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Showing 1 - 200 of 3175 Journals sorted alphabetically
A Practical Logic of Cognitive Systems     Full-text available via subscription   (Followers: 8)
AASRI Procedia     Open Access   (Followers: 14)
Academic Pediatrics     Hybrid Journal   (Followers: 28, SJR: 1.402, h-index: 51)
Academic Radiology     Hybrid Journal   (Followers: 22, SJR: 1.008, h-index: 75)
Accident Analysis & Prevention     Partially Free   (Followers: 90, 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: 33, SJR: 2.515, h-index: 90)
Achievements in the Life Sciences     Open Access   (Followers: 5)
Acta Anaesthesiologica Taiwanica     Open Access   (Followers: 6, SJR: 0.338, h-index: 19)
Acta Astronautica     Hybrid Journal   (Followers: 376, SJR: 0.726, h-index: 43)
Acta Automatica Sinica     Full-text available via subscription   (Followers: 2)
Acta Biomaterialia     Hybrid Journal   (Followers: 27, SJR: 2.02, h-index: 104)
Acta Colombiana de Cuidado Intensivo     Full-text available via subscription   (Followers: 2)
Acta de Investigación Psicológica     Open Access   (Followers: 3)
Acta Ecologica Sinica     Open Access   (Followers: 8, SJR: 0.172, h-index: 29)
Acta Haematologica Polonica     Free   (Followers: 1, 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  
Acta Otorrinolaringológica Española     Full-text available via subscription   (Followers: 2, SJR: 0.311, h-index: 16)
Acta Pharmaceutica Sinica B     Open Access   (Followers: 1)
Acta Poética     Open Access   (Followers: 4)
Acta Psychologica     Hybrid Journal   (Followers: 25, 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: 3)
Actas Dermo-Sifiliográficas (English Edition)     Full-text available via subscription   (Followers: 2)
Actas Urológicas Españolas     Full-text available via subscription   (Followers: 3, SJR: 0.383, h-index: 19)
Actas Urológicas Españolas (English Edition)     Full-text available via subscription   (Followers: 1)
Actualites Pharmaceutiques     Full-text available via subscription   (Followers: 6, SJR: 0.141, h-index: 3)
Actualites Pharmaceutiques Hospitalieres     Full-text available via subscription   (Followers: 3, SJR: 0.112, h-index: 2)
Acupuncture and Related Therapies     Hybrid Journal   (Followers: 6)
Acute Pain     Full-text available via subscription   (Followers: 14)
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: 7)
Additive Manufacturing     Hybrid Journal   (Followers: 9, SJR: 1.039, h-index: 5)
Additives for Polymers     Full-text available via subscription   (Followers: 22)
Advanced Cement Based Materials     Full-text available via subscription   (Followers: 3)
Advanced Drug Delivery Reviews     Hybrid Journal   (Followers: 129, SJR: 5.2, h-index: 222)
Advanced Engineering Informatics     Hybrid Journal   (Followers: 11, SJR: 1.265, h-index: 53)
Advanced Powder Technology     Hybrid Journal   (Followers: 16, SJR: 0.739, h-index: 33)
Advances in Accounting     Hybrid Journal   (Followers: 8, SJR: 0.299, h-index: 15)
Advances in Agronomy     Full-text available via subscription   (Followers: 12, SJR: 2.071, h-index: 82)
Advances in Anesthesia     Full-text available via subscription   (Followers: 27, SJR: 0.169, h-index: 4)
Advances in Antiviral Drug Design     Full-text available via subscription   (Followers: 2)
Advances in Applied Mathematics     Full-text available via subscription   (Followers: 10, SJR: 1.054, h-index: 35)
Advances in Applied Mechanics     Full-text available via subscription   (Followers: 10, SJR: 0.801, h-index: 26)
Advances in Applied Microbiology     Full-text available via subscription   (Followers: 22, SJR: 1.286, h-index: 49)
Advances In Atomic, Molecular, and Optical Physics     Full-text available via subscription   (Followers: 14, 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: 2, SJR: 0.619, h-index: 48)
Advances in Cancer Research     Full-text available via subscription   (Followers: 28, SJR: 2.215, h-index: 78)
Advances in Carbohydrate Chemistry and Biochemistry     Full-text available via subscription   (Followers: 7, SJR: 0.9, h-index: 30)
Advances in Catalysis     Full-text available via subscription   (Followers: 5, SJR: 2.139, h-index: 42)
Advances in Cell Aging and Gerontology     Full-text available via subscription   (Followers: 3)
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: 27, SJR: 0.183, h-index: 23)
Advances in Child Development and Behavior     Full-text available via subscription   (Followers: 10, SJR: 0.665, h-index: 29)
Advances in Chronic Kidney Disease     Full-text available via subscription   (Followers: 10, SJR: 1.268, h-index: 45)
Advances in Clinical Chemistry     Full-text available via subscription   (Followers: 28, SJR: 0.938, h-index: 33)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 19, SJR: 2.314, h-index: 130)
Advances in Computers     Full-text available via subscription   (Followers: 14, SJR: 0.223, h-index: 22)
Advances in Dermatology     Full-text available via subscription   (Followers: 14)
Advances in Developmental Biology     Full-text available via subscription   (Followers: 10)
Advances in Digestive Medicine     Open Access   (Followers: 8)
Advances in DNA Sequence-Specific Agents     Full-text available via subscription   (Followers: 5)
Advances in Drug Research     Full-text available via subscription   (Followers: 21)
Advances in Ecological Research     Full-text available via subscription   (Followers: 42, SJR: 3.25, h-index: 43)
Advances in Engineering Software     Hybrid Journal   (Followers: 27, SJR: 0.486, h-index: 10)
Advances in Experimental Biology     Full-text available via subscription   (Followers: 6)
Advances in Experimental Social Psychology     Full-text available via subscription   (Followers: 42, SJR: 5.465, h-index: 64)
Advances in Exploration Geophysics     Full-text available via subscription   (Followers: 1)
Advances in Fluorine Science     Full-text available via subscription   (Followers: 7)
Advances in Food and Nutrition Research     Full-text available via subscription   (Followers: 54, SJR: 0.674, h-index: 38)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 15)
Advances in Genetics     Full-text available via subscription   (Followers: 14, SJR: 2.558, h-index: 54)
Advances in Genome Biology     Full-text available via subscription   (Followers: 7)
Advances in Geophysics     Full-text available via subscription   (Followers: 6, SJR: 2.325, h-index: 20)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 21, SJR: 0.906, h-index: 24)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 9, SJR: 0.497, h-index: 31)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 23)
Advances in Imaging and Electron Physics     Full-text available via subscription   (Followers: 1, SJR: 0.396, h-index: 27)
Advances in Immunology     Full-text available via subscription   (Followers: 36, SJR: 4.152, h-index: 85)
Advances in Inorganic Chemistry     Full-text available via subscription   (Followers: 8, SJR: 1.132, h-index: 42)
Advances in Insect Physiology     Full-text available via subscription   (Followers: 2, SJR: 1.274, h-index: 27)
Advances in Integrative Medicine     Hybrid Journal   (Followers: 6)
Advances in Intl. Accounting     Full-text available via subscription   (Followers: 3)
Advances in Life Course Research     Hybrid Journal   (Followers: 8, SJR: 0.764, h-index: 15)
Advances in Lipobiology     Full-text available via subscription   (Followers: 1)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 9)
Advances in Marine Biology     Full-text available via subscription   (Followers: 14, 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: 21)
Advances in Molecular and Cellular Endocrinology     Full-text available via subscription   (Followers: 8)
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: 3)
Advances in Oncobiology     Full-text available via subscription   (Followers: 1)
Advances in Organ Biology     Full-text available via subscription   (Followers: 1)
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: 6, SJR: 0.148, h-index: 11)
Advances in Parasitology     Full-text available via subscription   (Followers: 5, 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: 10)
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: 7)
Advances in Plant Pathology     Full-text available via subscription   (Followers: 5)
Advances in Porous Media     Full-text available via subscription   (Followers: 5)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 17)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 18, SJR: 1.5, h-index: 62)
Advances in Psychology     Full-text available via subscription   (Followers: 59)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 6, 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 Biology and Medicine     Full-text available via subscription   (Followers: 5)
Advances in Space Research     Full-text available via subscription   (Followers: 374, SJR: 0.606, h-index: 65)
Advances in Structural Biology     Full-text available via subscription   (Followers: 5)
Advances in Surgery     Full-text available via subscription   (Followers: 9, SJR: 0.823, h-index: 27)
Advances in the Study of Behavior     Full-text available via subscription   (Followers: 29, SJR: 1.321, h-index: 56)
Advances in Veterinary Medicine     Full-text available via subscription   (Followers: 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: 46, SJR: 2.408, h-index: 94)
Aeolian Research     Hybrid Journal   (Followers: 6, SJR: 0.973, h-index: 22)
Aerospace Science and Technology     Hybrid Journal   (Followers: 333, 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: 6, SJR: 0.344, h-index: 6)
Ageing Research Reviews     Hybrid Journal   (Followers: 9, SJR: 3.289, h-index: 78)
Aggression and Violent Behavior     Hybrid Journal   (Followers: 429, SJR: 1.385, h-index: 72)
Agri Gene     Hybrid Journal  
Agricultural and Forest Meteorology     Hybrid Journal   (Followers: 15, SJR: 2.18, h-index: 116)
Agricultural Systems     Hybrid Journal   (Followers: 31, SJR: 1.275, h-index: 74)
Agricultural Water Management     Hybrid Journal   (Followers: 43, SJR: 1.546, h-index: 79)
Agriculture and Agricultural Science Procedia     Open Access   (Followers: 1)
Agriculture and Natural Resources     Open Access   (Followers: 2)
Agriculture, Ecosystems & Environment     Hybrid Journal   (Followers: 56, 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: 9)
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   (Followers: 1)
Algal Research     Partially Free   (Followers: 9, SJR: 2.05, h-index: 20)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 2)
Allergologia et Immunopathologia     Full-text available via subscription   (Followers: 1, SJR: 0.46, h-index: 29)
Allergology Intl.     Open Access   (Followers: 5, SJR: 0.776, h-index: 35)
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: 9, 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: 4)
Alzheimer's & Dementia: Translational Research & Clinical Interventions     Open Access   (Followers: 4)
Ambulatory Pediatrics     Hybrid Journal   (Followers: 6)
American Heart J.     Hybrid Journal   (Followers: 50, SJR: 3.157, h-index: 153)
American J. of Cardiology     Hybrid Journal   (Followers: 50, SJR: 2.063, h-index: 186)
American J. of Emergency Medicine     Hybrid Journal   (Followers: 42, SJR: 0.574, h-index: 65)
American J. of Geriatric Pharmacotherapy     Full-text available via subscription   (Followers: 10, SJR: 1.091, h-index: 45)
American J. of Geriatric Psychiatry     Hybrid Journal   (Followers: 14, 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: 26, 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: 42, 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: 190, SJR: 2.255, h-index: 171)
American J. of Ophthalmology     Hybrid Journal   (Followers: 62, SJR: 2.803, h-index: 148)
American J. of Ophthalmology Case Reports     Open Access   (Followers: 6)
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: 27, SJR: 2.653, h-index: 228)
American J. of Preventive Medicine     Hybrid Journal   (Followers: 27, SJR: 2.764, h-index: 154)
American J. of Surgery     Hybrid Journal   (Followers: 37, 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: 6)
Anaerobe     Hybrid Journal   (Followers: 4, SJR: 1.066, h-index: 51)
Anaesthesia & Intensive Care Medicine     Full-text available via subscription   (Followers: 61, SJR: 0.124, h-index: 9)
Anaesthesia Critical Care & Pain Medicine     Full-text available via subscription   (Followers: 14)
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: 39, SJR: 1.548, h-index: 152)
Analytical Biochemistry     Hybrid Journal   (Followers: 166, SJR: 0.725, h-index: 154)
Analytical Chemistry Research     Open Access   (Followers: 10, 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   (Followers: 1)

