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Publisher: Elsevier   (Total: 3043 journals)

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Showing 1 - 200 of 3043 Journals sorted alphabetically
AASRI Procedia     Open Access   (Followers: 15)
Academic Pediatrics     Hybrid Journal   (Followers: 22, SJR: 1.402, h-index: 51)
Academic Radiology     Hybrid Journal   (Followers: 21, SJR: 1.008, h-index: 75)
Accident Analysis & Prevention     Partially Free   (Followers: 84, SJR: 1.109, h-index: 94)
Accounting Forum     Hybrid Journal   (Followers: 25, SJR: 0.612, h-index: 27)
Accounting, Organizations and Society     Hybrid Journal   (Followers: 30, 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: 352, SJR: 0.726, h-index: 43)
Acta Automatica Sinica     Full-text available via subscription   (Followers: 3)
Acta Biomaterialia     Hybrid Journal   (Followers: 25, SJR: 2.02, h-index: 104)
Acta Colombiana de Cuidado Intensivo     Full-text available via subscription   (Followers: 1)
Acta de Investigación Psicológica     Open Access   (Followers: 2)
Acta Ecologica Sinica     Open Access   (Followers: 8, SJR: 0.172, h-index: 29)
Acta Haematologica Polonica     Free   (SJR: 0.123, h-index: 8)
Acta Histochemica     Hybrid Journal   (Followers: 3, SJR: 0.604, h-index: 38)
Acta Materialia     Hybrid Journal   (Followers: 235, 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: 10, SJR: 0.915, h-index: 53)
Acta Otorrinolaringologica (English Edition)     Full-text available via subscription   (Followers: 1)
Acta Otorrinolaringológica Española     Full-text available via subscription   (Followers: 3, SJR: 0.311, h-index: 16)
Acta Pharmaceutica Sinica B     Open Access   (Followers: 2)
Acta Poética     Open Access   (Followers: 4)
Acta Psychologica     Hybrid Journal   (Followers: 23, SJR: 1.365, h-index: 73)
Acta Sociológica     Open Access  
Acta Tropica     Hybrid Journal   (Followers: 6, SJR: 1.059, h-index: 77)
Acta Urológica Portuguesa     Open Access  
Actas Dermo-Sifiliograficas     Full-text available via subscription   (Followers: 4)
Actas Dermo-Sifiliográficas (English Edition)     Full-text available via subscription   (Followers: 3)
Actas Urológicas Españolas     Full-text available via subscription   (Followers: 4, SJR: 0.383, h-index: 19)
Actas Urológicas Españolas (English Edition)     Full-text available via subscription   (Followers: 2)
Actualites Pharmaceutiques     Full-text available via subscription   (Followers: 5, SJR: 0.141, h-index: 3)
Actualites Pharmaceutiques Hospitalieres     Full-text available via subscription   (Followers: 4, SJR: 0.112, h-index: 2)
Acupuncture and Related Therapies     Hybrid Journal   (Followers: 4)
Acute Pain     Full-text available via subscription   (Followers: 13)
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: 21)
Advanced Drug Delivery Reviews     Hybrid Journal   (Followers: 135, 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: 17, 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: 11, SJR: 0.801, h-index: 26)
Advances in Applied Microbiology     Full-text available via subscription   (Followers: 22, SJR: 1.286, h-index: 49)
Advances In Atomic, Molecular, and Optical Physics     Full-text available via subscription   (Followers: 16, SJR: 3.31, h-index: 42)
Advances in Biological Regulation     Hybrid Journal   (Followers: 4, SJR: 2.277, h-index: 43)
Advances in Botanical Research     Full-text available via subscription   (Followers: 3, SJR: 0.619, h-index: 48)
Advances in Cancer Research     Full-text available via subscription   (Followers: 25, SJR: 2.215, h-index: 78)
Advances in Carbohydrate Chemistry and Biochemistry     Full-text available via subscription   (Followers: 9, SJR: 0.9, h-index: 30)
Advances in Catalysis     Full-text available via subscription   (Followers: 5, SJR: 2.139, h-index: 42)
Advances in Cellular and Molecular Biology of Membranes and Organelles     Full-text available via subscription   (Followers: 12)
Advances in Chemical Engineering     Full-text available via subscription   (Followers: 26, 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: 9, SJR: 1.268, h-index: 45)
Advances in Clinical Chemistry     Full-text available via subscription   (Followers: 29, 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 Dermatology     Full-text available via subscription   (Followers: 12)
Advances in Developmental Biology     Full-text available via subscription   (Followers: 11)
Advances in Digestive Medicine     Open Access   (Followers: 6)
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: 41, 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: 41, SJR: 5.465, h-index: 64)
Advances in Exploration Geophysics     Full-text available via subscription   (Followers: 3)
Advances in Food and Nutrition Research     Full-text available via subscription   (Followers: 50, SJR: 0.674, h-index: 38)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 16)
Advances in Genetics     Full-text available via subscription   (Followers: 15, SJR: 2.558, h-index: 54)
Advances in Genome Biology     Full-text available via subscription   (Followers: 11)
Advances in Geophysics     Full-text available via subscription   (Followers: 6, SJR: 2.325, h-index: 20)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 22, SJR: 0.906, h-index: 24)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 9, SJR: 0.497, h-index: 31)
Advances in Imaging and Electron Physics     Full-text available via subscription   (Followers: 2, SJR: 0.396, h-index: 27)
Advances in Immunology     Full-text available via subscription   (Followers: 35, SJR: 4.152, h-index: 85)
Advances in Inorganic Chemistry     Full-text available via subscription   (Followers: 9, SJR: 1.132, h-index: 42)
Advances in Insect Physiology     Full-text available via subscription   (Followers: 3, SJR: 1.274, h-index: 27)
Advances in Integrative Medicine     Hybrid Journal   (Followers: 6)
Advances in Life Course Research     Hybrid Journal   (Followers: 8, SJR: 0.764, h-index: 15)
Advances in Lipobiology     Full-text available via subscription   (Followers: 2)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 9)
Advances in Marine Biology     Full-text available via subscription   (Followers: 16, SJR: 1.645, h-index: 45)
Advances in Mathematics     Full-text available via subscription   (Followers: 10, SJR: 3.261, h-index: 65)
Advances in Medical Sciences     Hybrid Journal   (Followers: 6, SJR: 0.489, h-index: 25)
Advances in Medicinal Chemistry     Full-text available via subscription   (Followers: 5)
Advances in Microbial Physiology     Full-text available via subscription   (Followers: 4, SJR: 1.44, h-index: 51)
Advances in Molecular and Cell Biology     Full-text available via subscription   (Followers: 22)
Advances in Molecular and Cellular Endocrinology     Full-text available via subscription   (Followers: 10)
Advances in Molecular Toxicology     Full-text available via subscription   (Followers: 7, SJR: 0.324, h-index: 8)
Advances in Nanoporous Materials     Full-text available via subscription   (Followers: 4)
Advances in Oncobiology     Full-text available via subscription   (Followers: 3)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 15, SJR: 2.885, h-index: 45)
Advances in Parallel Computing     Full-text available via subscription   (Followers: 7, SJR: 0.148, h-index: 11)
Advances in Parasitology     Full-text available via subscription   (Followers: 7, SJR: 2.37, h-index: 73)
Advances in Pediatrics     Full-text available via subscription   (Followers: 24, SJR: 0.4, h-index: 28)
Advances in Pharmaceutical Sciences     Full-text available via subscription   (Followers: 13)
Advances in Pharmacology     Full-text available via subscription   (Followers: 15, SJR: 1.718, h-index: 58)
Advances in Physical Organic Chemistry     Full-text available via subscription   (Followers: 8, 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: 17)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 20, SJR: 1.5, h-index: 62)
Advances in Psychology     Full-text available via subscription   (Followers: 61)
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: 3, SJR: 0.1, h-index: 2)
Advances in Space Research     Full-text available via subscription   (Followers: 353, SJR: 0.606, h-index: 65)
Advances in Structural Biology     Full-text available via subscription   (Followers: 8)
Advances in Surgery     Full-text available via subscription   (Followers: 7, SJR: 0.823, h-index: 27)
Advances in the Study of Behavior     Full-text available via subscription   (Followers: 30, SJR: 1.321, h-index: 56)
Advances in Veterinary Medicine     Full-text available via subscription   (Followers: 17)
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: 325, SJR: 0.816, h-index: 49)
AEU - Intl. J. of Electronics and Communications     Hybrid Journal   (Followers: 8, SJR: 0.318, h-index: 36)
African J. of Emergency Medicine     Open Access   (Followers: 5, SJR: 0.344, h-index: 6)
Ageing Research Reviews     Hybrid Journal   (Followers: 8, SJR: 3.289, h-index: 78)
Aggression and Violent Behavior     Hybrid Journal   (Followers: 406, SJR: 1.385, h-index: 72)
Agri Gene     Hybrid Journal  
Agricultural and Forest Meteorology     Hybrid Journal   (Followers: 16, SJR: 2.18, h-index: 116)
Agricultural Systems     Hybrid Journal   (Followers: 30, SJR: 1.275, h-index: 74)
Agricultural Water Management     Hybrid Journal   (Followers: 39, 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: 54, 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: 11, SJR: 0.922, h-index: 66)
Alcoholism and Drug Addiction     Open Access   (Followers: 8)
Alergologia Polska : Polish J. of Allergology     Full-text available via subscription   (Followers: 1)
Alexandria Engineering J.     Open Access   (Followers: 1, SJR: 0.436, h-index: 12)
Alexandria J. of Medicine     Open Access  
Algal Research     Partially Free   (Followers: 8, SJR: 2.05, h-index: 20)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 3)
Allergologia et Immunopathologia     Full-text available via subscription   (Followers: 1, SJR: 0.46, h-index: 29)
Allergology Intl.     Open Access   (Followers: 4, SJR: 0.776, h-index: 35)
Alpha Omegan     Full-text available via subscription   (SJR: 0.121, h-index: 9)
ALTER - European J. of Disability Research / Revue Européenne de Recherche sur le Handicap     Full-text available via subscription   (Followers: 8, SJR: 0.158, h-index: 9)
Alzheimer's & Dementia     Hybrid Journal   (Followers: 48, SJR: 4.289, h-index: 64)
Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring     Open Access   (Followers: 6)
Alzheimer's & Dementia: Translational Research & Clinical Interventions     Open Access   (Followers: 5)
American Heart J.     Hybrid Journal   (Followers: 49, SJR: 3.157, h-index: 153)
American J. of Cardiology     Hybrid Journal   (Followers: 47, SJR: 2.063, h-index: 186)
American J. of Emergency Medicine     Hybrid Journal   (Followers: 39, SJR: 0.574, h-index: 65)
American J. of Geriatric Pharmacotherapy     Full-text available via subscription   (Followers: 8, 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: 31, SJR: 8.769, h-index: 256)
American J. of Infection Control     Hybrid Journal   (Followers: 25, 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: 45, 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: 233, SJR: 2.255, h-index: 171)
American J. of Ophthalmology     Hybrid Journal   (Followers: 58, SJR: 2.803, h-index: 148)
American J. of Ophthalmology Case Reports     Open Access   (Followers: 5)
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: 25, SJR: 0.59, h-index: 45)
American J. of Pathology     Hybrid Journal   (Followers: 26, SJR: 2.653, h-index: 228)
American J. of Preventive Medicine     Hybrid Journal   (Followers: 22, SJR: 2.764, h-index: 154)
American J. of Surgery     Hybrid Journal   (Followers: 34, SJR: 1.286, h-index: 125)
American J. of the Medical Sciences     Hybrid Journal   (Followers: 12, SJR: 0.653, h-index: 70)
Ampersand : An Intl. J. of General and Applied Linguistics     Open Access   (Followers: 5)
Anaerobe     Hybrid Journal   (Followers: 4, SJR: 1.066, h-index: 51)
Anaesthesia & Intensive Care Medicine     Full-text available via subscription   (Followers: 57, SJR: 0.124, h-index: 9)
Anaesthesia Critical Care & Pain Medicine     Full-text available via subscription   (Followers: 11)
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: 4, SJR: 2.577, h-index: 7)
Analytica Chimica Acta     Hybrid Journal   (Followers: 37, SJR: 1.548, h-index: 152)
Analytical Biochemistry     Hybrid Journal   (Followers: 167, SJR: 0.725, h-index: 154)
Analytical Chemistry Research     Open Access   (Followers: 8, SJR: 0.18, h-index: 2)
Analytical Spectroscopy Library     Full-text available via subscription   (Followers: 11)
Anesthésie & Réanimation     Full-text available via subscription   (Followers: 1)
Anesthesiology Clinics     Full-text available via subscription   (Followers: 22, SJR: 0.421, h-index: 40)
Angiología     Full-text available via subscription   (SJR: 0.124, h-index: 9)
Angiologia e Cirurgia Vascular     Open Access  
Animal Behaviour     Hybrid Journal   (Followers: 161, SJR: 1.907, h-index: 126)
Animal Feed Science and Technology     Hybrid Journal   (Followers: 5, SJR: 1.151, h-index: 83)
Animal Reproduction Science     Hybrid Journal   (Followers: 5, SJR: 0.711, h-index: 78)
Annales d'Endocrinologie     Full-text available via subscription   (Followers: 1, SJR: 0.394, h-index: 30)
Annales d'Urologie     Full-text available via subscription  
Annales de Cardiologie et d'Angéiologie     Full-text available via subscription   (SJR: 0.177, h-index: 13)
Annales de Chirurgie de la Main et du Membre Supérieur     Full-text available via subscription  
Annales de Chirurgie Plastique Esthétique     Full-text available via subscription   (Followers: 2, SJR: 0.354, h-index: 22)
Annales de Chirurgie Vasculaire     Full-text available via subscription   (Followers: 1)

