
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Yong Chen, Xiao-yang Li, Zheng Sun, Zhi-gang Zhou
      The use of wastewater-grown algae for biofuel production is economical and eco-friendly. In the present study, an algal strain was isolated from the wastewater of a local dairy farm. On the basis of the morphology, ultrastructure, and 18S rRNA gene sequences, the specimen was identified to be conspecific with Choricystis minor Fott, which is a newly reported species in China. The C. minor cells accumulated predominantly neutral lipids that accounted for 60.82% of total lipids with 35.61% being triacylglycerol. Enlarged oil droplets were observed under nitrogen-depleted condition. C. minor was further cultivated outdoors on a larger scale, in which we employed both flat-plate and tubular photobioreactors (PBRs). The algae quickly adapted to the outdoor conditions and exhibited good growth performance (biomass and lipid productivities were 162.86 and 36 mg L−1 day−1 in flat-plate PBRs). Taken together, these results support the finding that C. minor is a promising source of low-cost, high-quality oil for biofuel production.

      PubDate: 2017-05-21T15:08:30Z
      DOI: 10.1016/j.algal.2017.05.012
      Issue No: Vol. 25 (2017)
       
  • Enzymatic cell disruption of the microalgae Chlamydomonas reinhardtii for
           lipid and protein extraction
    • Authors: Laura Soto Sierra; Chelsea K. Dixon; Lisa R. Wilken
      Pages: 149 - 159
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Laura Soto Sierra, Chelsea K. Dixon, Lisa R. Wilken
      Microalgae has potential as a biofuel feedstock and as a source of valuable bioproducts for a variety of food, feed, nutraceutical, and pharmaceutical industries due to high yields of proteins, starch, and lipids. However, several challenges are associated with bioproduct extraction from microalgae. The complexity of microalgae cell walls necessitates use of energy intensive disruption methods, but current chemical or mechanical techniques can degrade economically valuable bioproducts. Therefore, disruption methods that target microalgae cell walls are essential, such as enzymatic biomass pretreatment for the release of specific biomolecules. Aqueous enzymatic pretreatment can preserve valuable bioproducts while permitting high levels of cell disruption. In this study, we optimized harvesting times that maximized protein yields in nitrogen depleted cultures and promoted lipid accumulation in the microalgae Chlamydomonas reinhardtii. Furthermore, an aqueous enzymatic assisted extraction (AEAE) treatment was developed. Four lytic enzymes were tested for their ability to permeate C. reinhardtii cell walls. Autolysin treatment was chosen as preferred cell disruption method. Treated cells were visualized by TEM imaging. TEM images and cell counts confirmed cell permeability (100%) and further cell lysis (50%) and product release when cells were treated with autolysin for 24h. Biomass was also subjected to lipid and protein extraction after autolysin treatment and yields were compared to other mechanical and chemical extraction methods. Protein extractability was significantly enhanced by the autolysin pretreatment when compared to sonication pretreatment. Solvent extraction accompanied with autolysin biomass pretreatment significantly enhanced lipid extractable yields as compared to only solvent extraction and solvent plus sonication extraction.
      Graphical abstract image

      PubDate: 2017-05-26T15:12:03Z
      DOI: 10.1016/j.algal.2017.04.004
      Issue No: Vol. 25 (2017)
       
  • The role of starch as transient energy buffer in synchronized microalgal
           growth in Acutodesmus obliquus
    • Authors: G. Mitsue León-Saiki; Ilse M. Remmers; Dirk E. Martens; Packo P. Lamers; René H. Wijffels; Douwe van der Veen
      Pages: 160 - 167
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): G. Mitsue León-Saiki, Ilse M. Remmers, Dirk E. Martens, Packo P. Lamers, René H. Wijffels, Douwe van der Veen
      Photosynthetic organisms have evolved to use light efficiently by scheduling their cellular processes, such as growth and cell division, at specific times of the day. During the day, fixed carbon is used for growth and is partially stored as carbohydrates (e.g., starch). It is commonly assumed that this accumulated starch is essential for fuelling up cell division at night. To test this hypothesis, this study investigates growth, cell division and presence of a transitory energy storage (TES) in both the wild-type and starchless mutant strain of Acutodesmus obliquus under light/dark (LD) cycles and nitrogen replete conditions. A. obliquus (formerly known as Scenedesmus obliquus) wild-type utilized light 20% more efficiently under LD regimes compared with continuous light. When exposed to LD regimes, the wild-type scheduled cell division in a 4-hour period starting 2h before ‘sunset’. Starch acted as the major transitory energy storage (TES) compound: it was accumulated during the last part of the light period and was consumed throughout the entire dark period. The slm1 mutant, with a blocked starch synthesis pathway, showed diurnal rhythms in growth and cell division. However, no other carbohydrates nor triacylglycerols took over the role of TES compound in slm1. Therefore, in contrast to what is generally acknowledged, this study shows that neither starch nor any other major alternative TES is required for synchronized growth and cell division in A. obliquus. The starchless mutant did show a reduced growth and cell division rate compared to the wild-type. Starch, thus, plays a major role in efficient harnessing of light energy over LD cycles, likely because the ability to accumulate starch enhances biomass production capacity and accelerates cell division rate in A. obliquus.

      PubDate: 2017-05-26T15:12:03Z
      DOI: 10.1016/j.algal.2017.05.018
      Issue No: Vol. 25 (2017)
       
  • The Algae Testbed Public-Private Partnership (ATP3) framework;
           establishment of a national network of testbed sites to support
           sustainable algae production
    • Authors: John McGowen; Eric P. Knoshaug; Lieve M.L. Laurens; Thomas A. Dempster; Philip T. Pienkos; Ed Wolfrum; Valerie L. Harmon
      Pages: 168 - 177
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): John McGowen, Eric P. Knoshaug, Lieve M.L. Laurens, Thomas A. Dempster, Philip T. Pienkos, Ed Wolfrum, Valerie L. Harmon
      Well-controlled experiments that directly compare seasonal algal productivities across geographically distinct locations have not been reported before. To fill this gap, six cultivation testbed facilities were chosen across the United States to evaluate different climatic zones with respect to algal biomass productivity potential. The geographical locations and climates were as follows: Southwest, desert; Western, coastal; Southeast, inland; Southeast, coastal; Pacific, tropical; and Midwest, greenhouse. The testbed facilities were equipped with identical systems for inoculum production and open pond operation and methods were standardized across all testbeds to ensure accurate measurement of physical and biological variables. The ability of the testbed sites to culture and analyze the same algal species, Nannochloropsis oceanica KA32, using identical pond operational and data collection procedures was evaluated during the same seasonal timeframe. This manuscript describes the results of a first-of-its-kind coordinated testbed validation field study while providing critical details on how geographical variations in temperature, light, and weather variables influenced algal productivity, nitrate consumption, and biomass composition. We found distinct differences in growth characteristics due to the geographic location and the resulting climatic and seasonal conditions across the sites, with the highest productivities observed at the desert Southwest and tropical Pacific regions, followed by the Western coastal region. The lowest productivities were observed at the Southeast inland and Midwest greenhouse locations. These differences in productivities among the sites correlated with the differences in pond water temperature and available solar radiation. In addition two sites, the tropical Pacific and Southeast inland experienced unusual events, spontaneous flocculation, and unusually cold and wet (rainfall) conditions respectively, that negatively affected outdoor algal growth. In addition, minor variability in productivity was observed between the different experimental treatments at each site, much smaller compared to differences due to geographic location. Finally, the successful demonstration of the coordinated and standardized operation of the testbed sites established a rigorous basis for future validation of algal strains and operational conditions and protocols across a geographically diverse testbed network.