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Journal Cover Algal Research
  [SJR: 2.05]   [H-I: 20]   [9 followers]  Follow
   Partially Free Journal Partially Free Journal
   ISSN (Online) 2211-9264
   Published by Elsevier Homepage  [3175 journals]
  • The responses of two genes encoding phytoene synthase (Psy) and phytoene
           desaturase (Pds) to nitrogen limitation and salinity up-shock with special
           emphasis on carotenogenesis in Dunaliella parva
    • Authors: Changhua Shang; Wen Wang; Shunni Zhu; Zhongming Wang; Lei Qin; Mohammad Asraful Alam; Jun Xie; Zhenhong Yuan
      Pages: 1 - 10
      Abstract: Publication date: June 2018
      Source:Algal Research, Volume 32
      Author(s): Changhua Shang, Wen Wang, Shunni Zhu, Zhongming Wang, Lei Qin, Mohammad Asraful Alam, Jun Xie, Zhenhong Yuan
      Green alga Dunaliella parva can adapt to environmental stresses such as salinity up-shock and nitrogen limitation which are associated with carotenoid accumulation. However, the underlying molecular basis related to the change of carotenoid content needs further study. In the present study, we cloned two carotenoid biosynthesis genes coding for phytoene synthase and phytoene desaturase. In addition, the effects of salinity up-shock and nitrogen limitation on carotenoid content and expression of these two genes were studied in D. parva FACHB-815. The results showed that both salinity up-shock and nitrogen limitation had important effect on carotenoid yield and expression of these two genes. Cloning and expression analysis of these two genes will contribute to the understanding of molecular basis in stress-induced carotenoid accumulation, which is favorable for performing metabolic and genetic engineering to improve traits of D. parva.

      PubDate: 2018-03-18T15:48:21Z
      DOI: 10.1016/j.algal.2018.03.002
      Issue No: Vol. 32 (2018)
  • Analyzing the pyrolysis kinetics of several microalgae species by various
           differential and integral isoconversional kinetic methods and the
           Distributed Activation Energy Model
    • Authors: Antonio Soria-Verdugo; Elke Goos; Nestor García-Hernando; Uwe Riedel
      Pages: 11 - 29
      Abstract: Publication date: June 2018
      Source:Algal Research, Volume 32
      Author(s): Antonio Soria-Verdugo, Elke Goos, Nestor García-Hernando, Uwe Riedel
      The pyrolysis kinetics of the microalgae Chlorella vulgaris (CV), Isochrysis galbana (IG), Nannochloropsis gaditana (NG), Nannochloropsis limnetica (NL), Phaeodactylum tricornutum (PT), and Spirulina platensis (SP) were studied by non-isothermal thermogravimetric analysis conducted at nine different constant heating rates. The kinetic parameters of each microalgae species were calculated using several kinetic methods, such as those of Kissinger, Friedman, Ozawa-Flynn-Wall (OFW), Kissinger-Akahira-Sunose (KAS), Vyazovkin, and the simplified Distributed Activation Energy Model (DAEM). The results show that the kinetic parameters calculated from the integral isoconversional methods OFW, KAS and Vyazovkin are similar to those determined by applying the simplified DAEM. In contrast, application of the differential isoconversional method of Friedman led to moderate deviations in the activation energies and pre-exponential factors computed, whereas the unique values of the kinetic parameters determined by the Kissinger method resulted in the highest deviations.