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Journal Cover Algal Research
  [SJR: 2.05]   [H-I: 20]   [8 followers]  Follow
    
   Partially Free Journal Partially Free Journal
   ISSN (Online) 2211-9264
   Published by Elsevier Homepage  [3043 journals]
  • Phlorotannin extracts from Fucales: Marine polyphenols as bioregulators
           engaged in inflammation-related mediators and enzymes
    • Authors: Mariana Barbosa; Graciliana Lopes; Federico Ferreres; Paula B. Andrade; David M. Pereira; Ángel Gil-Izquierdo; Patrícia Valentão
      Pages: 1 - 8
      Abstract: Publication date: December 2017
      Source:Algal Research, Volume 28
      Author(s): Mariana Barbosa, Graciliana Lopes, Federico Ferreres, Paula B. Andrade, David M. Pereira, Ángel Gil-Izquierdo, Patrícia Valentão
      Phlorotannins are widely recognized as an inexhaustible family of naturally occurring molecules, with great potential in food and pharmaceutical industries. The present work explores the anti-inflammatory activity of phlorotannins from different Fucus species native from the Northern Atlantic coast, and from Fucus vesiculosus Linnaeus grown in an integrated multi-trophic aquaculture (IMTA) system, all scarcely studied regarding these compounds. Purified phlorotannin extracts were evaluated for their toxicity and anti-inflammatory potential in both cell (RAW 264.7 macrophages) and cell-free systems [lipoxygenase (LOX) inhibition and nitric oxide radical (NO) scavenging activity]. Phlorotannin content ranged between 110.28 and 288.36μgofphloroglucinol equivalents(PGE)/100mg dry purified extract (DE), wild species presenting higher content than those from IMTA. Regarding LOX, a strong correlation (r =−0.9118; p <0.0001) between the IC50 values and total phlorotannin content was found, Fucus guiryi G.I. Zardi, K.R. Nicastro, E.S. Serrão & G.A. Pearson exhibiting the best inhibitory capacity (IC50 =82.10μg/mL), while F. vesiculosus from IMTA was the less effective (IC50 >500μg/mL). Correlation was also observed for NO scavenging (r =−0.6363; p =0.0108). The anti-inflammatory capacity of phlorotannin extracts was further evaluated using RAW 264.7 macrophages stimulated with bacterial lipopolysaccharide, as model of inflammation. The extracts studied were not toxic at the tested concentrations (31.25–500μg/mL). F. vesiculosus from wild origin was the most effective in reducing NO in cell culture medium (IC25 =56.52μg/mL), closely followed by other seaweed species under study. The IMTA species was the less effective one (IC25 =317.41μg/mL). According to the results obtained, phlorotannin extracts from Fucales arise as potentially beneficial in inflammation-related conditions, effectively acting upon enzymatic and non-enzymatic inflammatory targets.
      Graphical abstract image

      PubDate: 2017-10-12T17:18:50Z
      DOI: 10.1016/j.algal.2017.09.009
      Issue No: Vol. 28 (2017)
       
  • Biological synthesis of gold nanoparticles by the diatom Stephanopyxis
           turris and in vivo SERS analyses
    • Authors: Nathalie Pytlik; Janine Kaden; Matthias Finger; Julia Naumann; Stefan Wanke; Susanne Machill; Eike Brunner
      Pages: 9 - 15
      Abstract: Publication date: December 2017
      Source:Algal Research, Volume 28
      Author(s): Nathalie Pytlik, Janine Kaden, Matthias Finger, Julia Naumann, Stefan Wanke, Susanne Machill, Eike Brunner
      Cultivation of the sea water diatom Stephanopyxis turris (S. turris) in a gold salt containing medium leads to the formation of gold nanoparticles. These biosynthesized nanoparticles were characterized using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), and selected area electron diffraction (SAED). According to their diameter, they are classified into two groups with average diameters of around 30 and 10nm. It is demonstrated that both types of nanoparticles consist exclusively of gold. The location of the gold nanoparticles with respect to the diatom cell was revealed using surface enhanced Raman scattering (SERS). To ensure a reliable observation of SERS spectra in each measured cell, the concentration of the gold solution as well as the incubation time of S. turris in this solution were optimized. 3D Raman imaging of entire S. turris cells was performed to localize SERS spectra of compounds resulting from closely neighbored nanoparticles. Interestingly, intracellular SERS spectra were observed indicating the presence of gold nanoparticles inside S. turris cells. Further investigation shows that the SERS spectra generated by biosynthesized nanoparticles differ significantly from the conventional Raman spectrum of diatoms. While pigments are dominating the resonance enhanced Raman spectrum, SERS spectra exhibit a completely different appearance. Their bands coincide with bands in SERS spectra of various biologically relevant compounds, e.g., hydroxyurea and retinol. The biosynthesized gold nanoparticles therefore have a high potential for prospective in vivo research of algal metabolism and its regulation.
      Graphical abstract image

      PubDate: 2017-10-13T17:22:04Z
      DOI: 10.1016/j.algal.2017.10.004
      Issue No: Vol. 28 (2017)
       
  • Facile production of seaweed-based biomaterials with antioxidant and
           anti-inflammatory activities
    • Authors: Susana Guzman-Puyol; Debora Russo; Ilaria Penna; Luca Ceseracciu; Francisco Palazon; Alice Scarpellini; Roberto Cingolani; Rosalia Bertorelli; Ilker S. Bayer; José A. Heredia-Guerrero; Athanassia Athanassiou
      Pages: 1 - 11
      Abstract: Publication date: November 2017
      Source:Algal Research, Volume 27
      Author(s): Susana Guzman-Puyol, Debora Russo, Ilaria Penna, Luca Ceseracciu, Francisco Palazon, Alice Scarpellini, Roberto Cingolani, Rosalia Bertorelli, Ilker S. Bayer, José A. Heredia-Guerrero, Athanassia Athanassiou
      New seaweed-based biomaterials have been prepared using a simple method based on the selective dissolution in trifluoroacetic acid (TFA) of specific polymers and bioactive substances from red, green, and brown seaweeds. Depending on the seaweed's origin, the properties were found to be different, especially the mechanical ones. Furthermore, the samples were fully biodegradable in seawater in one month. Moreover, the antioxidant capacity of the biomaterials was highly increased respect to the pristine materials, demonstrating a selective extraction during the process of solubilization. Finally, biocompatibility and anti-inflammatory experiments demonstrated the non-toxicity of the biomaterials prepared from brown seaweed and a similar anti-inflammatory effect to commercial available drugs, confirming the potential application of the prepared biomaterials for the fabrication of biomedical devices.
      Graphical abstract image

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

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

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

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

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

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

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

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

      PubDate: 2017-08-21T16:47:00Z
      DOI: 10.1016/j.algal.2017.08.022
      Issue No: Vol. 27 (2017)
       
  • The comparative study for physiological and biochemical mechanisms of
           Thalassiosira pseudonana and Chaetoceros calcitrans in response to
           different light intensities
    • Authors: Runtao Zhang; Zhouyan Kong; Sihan Chen; Zhaoshou Ran; Mengwei Ye; Jilin Xu; Chengxu Zhou; Kai Liao; Jiayi Cao; Xiaojun Yan
      Pages: 89 - 98
      Abstract: Publication date: November 2017
      Source:Algal Research, Volume 27
      Author(s): Runtao Zhang, Zhouyan Kong, Sihan Chen, Zhaoshou Ran, Mengwei Ye, Jilin Xu, Chengxu Zhou, Kai Liao, Jiayi Cao, Xiaojun Yan
      Both Thalassiosira pseudonana and Chaetoceros calcitrans are important species of marine microalgae. Their adaptive capacity to light intensity significantly varies during actual cultivation. We investigated the responses of these two species to different light intensities at 25°C through analyses of photoacclimation, antioxidant ability as well as many physiological and biochemical parameters. The growth rate of T. pseudonana was positively correlated with light intensity in the first 8days. However, after that, the greatest growth rate of T. pseudonana was found at a light intensity of 40μmolm−2 s−1. For C. calcitrans, the growth rate at 200μmolm−2 s−1 was the highest among the three light intensities in the first 10days, while the growth rate at 120μmolm−2 s−1 became the highest after 10days. Both algae could yield the most chlorophyll a at 40μmolm−2 s−1, and β-carotene content was increased in T. pseudonana but decreased in C. calcitrans with the increase of light intensity. Moreover, maximal photochemical efficiency of PSII (Fv/Fm) and effective photochemical efficiency of PSII (Fv′/Fm′) in T. pseudonana were decreased with the increase of light intensity, while non-photochemical quenching (NPQ) and superoxide dismutase (SOD) activities were increased. However, Fv/Fm and Fv′/Fm′ in C. calcitrans under all light intensities remained relatively constant, and Fv/Fm was maintained at around 0.6. NPQ was increased and SOD activity was decreased in C. calcitrans with the increase of light intensity. These findings suggested that T. pseudonana employed a more positive physiological strategy for adaptation to environmental stress under low light intensity, while C. calcitrans possessed a good physiological strategy for adaptation to environmental stress under high light intensity. Taken together, we provided a better understanding of the growth effects of these two microalgae under different light intensities and offered novel insights into their mass culture.