      PubDate: 2017-05-26T15:12:03Z
      DOI: 10.1016/j.algal.2017.05.017
      Issue No: Vol. 25 (2017)
       
  • Cuparane sesquiterpenes from Laurencia natalensis Kylin as inhibitors of
           alpha-glucosidase, dipeptidyl peptidase IV and xanthine oxidase
    • Authors: Kannan R.R. Rengasamy; Lenka Poštová Slavětínská; Manoj G. Kulkarni; Wendy A. Stirk; Johannes Van Staden
      Pages: 178 - 183
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Kannan R.R. Rengasamy, Lenka Poštová Slavětínská, Manoj G. Kulkarni, Wendy A. Stirk, Johannes Van Staden
      The unexplored southern African red marine alga Laurencia natalensis was studied in a search for new enzyme inhibitors. A new cuparane sesquiterpenoid, 8-deoxyalgoane (1) along with two known sesquiterpenoids namely 1-deacetoxyalgoane (2) and algoane (3) were isolated from the MeOH:DCM extract using silica column chromatography with an hexane:EtOAc solvent system. Algoane was obtained as colourless prisms and structures of the three compounds were confirmed by NMR. The three compounds were tested for enzyme inhibitory activities against alpha-glucosidase and dipeptidyl peptidase IV (DPP-IV). Algoane was also tested against xanthine oxidase. In addition, molecular properties were determined to establish drug likeness, and other physico-chemical properties. This is the first report on the chemistry and biological properties of L. natalensis.

      PubDate: 2017-05-26T15:12:03Z
      DOI: 10.1016/j.algal.2017.05.008
      Issue No: Vol. 25 (2017)
       
  • Long-term impact of cadmium shows little damage in Scenedesmus acutiformis
           cultures
    • Authors: Jozef Kováčik; Petr Babula; Viera Peterková; Josef Hedbavny
      Pages: 184 - 190
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Jozef Kováčik, Petr Babula, Viera Peterková, Josef Hedbavny
      Long-term (30days) responses of green alga Scenedesmus acutiformis to cadmium (Cd) excess (1 or 10μM) were studied under in vitro heterotrophic conditions (Milieu Bristol medium containing glucose and casein). No extensive changes of morphology were observed but Cd slightly depleted chlorophyll autofluorescence and some mineral content (K, Ca, and Mg). However, Cd (mainly at 10μM) stimulated increase in biomass and accumulation of ascorbic acid, non-protein thiols, and phenols. Signs of oxidative stress (elevation of ROS, depletion of nitric oxide and viability, changes in the activities of SOD, CAT and GR) were also observed. Total Cd reached only 17.3 and 45.2μg/g DW at 1 or 10μM Cd but bioaccumulation factor (BAF) was comparable with other species and cultivation/exposure conditions (BAF~40 at 10μM Cd) indicating that rather inorganic compounds than glucose or casein affect Cd accumulation. Short-term (24h) exposure of algae to identical Cd doses in HEPES buffer revealed higher absolute Cd content in comparison with 30days of cultivation (8- and 17-fold) and comparison with previous studies indicates that S. acutiformis is a better cadmium accumulator. The extensive use of fluorescence microscopy for oxidative stress detection in algae is also carefully discussed.
      Graphical abstract image

      PubDate: 2017-05-26T15:12:03Z
      DOI: 10.1016/j.algal.2017.04.029
      Issue No: Vol. 25 (2017)
       
  • Single cell lipid profiling of Scenedesmus quadricauda CASA-CC202 under
           nitrogen starved condition by surface enhanced Raman scattering (SERS)
           fingerprinting
    • Authors: A.N. Ramya; P.S. Ambily; B.S. Sujitha; Muthu Arumugam; Kaustabh Kumar Maiti
      Pages: 200 - 206
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): A.N. Ramya, P.S. Ambily, B.S. Sujitha, Muthu Arumugam, Kaustabh Kumar Maiti
      Oleaginous microalgae tend to accumulate neutral lipids as their energy reserve mainly in the form of triacylglycerol (TAG) which can be utilized as the precursor molecule for biodiesel and other nutraceutical application. The TAG level and the fatty acid composition of microalgae modulated by exposing the algal strains to different physicochemical, nutritional and environmental factors. Nitrogen starvation is considered as an important and practically feasible way by which the lipid content can be enriched in large scale production. In the present investigation, Scenedesmus quadricauda CASA-CC202, oleaginous microalgae with high biomass productivity has been subjected to nitrogen starvation and the stress mediated lipids were analyzed on a single cell basis. As a new insight, we have successfully identified the unsaturated and saturated functionalities of fatty acids by surface enhanced Raman scattering (SERS) spectral footprint under nitrogen starved condition in acidic and, neutral pH. In addition, other macromolecules like chlorophyll, carotenoids, proteins and carbohydrates were also selectively mapped. Most promising SERS mapping pattern of single algal cells depicts high lipid rich component under nitrogen starved condition and degree of unsaturation vs. saturation has been validated through SERS spectral analysis by comparing with the Raman spectra of standard fatty acids. Moreover, the present investigation, clearly distinguish the lipids from other macromolecules like protein, carbohydrate and photosynthetic pigments in whole cell. Finally, SERS based analysis dually by spectral and mapping techniques of lipid enriched S. quadricauda CASA-CC202 has been superimposed with Nile red staining of the same algal cells which unambiguously identify the neutral lipid components under the starved condition.

      PubDate: 2017-05-26T15:12:03Z
      DOI: 10.1016/j.algal.2017.05.011
      Issue No: Vol. 25 (2017)
       
  • Protic ionic liquid-assisted cell disruption and lipid extraction from
           fresh water Chlorella and Chlorococcum microalgae
    • Authors: Mukund Shankar; Pratap K. Chhotaray; Ayushi Agrawal; Ramesh L. Gardas; Krishnamurthi Tamilarasan; Mathur Rajesh
      Pages: 228 - 236
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Mukund Shankar, Pratap K. Chhotaray, Ayushi Agrawal, Ramesh L. Gardas, Krishnamurthi Tamilarasan, Mathur Rajesh
      Protic ionic liquids (PILs) with their ability to host labile protons and form hydrogen bonds are likely to be efficient catalyst for bioprocessing. This is one of the first reports investigating PIL-assisted microalgal cell disruption and lipid extraction. The applicability of several PILs with butyrolactam, caprolactam, propylammonium and hydroxypropylammonium cations in combination with formate, acetate and hexanoate anions for cell disruption and lipid extraction from fresh water Chlorella and Chlorococcum sp. have been evaluated in this study. The investigations were performed with de-watered wet microalgae under ambient temperatures and hence do not require any energy intensive drying and/or processing steps. The PILs with formate and hexanoate anions when compared with conventional pre-treatment techniques: sonication, microwave and cellulase provided better microalgal cell disruption efficiencies. The FESEM analysis for the Butyrolactam hexanoate (BTH) treated cells show extensive pattern of microalgal cell disruption. The fluorescence imaging analysis coupled with culturing experiments indicates a near-complete disruption and loss in viability of the PIL-treated microalgal cells. The lipid yield from the formate and hexanoate anions-PILs was statistically comparable and/or higher to the Bligh & dyer control method. Among the PILs, BTH recorded 1.86 and 1.72 folds higher lipid yields than the control method with Chlorella and Chlorococcum sp. respectively. The lipids show predominance of C16 and C18 fatty acids similar to lipid profile obtained with the control method. Furthermore, the PILs were also found to have a beneficial role in reducing the chlorophyll pigments in the final lipid product. Overall, the results show PILs with formate and hexanoate anions can be utilized for a relatively energy efficient, one-step cell disruption and lipid extraction process from wet microalgae.