      PubDate: 2018-04-15T04:40:39Z
      DOI: 10.1016/j.algal.2018.03.005
      Issue No: Vol. 32 (2018)
  • Sulfate amendment improves the growth and bioremediation capacity of a
           cyanobacteria cultured on municipal wastewater centrate
    • Authors: Alexander R. Hughes; Abby Sulesky; Björn Andersson; Graham Peers
      Pages: 30 - 37
      Abstract: Publication date: June 2018
      Source:Algal Research, Volume 32
      Author(s): Alexander R. Hughes, Abby Sulesky, Björn Andersson, Graham Peers
      A series of experiments were performed to evaluate the growth of the model cyanobacterium Synechocystis sp. PCC6803 cultured on wastewater centrate sourced from a municipal water reclamation facility. Centrate is the liquid removed from sludge during sewage processing. The addition of 304 μM Na2SO4 to centrate diluted by 90% in water yielded final cell concentrations that were over 6 times higher than cultures grown on just centrate. This suggested that S is the primary limiting nutrient for photoautorophic growth on centrate. The expression of the sulfate transporter system encoded by the spbA-cysTWA operon was upregulated when cells were grown in non-amended centrate, confirming that Synechocystis sp. PCC6803 experienced S-limitation during growth on centrate alone. Elemental analysis of centrate further confirmed that the proportion of S relative to other macronutrients is lower in centrate compared to the measured elemental ratios found in cyanobacterial biomass. The cyanobacteria removed 69% of the total soluble nitrogen (TN) in S-amended centrate compared to 25% from cultures grown in centrate alone. It is proposed that S could be recycled from the production of H2S during anaerobic digestion of wastewater, or it could be added from exogenous material such as gypsum. Overall, this work suggests that S-amendment of centrate could improve the sustainability of wastewater remediation and biomass production using photosynthetic microbes.

      PubDate: 2018-04-15T04:40:39Z
      DOI: 10.1016/j.algal.2018.03.004
      Issue No: Vol. 32 (2018)
  • Novel approach for the direct transesterification of fresh microalgal
           cells via micro-reactor
    • Authors: Jiao Liu; Xupeng Cao; Yadong Chu; Yuchao Zhao; Peichun Wu; Song Xue
      Pages: 38 - 43
      Abstract: Publication date: June 2018
      Source:Algal Research, Volume 32
      Author(s): Jiao Liu, Xupeng Cao, Yadong Chu, Yuchao Zhao, Peichun Wu, Song Xue
      Transesterification is prevalent in the fatty acid (FA) analysis of lipids, as well as in biodiesel preparation. However, it is very inefficient to obtain the FA composition from microalgal biomass via traditional transesterification. Therefore, to satisfy the demand for rapid FA analysis in microalgal research and to simplify the microalgal biodiesel production process, we developed an approach for the direct transesterification of fresh microalgal cells by overcoming the bottlenecks of mass transfer and the solid-liquid homogeneity of transesterification in a micro-reactor with polyethylene glycol as a suspension agent. This direct transesterification takes only 10 min, and the minimum amount of fresh microalgal cells required for accurate FA analysis was reduced to a few milligrams. This new approach allows near real-time microalgal FA measurement in microorganism-related research and represents significant progress in improving the competitiveness and the possibility of the practical application of microalgal biodiesel, since drying and lipid extraction are avoided.

      PubDate: 2018-04-15T04:40:39Z
      DOI: 10.1016/j.algal.2018.03.008
      Issue No: Vol. 32 (2018)
  • Isolation and characterization of microalgal strains for biomass
           production and wastewater reclamation in Northern Sweden
    • Authors: Lorenza Ferro; Francesco G. Gentili; Christiane Funk
      Pages: 44 - 53
      Abstract: Publication date: June 2018
      Source:Algal Research, Volume 32
      Author(s): Lorenza Ferro, Francesco G. Gentili, Christiane Funk
      Microalgal strains adapted to the harsh Nordic climate were isolated from Swedish fresh- and wastewater sources and tested for their ability to grow in municipal wastewater. The 62 strains able to grow in municipal wastewater belonged to 12 different genera, of those Desmodesmus, Scenedesmus and Chlorella were most representative. Eight axenic strains were further characterized, all of which could efficiently remove nitrogen (>90%) and phosphate (>99%) from the wastewater in less than two weeks. The microalga Coelastrella sp. had the highest performance in terms of both biomass concentration and total lipid content (1.46 g/L, 30.8%) after 13 days of cultivation. This is the first report of a Coelastrella strain isolated in Sweden. Even Chlorella vulgaris performed very well with a biomass concentration and total lipid content of 1.15 g/L and 34.2%, respectively. Finally, two Desmodesmus sp. strains showed desirable traits for biofuel-feedstock, due to their fast growth rates (1.18 and 1.08 d−1) together with high oil content (29.8% and 36.7% of DW).

      PubDate: 2018-04-15T04:40:39Z
      DOI: 10.1016/j.algal.2018.03.006
      Issue No: Vol. 32 (2018)
  • Fucoidanase inhibitory activity of phlorotannins from brown algae
    • Authors: Tatiana I. Imbs; Artem S. Silchenko; Sergey A. Fedoreev; Vladimir V. Isakov; Svetlana P. Ermakova; Tatiana N. Zvyagintseva
      Pages: 54 - 59
      Abstract: Publication date: June 2018
      Source:Algal Research, Volume 32
      Author(s): Tatiana I. Imbs, Artem S. Silchenko, Sergey A. Fedoreev, Vladimir V. Isakov, Svetlana P. Ermakova, Tatiana N. Zvyagintseva
      The inhibitors of recombinant fucoidanase FFA2 from the marine bacterium Formosa algae KMM 3553T were found among the metabolites of brown algae Fucus evanescens and Costaria costata. NMR spectroscopy and mass spectrometry analysis showed that high molecular weight phlorethols (degree of polymerization (DP) of 12–25 monomers) from C. costata (ICc) and fucophloretol (DP = 3) from F. evanescens (IFe) were inhibitors of fucoidanase. To inhibit one mole of FFA2 fucoidanase about two molecules of the ICc inhibitor or 7 molecules of the IFe inhibitor are needed. It has been suggested that the effectiveness of inhibition increases with the increasing molecular weight of phlorotannins. An irreversible type of inhibition was established.

      PubDate: 2018-04-15T04:40:39Z
      DOI: 10.1016/j.algal.2018.03.009
      Issue No: Vol. 32 (2018)
  • Analytical pyrolysis reaction characteristics of Porphyra tenera
    • Authors: Young-Min Kim; Tae Uk Han; Boram Lee; Atsushi Watanabe; Norio Teramae; Jeong-Hoon Kim; Young-Kwon Park; Hyunwoong Park; Seungdo Kim
      Pages: 60 - 69
      Abstract: Publication date: June 2018
      Source:Algal Research, Volume 32
      Author(s): Young-Min Kim, Tae Uk Han, Boram Lee, Atsushi Watanabe, Norio Teramae, Jeong-Hoon Kim, Young-Kwon Park, Hyunwoong Park, Seungdo Kim
      The non-isothermal pyrolysis of red algae (Porphyra tenera) was studied via thermogravimetric (TG) analysis in combination with two types of analytical pyrolyzer-gas chromatography/mass spectrometry (Py-GC/MS) techniques, namely, evolved gas analysis (EGA)-MS and multi-shot Py-GC/MS. The TG and model-free kinetic analyses revealed that the pyrolysis of P. tenera proceeded via the independent decomposition of carbohydrates, proteins, and lipids. Differential TG and EGA-MS indicated the existence of three decomposition temperature regions. In the first temperature region (<300 °C), carbohydrates were mainly decomposed. Large amounts of pyrolyzates of proteins and lipids such as toluene, phenols, aromatic amino acids, and hexadecanoic acid were produced in the second temperature region (301–380 °C). In the third region (>380 °C), large amounts of aromatic hydrocarbons and alkanes were obtained by the secondary cracking of the pyrolyzates of proteins and lipids.