      PubDate: 2017-08-31T17:27:16Z
      DOI: 10.1016/j.algal.2017.08.026
      Issue No: Vol. 27 (2017)
       
  • Long-chain poly-arginine functionalized porous Fe3O4 microspheres as
           magnetic flocculant for efficient harvesting of oleaginous microalgae
    • Authors: Pei-Rui Liu; Ting Wang; Zi-Yu Yang; Yu Hong; Yang-Long Hou
      Pages: 99 - 108
      Abstract: Publication date: November 2017
      Source:Algal Research, Volume 27
      Author(s): Pei-Rui Liu, Ting Wang, Zi-Yu Yang, Yu Hong, Yang-Long Hou
      Considering the porous characteristics of magnetic porous Fe3O4 microspheres, this study aims to utilize long-chain poly-arginine (PA) to obtain PA-modified porous Fe3O4 microspheres (p-Fe3O4@PA). The microspheres possessed a loose porous structure on the surface, and the average pore size was 224.2Å. The harvesting efficiency for Chlorella sp. HQ improved markedly compared with that of p-Fe3O4 after modification with three PAs with different molecular weights. p-Fe3O4@PA-2 (PA molecular weight: 15,000–70,000) had the best performance with a decreasing dosage from 300mgL−1 to 10mgL−1. The results indicated that PA modification at a higher molecular weight could promote microalgae adsorption, whereas PA modification of an excessively high molecular weight (>70,000) was not conducive to microalgae harvesting. The modification percentage of p-Fe3O4@PA (57.9%) provided abundant adsorption media and active sites for Chlorella sp. HQ adsorption. Bridging flocculation and hydrogen bonding between Chlorella sp. HQ and p-Fe3O4@PA greatly enhanced harvesting efficiency. In addition, the p-Fe3O4@PA could maintain good cycling stability because of the relatively large size of the microspheres.
      Graphical abstract image

      PubDate: 2017-08-31T17:27:16Z
      DOI: 10.1016/j.algal.2017.08.025
      Issue No: Vol. 27 (2017)
       
  • 2D dielectrophoretic signature of Coscinodiscus wailesii algae in
           non-uniform electric fields
    • Authors: Rajeshwari Taruvai Kalyana Kumar; Pradyotha Kanchustambham; David Kinnamon; Shalini Prasad
      Pages: 109 - 114
      Abstract: Publication date: November 2017
      Source:Algal Research, Volume 27
      Author(s): Rajeshwari Taruvai Kalyana Kumar, Pradyotha Kanchustambham, David Kinnamon, Shalini Prasad
      This paper investigates the 2D dielectrophoretic signature of a unicellular centric green alga, Coscinodiscus wailesii, in non-uniform electric fields. The electrokinetic response was studied as a function of applied signal frequency and voltage. The effective permittivity of the diatoms was studied through mathematical simulation resulting in analyzing the diatoms' frequency response. Three different types of dielectrophoretic responses were measured and analyzed (i) lateral displacement of cells, movement of diatoms in a particular direction based on their dielectric polarizability, (ii) dielectrophoretic force, the translational force experienced by the diatoms as a result of applied non-uniform electric fields and (iii) translational dielectrophoretic velocity, the speed at which the diatoms move either towards or away from strong electric fields. The approaches discussed in this paper will improve the predictability of the dielectric properties of the diatoms using a combination of these parameters. The calibration of the physical diatom model to the experimental data results in the estimation of their dielectrophoretic behavior depending on the geometric structure of the diatom model. This method offers a practical means of label-free manipulation of diatoms and for rapid screening for environmental effects on the dielectric properties of algal cells.

      PubDate: 2017-09-06T17:35:55Z
      DOI: 10.1016/j.algal.2017.08.031
      Issue No: Vol. 27 (2017)
       
  • Harvesting of algae in municipal wastewater treatment by calcium phosphate
           precipitation mediated by photosynthesis, sodium hydroxide and lime
    • Authors: J. Phasey; D. Vandamme; H.J. Fallowfield
      Pages: 115 - 120
      Abstract: Publication date: November 2017
      Source:Algal Research, Volume 27
      Author(s): J. Phasey, D. Vandamme, H.J. Fallowfield
      The cultivation of microalgae within municipal and agricultural wastewater offers the opportunity to treat the water and partition nutrients into valuable biomass. Harvesting of those algae is a challenge, as conventional coagulants (iron and aluminum salts) contaminate algae and lock up phosphorus preventing beneficial reuse. We show that flocculation by calcium phosphate precipitation is capable of harvesting algae and phosphate from municipal wastewater in a form suitable for reuse. However, the initiation of flocculation by natural pH increase was infeasible. We harvested 93% of algal solids with an initial concentration of 113mg VSS/L and 96% of total phosphate from a waste stabilization pond effluent by initiating flocculation with 129mg-P/L of soluble phosphate and addition of 364mg/L quicklime to achieve a pH of 10.0, at a calculated cost of $0.05 USD per kL for alkali addition, which is similar to the chemical addition costs of conventional coagulation.

      PubDate: 2017-09-11T07:07:57Z
      DOI: 10.1016/j.algal.2017.06.015
      Issue No: Vol. 27 (2017)
       
  • Microbial community characterization during anaerobic digestion of
           Scenedesmus spp. under mesophilic and thermophilic conditions
    • Authors: Silvia Greses; John Christian Gaby; Daniel Aguado; José Ferrer; Aurora Seco; Svein Jarle Horn
      Pages: 121 - 130
      Abstract: Publication date: November 2017
      Source:Algal Research, Volume 27
      Author(s): Silvia Greses, John Christian Gaby, Daniel Aguado, José Ferrer, Aurora Seco, Svein Jarle Horn
      Microbial communities were thoroughly characterized in a mesophilic anaerobic membrane bioreactor (AnMBR) and a thermophilic continuous stirred tank reactor (CSTR), which were both treating recalcitrant microalgal biomass dominated by Scenedesmus. 16S rRNA amplicon sequencing analysis was performed when the AnMBR achieved 70% algal biodegradation and revealed high microbial diversity, probably due to the high solid retention time (SRT) of the AnMBR configuration. The bacterial community consisted of Chloroflexi (27.9%), WWE1 (19.0%) and Proteobacteria (15.4%) as the major phyla, followed by Spirochaetes (7.7%), Bacteroidetes (5.9%) and Firmicutes (3.6%). These phyla are known to exhibit proteolytic and cellulolytic capabilities required to degrade the Scenedesmus cell-wall. Methanosaeta was the most abundant methanogen detected in the AnMBR suggesting that methane was mainly produced by the acetoclastic pathway. In comparison, the thermophilic CSTR achieved 32.6% algal biodegradation, and its bacterial community had fewer Operational Taxonomic Units (977 OTUs) than the AnMBR (1396 OTUs), as is generally observed for high temperature biogas reactors. However, phyla with high hydrolytic potential were detected such as Firmicutes (34.6%) and the candidate taxon EM3 (38.7%) in the thermophilic CSTR. Although the functional metabolism of EM3 in anaerobic digesters is unknown, the high abundance of EM3 suggests that this taxon plays an important role in the thermophilic, anaerobic degradation of Scenedesmus. The abundant syntrophic bacteria and the detection of hydrogenotrophic methanogens in the thermophilic CSTR suggest that the hydrogenotrophic pathway was the dominant pathway for methane production in this reactor.

      PubDate: 2017-09-11T07:07:57Z
      DOI: 10.1016/j.algal.2017.09.002
      Issue No: Vol. 27 (2017)
       
  • Inhibitory effect of benthic diatom species on three aquaculture
           pathogenic vibrios
    • Authors: Ceres A. Molina-Cárdenas; M. del Pilar Sánchez-Saavedra
      Pages: 131 - 139
      Abstract: Publication date: November 2017
      Source:Algal Research, Volume 27
      Author(s): Ceres A. Molina-Cárdenas, M. del Pilar Sánchez-Saavedra


      PubDate: 2017-09-11T07:07:57Z
      DOI: 10.1016/j.algal.2017.09.004
      Issue No: Vol. 27 (2017)
       
  • A comprehensive assessment of the biosynthetic pathways of ascorbate,
           
    • Authors: Mafruha T. Hasan; Angela Sun; Mehdi Mirzaei; Junior Te'o; Graham Hobba; Anwar Sunna; Helena Nevalainen
      Pages: 140 - 151
      Abstract: Publication date: November 2017
      Source:Algal Research, Volume 27
      Author(s): Mafruha T. Hasan, Angela Sun, Mehdi Mirzaei, Junior Te'o, Graham Hobba, Anwar Sunna, Helena Nevalainen
      Euglena gracilis produces several important health-enhancing metabolites including ascorbate, α-tocopherol and free amino acids (faa). The yield of metabolites is dependent on the strain of E. gracilis and the metabolic growth condition. Here we investigated the effects of photoautotrophic (PT), mixotrophic (MT) and heterotrophic (HT) cultivation on the synthesis of ascorbate, α-tocopherol and faa in E. gracilis var. saccharophila, using label-free shotgun proteomics, and metabolite analysis using colourimetric assay, high-performance and ultra-performance liquid chromatography (HPLC/UPLC). PT cultivation resulted in the production of more antioxidants (up to 4.13mgg−1 ascorbate and 2.52mgg−1 α-tocopherol) than the MT and HT growth conditions (up to 0.97 and 0.50mgg−1 ascorbate, and 1.40 and 0.21mgg−1 α-tocopherol, respectively). The relative abundance of several faa varied between mid-log and initial stationary growth phases, but the total amount of faa remained about the same, with arginine as the most abundant amino acid. Proteomic analysis revealed a total of 3843 non-redundant proteins in E. gracilis var. saccharophila, of which 1890 were common among all cultivations. Gene ontology annotations suggested derivatisation of metabolic pathways from different organisms, such as lysine biosynthesis from fungi and serine biosynthesis from plants, while a few pathways were unique to Euglena, such as those of ascorbate and arginine. Some enzymes exhibited several isoforms that were influenced by the metabolic growth condition. For example, one of the isozymes of threonine aldolase was expressed in HT/MT cultures only, and one of the isozymes of phosphoglycerate dehydrogenase was expressed in PT cultures only. This is the first proteomic study of E. gracilis var. saccharophila, which provides a mechanistic insight into the biosynthetic pathway dynamics of primary metabolites (antioxidants and faa). This new information can serve as a framework for further development of Euglena as a producer of nutraceuticals.