      PubDate: 2017-05-26T15:12:03Z
      DOI: 10.1016/j.algal.2017.05.009
      Issue No: Vol. 25 (2017)
       
  • Wirelessly powered submerged-light illuminated photobioreactors for
           efficient microalgae cultivation
    • Authors: Alexandra Marie Murray; Ioannis A. Fotidis; Alex Isenschmid; Karl Rasmus August Haxthausen; Irini Angelidaki
      Pages: 244 - 251
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Alexandra Marie Murray, Ioannis A. Fotidis, Alex Isenschmid, Karl Rasmus August Haxthausen, Irini Angelidaki
      A novel submerged-light photobioreactor (SL-PBR) with free-floating, wireless internal light sources powered by near-field resonant inductive coupling was investigated using a quick (Chlorella vulgaris) and a slow (Haematococcus pluvialis) growing microalgal species. During testing of the SL-PBR, the yield on photons was 1.18 and 1.15g biomass mol−1 photons for C. vulgaris and H. pluvialis, respectively. At the same time, a conventional, externally illuminated PBR with the same internal light intensity produced yields of 0.78 and 0.05g biomass mol−1 photons for C. vulgaris and H. pluvialis, respectively. Thus, the wireless internal light source was proven to be up to fivefold more effective light delivery system compared to the conventional illumination system. Meanwhile, it was discovered that some of the internal light sources had ceased to function, which might have caused underestimation of the true yield. Interestingly, the SL-PBR provided more uniform light to the culture and had the ability to reduce the presence of dark zones and the effect of self-shading. Thus, the SL-PBR showed potential, if subsequent prototype designs address the technical challenges identified during this study.
      Graphical abstract image

      PubDate: 2017-05-31T11:55:30Z
      DOI: 10.1016/j.algal.2017.05.015
      Issue No: Vol. 25 (2017)
       
  • Fouling of extracellular algal organic matter during ultrafiltration: The
           influence of iron and the fouling mechanism
    • Authors: Weiwei Huang; Mengliu Hu; Xiao Qin; Wenzong Zhou; Weiguang Lv; Bingzhi Dong
      Pages: 252 - 262
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Weiwei Huang, Mengliu Hu, Xiao Qin, Wenzong Zhou, Weiguang Lv, Bingzhi Dong
      In this study, membrane fouling and the mechanism of algal extracellular organic matter (EOM) due to various trace heavy metals (iron) during ultrafiltration (UF) was investigated in detail. In both early and late exponential growth phases, the results indicated that the membrane fouling caused by EOM at low iron concentrations in this study was more severe than that at high and normal iron concentrations. Low iron concentrations produced the highest total (R) and reversible fouling resistance (Rre), of which Rre was higher, followed by membrane resistance (Rm), and irreversible fouling resistance (Rir). The analysis of EOM characteristics indicated that low iron in this study stimulated the growth of algae beyond high and normal iron concentrations, including increases in chlorophyll a; protein (tryptophan-like and tyrosine-like organic matter) content; and macro, medium and small molecular organic matters. Humic-like organics were more synthesized under high iron concentrations. Analyses of membrane fouling behavior illustrated that cake formation was the major fouling mechanism for the three iron concentrations, and it accounted for a greater proportion of fouling in the low iron concentration than in the other two iron concentrations; cake resistance played a more critical role in the late exponential growth phase than in the primary exponential phase.
      Graphical abstract image

      PubDate: 2017-06-06T12:25:52Z
      DOI: 10.1016/j.algal.2017.05.002
      Issue No: Vol. 25 (2017)
       
  • Trends and strategies to enhance triacylglycerols and high-value compounds
           in microalgae
    • Authors: Lisa M. Schüler; Peter S.C. Schulze; Hugo Pereira; Luísa Barreira; Rosa León; João Varela
      Pages: 263 - 273
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Lisa M. Schüler, Peter S.C. Schulze, Hugo Pereira, Luísa Barreira, Rosa León, João Varela
      Microalgae are important sources of triacylglycerols (TAGs) and high-value compounds such as carotenoids and long-chain polyunsaturated fatty acids (LC-PUFAs). TAGs are feedstocks for biofuels or edible oils; carotenoids are used as pigments in the food and feed industries; and LC-PUFAs are beneficial for human health, being also key to the correct development of fish in aquaculture. Current trends in microalgal biotechnology propose the combined production of biofuels with high-value compounds to turn large-scale production of microalgal biomass into an economically feasible venture. As TAGs, carotenoids and LC-PUFAs are lipophilic biomolecules, they not only share biosynthetic precursors and storage sinks, but also their regulation often depends on common environmental stimuli. In general, stressful conditions favor carotenoid and TAGs biosynthesis, whereas the highest accumulation of LC-PUFAs is usually obtained under conditions promoting growth. However, there are known exceptions to these general rules, as a few species are able to accumulate LC-PUFAs under low light, low temperature or long-term stress conditions. Thus, future research on how microalgae sense, transduce and respond to environmental stress will be crucial to understand how the biosynthesis and storage of these lipophilic molecules are regulated. The use of high-throughput methods (e.g. fluorescent activated cell sorting) will provide an excellent opportunity to isolate triple-producers, i.e. microalgae able to accumulate high levels of LC-PUFAs, carotenoids and TAGs simultaneously. Comparative transcriptomics between wild type and triple-producers could then be used to identify key gene products involved in the regulation of these biomolecules even in microalgal species not amenable to reverse genetics. This combined approach could be a major step towards a better understanding of the microalgal metabolism under different stress conditions. Moreover, the generation of triple-producers would be essential to raise the biomass value in a biorefinery setting and contribute to meet the world's rising demand for food, feed and energy.

      PubDate: 2017-05-31T11:55:30Z
      DOI: 10.1016/j.algal.2017.05.025
      Issue No: Vol. 25 (2017)
       
  • Sequential Hydrothermal Liquefaction characterization and nutrient
           recovery assessment
    • Authors: Jose S. Martinez-Fernandez; Shulin Chen
      Pages: 274 - 284
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Jose S. Martinez-Fernandez, Shulin Chen
      Hydrothermal Liquefaction (HTL) has been considered as an effective process for converting wet algal biomass to biocrude. A major limitation of HTL however, is its inability to harvest high value-added byproducts or recover nutrients. Sequential Hydrothermal Liquefaction (SEQHTL) was recently developed to overcome this limitation to allow the simultaneous extraction of co-products and biocrude production. In this study, the performance for SEQHTL treating different algal species was assessed in terms of process versatility, biocrude production and nutrient recovery. The impact of feedstock and relevant feed stream thermophysical properties was evaluated. The biocrudes produced had moderately low oxygen content (<14%), reduced nitrogen content (<8%), very low sulfur (<1.4%), and HHV ranging from 33 to 37MJ/kg. Galdieria sulphuraria produced less crude (~20wt%) as well as less char (~11wt%). The Chlorella sp. had higher crude yields (~30wt%) and superior nutrient recovery in aqueous effluents, ranging from 2640 to 3600mg/L of phosphorous and from 2100 to 3700mg/L of total nitrogen. The results also show non-Newtonian shear thinning and increasing effective viscosity at higher solid loadings. Although SEQHTL proved more suitable for algae with moderate to high lipid content, its versatility and mild reaction conditions allow for the harvesting significant quantities of water-soluble nutrients. These findings compare favorably to HTL studies and suggest that these compounds can be recovered for either recycle or producing other value-added co-products.