      PubDate: 2018-04-15T04:40:39Z
      DOI: 10.1016/j.algal.2018.03.003
      Issue No: Vol. 32 (2018)
  • An investigation on involvement of the ascorbate-glutathione cycle in
           modulating NaCl toxicity in two cyanobacteria photoacclimatized to
           different photosynthetic active radiation
    • Authors: Jitendra Kumar; Vijay Pratap Singh; Sheo Mohan Prasad
      Pages: 70 - 78
      Abstract: Publication date: June 2018
      Source:Algal Research, Volume 32
      Author(s): Jitendra Kumar, Vijay Pratap Singh, Sheo Mohan Prasad
      In the present study, comparative responses of two cyanobacteria viz. Nostoc muscorum and Phormidium foveolarum, photoacclimatized at three distinct levels (sub-optimum; 25±0.5, optimum; 75±2.5 and supra-optimum; 225±3.5μmolphotonsm−2 s−1) of photosynthetic active radiation (PAR), and subsequently treated with two doses (30 and 90mM) of NaCl were determined by analyzing changes in growth pattern, oxidative stress markers, enzymes of the ascorbate-glutathione cycle i.e. ascorbate peroxidase (APX), glutathione reductase (GR), monodehydroascorbate reductase (MDHAR) and dehydroascorbate reductase (DHAR), and associated metabolites (ascorbate and glutathione). PAR influences growth behavior of both cyanobacteria, as maximum growth observed in supra-optimum PAR acclimatized cells followed by optimum and sub-optimum PAR. Maximum superoxide radical (SOR) and hydrogen peroxide (H2O2) contents and their consequent damages to lipids in terms of MDA equivalents were observed in supra-optimum PAR acclimatized cells in individual as well as in combined treatment of NaCl. Further, NaCl-induced the least percent reduction in growth was observed in supra-optimum PAR acclimatized cells, which was in consistence with increased activities of the AsA-GSH cycle enzymes (APX, GR, MDHAR and DHAR) and its associated metabolites i.e. ascorbate (AsA) and glutathione (GSH) contents and reduced and oxidized ratios of ascorbate (AsA/GSH) and glutathione (GSH/GSSG). The results suggest that the AsA-GSH cycle might have associated with better growth in supra-optimum PAR acclimatized cells than optimum and sub-optimum PAR acclimatized cells under NaCl stress. Besides this, study also establishes fact that P. foveolarum is more tolerant than N. muscorum against these twin stresses, and may be inoculated in paddy fields under existing environmental conditions for increasing fertility of the soil.

      PubDate: 2018-04-15T04:40:39Z
      DOI: 10.1016/j.algal.2017.10.019
      Issue No: Vol. 32 (2018)
  • Alterations in lipidome and metabolome profiles of Nannochloropsis salina
           in response to reduced culture temperature during sinusoidal temperature
           and light
    • Authors: Stephanie Willette; Saba S. Gill; Barry Dungan; Tanner M. Schaub; Jacqueline M. Jarvis; Rolston St. Hilaire; F. Omar Holguin
      Pages: 79 - 92
      Abstract: Publication date: June 2018
      Source:Algal Research, Volume 32
      Author(s): Stephanie Willette, Saba S. Gill, Barry Dungan, Tanner M. Schaub, Jacqueline M. Jarvis, Rolston St. Hilaire, F. Omar Holguin
      Metabolic response to four suboptimal cultivation temperatures was explored in Nannochloropsis salina, with an emphasis on fatty acid and lipid metabolism. Cultures were cultivated in controlled environmental photobioreactors. Physiological performance, characterized by growth rate and photosynthetic output, were reduced at all three cold stress temperatures (5 °C, 10 °C, 15 °C). However, biomass productivity and overall growth for cultures at 20 °C was like that of those grown at the optimal temperature (25 °C). Fatty acid productivity was elevated at all suboptimal temperatures, and both total fatty acid and eicosapentaenoic acid content were statically elevated at 20 °C. Lipid accumulation was observed exclusively in response to cold stress; however, lipid turnover and enrichment in polyunsaturated fatty acids occurred in all temperature variants. In addition, extensive lipid remodeling occurred in both polar and neutral lipid pools, specifically in monogalactosyl diacylglycerol and triacylglycerol pools. While 20 °C is optimal for eicosapentaenoic acid and total fatty acid productivity, cold stress is necessary to induce both productivity and polyunsaturated fatty acid enrichment in triacylglycerol pools.

      PubDate: 2018-04-15T04:40:39Z
      DOI: 10.1016/j.algal.2018.03.001
      Issue No: Vol. 32 (2018)
  • Docosahexaenoic acid production by a novel high yielding strain of
           Thraustochytrium sp. of Indian origin: Isolation and bioprocess
           optimization studies
    • Authors: Kabilan Chandrasekaran; Rony K. Roy; Anju Chadha
      Pages: 93 - 100
      Abstract: Publication date: June 2018
      Source:Algal Research, Volume 32
      Author(s): Kabilan Chandrasekaran, Rony K. Roy, Anju Chadha
      Docosahexaenoic acid [DHA], an important nutraceutical, generally isolated from fish can be derived from a marine heterotroph microalgae of the thraustochytrid family. In this study, strategic screening for a high yielding strain from the mangroves of South India for the production of DHA resulted in a strain which showed promising yields of biomass and DHA. Phylogenetic (18S rRNA) analysis of this strain revealed that the isolate belonged to Thraustochytrium sp. and was labeled T01. The total lipid of the wet cell volume was detected by Nile red fluorescence spectroscopy and the lipid content was estimated by gravimetric analysis, was found to be 50 ± 2% of dry cell weight. The maximum biomass and DHA obtained using optimized (central composite design) media composition after 108 h at 25 °C and 180 rpm were 31 ± 0.2 g L−1 and 6.9 ± 0.05 g L−1 respectively. Of the total fatty acid methyl ester content in the biomass, 45.3 ± 1.7% of DHA methyl ester was observed which was improved to 80% by the urea complexation method (3.3 M urea and 3.3 Urea/FAME). This strain thus could be an ideal candidate for commercial production of DHA.
      Graphical abstract image