      PubDate: 2017-09-11T07:07:57Z
      DOI: 10.1016/j.algal.2017.08.029
      Issue No: Vol. 27 (2017)
       
  • Precise excision of a selectable marker gene in transgenic Coccomyxa
           strains by the piggyBac transposase
    • Authors: Yuki Kasai; Kenta Matsuzaki; Fukiko Ikeda; Yuya Yoshimitsu; Shigeaki Harayama
      Pages: 152 - 161
      Abstract: Publication date: November 2017
      Source:Algal Research, Volume 27
      Author(s): Yuki Kasai, Kenta Matsuzaki, Fukiko Ikeda, Yuya Yoshimitsu, Shigeaki Harayama
      The piggyBac transposon isolated from the cabbage looper moth Trichoplusia ni, is integrated into the host genome, and then excised from it without leaving a footprint. The piggyBac transposon system has been used as a genomic engineering tool in a variety of organisms. In this study, we used two improved versions of the piggyBac transposase (PBase) to create marker-free transgenic strains of the unicellular green alga Coccomyxa sp. strain KJ as follows: Uracil-auxotrophic (Ura−) mutants of strain KJ defective in the gene for uridine monophosphate synthase (KJUMPS) were isolated on agar plates containing 5-fluoroorotic acid. Subsequently, cDNA of KJUMPS (cKJUMPS) was cloned between the promoter and terminator of the elongation factor 1 alpha gene to construct a cKJUMPS expression cassette. A DNA fragment carrying the cKJUMPS expression cassette flanked with piggyBac transposon terminal repeats was then constructed (TR_cKJUMPS) and introduced into an Ura− mutant, and Ura+ transformants were isolated. One of the Ura+ transformants was named strain TR2-7. Hyperactive PBase (hyPBase) is a mutant PBase with increased excision and integration frequencies. Herein, we synthesized a coding sequence for hyPBase (KJhyPBase), which has optimized codons for expression in strain KJ, and its expression cassette was introduced into strain TR2-7. Fourteen transformants stably carried the KJhyPBase expression cassette, and TR_cKJUMPS was excised from seven of these. We also introduced an expression cassette of KJhyPBase_Ex, which encodes the excision-competent/integration-defective R372A/K375A/D450N mutant of KJhyPBase (KJhyPBase_Ex), into strain TR2-7, and found that the excision frequency of TR_cKJUMPS in KJhyPBase_Ex transformants was significantly higher than that in KJhyPBase transformants. In further experiments, we purified His-tagged KJhyPBase_Ex, and transfected it into strain TR2-7 using electroporation. Under these conditions, TR_cKJUMPS was precisely excised at a frequency of 8.8×10−8 cell−1. The present data extend applications of the present piggyBac transposase-catalyzed excision system in green algae.

      PubDate: 2017-09-17T07:27:13Z
      DOI: 10.1016/j.algal.2017.09.007
      Issue No: Vol. 27 (2017)
       
  • Lipid turnover between membrane lipids and neutral lipids via inhibition
           of diacylglyceryl N,N,N-trimethylhomoserine synthesis in Chlamydomonas
           reinhardtii
    • Authors: Jun-Woo Lee; Sang-Yoon Shin; Hee-Sik Kim; EonSeon Jin; Hyung-Gwan Lee; Hee-Mock Oh
      Pages: 162 - 169
      Abstract: Publication date: November 2017
      Source:Algal Research, Volume 27
      Author(s): Jun-Woo Lee, Sang-Yoon Shin, Hee-Sik Kim, EonSeon Jin, Hyung-Gwan Lee, Hee-Mock Oh
      Chlamydomonas reinhardtii of the microalgal model species lacks phosphatidylcholine (PC), and PC is replaced by diacylglyceryl N,N,N-trimethylhomoserine (DGTS). DGTS is a betaine lipid that is placed in the endoplasmic reticulum (ER) and is synthesized by a single gene, BTA1. In this study, we aimed to ascertain the turnover between membrane and neutral lipids via BTA1 knockdown transformants. Transgenic lines CrBta-hm13 and CrBta-hm31 were 80% and 60% downregulated in BTA1 gene expression levels, respectively. Both transformants had half the amount of DGTS, which coincided with decreased monogalactosyldiacylglycerol (MGDG), which was increased approximately threefold in neutral lipids. While the reduction of DGTS was shown to arise from inhibition of DGTS synthesis, decreased MGDG was affected by internal stress, such as ER stress, which was induced to have a decreased amount of DGTS in the ER. However, galactolipids, except for MGDG, and phospholipids in the transformants were maintained at similar levels. In the transformants, the molar proportion of C16:4 and C18:3(9,12,15), which are the major fatty acids of MGDG, was significantly increased in triacylglycerol (TAG) because of MGDG degradation. Thus, lipid turnover arising from the downregulation of DGTS and induction of ER stress caused a decrease in DGTS and MGDG, which generated a synergy effect on the accumulation of TAG. This study implies that genetic modification of a membrane lipid synthesis pathway could not only be a suitable approach to target accumulation of TAG, but could also suggest a mechanism for the lipid turnover between membrane lipids and neutral lipids.

      PubDate: 2017-09-17T07:27:13Z
      DOI: 10.1016/j.algal.2017.09.001
      Issue No: Vol. 27 (2017)
       
  • Effect of permeate recycling and light intensity on growth kinetics of
           Synechocystis sp. PCC 6803
    • Authors: Jae-Hoon Hwang; Bruce E. Rittmann
      Pages: 170 - 176
      Abstract: Publication date: November 2017
      Source:Algal Research, Volume 27
      Author(s): Jae-Hoon Hwang, Bruce E. Rittmann
      Permeate reuse for cultivating Synechocystis sp. PCC 6803 was studied in batch photosynthetic-growth experiments having a wide range of the ratio of membrane permeate to BG-11 medium. The 50% dilution of permeate gave the greatest biomass concentration and specific growth rate for Synechocystis, but up to 100% permeate had minimal impact on biomass growth; thus, a high ratio of permeate supported good growth of Synechocystis. With initial values of the spatially averaged light intensity (LISA) ranging from 49 to 479μEm−2 s−1, Synechocystis exhibited typical photo-inhibition growth kinetics in 50% permeate. The half-maximum-rate light irradiance (KL) was 39μEm−2 s−1, and the half-inhibition-rate light irradiance (KI) was 281μEm−2 s−1. The KI value is larger than seen previously for Synechocystis in BG-11 medium, which suggests that culturing in permeate may have made Synechocystis less sensitive to photo-inhibition. The exponential growth rate of Synechocystis sp. PCC 6803 was not inhibited by recycled permeate through multiple rounds of growth in 50% permeate. These results demonstrate that permeate recycling is a feasible strategy for reusing nutrients and minimizing water loss.

      PubDate: 2017-09-17T07:27:13Z
      DOI: 10.1016/j.algal.2017.09.008
      Issue No: Vol. 27 (2017)
       
  • Effects of growth phase and nitrogen limitation on biochemical composition
           of two strains of Tisochrysis lutea
    • Authors: Fiz da Costa; Fabienne Le Grand; Claudie Quéré; Gaël Bougaran; Jean Paul Cadoret; René Robert; Philippe Soudant
      Pages: 177 - 189
      Abstract: Publication date: November 2017
      Source:Algal Research, Volume 27
      Author(s): Fiz da Costa, Fabienne Le Grand, Claudie Quéré, Gaël Bougaran, Jean Paul Cadoret, René Robert, Philippe Soudant
      Standard and mutant Tisochrysis lutea strains were grown in batch culture for 10days under nitrogen (N)-replete and N-reduced conditions to determine the effects of N supply in culture medium and growth phase on microalgal physiology and biochemistry. These two T. lutea strains were compared in terms of growth, morphology, associated free-living bacterial community, viability, intracellular lipid content (as measured by Bodipy staining), chlorophyll autofluorescence, and biochemical composition, with a focus on lipid class and fatty acid compositions. The standard strain (T) reached higher cell counts regardless of N supply in culture medium. In both T. lutea strains, microalgal final cell density was significantly lower in N-reduced medium. Carbohydrates were enhanced at stationary phase in both strains, regardless of N supply. The oleaginous strain (T+) accumulated triacylglycerols; whereas, the standard strain T accumulated alkenones as reserve lipids, especially in N-reduced medium and stationary phase. Each T. lutea strain exhibited an intrinsic specific FA profile in neutral lipids (NL) and, to a lesser extent, in polar lipids (PL) independent of N supply and growth phase. T+ contained more saturated and monounsaturated fatty acids (especially 14:0 and 18:1n-9), but less polyunsaturated fatty acids (18:4n-3 and 22:6n-3) than T. Overall, growth phase induced more changes in fatty acid profiles of both T. lutea strains in NL and PL than N supply in culture medium.

      PubDate: 2017-09-17T07:27:13Z
      DOI: 10.1016/j.algal.2017.09.003
      Issue No: Vol. 27 (2017)
       
  • Attached microalgae cultivation and nutrients removal in a novel
           capillary-driven photo-biofilm reactor
    • Authors: Xue-Qiao Xu; Jing-Han Wang; Tian-Yuan Zhang; Guo-Hua Dao; Guang-Xue Wu; Hong-Ying Hu
      Pages: 198 - 205
      Abstract: Publication date: November 2017
      Source:Algal Research, Volume 27
      Author(s): Xue-Qiao Xu, Jing-Han Wang, Tian-Yuan Zhang, Guo-Hua Dao, Guang-Xue Wu, Hong-Ying Hu
      Microalgae cultivation is a promising candidate for autotrophic sequestrating CO2 transformation into renewable bio-products. However, potential of microalgae has not been fully explored due to the bottlenecks of biomass harvesting during large-scale microalgae cultivation. A novel capillary-driven photobioreactor (CPBR) is proposed in this study for attached microalgae cultivation obtaining high biomass productivity and overcoming the biomass harvesting limitation in traditional suspended cultures. Performances on microalgal growth, cellular composition, nutrients uptake from water, and corresponding light utilization efficiencies were investigated and emphasized. During 12days of system operation, attached microalgal biomass on the carriers were in the range of 83.6g/m2-footprint area of 121.5g/m2-footprint area, corresponding to light utilization efficiency of 3.3% to 4.8%. With proper carriers packing density of 16% to 32%, obtained biomass productivities of CPBR were approximately 10g/m2/d (footprint area). Biomass composition analysis revealed that lipid and carbohydrates contents in attached microalgal biomass were higher than in suspended microalgal biomass with same cultivating conditions, proving the potential of microalgae cultivated in CPBR as feedstock of biofuels.