      PubDate: 2017-05-31T11:55:30Z
      DOI: 10.1016/j.algal.2017.05.022
      Issue No: Vol. 25 (2017)
       
  • Biodegradation and rapid removal of methyl parathion by the paddy field
           cyanobacterium Fischerella sp.
    • Authors: Balkrishna Tiwari; Sindhunath Chakraborty; Alok Kumar Srivastava; Arun Kumar Mishra
      Pages: 285 - 296
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Balkrishna Tiwari, Sindhunath Chakraborty, Alok Kumar Srivastava, Arun Kumar Mishra
      A paddy field cyanobacterial isolate that is capable of degrading and utilizing the organophosphorus pesticide methyl parathion (MP) as a phosphate source has been characterized as Fischerella sp. To investigate the MP removal and degradation capabilities of this cyanobacterium along with the mechanism it has adopted to combat the pesticide's toxicity, different doses of MP (0, 5, 10, 20 and 30mgL−1) were applied to the cyanobacterial culture. At 20mgL−1 of MP, the cyanobacterium efficiently modulated its antioxidative defense system and its fatty acid and hydrocarbon profiles to support growth. The initial rapid removal of methyl parathion (~80%) was due to the adsorption of the pesticide onto the cyanobacterial surface. Fourier transform infrared (FTIR) spectral analysis revealed that MP interacts with the OH group on the cell surface, and this chemical interaction may lead to chemisorptions. The initial removal pattern has followed the pseudo-second-order kinetics model of biosorption that also defines the chemisorptions mechanism. The appearance of p-nitrophenol in the medium coupled with modulation of the physiological indices of this cyanobacterium has indicated that biosorption followed by the simultaneous bioaccumulation and biodegradation of MP led to its complete removal from the medium. Under phosphorus-deficient conditions, MP exposure induced the growth and intracellular alkaline phosphatase activity of the cyanobacterium, which both support the view that the organism can use this pesticide as a phosphorus source. Thus, due to its tremendous efficiency in degrading and removing the organophosphorus pesticide MP, the isolated cyanobacterium Fischerella sp. can be used as a potent bioremediation agent.
      Graphical abstract image

      PubDate: 2017-06-06T12:25:52Z
      DOI: 10.1016/j.algal.2017.05.024
      Issue No: Vol. 25 (2017)
       
  • Effect of ash on hydrothermal liquefaction of high-ash content algal
           biomass
    • Authors: Wan-Ting Chen; Wanyi Qian; Yuanhui Zhang; Zachary Mazur; Chih-Ting Kuo; Karalyn Scheppe; Lance Charles Schideman; Brajendra Kumar Sharma
      Pages: 297 - 306
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Wan-Ting Chen, Wanyi Qian, Yuanhui Zhang, Zachary Mazur, Chih-Ting Kuo, Karalyn Scheppe, Lance Charles Schideman, Brajendra Kumar Sharma
      Previous studies demonstrate that the high ash contents appeared to inhibit the formation of biocrude oil in the hydrothermal liquefaction (HTL) processes. In order to investigate the effect of ash contents on the HTL reaction, mixed-culture algal biomass from wastewater systems (AW) was separated into two fractions (AW-41.8 and AW-38.5) and converted into biocrude oil via HTL at 300°C for a 60min reaction time (the previously determined optimum condition). Compared to AW biomass before screen pretreatments, the ash contents of AW-41.8 and AW-38.5 were respectively decreased from 53.3wt% to 41.8wt% and 38.5wt%. Moreover, the higher heating value (HHV) of resulting biocrude oil was increased from 27.5MJ/kg to 32.3MJ/kg, and the fraction of light oil (boiling point of 110–300°C) was increased from 31wt% to 49wt%. The above results indicate that algal biomass with certain amounts of ash contents can be converted into biocrude oil with reasonable quality and quantity. To explore the range of concentrations of ash where it may present a positive effect on the biocrude oil yield or quality, further HTL conversions with pure algal feedstock and representative ash contents were conducted. The HHV and boiling point distribution of the algal biocrude oil was hardly affected when the ash contents in the algal feedstock was below 40wt%. This fact substantiates the feasibility of using high-ash algae from wastewater treatment systems for HTL feedstocks and diminishes the necessity of multi-step pretreatments and modifications of high-ash algal biomass for biofuel application.
      Graphical abstract image

      PubDate: 2017-06-06T12:25:52Z
      DOI: 10.1016/j.algal.2017.05.010
      Issue No: Vol. 25 (2017)
       
  • Characterization of ash in algae and other materials by determination of
           wet acid indigestible ash and microscopic examination
    • Authors: Keshun Liu
      Pages: 307 - 321
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Keshun Liu
      Algae are known for high ash content. It is important to properly characterize their ash for value added utilization of algae as food, feed, and feedstock for biofuels. In this study, 12 algae of different sources were measured for proximate composition and mineral profile. Results showed that the relative difference between ash content by dry ashing and total minerals content by wet digestion increased with ash content. A major cause was soon identified: when using a common procedure of strong attacks for sample digestion before mineral analysis, incomplete digestion existed for most algae samples due to the presence of siliceous materials. It was proposed that algae consist of wet acid indigestible ash (WAIA) and wet acid digestible ash, whereas WAIA is siliceous. Methods to measure WAIA content in the 12 algae, along with oat grain, oat forage, defatted soymeal and fine sand, were then developed based on digestion with nitric acid or sulfuric acid-hydrogen peroxide. For the 12 algae, ash ranged 1.9 to 37.4% dry matter while WAIA by nitric acid digestion varied 0.1% to 25.6%. High correlation between WAIA and ash contents indicates WAIA as an important contributor for algae ash. For identifying what constituted the siliceous materials, all samples in three matrixes (original, ash by dry ashing, and WAIA) were microscopically examined. Because wet acid digestion had an ability to concentrate siliceous materials and maintain their original shape and size, WAIA was the best matrix for microscopic examination. Micrographs of WAIA show three types of siliceous materials in algae: non-diatom cellular structures, diatom cell walls, and sandy particles. It was concluded that high ash content of algae resulted partly from contamination of diatoms and/or sandy particles of geologic origin and that WAIA should be an important quality parameter for algae. Subsequently, several measures are proposed to produce algae with low ash content.

      PubDate: 2017-06-06T12:25:52Z
      DOI: 10.1016/j.algal.2017.04.014
      Issue No: Vol. 25 (2017)
       
  • Higher packing of thylakoid complexes ensures a preserved Photosystem II
           activity in mixotrophic Neochloris oleoabundans
    • Authors: Martina Giovanardi; Mariachiara Poggioli; Lorenzo Ferroni; Maija Lespinasse; Costanza Baldisserotto; Eva-Mari Aro; Simonetta Pancaldi
      Pages: 322 - 332
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Martina Giovanardi, Mariachiara Poggioli, Lorenzo Ferroni, Maija Lespinasse, Costanza Baldisserotto, Eva-Mari Aro, Simonetta Pancaldi
      A better understanding of the microalgal basic biology is still required to improve the feasibility of algal bio-products. The photosynthetic capability is one of the parameters that need further progress in research. A superior PSII activity was previously described in the green alga Neochloris oleoabundans. In this study, N. oleoabundans was grown in a glucose-supplied culture medium, in order to provide new information on the organisation and interaction of thylakoid protein complexes under mixotrophy. Fluorescence measurements suggested a strong association of light harvesting complex II (LHCII) to PSII in mixotrophic samples, confirmed by the lack of LHCII phosphorylation under growth light and the presence of PSI-PSII-LHCII megacomplexes in Blue-Native gel profile. The chloroplast ultrastructure was accordingly characterised by a higher degree of thylakoid appression compared to autotrophic microalgae. This also affected the capability of mixotrophic microalgae to avoid photodamage when exposed to high-light conditions. On the whole, it emerged that the presence of glucose affected the photosynthetic performance of mixotrophic samples, apparently limiting the dynamicity of thylakoid protein complexes. As a consequence, PSII is preserved against degradation and the PSI:PSII is lowered upon mixotrophic growth. Apparent increase in PSII photochemical activity was attributed to a down-regulated chlororespiratory electron recycling.