      PubDate: 2018-04-15T04:40:39Z
      DOI: 10.1016/j.algal.2018.03.011
      Issue No: Vol. 32 (2018)
  • Low-cost optical sensor to automatically monitor and control biomass
           concentration in microalgal cultivation
    • Authors: Binh T. Nguyen; Bruce E. Rittmann
      Pages: 101 - 106
      Abstract: Publication date: June 2018
      Source:Algal Research, Volume 32
      Author(s): Binh T. Nguyen, Bruce E. Rittmann
      Low productivity of microalgal cultures leads to a high cost of the fuel feedstock. Turbidostat operation, which automatically monitors and controls biomass density, is a mean to manage biomass density and internal light intensity, so that biomass productivity can be maximized. Available versions of turbidostat control are expensive and not amenable to large-scale operation. We designed a system that costs less than $250 and that can be used for any type of microbiological system. It includes an in-line, infrared turbidity sensor connected to an Arduino ATmega microcontroller and auxiliary power replays. The target biomass density is adjustable, and key operating data – such as time stamps, pump status, and set and measured values of biomass density – are available in real time and logged continuously. The sensor's output was linear for OD730 from 0.5 to 4.5, which brackets the realistic ranges for microalgae culturing. We tested the turbidostat with step-down and step-up experiments with Synechocystis cultures. The turbidostat maintained stable biomass concentrations for all steps. The results of the turbidostat experiments demonstrated how turbidity control leads to systematic management of average internal light intensity, specific growth rate, and biomass production rate. This open-design, low-cost system should promote higher productivity and help make microalgae biomass an affordable fuel feedstock.
      Graphical abstract image

      PubDate: 2018-04-15T04:40:39Z
      DOI: 10.1016/j.algal.2018.03.013
      Issue No: Vol. 32 (2018)
  • Seasonal and depth variations in the chemical composition of cultivated
           Saccharina latissima
    • Authors: Sandeep Sharma; Luiza Neves; Jon Funderud; Liv Torunn Mydland; Margareth Øverland; Svein Jarle Horn
      Pages: 107 - 112
      Abstract: Publication date: June 2018
      Source:Algal Research, Volume 32
      Author(s): Sandeep Sharma, Luiza Neves, Jon Funderud, Liv Torunn Mydland, Margareth Øverland, Svein Jarle Horn
      Sugar kelp (Saccharina latissima) is an abundantly available macroalgae species along the Norwegian coast, and there is currently emerging an industry based on seaweed cultivation. In this study, the biomass growth of cultivated S. latissima deployed in February was studied at cultivation depths of 3 and 8 meters (m) and monitored over the period of May, June, and August. The highest biomass production was observed in June at the depth of 3 m (38.3 kg wet weight m−2). Furthermore, all seaweed samples underwent a detailed chemical characterization including analysis of carbohydrates (glucose, mannitol, fucose, xylose, uronic acids), amino acids and minerals. The macroalgae deployed in February at 3 m depth and sampled in June had the highest proportion of total sugars (534.5 g kg−1 of DM) and the lowest content of ash (252.7 g kg−1 of DM). Thus, cultivation at 3 m and harvesting in June are suitable when the feedstock is used for biochemical production of fuels and chemicals. Macroalgae deployed at 8 m depth and harvested in August had the highest proportion of total amino acids (242.4 g kg−1 DM) and ash content (411.5 g kg−1 DM). This biomass may be suitable as a nitrogen and mineral source in microbial growth media. Overall, the choice of cultivation depth and harvesting time depends on the intended use of the seaweed biomass.

      PubDate: 2018-04-15T04:40:39Z
      DOI: 10.1016/j.algal.2018.03.012
      Issue No: Vol. 32 (2018)
  • Pilot-scale production of antibacterial substances by the marine diatom
           Phaeodactylum tricornutum Bohlin
    • Authors: Song Wang; Inamullah Hakeem Said; Candice Thorstenson; Claudia Thomsen; Matthias S. Ullrich; Nikolai Kuhnert; Laurenz Thomsen
      Pages: 113 - 120
      Abstract: Publication date: June 2018
      Source:Algal Research, Volume 32
      Author(s): Song Wang, Inamullah Hakeem Said, Candice Thorstenson, Claudia Thomsen, Matthias S. Ullrich, Nikolai Kuhnert, Laurenz Thomsen
      The production and extraction of antibacterial substances from Phaeodactylum tricornutum biomass were tested on a pilot scale in a photo-bioreactor greenhouse installation. Using column chromatography two antibacterial active fractions were obtained from the algal biomass: a pure fraction of eicosapentaenoic acid (EPA) and a potentially new antibacterial substance(s) (identified as fraction B) produced by P. tricornutum. Both fractions exhibited antibacterial activities against three human pathogens: Vibrio vulnificus, V. parahaemolyticus, and V. cholerae. Minimal inhibitory concentrations against Bacillus subtilis of active fractions and one antibacterial commercial product were determined revealing a higher antibacterial activity of EPA in comparison to the commercial product. Consequently, EPA as well as the raw algal biomass with both EPA and the fraction B compounds could be used as food additives and feeds in aquaculture, poultry, and livestock breeding. Two types of phytohormones, methyl jasmonate and salicylic acid, as well as one phytotoxin, coronatine, were tested for induction of the defense system of P. tricornutum. However, only a minor change in the fatty acids profile and antibacterial effects of the treated cultures indicated that P. tricornutum must employ another strategy to regulate its antibacterial defense system.

      PubDate: 2018-04-15T04:40:39Z
      DOI: 10.1016/j.algal.2018.03.014
      Issue No: Vol. 32 (2018)
  • Sulfated polysaccharide from Kappaphycus alvarezii (Doty) Doty ex P.C.
           Silva primes defense responses against anthracnose disease of Capsicum
           annuum Linn.
    • Authors: Sumithra Devi Mani; Radhakrishnan Nagarathnam
      Pages: 121 - 130
      Abstract: Publication date: June 2018
      Source:Algal Research, Volume 32
      Author(s): Sumithra Devi Mani, Radhakrishnan Nagarathnam
      Organic approaches for controlling plant diseases with biopolymers have garnered increasing attention in recent years because of their eco-friendliness. In the present study, the biopolymer carrageenan was extracted from the red seaweed Kappaphycus alvarezii and used as a potent elicitor of plant resistance against anthracnose disease in chili plants. Biophysical analysis by FT-IR confirmed that the isolated polysaccharide is κ-carrageenan. Foliar applications of κ-carrageenan induced the defense-related antioxidant enzyme peroxidase in chili leaves. Furthermore, two-dimensional gel electrophoresis (2D-PAGE) and liquid chromatography mass spectrometry (LC-MS/MS) analyses of chili leaves pretreated with κ-carrageenan showed up-regulation of 13 known proteins and induction of 4 new proteins, including dehydroascorbate reductase I, dehydroascorbate reductase II, NAD(P)H Quinone oxidoreductase, and Eukaryotic Translation Initiation Factor 5A. An analysis of gene expression using quantitative real time polymerase chain reaction (qRT-PCR) also confirmed the expression of the pathogenesis-related proteins PR1, PR5, PDF1.2, and NPR1 following treatment with carrageenan. In vitro experiments using κ-carrageenan support its fungistatic potential through alteration of the membrane permeability of Colletotrichum gloeosporioides (Penz.) Sacc. Pathogenesis tests yielded a lower disease score for chili plants pretreated with κ-carrageenan. Hence, κ-carrageenan could be a potent natural fungicide and elicitor of disease resistance in plants.