      PubDate: 2017-09-23T11:25:29Z
      DOI: 10.1016/j.algal.2017.08.028
      Issue No: Vol. 27 (2017)
       
  • Enhancement of biogas production from Ulva sp. by using solid-state
           fermentation as biological pretreatment
    • Authors: Nesrine Ben Yahmed; Hélène Carrere; M. Nejib Marzouki; Issam Smaali
      Pages: 206 - 214
      Abstract: Publication date: November 2017
      Source:Algal Research, Volume 27
      Author(s): Nesrine Ben Yahmed, Hélène Carrere, M. Nejib Marzouki, Issam Smaali
      The green macroalgal biomass corresponds to an emerging and promising biofuel feedstock. Their biological pretreatment and energetic conversion to biomethane were investigated and the enhancement of biogas production using the solid-state fermentation (SSF) as an eco-friendly innovative pretreatment of Ulva sp. was precisely assessed. Compared to conventional acid and alkali pretreatments, the highest methane potential of 153±3mLCH4 g−1VS with an anaerobic biodegradability of 57% was obtained using SSF pretreatment with a locally isolated Aspergillus fumigatus SL1 strain. It was 132±2mLCH4 g−1VS for raw Ulva sp. with biodegradability of 49%. Acid pretreatment with 4% HCl at 150°C had a negative effect on Ulva sp.'s methane potential while alkali pretreatment with 4% NaOH at 20°C showed a significant effect. The proposed SSF-based pretreatment enhanced therefore biogas production of 21% and permitted an eco-friendly valorization of large amounts of abundant macroalgae.

      PubDate: 2017-09-23T11:25:29Z
      DOI: 10.1016/j.algal.2017.09.005
      Issue No: Vol. 27 (2017)
       
  • A comparative assessment on how molasses and CO2 gas prevent carbon
           limitation in the large-scale culture of freshwater macroalgae
    • Authors: Andrew J. Cole; Matthew J. Vucko; Rocky de Nys
      Pages: 215 - 222
      Abstract: Publication date: November 2017
      Source:Algal Research, Volume 27
      Author(s): Andrew J. Cole, Matthew J. Vucko, Rocky de Nys
      Freshwater macroalgae are an attractive treatment option for waste streams that have very high concentrations of nutrients. However, the long water residence times required in these scenarios will result in carbon becoming a limiting nutrient that negatively impacts the rate of biomass productivity and, subsequently, the potential for nutrient uptake. This study examined how the rate of carbon supplementation influenced the biomass productivity of Oedogonium intermedium, during both winter and summer periods in high rate algal ponds (HRAPs) maintained under batch conditions. We also examined the novel use of molasses as a source of carbon for intensive algal cultures and compared its effect on biomass productivity to that of CO2 gas. Oedogonium intermedium responded positively to carbon supplementation from both molasses and CO2 gas, with biomass productivity increasing as the rate of carbon supplementation increased. In cultures with no carbon supplementation, the average productivity of O. intermedium was 2.2 (±0.8) gm−2 day−1, and a maximum of 17.3gm−2 day−1 and 20.8gm−2 day−1 during summer when carbon was supplemented through the addition of molasses and CO2, respectively. The optimal rate of carbon supplementation was 0.06g of carbon per liter (g(C)L−1) in winter and 0.08g(C)L−1 during summer. The addition of an exogenous source of carbon resulted in a decline in the culture pH and increased the availability of the dissolved inorganic carbon (DIC) pool and subsequently, carbon uptake by the algae. This study has identified a novel method to supplement carbon to algal cultures, where the waste residue from the sugar industry can be used as viable source of inorganic carbon. Importantly, we have demonstrated that O. intermedium can be cultivated in HRAPs without requiring a high rate of water exchange, providing that its requirements of DIC are satisfied.

      PubDate: 2017-09-23T11:25:29Z
      DOI: 10.1016/j.algal.2017.09.014
      Issue No: Vol. 27 (2017)
       
  • Application of a new ceramic hydrophobic membrane for providing CO2 in
           algal photobioreactor during cultivation of Arthrospira sp.
    • Authors: Animesh Jana; Priyankari Bhattacharya; Srijon Guha; Sourja Ghosh; Swachchha Majumdar
      Pages: 223 - 234
      Abstract: Publication date: November 2017
      Source:Algal Research, Volume 27
      Author(s): Animesh Jana, Priyankari Bhattacharya, Srijon Guha, Sourja Ghosh, Swachchha Majumdar
      Biological sequestration of CO2 using microalgal route emerges as a promising option due to its cleaner approach which can be used to produce various forms of bioenergy. The current study reports on development of a new ceramic hydrophobic membrane and its application in an algal photobioreactor towards an efficient dissolution of CO2 during cultivation of Arthrospira sp. Clay-alumina based ceramic capillary support elements were coated with bentonite clay and surface modified using polydimethyl siloxane (PDMS) to impart hydrophobicity. The prepared membrane indicated pore size of 5.0nm with around 35.3% porosity and contact angle of 147°. A two-element membrane module having 150mm length, 3.16 outer diameter and 2.16mm inner diameter was used as a nano bubble sparger to provide CO2 in 1L of the culture medium and an enhanced overall mass transfer coefficient of about 38×10−4 m/s was obtained using 19.5% CO2 gas mixture and 0.23m/s gas velocity. The membrane was efficient in removal of dissolved oxygen produced during photosynthesis, resulting in higher algal growth and higher CO2 sequestration. Algal growth of about 178.2g(dwt)/m3/day were obtained at 24h interval of CO2 supply in the photobioreactor and subsequent CO2 sequestration obtained was 13.99g/m3/h. Under optimized growth conditions the produced biomass yielded biodiesel content of about 5.82% of dry weight of algae. Application of the ceramic hydrophobic membrane thus enables enhanced mass transfer coefficient and dissolved oxygen removal efficiency making it suitable in photobioreactor application towards algal bio-sequestration of CO2 and subsequent biomass and biofuel production.
      Graphical abstract image

      PubDate: 2017-09-23T11:25:29Z
      DOI: 10.1016/j.algal.2017.08.030
      Issue No: Vol. 27 (2017)
       
  • Assessment of synergistic interactions between environmental factors on
           Microcystis aeruginosa growth and microcystin production
    • Authors: Pedro Geada; Ricardo N. Pereira; Vítor Vasconcelos; António A. Vicente; Bruno D. Fernandes
      Pages: 235 - 243
      Abstract: Publication date: November 2017
      Source:Algal Research, Volume 27
      Author(s): Pedro Geada, Ricardo N. Pereira, Vítor Vasconcelos, António A. Vicente, Bruno D. Fernandes
      The combined effect of four abiotic factors on Microcystis aeruginosa growth and toxin production was assessed by culturing the cyanobacterium under different light intensities (10–190μmol photons·m−2·s−1), CO2 concentrations (0–10% (v/v)), temperatures (15–40°C), and pH values (6.5–9.5). Results indicate a significant influence caused by the synergistic effect of environmental factors over growth-related parameters and cyanobacteria toxicity. The combined use of low to medium light intensities (50–120μmol photons·m−2·s−1) and CO2 concentration (1–6% v/v) led to higher cell concentrations, while specific growth rate and biomass productivity were favoured by medium to high light intensities (110–190μmol photons·m−2·s−1), CO2 concentrations (4–9.5% v/v) and temperatures (29–39°C). Regarding microcystin (MC) production, higher concentrations were obtained at low light intensities and low CO2 concentrations while approximately 2000-fold lower MC concentrations were achieved by simultaneous use of high values of light intensity, CO2 concentration and temperature.

      PubDate: 2017-09-23T11:25:29Z
      DOI: 10.1016/j.algal.2017.09.006
      Issue No: Vol. 27 (2017)
       
  • Dehydration and rehydration - induced temporal changes in cytosolic and
           membrane proteome of the nitrogen fixing cyanobacterium Anabaena sp. PCC
           7120
    • Authors: Sonia Sen; Shweta Rai; Shivam Yadav; Chhavi Agrawal; Ruchi Rai; Antra Chatterjee; L.C. Rai
      Pages: 244 - 258
      Abstract: Publication date: November 2017
      Source:Algal Research, Volume 27
      Author(s): Sonia Sen, Shweta Rai, Shivam Yadav, Chhavi Agrawal, Ruchi Rai, Antra Chatterjee, L.C. Rai
      The effect of drought stress on cytosolic and membrane proteome of nitrogen fixing cyanobacterium, Anabaena PCC 7120 was investigated at different time interval using two-dimensional gel electrophoresis and mass spectrometry. >300 and 140 protein spots in cytosolic and membrane gels respectively detected by proteomic analysis showed reproducible abundance within replications. Of these proteins, 69 and 86 protein spots in cytosolic and membrane proteome respectively displayed differential expression pattern. The survival strategy adopted by Anabaena PCC 7120 under dehydration as presumed by proteomic analysis can be summarized as 1) increased abundance of proteins: Mn catalase, OR, AhpC, SodA, SodB, GST and All1124 to mitigate oxidative damage, 2) minimization of energy expenditure by inhibition of photosynthesis through down-regulation of photosynthetic apparatus, antenna proteins, PSI, PSII and cytochrome b6f and respiration, 3) increased abundance of membrane porins (Omp85, OprB-I, All7614 and Alr4550) and TolC conceivably to support carbohydrate transport for enduring stress and recovery, 4) increase in phosphate transporter (PstS1) to improve phosphate assimilation required to recover cellular damage during rehydration and 5) increased abundance of K+ ATPase during prolonged dehydration and minor abundance of Na+/H+ ATPase during early rehydration to maintain cellular ion homeostasis. Dehydration, however, strongly impaired cytosolic proteins associated with nitrogen fixation, energy metabolism, amino acid and nucleic acid biosynthesis which were resumed after prolonged rewetting. Severely decreased abundance of novel proteins Alr1819, Alr2903, Alr3514, Alr2751 and All3324 serve as the marker for dehydration stress. The above results help in investigating the involvement of the proteins in protection and adaptation mechanisms associated with rejuvenation of the active state of Anabaena sp. PCC 7120.
      Graphical abstract image

      PubDate: 2017-09-29T14:40:55Z
      DOI: 10.1016/j.algal.2017.09.012
      Issue No: Vol. 27 (2017)
       
  • Autotrophic biofloc technology system (ABFT) using Chlorella vulgaris and
           Scenedesmus obliquus positively affects performance of Nile tilapia
           (Oreochromis niloticus)
    • Authors: Joo-Young Jung; Jim Hyacinth Damusaru; Youngjin Park; Kyochan Kim; Minji Seong; Hyeong-Woo Je; Soohwan Kim; Sungchul C. Bai
      Pages: 259 - 264
      Abstract: Publication date: November 2017
      Source:Algal Research, Volume 27
      Author(s): Joo-Young Jung, Jim Hyacinth Damusaru, Youngjin Park, Kyochan Kim, Minji Seong, Hyeong-Woo Je, Soohwan Kim, Sungchul C. Bai
      The present study evaluated the possibilities of the autotrophic biofloc technology (ABFT) system replacing the heterotrophic microbial biofloc technology (BFT) system with microalgae (Chlorella vulgaris and Scenedesmus obliquus). There were no significant differences in Nile tilapia (Oreochromis niloticus) survival, growth or body composition, though there was, in fact, a superior immune response by the two microalgae species as compared with the controls. The ABFT system also showed better cost effectiveness, with an 82% reduction of water exchange (from 56,000L to 10,000L), which served to demonstrate that Chlorella vulgaris and Scenedesmus obliquus in the ABFT system can be effective alternative amino acid sources for tilapia growth. In summary, the results of this study indicated that the ABFT system can be effectively utilized as a new aquaculture system and would be able to overcome some of the barriers, including economical, that have been encountered with respect to the BFT system. This technology is expected to be applicable at the seedling or juvenile farming stage, considering the relevance to industrial applications.