      PubDate: 2017-06-15T01:37:07Z
      DOI: 10.1016/j.algal.2017.05.020
      Issue No: Vol. 25 (2017)
       
  • Flocculation mechanism of Aspergillus niger on harvesting of Chlorella
           vulgaris biomass
    • Authors: Yi Li; Yanting Xu; Lei Liu; Ping Li; Yue Yan; Tong Chen; Tianling Zheng; Hailei Wang
      Pages: 402 - 412
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Yi Li, Yanting Xu, Lei Liu, Ping Li, Yue Yan, Tong Chen, Tianling Zheng, Hailei Wang
      Fungal flocculation and its mechanism are rarely observed on biofuel-producing microalgae. In this study, the flocculation activity and mechanism of Aspergillus niger hsn26, a filamentous fungus, on Chlorella vulgaris biomass was investigated for the first time. Mycelial pellets showed high flocculation efficiency on algal cells. Moreover, the source of flocculation activity is located at the surface of mycelium. The characteristics of flocculation activity indicated that surface proteins with low molecular weight play a significant role during flocculation process. Calcium can be added into algal culture as coagulants to significantly improve flocculation efficiency. Calcium addition can also simultaneously bind the surfaces of mycelium and algal cells. Therefore, calcium bridging is the main flocculation mechanism for mycelial pellets. The increase of hydrophobic interaction can also promote the flocculation activity. Lastly, results indicate that flocculation mechanism of mycelial pellets on microalgae biomass is a surface proteins-mediated, calcium bridging-dependent and hydrophobic interaction-involved process.

      PubDate: 2017-06-20T01:51:46Z
      DOI: 10.1016/j.algal.2017.06.001
      Issue No: Vol. 25 (2017)
       
  • Microalgae cultivation for carbon dioxide sequestration and protein
           production using a high-efficiency photobioreactor system
    • Authors: David Pavlik; Yingkui Zhong; Carly Daiek; Wei Liao; Robert Morgan; William Clary; Yan Liu
      Pages: 413 - 420
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): David Pavlik, Yingkui Zhong, Carly Daiek, Wei Liao, Robert Morgan, William Clary, Yan Liu
      Pilot-scale algae photobioreactors (APBs) were used to culture microalga Chlorella vulgaris 395 on flue gas from the T.B. Simon Power Plant at Michigan State University. The flue gas was pumped directly into the APBs to provide a carbon source for the culture. Various photosynthetic photon flux densities (PPFD) (31, 104, 177, 531μmolm−2 s−1) and harvest ratios (20% and 30 %v/v) were applied on the photobioreactor to study their effects on algal growth. The results suggested that increasing PPFD significantly enhanced biomass production in terms of productivity, biomass concentration, and total dry weight at both harvest ratios. The highest biomass productivity of 0.40gL−1 d−1, along with corresponding biomass concentration of 1.30gL−1 and biomass dry weight of 40.0gd−1 APB−1, were achieved at the PPFD of 531μmolm−2 s−1 with the 30% harvest ratio. A photovoltaic (PV) powered APB was then simulated to carry out a techno-economic analysis. The mass balance analysis concluded that a one-metric-ton unit with 224m2 PV panels can generate 0.4kg of dry algae biomass with 51% protein content and sequester about 0.8kg of CO2 per day. The economic analysis indicated that a net positive revenue of $55,353 per year could be achieved for a system with an effective reactor volume of 100m3 and the corresponding PV panels of 22,400m2.

      PubDate: 2017-06-20T01:51:46Z
      DOI: 10.1016/j.algal.2017.06.003
      Issue No: Vol. 25 (2017)
       
  • Flashing light effects on CO2 absorption by microalgae grown on a biofilm
           photobioreactor
    • Authors: Isabel Martín-Girela; María Dolores Curt; Jesús Fernández
      Pages: 421 - 430
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Isabel Martín-Girela, María Dolores Curt, Jesús Fernández
      The effect of flashing light and continuous light from red light emitting diodes on the photosynthetic activity of microalgae biofilms was investigated. In contrast to suspended microalgae cultures, biofilm-based microalgae photobioreactors allow a uniform exposure of the microalgae to incident radiation throughout the period of microalgae cultivation. In this work, multi-species microalgae biofilms were produced in a biofilm photobioreactor to be subsequently taken to an ad-hoc laboratory for biofilm light emitting diodes trials. Continuous light and flashing light at three light/dark frequencies: 0.1, 1 and 10kHz and four light fractions: 5, 25, 50, and 75% were tested on microalgae biofilms. All flashing light experiments resulted in higher net photosynthetic activity of microalgae biofilms than the continuous light; the highest increase was obtained for 10kHz frequency at 5% light fraction, for which the net photosynthetic activity was 7-times the continuous light (51μmolphotonsm−2 s−1). Over the whole experiment, the quantum yield varied from 0.014 (at 10kHz & 1kHz, 766μmolphotonsm−2 s−1) to 0.161 (at 10kHz, 51μmolphotonsm−2 s−1); the latter value was much higher than the theoretical maximum one, estimated at 0.125μmolCO2 μmolphotons−1. Some hypotheses for this finding were raised, which would require further investigation.

      PubDate: 2017-06-27T07:36:48Z
      DOI: 10.1016/j.algal.2017.06.008
      Issue No: Vol. 25 (2017)
       
  • Applying principles of resource competition theory to microalgae biomass
           production: A more refined relationship between species richness and
           productivity
    • Authors: Daniel L. Roelke
      Pages: 431 - 438
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Daniel L. Roelke
      Ecosystem productivity is commonly greater when biodiversity is high, an observation that extends to artificial systems, such as microalgae production systems employing polycultures. Regarding these, when functional diversity within polycultures is also high, the stability of production is increased. There are various strategies to designing biomass production systems; some differentiate between ways in which nutrients are resupplied to production chambers after harvesting. Here, a mathematical model is developed that depicts a microalgae biomass production facility. Simulation analyses are then performed to explore optimization strategies that consider production magnitude and functional diversity within polycultures. Two nutrient resupply strategies are explored. The first involves using the same concentrations of nutrients with each resupply after harvesting. The second involves using alternating nutrient concentrations of varied proportions (relative to each other) for the resupply after harvesting. The first nutrient resupply strategy is best depicted by an ecological paradigm described by the resource-saturation limitation (RSL) model. The second nutrient resupply strategy is best depicted by another ecological paradigm described by the resource-ratio (RR) model. Findings suggest that if confidence is high that the polycultures being employed are resilient, then designing a biomass production system following the RSL-model approach is best. In such a system, the complementarity of the polyculture being employed should be maximized, as this will produce the highest biomass production. But if confidence is low that the polycultures are resilient, then designing a biomass production system following the RR-model approach is best. In this case, designing the resource supply fluctuations with intermediate proportional alternations, and employing polycultures of lesser complementarity, is best. This will maximize functional diversity, and therefore production stability.