      PubDate: 2018-04-15T04:40:39Z
      DOI: 10.1016/j.algal.2018.02.025
      Issue No: Vol. 32 (2018)
  • Kinetic modelling of microalgae cultivation for wastewater treatment and
           carbon dioxide sequestration
    • Authors: Valentine C. Eze; Sharon B. Velasquez-Orta; Andrea Hernández-García; Ignacio Monje-Ramírez; María T. Orta-Ledesma
      Pages: 131 - 141
      Abstract: Publication date: June 2018
      Source:Algal Research, Volume 32
      Author(s): Valentine C. Eze, Sharon B. Velasquez-Orta, Andrea Hernández-García, Ignacio Monje-Ramírez, María T. Orta-Ledesma
      A simple and robust microalgae kinetic model has been developed for application in the prediction and control of algae cultivations in wastewater. The microalgae kinetic model was calibrated using experimental cultivation data from Desmodesmus sp. to determine specific microalgae growth rates (μ max and μ maxNO3), microalgae death rates (μ d ), and the NH4 + to NO3 − oxidation rate (μ B ). Model parameters obtained were: μ max  = 0.17 day−1, μ d  = 0.004 day−1, and μ B  = 0.14 day−1. Microalgae specific growth rate based on NO3 − alone (μ maxNO3 = 0.1 day−1) was lower than the overall growth rate (μ max ). The kinetic model was validated using additional experimental data for the Desmodesmus sp. and Scenedesmus obliquus cultivation in wastewater containing 0% and 7% landfill leachate, with accuracy above 98% in all cases. These results demonstrated the kinetic model was accurate in predicting microalgae growth, wastewater nutrient removal, and changes in the culture media pH. Biomass productivity of the algae culture was associated with an exponential increase in the media pH, which led to ammonia volatilisation and decreased carbon intake. Between 28.8 and 29.7% of the initial NH4 + was lost to ammonia volatilisation in wastewater containing 7% landfill leachate. Hence, loss of ammonium nitrogen contained in domestic wastewater must be avoided to ensure steady and efficient inorganic carbon utilisation which inherently maximises biomass production efficiency. The optimal pH for the microalgae culture was 8.1, at which point microalgae could achieve about 99% carbon fixation efficiency. To ensure constant pH in the microalgae growing system, immediate removal of the OH− generated is needed, which could be facilitated by injections of 1.14 g CO2 and 0.067 g OH− per gram of produced algae when using NH4 + nutrient, and 1.54 g of CO2 per gram of produced algae when using NO3 − nutrient. This could be done in a wastewater pond by using an optical density-controlled smart CO2 injection system.
      Graphical abstract image

      PubDate: 2018-04-15T04:40:39Z
      DOI: 10.1016/j.algal.2018.03.015
      Issue No: Vol. 32 (2018)
  • Effects of extracts and isolated molecules of two species of Gracilaria
           (Gracilariales, Rhodophyta) on early growth of lettuce
    • Authors: Priscila Torres; Paula Novaes; Luciana Garcia Ferreira; Janaína Pires Santos; Ester Mazepa; Maria Eugênia R. Duarte; Miguel D. Noseda; Fungyi Chow; Deborah Y.A.C. dos Santos
      Pages: 142 - 149
      Abstract: Publication date: June 2018
      Source:Algal Research, Volume 32
      Author(s): Priscila Torres, Paula Novaes, Luciana Garcia Ferreira, Janaína Pires Santos, Ester Mazepa, Maria Eugênia R. Duarte, Miguel D. Noseda, Fungyi Chow, Deborah Y.A.C. dos Santos
      Crude extracts using hexane, dichloromethane, methanol, 80% methanol or water of two agarophytes (Gracilaria caudata and Gracilaria domingensis) and their phase partitions were evaluated on early growth of lettuce. Hexane, methanol, 80% methanol and aqueous extracts of G. caudata and dichloromethane and aqueous extracts of G. domingensis were biostimulants. Palmitic acid, the major compound of non-polar extracts and phase partition, showed a significant stimulant activity in the concentrations tested (ranging from 0.49 mM to 1.95 mM), increasing 83% of lettuce root length, comparing to control, at the highest concentration. The promoting effect of the aqueous extracts is probably related to the presence of agaran, a typical hydrocolloid polysaccharide from red algae, which is mostly an exclusive constituent of these extracts. The agarans of G. domingensis and G. caudata promoted an increase in lettuce root length of 60% and 40%, respectively (both at 1 mg·mL−1 of extract). Differences in the effects promoted by these two agarans are probably related to the different content of sulfate groups (higher for polysaccharide from G. domingensis). These results suggest that structural features of agaran-type polysaccharides can elicit distinct responses. To the best of our knowledge, this is the first report on the identification of compounds with biostimulating potential from Gracilaria.

      PubDate: 2018-04-15T04:40:39Z
      DOI: 10.1016/j.algal.2018.03.016
      Issue No: Vol. 32 (2018)
  • Comparison of microalgal biomasses as functional food ingredients: Focus
           on the composition of cell wall related polysaccharides
    • Authors: Tom M.M. Bernaerts; Lore Gheysen; Clare Kyomugasho; Zahra Jamsazzadeh Kermani; Stéphanie Vandionant; Imogen Foubert; Marc E. Hendrickx; Ann M. Van Loey
      Pages: 150 - 161
      Abstract: Publication date: June 2018
      Source:Algal Research, Volume 32
      Author(s): Tom M.M. Bernaerts, Lore Gheysen, Clare Kyomugasho, Zahra Jamsazzadeh Kermani, Stéphanie Vandionant, Imogen Foubert, Marc E. Hendrickx, Ann M. Van Loey
      Microalgae are rich in several nutritional and health-beneficial components, showing great potential as functional food ingredients. To this extent, knowledge of the biomass composition is essential in the selection of suitable microalgae species for specific food applications. Surprisingly, although cell wall polysaccharides are generally reported to play a role in functionality, limited attention has been given to the cell wall related polysaccharides of microalgae so far. Therefore, this study aimed to characterize dry biomasses of ten microalgae species with potential as functional food ingredients, with a particular focus on the composition of cell wall related polysaccharides. The investigated species were Arthrospira platensis, Chlorella vulgaris, Diacronema lutheri, Tisochrysis lutea, Nannochloropsis sp., Odontella aurita, Phaeodactylum tricornutum, Porphyridium cruentum, Schizochytrium sp. and Tetraselmis chuii. Lipids, proteins and ash made up a large fraction of the biomasses, except for the freshwater algae C. vulgaris and A. platensis which were mainly composed of proteins and polysaccharides. Generally, low amounts of storage polysaccharides (2–8%) were observed in the investigated microalgae species, while extracellular polymeric substances were only present in P. cruentum, O. aurita, C. vulgaris and A. platensis. Cell wall polysaccharides contributed approximately 10% of the biomass and were composed of heteropolysaccharides, showing at least five different monosaccharides. Moreover, the presence of uronic acids and sulfate groups provides anionic characteristics to the cell wall related polysaccharides of several microalgae. As a result, these polysaccharides show potential to display interesting functionalities as bioactive or technological substances.

      PubDate: 2018-04-15T04:40:39Z
      DOI: 10.1016/j.algal.2018.03.017
      Issue No: Vol. 32 (2018)
  • Microalgal bioremediation of nitrogenous compounds in landfill leachate
           – The importance of micronutrient balance in the treatment of leachates
           of variable composition
    • Authors: Andrea Paskuliakova; Ted McGowan; Steve Tonry; Nicolas Touzet
      Pages: 162 - 171
      Abstract: Publication date: June 2018
      Source:Algal Research, Volume 32
      Author(s): Andrea Paskuliakova, Ted McGowan, Steve Tonry, Nicolas Touzet
      Landfill leachate is a type of wastewater which is challenging to treat. Phycoremediation has been proposed as an alternative biological treatment for removal of ammonia nitrogen. Several studies have shown microalgae based bioremediation to be possible with ammonia tolerant microalgal species, provided that an optimal dilution is used and the initial molecular N:P ratio is adjusted. The composition of landfill leachate varies between sites and throughout the year. The performance of selected microalgal strains and their susceptibility to variation in landfill leachate composition is poorly understood. This study compares the growth of Chlamydomonas sp. strain SW15aRL in a variety of leachate samples. The leachate samples are from different sites including leachate sampled on different occasions from the same site. These substrates were diluted to obtain ammonia nitrogen concentration within the range of 30 to 220 mg·l−1. Results showed that strain SW15aRL was capable of growth in a variety of leachates but was dependent on the overall composition profile of the landfill leachate rather than just its dilution. Growth was negatively affected in two of the leachates tested, due to metal toxicity and mineral bioavailability or deficiency. Phosphate addition was essential for growth in the landfill leachates even though precipitation occurred in some instances. Ammonia nitrogen decrease varied between 70% and 100% in the substrates where microalgae could successfully grow. This study indicates that due to their overall mineral profile some landfill leachates are more suited for microalgae based remediation than others. Furthermore, this study indicates that a better understanding of other physicochemical processes that take place concurrently during the growth of microalgae in landfill leachate and which contribute to overall nutrient reduction is required.