      PubDate: 2017-09-29T14:40:55Z
      DOI: 10.1016/j.algal.2017.09.021
      Issue No: Vol. 27 (2017)
       
  • Reuse of rejuvenated media during laboratory and pilot scale cultivation
           of Nannochloropsis sp.
    • Authors: J. Fret; L. Roef; R. Blust; L. Diels; S. Tavernier; W. Vyverman; M. Michiels
      Pages: 265 - 273
      Abstract: Publication date: November 2017
      Source:Algal Research, Volume 27
      Author(s): J. Fret, L. Roef, R. Blust, L. Diels, S. Tavernier, W. Vyverman, M. Michiels
      Bulk cultivation of microalgae in large scale production systems is subject to high production costs. Recycling of growth medium contributes to reducing water, nutrient and salt expenditure, and hence to increase both the economic viability and sustainability of microalgae production systems. In this study it was shown that, upon algae harvesting by means of centrifugation, spent broth from a Nannochloropsis sp. production system can be treated by means of microfiltration and reapplied as rejuvenated growth medium without negatively influencing subsequent growth. During recirculation of growth medium, nutrients consumption rates were documented and used to adjust the medium recipe to enable long term medium recirculation. An 80% recycle rate could be maintained for 167days during a course of ten production runs, translating into a decrease in nutrient, salt and water expenditure of 44%, 74% and 80%, respectively. The potential for long term reuse of medium for monocultures of multiple economically interesting species should be assessed in future research to evaluate the broad applicability of medium re-use in microalgae cultivation.

      PubDate: 2017-09-29T14:40:55Z
      DOI: 10.1016/j.algal.2017.09.018
      Issue No: Vol. 27 (2017)
       
  • Rapid assessment of algal biomass and pigment contents using diffuse
           reflectance spectroscopy and chemometrics
    • Authors: Haritha Duppeti; Somsubhra Chakraborty; Bhabani Sankar Das; Nirupama Mallick; J.N.R. Kotamreddy
      Pages: 274 - 285
      Abstract: Publication date: November 2017
      Source:Algal Research, Volume 27
      Author(s): Haritha Duppeti, Somsubhra Chakraborty, Bhabani Sankar Das, Nirupama Mallick, J.N.R. Kotamreddy
      Rapid and cost-effective analysis of algal pigments and biomass with minimum processing would be an invaluable tool for industrial applications especially in pharmaceutical and food industries. In this study, diffuse reflectance spectroscopy (DRS) was used for quantifying biomass and pigments from Chlorella vulgaris, Nostoc muscorum and their mixed culture via partial least squares regression (PLSR) algorithm. Results indicated that all PLSR models were able to accurately predict algal biomass using visible to near infrared (VisNIR) spectrum, producing an identical R2 of 0.98. While using pigment spectra for modeling pigments for individual culture, DRS exhibited excellent model generalization capability with calibration R2 ranging from 0.92–0.99. Qualitative spectral analysis has identified culture specific spectral signatures. Moreover, while using the pooled data for predicting algal pigments, culture spectra produced similar model accuracies to those produced by using pigment spectra. For predicting total carotenoids, the PLSR model using culture spectra (R2 =0.94) outperformed the model, which used pigment spectra (R2 =0.35), indicating the potential for developing a new approach for estimating pigment concentrations in algae samples without consuming the sample.

      PubDate: 2017-09-29T14:40:55Z
      DOI: 10.1016/j.algal.2017.09.016
      Issue No: Vol. 27 (2017)
       
  • An integrative process for obtaining lipids and glucose from Chlorella
           vulgaris biomass with a single treatment of cell disruption
    • Authors: Young Mok Heo; Hanbyul Lee; Changsu Lee; Juwon Kang; Joon-Woo Ahn; Young Min Lee; Kyu-Young Kang; Yoon-E Choi; Jae-Jin Kim
      Pages: 286 - 294
      Abstract: Publication date: November 2017
      Source:Algal Research, Volume 27
      Author(s): Young Mok Heo, Hanbyul Lee, Changsu Lee, Juwon Kang, Joon-Woo Ahn, Young Min Lee, Kyu-Young Kang, Yoon-E Choi, Jae-Jin Kim
      To examine the possibility of better utilizing Chlorella vulgaris biomass including its carbohydrate as well as lipid contents, it was investigated whether cell disruption for lipid extraction could render the remaining microalgal residue (MR) suitable for enzymatic saccharification, possibly due to the disruption of cell wall structures. The C. vulgaris biomass was subjected to lipid extraction with different cell disruption methods (autoclaving, microwave irradiation, osmotic shock, and sonication), and recovered MRs were hydrolyzed using an enzyme produced from Trichoderma koningiopsis KUC21269 in this study. The enzyme was produced on-site with a highly simplified medium of barley straw, an agricultural byproduct. As a result, the saccharification rate of MR treated with microwave was more than twice that of the control group, and microwave irradiation appeared to be a promising method for both lipid extraction and subsequent saccharification. Our results suggested that both lipids and carbohydrates in C. vulgaris can be utilized by applying proper cell disruption method and a fungal enzyme produced on-site using an agricultural byproduct, respectively. This study revealed the high potential of C. vulgaris as an integrated bio-resource for both lipids and glucose, which can be converted to biodiesel and bioethanol, providing clues for overcoming hurdles in economically feasible biofuel production using microalgae.

      PubDate: 2017-10-06T14:55:26Z
      DOI: 10.1016/j.algal.2017.09.022
      Issue No: Vol. 27 (2017)
       
  • Modeling and analysis of flux distribution and bioproduct formation in
           Synechocystis sp. PCC 6803 using a new genome-scale metabolic
           reconstruction
    • Authors: Chintan J. Joshi; Christie A.M. Peebles; Ashok Prasad
      Pages: 295 - 310
      Abstract: Publication date: November 2017
      Source:Algal Research, Volume 27
      Author(s): Chintan J. Joshi, Christie A.M. Peebles, Ashok Prasad
      Cyanobacteria are prokaryotes capable of performing oxygenic photosynthesis. This makes them an attractive candidate for genetic engineering to produce commercially important chemicals. However, optimally harnessing this potential requires an understanding of metabolic regulation in cyanobacteria under photoautotrophic conditions. Here we present an updated genome-scale metabolic network reconstruction (iSynCJ816) of Synechocystis sp. PCC 6803. This updated model, containing 816 genes and 1045 reactions, builds upon previously published models. New features include an unconstrained photo-respiratory reaction mechanism and a mechanism to account for changes in energy absorption from light at different wavelengths. We used Flux Balance Analysis (FBA) to calculate the flux distribution within iSynCJ816 and compared in silico predictions with values obtained by previous in vivo metabolic flux analyses in Synechocystis sp. PCC 6803. A qualitative growth comparison of 167 gene-deletion mutants with experimental studies resulted in an accuracy rate between 70 and 79%. We used the model to estimate both the maximum theoretical yield of each metabolite and the feasibility of engineering Synechocystis to increase CO2 fixation. We found that it is theoretically possible to increase CO2 fixation by up to 35% from wild-type levels. We also carried out a dynamic flux balance analysis of fluxes throughout a light-dark cycle and obtained results that qualitatively matched experimental observations.

      PubDate: 2017-10-06T14:55:26Z
      DOI: 10.1016/j.algal.2017.09.013
      Issue No: Vol. 27 (2017)
       
  • Recycling nutrients from a sequential hydrothermal liquefaction process
           for microalgae culture
    • Authors: Limei Chen; Tao Zhu; Jose Salomon Martinez Fernandez; Shulin Chen; Demao Li
      Pages: 311 - 317
      Abstract: Publication date: November 2017
      Source:Algal Research, Volume 27
      Author(s): Limei Chen, Tao Zhu, Jose Salomon Martinez Fernandez, Shulin Chen, Demao Li
      Nutrient supply and reuse are critical considerations for culturing and processing algae as feedstock for biofuel production. Sequential Hydrothermal Liquefaction (SEQHTL) is used to convert microalgae biomass to biofuel and co-products. Along with biocrude and biochar of the co-products, SEQHTL produces aqueous products with high concentrations of phosphate, organic nitrogen and polysaccharides. In this study, three representative microalgaes, Chlorella sorokiniana, Chlorella vulgaris and Galdieria sulphuraria 5587.1 were evaluated for utilizing the nutrients recovered from the aqueous products of SEQTHL. C. sorokiniana and C. vulgaris exhibited the ability to hydrolyze polysaccharides, using 77% and 64% of the polysaccharides and removing 94% to 95% of the phosphate, respectively. G. sulphuraria on the other hand, could not use the polysaccharides. All three species could completely assimilate ammonia and use 33%–43% of the organic nitrogen. There were no significant differences in terms of lipid contents and composition, C. sorokiniana and C. vulgaris had higher lipid content (18% of DCW) than what G. sulphuraria did (only 10% of DCW). The findings indicate that although being species dependent, it is possible to reuse the nutrients recovered from SEQHTL of algal biomass for algal culture.