      PubDate: 2017-06-27T07:36:48Z
      DOI: 10.1016/j.algal.2017.06.002
      Issue No: Vol. 25 (2017)
       
  • Lyophilization pretreatment facilitates extraction of soluble proteins and
           active enzymes from the oil-accumulating microalga Chlorella vulgaris
    • Authors: Nicole Unterlander; Pascale Champagne; William C. Plaxton
      Pages: 439 - 444
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Nicole Unterlander, Pascale Champagne, William C. Plaxton
      Microalgae are being developed as a renewable source of triacylglycerides (TAGs) for industrial production of biodiesel, bioplastics, and biolubricants. Certain species such as Chlorella vulgaris are attractive models for studies of microalgal TAG biosynthesis because they accumulate significant quantities of TAGs when cultured mixotrophically in the presence of exogenous carbon sources such as glycerol. As the major byproduct of biodiesel production from TAG, glycerol recycling by bio-oil accumulating microalgae would be particularly advantageous. However, our current understanding of the organization and control of microalgal glycerol uptake, metabolism, and incorporation into TAG is very limited. One reason is that microalgae such as C. vulgaris are endowed with a complex and robust cell wall that significantly impedes cellular lysis for efficient extraction of soluble proteins and active enzymes. The aim of the current study was to optimize extraction of soluble proteins and glycerol kinase activity from glycerol-supplemented, mixotrophic cultures of C. vulgaris. Lyophilizing harvested cells prior to lysis using a French press, bead beater, mortar and pestle, or ultrasonication resulted in large (up to 6-fold) increases in soluble protein concentration (up to 60mg/gFW) and glycerol kinase activity (up to 2μmol/mingFW−1) in the resultant clarified extracts. In particular, the activity of glycerol kinase, hypothesized to catalyze a rate-determining step in the metabolism of exogenous glycerol into TAGs, was virtually undetectable in clarified extracts unless the harvested cells were lyophilized prior to extraction. This method was successfully applied to other key carbohydrate metabolizing enzymes (pyruvate kinase) and oleaginous microalgal species (Scenedesmus sp.). Deciphering the organization and control of microalgal carbon (including glycerol) metabolism is expected to facilitate harnessing the full potential of TAG-accumulating microalgae for downstream biofuel and industrial biotechnology applications.

      PubDate: 2017-06-27T07:36:48Z
      DOI: 10.1016/j.algal.2017.06.010
      Issue No: Vol. 25 (2017)
       
  • Utilization of ammonium by the hydrocarbon-producing microalga,
           Botryococcus braunii Showa
    • Authors: Hiromasa Nakamura; Takuhei Shiozaki; Natsuki Gonda; Ken Furuya; Shigeki Matsunaga; Shigeru Okada
      Pages: 445 - 451
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Hiromasa Nakamura, Takuhei Shiozaki, Natsuki Gonda, Ken Furuya, Shigeki Matsunaga, Shigeru Okada
      As a prospective feedstock for sustainable biofuels, the green microalga Botryococcus braunii race B has attracted significant attention since this colony-forming alga has the ability to accumulate considerable amounts of triterpene hydrocarbons, botryococcenes, in its extracellular matrix. However, its primary metabolism, nutrient uptake and utilization relevant to growth, are still poorly understood in this alga. From this perspective, we investigated the utilization of ammonium by B. braunii as a more reduced form of nitrogen source compared to nitrate, which is generally used for cultures of the alga. Isotope-ratio mass spectrometry analyses indicated that the uptake rate of ammonium was higher than that of nitrate at a certain concentration. When ammonium was added to culture medium, however, it inhibited algal growth even in the presence of nitrate. Buffered culture media ameliorated the toxicity of ammonium, and the alga accumulated the same levels of hydrocarbons and secondary carotenoids, irrespective of nitrogen source. To characterize utilization of ammonium by B. braunii at the molecular level, putative ammonium transporter (AMT) genes were screened from a cDNA library and four isogenes (BbAMT1;1, 1;2, 1;3 and 1;4) were cloned. Two of them, BbAMT1;1 and 1;2, were upregulated under nitrogen deficient conditions. BbAMT1;1 complemented the growth of an ammonium uptake-defective yeast strain, showing it to be a functional gene coding for AMT. These results could pave the way for culturing B. braunii more efficiently using ammonium as a sole nitrogen source by improving ammonium uptake through our understanding of AMT.

      PubDate: 2017-06-27T07:36:48Z
      DOI: 10.1016/j.algal.2017.06.007
      Issue No: Vol. 25 (2017)
       
  • Microalgal biomass as a (multi)functional ingredient in food products:
           Rheological properties of microalgal suspensions as affected by mechanical
           and thermal processing
    • Authors: Tom M.M. Bernaerts; Agnese Panozzo; Veerle Doumen; Imogen Foubert; Lore Gheysen; Koen Goiris; Paula Moldenaers; Marc E. Hendrickx; Ann M. Van Loey
      Pages: 452 - 463
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Tom M.M. Bernaerts, Agnese Panozzo, Veerle Doumen, Imogen Foubert, Lore Gheysen, Koen Goiris, Paula Moldenaers, Marc E. Hendrickx, Ann M. Van Loey
      Microalgae show great potential for use as novel ingredients in food products, as they are rich in several nutritional and health-beneficial components. However, addition of total microalgal biomass might alter the structural properties of the food system. Therefore, information is required about their rheological characteristics towards selection of microalgae species for specific food products. This study comprises the rheological characterization of seven commercially available microalgae species in aqueous suspensions, before and after mechanical and thermal processing. Substantial differences in rheological properties were observed between the investigated microalgal suspensions. Among the untreated suspensions, Porphyridium cruentum, Chlorella vulgaris and Odontella aurita showed the largest structural properties and could be described as weak gels. All suspensions showed shear-thinning flow behavior at the examined concentration of 8% w/w, except for Nannochloropsis species. Shear-thinning behavior was also observed for the separated serum phase of P. cruentum, which might be attributed to the presence of sulfated exopolysaccharides. During processing, rheological properties were significantly altered. High pressure homogenization was used as a mechanical treatment, followed by a pasteurization or sterilization process. Whereas suspensions of Arthrospira platensis and C. vulgaris showed an increased storage modulus and viscosity after processing, the opposite was observed for P. cruentum and O. aurita. No clear effect of processing was observed for suspensions of Nannochloropsis sp., Schizochytrium sp. and Phaeodactylum tricornutum. Investigation of the microstructure revealed differences in degree of cell disruption by high pressure homogenization, with Nannochloropsis sp. being the most resistant. Subsequent thermal processing resulted in aggregation of released cell material and/or intact cells. In conclusion, the obtained results provide the scientific knowledge base for the selection of microalgae species towards food applications. Whereas some microalgae species hardly affect the structural properties of the food product, other microalgae species show large potential for use as a structuring agent in food applications.