      PubDate: 2018-04-15T04:40:39Z
      DOI: 10.1016/j.algal.2018.03.010
      Issue No: Vol. 32 (2018)
  • Isolation and evaluation of phytoconstituents from red alga Acanthophora
           spicifera as potential apoptotic agents towards A549 and HeLa cancer cells
    • Authors: Veeresh Kumar Sali; R. Malarvizhi; V.M. Manikandamathavan; Hannah R. Vasanthi
      Pages: 172 - 181
      Abstract: Publication date: June 2018
      Source:Algal Research, Volume 32
      Author(s): Veeresh Kumar Sali, R. Malarvizhi, V.M. Manikandamathavan, Hannah R. Vasanthi
      In the present work, we isolated, characterized and examined the anticancer effect of bioactive molecules from Acanthophora spicifera (red algae) on A549 and HeLa cancer cell lines and compared with normal HEK cells. Among the different solvent fractions subjected to chromatographic purification, three molecules isolated showed potential cytotoxicity and induced apoptosis in a dose dependent manner. The structure of the active components was identified as Cholest-4-ene-3,6-dione, (1) a steroid and two non-steroid molecules namely 2-bromohexandecanoic acid (2) and 6-bromo indole (3) by GC–MS, FTIR and NMR (1H &13C) analysis. Compound 1 exhibited better cytotoxicity with an IC50 of 10.01 ± 0.11 μM (A549) and 12.32 ± 0.08 μM (HeLa) (1) than that of compound (2) IC50 of 72.6 ± 0.10 μM (A549), 26.42 ± 0.11 μM (HeLa) and (3) 108.2 ± 0.15 μM (A549) and 71.68 ± 0.60 μM (HeLa) at 24 h. Mechanistic investigation on apoptosis by the selected compounds was further confirmed by dual AO/EB and Annexin-V/PI staining assay. Interestingly, compound 1 also displayed remarkable loss of mitochondrial membrane potential (MMP assay), increased level of reactive oxygen species (ROS assay) and cell cycle arrest at sub-G1 phase. Further, Western blot analysis confirmed the involvement of caspase signaling cascade in A549 cell death by compound 1. Our findings demonstrate that the red alga Acanthophora spicifera from Gulf of Mannar is a potent source of these bioactive leads with an efficient anticancer activity mediated by apoptosis and autophagy.

      PubDate: 2018-04-15T04:40:39Z
      DOI: 10.1016/j.algal.2018.02.031
      Issue No: Vol. 32 (2018)
  • Kinetin and Gibberellic acid (GA3) act synergistically to produce high
           value polyunsaturated fatty acids in Nannochloropsis oceanica CASA CC201
    • Authors: Aswathy Udayan; S. Kathiresan; Muthu Arumugam
      Pages: 182 - 192
      Abstract: Publication date: June 2018
      Source:Algal Research, Volume 32
      Author(s): Aswathy Udayan, S. Kathiresan, Muthu Arumugam
      Two functionally different plant growth regulators, Kinetin and GA3, were evaluated individually or in combination for its effect on growth, lipid yield, PUFAs and EPA accumulation in Nannochloropsis oceanica CASA CC201. It was observed that the treatment with 0.215 ppm Kinetin resulted in high cell number of 521 × 106 cells per mL than the control (398 × 106 cells per mL), but GA3 had an adverse effect on cell number. Kinetin increases the specific growth rate to 0.24/day and doubling time to 2.86 days than control (4.38 days). Treatment with GA3 at a concentration of 50 ppm gives the highest cellular lipid accumulation of 61.5% DCW than the control (35.5% DCW). The combination of Kinetin and GA3 exhibited a synergistic effect on total lipid yield of 246.25 mg/L compared with control (121.5 mg/L). The addition of Kinetin increases the percentage of EPA 4 times as compared to the control.

      PubDate: 2018-04-15T04:40:39Z
      DOI: 10.1016/j.algal.2018.03.007
      Issue No: Vol. 32 (2018)
  • An integrated biorefinery process: Stepwise extraction of fucoxanthin,
           eicosapentaenoic acid and chrysolaminarin from the same Phaeodactylum
           tricornutum biomass
    • Authors: Wenyuan Zhang; Feifei Wang; Baoyan Gao; Luodong Huang; Chengwu Zhang
      Pages: 193 - 200
      Abstract: Publication date: June 2018
      Source:Algal Research, Volume 32
      Author(s): Wenyuan Zhang, Feifei Wang, Baoyan Gao, Luodong Huang, Chengwu Zhang
      The cultivation of microalgae is a high energy consumption process, which consumes a large amount of water, nutrients, electric energy and manpower. Thus, comprehensive utilization of algal biomass is a key to achieving cost-effective industrial production of bioproducts. In this paper, an integrated biorefinery process was conducted on Phaeodactylum tricornutum biomass to produce three valuable bioactive compounds via stepwise extraction using different solvent systems. Fucoxanthin, highly concentrated eicosapentaenoic acid (EPA), and chrysolaminarin were successively purified, concentrated, and characterized from P. tricornutum with a series of separation and identification technologies, and the yield (the weight of the purified compounds/the absolute weight in algal biomass, %) of these active compounds were 34.03 ± 0.72%, 23.00 ± 0.29%, and 43.54 ± 0.91%, respectively. Moreover, the fucoxanthin extraction conditions were also optimized, and ethanol and microwave-assisted treatments of 1 min provided the best fucoxanthin yield. In conclusion, this study suggested an effective biorefinery process for the production of fucoxanthin, EPA, and chrysolaminarin from the same P. tricornutum biomass.
      Graphical abstract image

      PubDate: 2018-04-15T04:40:39Z
      DOI: 10.1016/j.algal.2018.04.002
      Issue No: Vol. 32 (2018)
  • Effect of microalgae addition on active biodegradable starch film
    • Authors: Mariel Carissimi; Simone Hickmann Flôres; Rosane Rech
      Pages: 201 - 209
      Abstract: Publication date: June 2018
      Source:Algal Research, Volume 32
      Author(s): Mariel Carissimi, Simone Hickmann Flôres, Rosane Rech
      Despite its great importance, the traditional packaging is produced from non-renewable and non-biodegradable sources, causing several environmental problems. Therefore, biodegradable packaging has been attracting attention and interest from researchers and industries worldwide. This work developed biodegradable films with antioxidant properties, using cassava starch combined with biomass or biomass extract of microalgae Heterochlorella luteoviridis and Dunaliella tertiolecta. The films were characterized by their physicochemical, mechanical, barrier, optical and antioxidant properties. The film with the best characteristics was used as salmon packaging aiming protection against lipid oxidation. In general, the addition of biomass increased films' solubility, biodegradability and opacity, while the films with the addition of biomass extract showed the lowest values of these parameters. The addition of biomass increased films' elongation, rupture, and reduced the tensile strength and Young's modulus. Conversely, the addition of microalgae extract caused the inverse effect on these properties. All films with microalgae showed higher antioxidant activity, evaluated by peroxide index, compared to the control ones. The film containing 2.0% of H. luteoviridis extract presented the lowest water vapor permeability and good mechanical characteristics, and was applied in salmon packaging. The selected packaging decreased fish moisture and delayed lipid oxidation evaluated by TBARS index. The results showed incorporation of microalgae biomass resulted in biodegradable and highly soluble films, making it difficult to apply in moist foods. The films containing microalgae extracts were suitable to be used in foods with high water content.