      PubDate: 2017-10-06T14:55:26Z
      DOI: 10.1016/j.algal.2017.09.023
      Issue No: Vol. 27 (2017)
       
  • Hydrodynamic performance of two air nozzles diameters on the massive
           microalgae culture: Computational and experimental approaches
    • Authors: Bruno Galler Kubelka; Waldir Terra Pinto; Paulo Cesar Abreu
      Pages: 318 - 324
      Abstract: Publication date: November 2017
      Source:Algal Research, Volume 27
      Author(s): Bruno Galler Kubelka, Waldir Terra Pinto, Paulo Cesar Abreu
      The scaling of microalgae production in culture systems depends on preventing cells to settle down and assure a well-mixed water column. Doing so, each cell would have better exposure to light and nutrients. Computational Fluid Dynamics (CFD) can be an effective tool for understanding and predicting the multiphase flow inside tanks. In this study, we have used CFD to simulate the velocity field and the turbulent kinetic energy inside a computational tank to find best hydrodynamic performance for two nozzles configurations: case 1) one single 3mm air nozzle; case 2) a set of nine 1mm air nozzles. Computational results showed that smaller air nozzles are more efficient in reducing dead zones inside culturing tanks. Further, mean turbulent kinetic energy field suggested a more homogeneous dissipation, and higher intensities of turbulence were observed in the smaller nozzle simulation. The application of present numerical observations on culture systems was investigated by several experiments in 300L cylindrical photobioreactors and 1600L open circular tanks, both with different air nozzles sizes (1 and 3mm) where the marine microalga Nannochloropsis oceanica was grown. Microalga growth was determined by measurements of water absorbance at 750nm. Higher cell densities were determined in the photobioreactors and tanks with 1mm nozzles. Thus, smaller nozzle was efficient to improve the microalga production even with increasing volume and different culture system designs, supporting the numerical analyses predictions by CFD.

      PubDate: 2017-10-06T14:55:26Z
      DOI: 10.1016/j.algal.2017.09.024
      Issue No: Vol. 27 (2017)
       
  • Modeling of microfluidic bio-solar cell using microalgae through
           multiphysics platform: A greener approach en route for energy production
    • Authors: Liyakath Reshma; Amballa Chaitanyakumar; A.L.G.N. Aditya; Boopathy Ramaraj; Kannappan Santhakumar
      Pages: 47 - 55
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): Liyakath Reshma, Amballa Chaitanyakumar, A.L.G.N. Aditya, Boopathy Ramaraj, Kannappan Santhakumar
      Due to the growing energy demands and increased concern over environmental deterioration and energy climate catastrophe, bio-energy based mechanisms had gained interest over recent years and had attained acknowledgment as the “greener” energy self-sustainable technologies of the future. A new micro-fluidic bio-solar cell modeling and their integration using COMSOL multi-physics have been proposed in order to convert solar energy into bioelectricity. Synechocystis PCC6803 is used as the microbial source due to its electrical property for generating electrons through an anodic chamber. Using COMSOL multi-physics platform, the microfluidic bio-solar cell was designed with five functioning layers. Each layer is been assigned with the suitable electrical/electrode properties of the polymer and the anodic chamber layer been assigned with the properties of the microalgae. Finally, the microfluidic bio-solar cell was modeled to create interfaces between optical and electrical physics in order to determine their material transport, heat transfer, electrochemical behavior, current density and voltage distribution behavior of the microfluidic bio-solar cell. The open circuit voltage of about 0.42V is been obtained with 80% of absorption capacity. This modeling can be further developed into an extensible bio-solar panel by fabricating it using a microfluidic chamber for further application enhancement, which can replace inorganic solar cells with bio-solar cells for an eco-friendly environment with less production cost.
      Graphical abstract image

      PubDate: 2017-07-15T02:44:15Z
      DOI: 10.1016/j.algal.2017.07.002
      Issue No: Vol. 26 (2017)
       
  • Plasticity and remodelling of lipids support acclimation potential in two
           species of low-intertidal macroalgae, Fucus serratus (Phaeophyceae) and
           Palmaria palmata (Rhodophyta)
    • Authors: Matthias Schmid; Freddy Guihéneuf; Dagmar B. Stengel
      Pages: 104 - 114
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): Matthias Schmid, Freddy Guihéneuf, Dagmar B. Stengel
      This study aimed to investigate the seasonal changes in the lipid and pigment profiles of two macroalgae, Fucus serratus (Phaeophyceae) and Palmaria palmata (Rhodophyta). The two species displayed distinct differential seasonal patterns of lipid partitioning when collected from their natural habitat at times when species-specific maxima and minima in total fatty acids (TFA) concentrations occurred. F. serratus contained highest levels of TFA (40.07mgg−1 DW) and triacylglycerols (TAG) (26.83mgg−1 DW) during summer (July), in association with lowest levels of polyunsaturated fatty acids (PUFA, 30.2% of TFA) and pigments (1.44mgg−1 DW chlorophyll a). In P. palmata, high levels of TFA (13.00mgg−1 DW) were observed during spring (May), with high levels of polar lipids (10.00mgg−1 DW) rich in PUFA (52.3% of TFA), and high levels of pigments (1.25mgg−1 DW chlorophyll a and 10.88mgg−1 DW phycoerythrin). The results suggest that summer-acclimated F. serratus diverted excess energy into storage lipids (TAG), while P. palmata was more sensitive and susceptible to degradation of its chloroplast membranes, resulting in a decrease in TFA, PUFA-rich polar lipids and pigments, and a release of FFA. The ability to accumulate TAG may be a key factor allowing acclimation to environmental stressors for F. serratus, a species with broader vertical distribution than P. palmata which is restricted to low-intertidal and upper subtidal shores in western Ireland.

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

      PubDate: 2017-07-24T11:50:58Z
      DOI: 10.1016/j.algal.2017.07.009
      Issue No: Vol. 26 (2017)
       
  • Effects of disrupted omega-3 desaturase gene construct on fatty acid
           composition and expression of four fatty acid biosynthetic genes in
           transgenic Chlorella vulgaris
    • Authors: Cher Chien Lau; Saw Hong Loh; Ahmad Aziz; Thye San Cha
      Pages: 143 - 152
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): Cher Chien Lau, Saw Hong Loh, Ahmad Aziz, Thye San Cha
      This study demonstrated the genetic modification of Chlorella vulgaris by introducing a copy of disrupted omega-3 desaturase (ω-3 FAD) gene into its genome to study the effect on fatty acid biosynthesis pathway. Results revealed that the expression of endogenous ω-3 FAD gene in transgenic lines (C28 and C30) was temporarily suppressed during the early stage of sub-culture and then reactivated subsequently after six months of alternate sub-culturing. Furthermore, the endogenous ω-3 FAD expression was found to be upregulated to >3-fold without any notable changes in C18:3n3 composition when cultured under nitrate-deficient medium. Interestingly, a significant shift in fatty acid saturation profile towards the production of higher C16:0 was observed along with a reduction in C18:1 composition in transgenic lines. In addition, PCR walking experiment confirmed that the entire T-DNA region and vector backbone were co-transferred and randomly integrated into the host genome. These findings provide valuable insight in understanding the regulation of fatty acid biosynthesis pathway in C. vulgaris and could pave the way for further genetic improvement of the species for various downstream applications.

      PubDate: 2017-07-24T11:50:58Z
      DOI: 10.1016/j.algal.2017.07.011
      Issue No: Vol. 26 (2017)
       
  • Improvement of biomass and lipid yield under stress conditions by using
           diploid strains of Chlamydomonas reinhardtii
    • Authors: Minsoo Kwak; Won-Kun Park; Sung-Eun Shin; Hyun-Gi Koh; Bongsoo Lee; Byeong-ryool Jeong; Yong Keun Chang
      Pages: 180 - 189
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): Minsoo Kwak, Won-Kun Park, Sung-Eun Shin, Hyun-Gi Koh, Bongsoo Lee, Byeong-ryool Jeong, Yong Keun Chang
      Algal biofuel feedstocks are excellent candidates for sustainable and eco-friendly fuels for the next generation, which can be improved by genetic modifications for their maximal production of biomaterials. However, currently available genetic modifications involve the introduction of foreign DNA into the algal genome, and this may face legal and public conflicts due to the risk of environmental, economic, and/or health problems. In this regard, we employed an old concept of crop improvement that has been accepted in the long history of agriculture, i.e. polyploidization. Polyploidization of crop plants has been selected fortuitously or intentionally not only for increased quality and/or quantity of products, but also for enhanced stress tolerance. We induced diploidy in the model algae Chlamydomonas by treating haploid cells with the microtubule inhibitor colcemid, and the resulting diploids were selected for increased colony size and neutral lipid contents. Two of the isolated diploid strains containing doubled DNA contents, named CMD ex1 and CMD ex4, were increased in their cell size and cellular weight. These diploids were excellent in coping with abiotic stresses, including nutritional, oxidative, and cold stresses. Under these conditions, the diploids accumulated two times more biomass and FAME yield compared to the control. To understand underlying mechanisms, we performed RNA-Seq analyses for the diploid under the cold stress. Transcriptomic analyses revealed that the diploids showed enhanced expression of genes involved in photosynthesis, energy metabolism, and translation as well as reduced starch metabolism. Overall, diploids of Chlamydomonas showed improvements including increased yields of biomass and FAME and enhanced stress tolerance compared to wild-type organisms. The results demonstrate that polyploidization can be utilized in industrial microalgae for the production of biofuels and other biomaterials not only on a laboratory scale but also in outdoor cultivation, where stress conditions are inevitable.
      Graphical abstract image

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

      PubDate: 2017-08-02T02:18:12Z
      DOI: 10.1016/j.algal.2017.07.022
      Issue No: Vol. 26 (2017)
       
  • A lipid droplet-associated protein involved in lipid droplet biogenesis
           and triacylglycerol accumulation in the oleaginous microalga Phaeodactylum
           tricornutum
    • Authors: Xiang Wang; Ting-Bin Hao; Srinivasan Balamurugan; Wei-Dong Yang; Jie-Sheng Liu; Hong-Po Dong; Hong-Ye Li
      Pages: 215 - 224
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): Xiang Wang, Ting-Bin Hao, Srinivasan Balamurugan, Wei-Dong Yang, Jie-Sheng Liu, Hong-Po Dong, Hong-Ye Li
      Lipid droplets (LDs) are lipid monolayer-enclosed organelles comprising a lipid core and surface associated-proteins. However, the protein components and their regulatory functions in LDs have remained largely unknown in oleaginous diatoms. In this study, we identified a gene encoding lipid droplet (LD)-associated protein (PtLDP1) in Phaeodactylum tricornutum and examined its function. The PtLDP1 showed homology to the diatom-oleosome-associated protein 1 (DOAP1) from Fistulifera. Overexpression of the PtLDP1 gene elevated lipid content, enlarged LD size and increased relative expression levels of key genes involved in triacylglycerol (TAG) and fatty acid biosynthesis. In contrast, knockdown of PtLDP1 by RNAi decreased lipid and TAG content, and subsequently reduced LD size. In addition, LDs were isolated from P. tricornutum cells and the proteome of LDs was identified by mass spectrometry. We found that PtLDP1 was a significant protein in the LD proteome. Importantly, labeling of enhanced yellow fluorescent protein (EYFP) confirmed that the PtLDP1 was localized to the LDs. Altogether, our data suggest that the PtLDP1 could be an important LD-associated protein contributing to regulation of TAG synthesis and lipogenesis. The findings will provide new targets for genetic improvement of oleaginous microalgae.