      PubDate: 2017-06-27T07:36:48Z
      DOI: 10.1016/j.algal.2017.05.014
      Issue No: Vol. 25 (2017)
       
  • Screening for enhanced astaxanthin accumulation among Spirulina platensis
           mutants generated by atmospheric and room temperature plasmas
    • Authors: Jun An; Fuli Gao; Qiuyue Ma; Yang Xiang; Difeng Ren; Jun Lu
      Pages: 464 - 472
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Jun An, Fuli Gao, Qiuyue Ma, Yang Xiang, Difeng Ren, Jun Lu
      In this study, a high-throughput screening procedure was employed to generate mutants of Spirulina platensis for enhanced astaxanthin production using an atmospheric and room temperature plasma (ARTP) based on random mutagenesis process. The optimal culture conditions for cultivation of S. platensis in the laboratory were established to be 29°C, 6.3×10−3 μmol/cm2/s light intensity and a semi-continuous culture system. On the basis of the ARTP screening procedure, a mutant strain (Sp-A1) was successfully isolated, which showed astaxanthin production of 45.88±1.56μg/g, a 196% increase over that of the original wild type strain (15.50±1.52μg/g). The mutant strain accumulated higher content of chlorophyll a than that of the original wild type strain, whereas the β-carotene and polysaccharide contents as well as the superoxide dismutase (SOD) activity of the mutant strain were slightly lower. Under a single stress of 0.625g/L NaNO3, astaxanthin accumulation of mutant strain Sp-A1 reached 0.038±0.002μg/mL after 7days of culture, which was equivalent to 142.50±0.04μg/g of the astaxanthin content versus the dried S. platensis weight. This study demonstrates that ARTP is a novel powerful mutagenesis tool to generate S. platensis strains for increased yields of astaxanthin and may, therefore, play an important role in the enhanced expression of astaxanthin in microbial hosts.

      PubDate: 2017-06-27T07:36:48Z
      DOI: 10.1016/j.algal.2017.06.006
      Issue No: Vol. 25 (2017)
       
  • Lipidomic analysis of two closely related strains of the microalga
           Parietochloris (Trebouxiophyceae, Chlorophyta)
    • Authors: Tomáš Řezanka; Linda Nedbalová; Jaromír Lukavský; Lenka Procházková; Karel Sigler
      Pages: 473 - 482
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Tomáš Řezanka, Linda Nedbalová, Jaromír Lukavský, Lenka Procházková, Karel Sigler
      The analysis of ribosomal internal transcribed spacer 2 (ITS2) secondary structure and morphology of two strains of the green microalga Parietochloris (CCALA 1082 and 1084) confirmed that they represent one biological species. However, their fatty acid profiles showed slight differences, which was fully confirmed by a series of lipidomic analyses using both shotgun lipidomics and hydrophilic interaction liquid chromatography-tandem mass spectrometry with electrospray ionization. 26 classes of lipids were identified, including more than 430 molecular species of lipids. The analyses showed that the greatest differences are in three types of phospholipids - phosphatidylethanolamine, phosphatidylcholine and phosphatidylinositol. These phospholipids have different spatial configurations (cylindrical, conical, and conical inverted), especially for those molecular species containing at least one arachidonic acid. Based on the lipidomic analyses we were able to distinguish the two strains. This may be advantageous in cases when routine DNA analysis shows that two strains are nearly identical.
      Graphical abstract image

      PubDate: 2017-06-27T07:36:48Z
      DOI: 10.1016/j.algal.2017.06.005
      Issue No: Vol. 25 (2017)
       
  • Cosmetic attributes of algae - A review
    • Authors: Maíra Bueno Ariede; Thalita Marcílio Candido; Ana Lucia Morocho Jacome; Maria Valéria Robles Velasco; João Carlos M. de Carvalho; André Rolim Baby
      Pages: 483 - 487
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Maíra Bueno Ariede, Thalita Marcílio Candido, Ana Lucia Morocho Jacome, Maria Valéria Robles Velasco, João Carlos M. de Carvalho, André Rolim Baby
      Algae (macroalgae and microalgae) are aquatic photosynthetic organisms largely used due to the variety of bioactive compounds in their composition. Macroalgae have caught the attention of the food, cosmetic, pharmaceutical, and nutraceutical industries. The food industry has recently used microalgae biomass, and several others have used it as biofuel source in wastewater treatments, for example. Many algae-derived secondary metabolites are known for their skin benefits, which include protection from UV radiations and prevention of rough texture, wrinkles, and skin flaccidity. It also avoids skin aging due to the presence of antioxidant compounds. The variety of cosmetic formulations using biocompounds or algae extracts is increasing since they also provide the desired safe materials from environmental resources. Although the cosmetic effects of some of these compounds were described in recent publications, the majority of biomolecules in algae species have not yet been studied and, therefore, are not be used for cosmetic purposed. Besides that, the majority of algae effects in cosmetics are described in patents without considerable explanation about the type of biocompounds or the mechanisms responsible for each cosmetic performance. Thus, this review aimed at a better understanding of the recent uses of algae in cosmetic formulations with potential applications for new researches.

      PubDate: 2017-06-27T07:36:48Z
      DOI: 10.1016/j.algal.2017.05.019
      Issue No: Vol. 25 (2017)
       
  • Algal Research, Special Issue Editorial: Wastewater and Algae; Risk,
           biofuels and long-term sustainability
    • Authors: Adrian Unc; Miller Alonso Camargo-Valero; Stephen R. Smith
      Abstract: Publication date: June 2017
      Source:Algal Research, Volume 24, Part B
      Author(s): Adrian Unc, Miller Alonso Camargo-Valero, Stephen R. Smith


      PubDate: 2017-06-10T12:48:55Z
      DOI: 10.1016/j.algal.2017.05.004
      Issue No: Vol. 24 (2017)
       
  • A perspective on renewable bioenergy from photosynthetic algae as
           feedstock for biofuels and bioproducts
    • Authors: Lieve M.L. Laurens; Melodie Chen-Glasser; James D. McMillan
      Pages: 261 - 264
      Abstract: Publication date: June 2017
      Source:Algal Research, Volume 24, Part A
      Author(s): Lieve M.L. Laurens, Melodie Chen-Glasser, James D. McMillan
      There has been substantial technical progress in developing algae-based bioenergy in recent years and a large part of industry and academic research and deployment projects have pivoted away from a pure biofuels strategy. This letter summarizes the findings of a recently completed, comprehensive report, that represents a collaborative effort of at least 20 co-authors, where we analyzed the prospects for using microalgae and macroalgae as feedstocks for biofuels and bioenergy production. The scope of this report includes a discussion of international activities advancing bioenergy and non-energy bioproducts from algae, progress on the use of macroalgae (both cast and cultivated seaweeds) for biogas applications, distinct biochemical and thermochemical conversion pathways, multi-product biorefining opportunities, as well as a thorough review of process economics and sustainability considerations. It is envisioned that a higher value algal biomass-based bioproducts industry will provide the additional revenue needed to reduce the net cost of producing algae-based biofuels. As such, a biorefinery approach that generates multiple high-value products from algae will be essential to fully valorize algal biomass and enable economically viable coproduction of bioenergy. To accelerate the implementation of algae-based production, minimizing energy, water, nutrients and land use footprints of integrated algae-based operations needs to be a primary objective of larger scale demonstrations and future research and development.