      PubDate: 2017-08-02T02:18:12Z
      DOI: 10.1016/j.algal.2017.07.028
      Issue No: Vol. 26 (2017)
       
  • The role of alginate lyases in the enzymatic saccharification of brown
           macroalgae, Macrocystis pyrifera and Saccharina latissima
    • Authors: María Cristina Ravanal; Sandeep Sharma; Javier Gimpel; Felipe E. Reveco-Urzua; Margareth Øverland; Svein Jarle Horn; María Elena Lienqueo
      Pages: 287 - 293
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): María Cristina Ravanal, Sandeep Sharma, Javier Gimpel, Felipe E. Reveco-Urzua, Margareth Øverland, Svein Jarle Horn, María Elena Lienqueo
      In this work, we have compared the carbohydrate content and the enzymatic saccharification of the brown algae Macrocystis pyrifera from Chile and Saccharina latissima from Norway. M. pyrifera contained 40% mannitol, 31% uronic acids and 15% glucose, while S. latissima contained 37% glucose, 30% uronic acids and 25% mannitol. Thus, the ratio between mannitol and glucose was much higher for M. pyrifera. Acid pre-treated and untreated algae were enzymatically saccharified in two steps; first at pH7.5, 25°C for 12h with a blend of recombinant alginate and oligoalginate lyases, then the pH was changed to 5.2, a commercial cellulase cocktail was added and saccharification continued at 50°C for 4h. These experiments showed that the use of recombinant alginate lyases and oligoalginate lyases in combination with cellulases increased the release of glucose from untreated seaweed. However, for saccharification of pretreated algae, only cellulases were needed to achieve high glucose yields. Finally, it was shown that brown algae hydrolysates could be used as a growth medium to produce microbial ingredients, such as Candida utilis yeast.

      PubDate: 2017-08-11T08:52:55Z
      DOI: 10.1016/j.algal.2017.08.012
      Issue No: Vol. 26 (2017)
       
  • Chemical regulation of Fea1 driven transgene expression in Chlamydomonas
           reinhardtii
    • Authors: Paula Barjona do Nascimento Coutinho; Christine Friedl; Rainer Buchholz; Stephanie Christine Stute
      Pages: 323 - 329
      Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26
      Author(s): Paula Barjona do Nascimento Coutinho, Christine Friedl, Rainer Buchholz, Stephanie Christine Stute
      Inducible promoters can provide regulated gene expression allowing the biosynthesis of gene products at most suitable moments of cultivation. In this study, parameters of induction and deactivation of the iron-responsive Fea1 promoter (Allen et al., 2007) were investigated in the green alga Chlamydomonas reinhardtii. Our results indicate that the construct used, ble-2A-mCherry, can be expressed successfully by the Fea1 promoter under iron-deficient conditions. The fluorescence signals of the fluorescent protein mCherry obtained via flow cytometry were detectable at different intensities in response to concentrations of iron ranging from 0μM to 20μM in media. We also demonstrate that the addition of the iron chelator deferroxamine (DFO) to iron-replete media leads to promoter activation, resulting in the increase of mCherry fluorescence. Reversibility of promoter induction is detected already within 3h after transferring the cells to iron-replete chelator-free media. In this case, the progressive decrease in mCherry fluorescence can reach, within 48h, as low as 5% of the fluorescence observed in a 40h – treatment with DFO. Cell viability after DFO treatment is not affected up to a concentration of 100μM of the chelator, which enables the establishment of a cyclic process of induction and repression for the production of recombinant proteins under the control of the Fea1 inducible promoter.

      PubDate: 2017-08-11T08:52:55Z
      DOI: 10.1016/j.algal.2017.08.006
      Issue No: Vol. 26 (2017)
       
  • Determination of the life cycle climate change impacts of land use and
           albedo change in algal biofuel production
    • Authors: Marie-Odile P. Fortier; Griffin W. Roberts; Susan M. Stagg-Williams; Belinda S.M. Sturm
      Abstract: Publication date: Available online 12 October 2017
      Source:Algal Research
      Author(s): Marie-Odile P. Fortier, Griffin W. Roberts, Susan M. Stagg-Williams, Belinda S.M. Sturm
      Geographic factors including land use change (LUC) impacts could significantly affect the sustainability of algal biofuels. Life cycle assessments (LCAs) of algal biofuels must evolve in their methodology in order to more accurately reflect the spatial and temporal heterogeneity of environmental impacts, which includes impacts arising from direct LUC. In this study, LCA methods were developed to integrate climate change impacts of direct LUC associated with cultivation of microalgae in open ponds and the effects of temporal and geographic variables on algal growth. The climate change impacts of LUC include the impacts of changing the surface albedo of an area, changing the carbon flux on the land, and removing the original biomass from the transformed land. Two LCA cases were analyzed for algal biofuel feedstocks production in climatically similar regions: the Everglades ecoregion and the Tamaulipas-Texas Semi-Arid Plain ecoregion. The relative contributions of foreground fuel production processes and LUC to the life cycle climate change impacts of renewable gasoline from microalgae were compared. Site-specific GIS data was collected to model algal production on potentially available land for the two case studies. The LUC impacts arising from albedo change and carbon flux change contributed significantly to the life cycle climate change impacts and differed between the two climatically similar regions. The baseline life cycle climate change impacts of algal renewable gasoline production with LUC impacts in the Everglades are 33.8% higher than those of conventional gasoline, while production in the Tamaulipas-Texas Semi-Arid Plain leads to 8.97% lower life cycle climate change impacts. The inclusion of LUC impacts increased the mean result and the range of the Monte Carlo simulations for both ecoregions. This methodology can help assess the geographically specific sustainability of algal biofuels on a life cycle basis and can guide siting decisions for algal biofuel feedstock production.

      PubDate: 2017-10-12T17:18:50Z
      DOI: 10.1016/j.algal.2017.06.009
       
  • Evaluation of biochemical algal floc properties using Reflectance
           Fourier-Transform Infrared Imaging
    • Authors: Gonzalez-Torres A.M.; Rich C.E. Marjo R.K. Henderson
      Abstract: Publication date: November 2017
      Source:Algal Research, Volume 27
      Author(s): A. Gonzalez-Torres, A.M. Rich, C.E. Marjo, R.K. Henderson
      Coagulation and flocculation (C-F) followed by a separation process such as sedimentation or dissolved air flotation is a major barrier to algal or cyanobacterial cells in water treatment plants and a common harvesting technique for algae cultured for high value products. Tailoring algal physical floc properties (size, strength, and density) has been shown to be important to optimise separation, however, the chemical properties of the flocs that lead to the physical properties are not yet well understood. This study investigated the biochemical composition of algal (Chlorella vulgaris) and cyanobacterial (Microcystis aeruginosa) flocs produced under sweep flocculation using aluminium sulphate as a coagulant. These flocs had very different physical properties. A new approach was developed to undertake biochemical characterisation of associated flocs using reflectance Fourier transform infrared (FTIR) imaging. Analysing the biochemical composition of the algal and cyanobacterial flocs revealed that the distribution of proteins and carbohydrates in the flocs are most likely responsible for the unique physical floc characteristics observed. The large flocs of C. vulgaris were characterised by a homogenous distribution of proteins and polysaccharides, and a high glycoprotein and biopolymer content. In contrast, the smaller but stronger flocs of M. aeruginosa had more concentrated protein regions within the flocs that tended to associate at the edge of regions which were absent of biomolecules, potentially comprising coagulant. Overall, the technique shows great potential for analysing algal flocs to gain a better understanding of the underlying biochemical composition and distribution of these biomolecules that leads to the varying physical floc properties.
      Graphical abstract image

      PubDate: 2017-10-06T14:55:26Z
       
  • Effect of phytohormones on growth and accumulation of pigments and fatty
           acids in the microalgae Scenedesmus quadricauda
    • Authors: Tatiana Kozlova; Bruce Hardy Priti Krishna David Levin
      Abstract: Publication date: November 2017
      Source:Algal Research, Volume 27
      Author(s): Tatiana A. Kozlova, Bruce P. Hardy, Priti Krishna, David B. Levin
      The phytohormones abscisic acid (ABA), 24-epibrassinolide (EBL), brassinolide (BL), and 3-indoleacetic acid (IAA), at concentrations relevant to that in hydroponic wastewater, were investigated for their physiological effects on the microalga Scenedesmus quadricauda. All phytohormones tested had positive stimulatory effects on S. quadricauda cell growth, biomass production, as well as on intracellular concentrations of chlorophyll-a, carotenoid, and lipids biosynthesis. The most powerful inducers of chlorophyll-a and carotenoid biosynthesis were EBL and IAA, while the phytohormone effect on fatty acids biosynthesis followed the order: IAA≥ABA>EBL>BL. Both the quantities of fatty acids and their profiles depended on the phytohormone type and the specific concentrations tested. All tested phytohormones altered S. quadricauda cell size and positive or negative effects were dose-dependent. To our knowledge, this is the first report that systematically compares the influence of four phytohormones, including two types of brassinosteroids, on a broad-range of S. quadricauda physiological parameters.

      PubDate: 2017-10-06T14:55:26Z
       
  • Inside Front Cover - Editorial Board Page/Cover image legend if applicable
    • Abstract: Publication date: September 2017
      Source:Algal Research, Volume 26


      PubDate: 2017-09-23T11:25:29Z
       
  • Microzooplanktonic grazers – A potentially devastating threat to the
           commercial success of microalgal mass culture
    • Authors: John G. Day; Yingchun Gong; Qiang Hu
      Abstract: Publication date: Available online 8 September 2017
      Source:Algal Research
      Author(s): John G. Day, Yingchun Gong, Qiang Hu
      Eukaryotic microalgae and prokaryotic cyanobacteria are globally the most important primary producers, forming the base of food web in aquatic ecosystems. As such, they are eaten by a huge diversity of protistan taxa (e.g., amoeba, flagellates and ciliates), as well as zooplanktonic and larger metazoan grazers. As in terrestrial agriculture, grazing has the potential to devastate the microalgal “crop” and this has obvious implications to the commercial success of the developing microalgal industry. Whilst in conventional agriculture thousands of years of exploitation of a relatively small number of crop plants, has resulted in tools, knowledge and strategies that can manage this issue, in the case of microalgal mass culture this is relatively undeveloped. This review explores our current understanding of the issue and where further research is needed, focusing on the diversity of grazers and how microalgae under various environmental regimes and culture conditions avoid being annihilated. In addition, the implications of algal mass culture, where the objective is to maintain a virtual monoculture, are discussed in the context of how infection could be prevented/minimised and if infection occurs, how this may be managed to prevent excessive losses in productivity or quality of the algal crop. The ultimate objective would be the development of robust methodologies for the early detection of “infection” of microalgal mass-cultures. This would allow the timely implementation of best management practices to prevent/reduce, damage caused by grazing. In reality, whilst there will be areas of commonality, as in terrestrial agricultural crops, methods will be need to be specifically tailored for each algal taxon, cultivation system and location.

      PubDate: 2017-09-11T07:07:57Z
      DOI: 10.1016/j.algal.2017.08.024
       
 
 
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