      PubDate: 2017-04-16T11:25:30Z
      DOI: 10.1016/j.algal.2017.04.002
      Issue No: Vol. 24 (2017)
       
  • Evaluation of an electro-flotation-oxidation process for harvesting
           bio-flocculated algal biomass and simultaneous treatment of residual
           pollutants in coke wastewater following an algal-bacterial process
    • Authors: Byung-Gon Ryu; Jungmin Kim; Jong-In Han; Kyochan Kim; Donghyun Kim; Bum-Kyoung Seo; Chang-Min Kang; Ji-Won Yang
      Abstract: Publication date: Available online 26 June 2017
      Source:Algal Research
      Author(s): Byung-Gon Ryu, Jungmin Kim, Jong-In Han, Kyochan Kim, Donghyun Kim, Bum-Kyoung Seo, Chang-Min Kang, Ji-Won Yang
      This study investigated the feasibility of employing an electro-flotation-oxidation process that employs a pair of boron-doped diamond (BDD) and aluminum (Al) electrodes for electrochemical harvesting of green microalgae (Scenedesmus quadricauda) and treatment of residual pollutants in coke effluent, following an algal-bacterial process. Electro-coagulation-flotation with polarity exchange and with direct electro-flotation at 15mAcm−2 or more for 40min allowed almost complete harvesting of microalgae. Similar harvesting efficiencies were achieved using direct electro-flotation, without electro-coagulation, under different electrical densities because algal biomass formed flocs with the other microorganisms in the activated sludge (AS). These results also indicate that the proposed approach of inducing bioaggregation via floc-forming microorganisms with microalgae is an efficient alternative to chemical flocculation, because it can minimize the release of toxic metal coagulants during electrochemical harvesting. During sequential electro-oxidation, anodic oxidation using the BDD electrode simultaneously mineralized residual soluble chemical oxygen demand (SCOD) and thiocyanate (SCN−), which are not degraded by algal-bacterial mixed cultures. Although the degradation rate of SCN− was much higher than that of SCOD under certain current densities, further investigation is needed to clarify the mechanism of SCN− mineralization during BDD-anodic oxidation. To satisfy the standard level of electrical power consumption for wastewater treatment, an electric current density below 15mAcm−2 must be supplied. The proposed electrochemical approach involving bioflocculation could be used as an efficient post treatment of microalgae-mediated process for treating coke wastewater.

      PubDate: 2017-06-27T07:36:48Z
      DOI: 10.1016/j.algal.2017.06.012
       
  • Inside Front Cover - Editorial Board Page/Cover image legend if applicable
    • Abstract: Publication date: June 2017
      Source:Algal Research, Volume 24, Part B


      PubDate: 2017-06-10T12:48:55Z
       
  • Post-extraction algal residue in beef steer finishing diets: I. Nutrient
           utilization and carcass characteristics
    • Authors: J.C. Morrill; J.E. Sawyer; S.B. Smith; R.K. Miller; J.R. Baber; T.A. Wickersham
      Abstract: Publication date: Available online 2 June 2017
      Source:Algal Research
      Author(s): J.C. Morrill, J.E. Sawyer, S.B. Smith, R.K. Miller, J.R. Baber, T.A. Wickersham
      In Part I of a two-part study, an experiment was conducted to determine effects of post-extraction algal residue (PEAR) inclusion on nutrient utilization and carcass characteristics in finishing steers. Eighteen Angus×Hereford steers (initial body weight=549±38.8kg) were randomly assigned to one of three treatments for the last 35days prior to harvest: PEAR added to the ration at 1.0kg organic matter (OM)/day (PEAR), or 1.0kg OM/day glucose infused ruminally (GR) or abomasally (GA). The basal diet consisted of a standard finishing ration with additional roughage provided in the diet to prevent sudden changes in intake as a result of infusion treatments. Greater dry matter intake (DMI) was observed for PEAR (13.0kg/d) than GR (10.3kg/d; P <0.05); DMI for steers receiving GA (11.2kg/d) was intermediate and not different from either PEAR or GR (P ≥0.14). Intake of digestible energy (DE) was similar among treatments (P =0.45) and averaged 36 Mcal/d as was digestible OM intake which averaged 8.8kg/d (P =0.51). Digestion of gross energy (GE) was 72.9, 82.6, and 80.9% for PEAR, GA, and GR, respectively (P <0.01). Digestion of neutral detergent fiber (NDF) was substantially less (55.7%) for PEAR than GA (75.4%) and GR (75.0%; P <0.01). Steers fed PEAR had greater marbling scores (Mt20) than GA (Sm63) and GR (Sm52; P =0.01). Accordingly, USDA Quality Grade was greater for PEAR than GA and GR (P =0.01; Ch40, Ch21, and Ch17, respectively). There was no difference in USDA Yield Grade or hot carcass weight (HCW) between treatments (P ≥0.66). In Part II, flavor and fatty acid composition of beef cuts from carcasses used in this study were assessed, and results are addressed in a separate publication.

      PubDate: 2017-06-06T12:25:52Z
      DOI: 10.1016/j.algal.2017.05.026
       
  • Response mechanism of the docosahexaenoic acid producer Aurantiochytrium
           under cold stress
    • Authors: Zengxin Miaomiao; Tian Yanzhen Tan Guzhen Cui Yingang Feng Qiu
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Zengxin Ma, Miaomiao Tian, Yanzhen Tan, Guzhen Cui, Yingang Feng, Qiu Cui, Xiaojin Song
      Aurantiochytrium is a commercial docosahexaenoic acid (DHA) producer, and its DHA content can be significantly increased under cold stress. Given this response to low temperature, we examined proteomics changes in Aurantiochytrium under cold stress. We detected approximately 700 protein spots using two-dimensional gels, whereas using iTRAQ technology, we detected 4650 types of proteins and successfully identified >53%. The results indicated that cold stress inhibits the cellular energy supply from glycolysis and the TCA cycle, to ensure a sufficient supply of NADPH and ribose for anabolism. In contrast, the pentose phosphate pathway was not affected. With respect to lipid synthesis, low temperature led to a significant down-regulation and up-regulation of fatty acid synthase and polyunsaturated fatty acid synthase, respectively, and restricted the protein synthesis of diacylglycerol O-acyltransferase and phospholipid: diacylglycerol acyltransferase. These results show the preferential biosynthesis of polyunsaturated fatty acids and phospholipids by Aurantiochytrium, which collectively serve to increase cell survival rates in cold environments.
      Graphical abstract image

      PubDate: 2017-05-26T15:12:03Z
       
  • A comparative analysis of biogas upgrading technologies: Photosynthetic vs
           physical/chemical processes
    • Authors: Alma Toledo-Cervantes; Estrada Raquel Lebrero
      Abstract: Publication date: July 2017
      Source:Algal Research, Volume 25
      Author(s): Alma Toledo-Cervantes, José M. Estrada, Raquel Lebrero, Raúl Muñoz
      Two biogas upgrading technologies, viz. an innovative algal-bacterial photobioreactor and a conventional activated carbon filter coupled with a water scrubber, were comparatively evaluated in terms of environmental, economic and social performance by using the IChemE Sustainability Metrics. The upgrading of 300Nm3/h of biogas generated from the anaerobic digestion of mixed sludge in a wastewater treatment plant was used as a model scenario for the comparative analysis. Despite the algal-bacterial photobioreactor entailed 1860 times higher land requirements, the two-stage physical/chemical technology exhibited ×3.8 higher energy consumptions and larger environmental impacts in terms of material and water consumption and greenhouse gas emissions (the latter by a factor of ~45). The investment cost for the algal-bacterial photobioreactor was 1.6 times higher than that of its physical/chemical counterpart due to the biomass drying unit required to produce an algae-based fertilizer. However, the operating cost of the physical/chemical technology was ~7 times higher due to the frequent replacement of the activated carbon. A further analysis of the net present value (NPV 20) revealed that photosynthetic upgrading would yield revenues from year 5 of operation mainly due to the sale of the algal bio-fertilizer produced, even without tax incentives for bio-methane.
      Graphical abstract image

      PubDate: 2017-05-26T15:12:03Z
       
  • Inside Front Cover - Editorial Board Page/Cover image legend if applicable
    • Abstract: Publication date: June 2017
      Source:Algal Research, Volume 24, Part A


      PubDate: 2017-05-26T15:12:03Z
       
 
 
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