      PubDate: 2018-04-15T04:40:39Z
      DOI: 10.1016/j.algal.2018.04.001
      Issue No: Vol. 32 (2018)
  • Non-steroidal anti-inflammatory drugs initiate morphological changes but
           inhibit carotenoid accumulation in Haematococcus pluvialis
    • Authors: István Bácsi; József Deli; Sándor Gonda; Ilona Mészáros; Gréta Veréb; Dalma Dobronoki; Sándor Alex Nagy; Viktória B-Béres; Gábor Vasas
      Pages: 1 - 13
      Abstract: Publication date: April 2018
      Source:Algal Research, Volume 31
      Author(s): István Bácsi, József Deli, Sándor Gonda, Ilona Mészáros, Gréta Veréb, Dalma Dobronoki, Sándor Alex Nagy, Viktória B-Béres, Gábor Vasas
      The economic role of certain types of cysts is unquestionable, since the production of several valuable biomolecules is connected to the resting stages of algae, including the red ketocarotenoid astaxanthin. It is relatively well known, how adverse environmental conditions induce cyst formation and astaxanthin accumulation. In the contrary, there is very limited information about stressors inhibiting these processes. An undesirable consequence of increasing drug use of the human and veterinary medicine is the appearance of the drugs both in natural and in mains water. Therefore, to study the effects of micro-contaminants, e.g. pharmaceuticals to non-target aquatic organisms is a recent issue both from ecological and economical point of view. In this study, the effects of three non-steroidal anti-inflammatory drugs (NSAIDs: diclofenac, diflunisal and mefenamic acid) on growth, cyst formation and astaxanthin accumulation of the flagellated green alga Haematococcus pluvialis were investigated. All three drugs inhibited growth, inhibition ranged from 29 to 81% on the basis of vegetative cell numbers on the 14th day of the experiments. Higher concentrations of the drugs led to higher proportion of cysts, which exceeded 60% of total cell number to the 14th day in diclofenac and diflunisal treatments. On the contrary, astaxanthin contents of treated cultures were lower with the increasing drug concentration, the pigment was undetectable in the presence of 0.075 and 0.05 mg ml−1 diclofenac. Results of carotenoid and chlorophyll content analysis suggest more specific processes behind the observed phenomena than membrane damage. Furthermore, the different phenomena or different extents of the same phenomena suggest that NSAIDs with diverse chemical structures may have different target points in physiological processes. Our results clearly show that NSAIDs could have much wider effective spectra than expected, long-term effects on microalgae might have unexpected ecological or economical consequences due to continuous exposure to these chemicals.
      Graphical abstract image

      PubDate: 2018-02-03T14:13:46Z
      DOI: 10.1016/j.algal.2018.01.007
      Issue No: Vol. 31 (2018)
  • Potential new genera of cyanobacterial strains isolated from thermal
           springs of western Sichuan, China
    • Authors: Jie Tang; Dong Jiang; Yifan Luo; Yuanmei Liang; Liheng Li; Md. Mahfuzur R. Shah; Maurycy Daroch
      Pages: 14 - 20
      Abstract: Publication date: April 2018
      Source:Algal Research, Volume 31
      Author(s): Jie Tang, Dong Jiang, Yifan Luo, Yuanmei Liang, Liheng Li, Md. Mahfuzur R. Shah, Maurycy Daroch
      Cyanobacteria have shown great potential for energy and environmental applications. Cyanobacterial resources, however, are still largely unexplored. Here, forty-nine out of one hundred thirty-two cyanobacterial isolates recovered from thermal springs of western Sichuan, China, were characterized. The phylogenetic analysis of 16S rRNA gene sequences categorized the isolates into three genera, Thermosynechococcus (63.3%), Leptolyngbya (34.7%) and Stanieria (2.0%). Based on sequence similarity, five phylotypes were identified as either putative new species of genus Leptolyngbya or possibly completely new genera. Temperature test showed that all isolates were thermotolerant and twenty-five isolates were capable of growth at temperature of 60 °C, suggesting that these isolates may have strong biotechnological potential. Additionally, three isolates exhibited NaHCO3 tolerance as high as 1 M, indicating that the isolates are promising candidates for bicarbonate-based cyanobacteria production system. Overall, this research laid solid basis for taxonomy and future exploration of extremophilic cyanobacteria for biotechnological and environmental applications.

      PubDate: 2018-02-14T00:20:43Z
      DOI: 10.1016/j.algal.2018.01.008
      Issue No: Vol. 31 (2018)
  • Enhancing fermentation wastewater treatment by co-culture of microalgae
           with volatile fatty acid- and alcohol-degrading bacteria
    • Authors: Wenqiang Qi; Shouhua Mei; Yizhong Yuan; Xuyang Li; Tao Tang; Quanyu Zhao; Minghong Wu; Wei Wei; Yuhan Sun
      Pages: 31 - 39
      Abstract: Publication date: April 2018
      Source:Algal Research, Volume 31
      Author(s): Wenqiang Qi, Shouhua Mei, Yizhong Yuan, Xuyang Li, Tao Tang, Quanyu Zhao, Minghong Wu, Wei Wei, Yuhan Sun
      Co-culture of microalgae and bacteria is a promising method for wastewater treatment. The suitable selection of the bacteria in co-cultures with microalgae is critical for wastewater treatment. Three bacteria, Exiguobacterium aurantiacum, Stenotrophomonas acidaminiphila, and Chryseobacterium scophthalmus, were the dominant bacterial species in fermentation wastewater treated by microalgae and activated sludge. Pure cultures and co-cultures of microalgae (Chlorella sorokiniana L3) and these bacteria were evaluated for the treatment of fermentation wastewater, which contains high concentrations of acetate acid, butyric acid, ethanol and butanol. The performance of the co-cultures was better than that of pure cultures of microalgae or bacteria for the removal of four organic compounds, and the removal efficiency of volatile fatty acids and alcohols in the best co-culture case was increased by 22.70% compared to that of pure cultures. Butanol and butyric acid were much more difficult for microalgae and bacteria to remove than were acetic acid and ethanol. The co-cultures of Chlorella sorokiniana L3 with Stenotrophomonas acidaminiphila or Chryseobacterium scophthalmus had the highest removal efficiencies for the four organic compounds in all treatments. The co-cultures of Chlorella sorokiniana L3 with Exiguobacterium aurantiacum, Stenotrophomonas acidaminiphila or Chryseobacterium scophthalmus promoted not only chlorophyll a + b production but also biomass accumulation of Chlorella sorokiniana L3 during the 3 days of cultivation compared with those in pure cultures. More than 77.8% of NH4 +-N, 45.6% of total PO4 3−-P and 63.7% of COD (chemical oxygen demand) were removed in all co-cultures. These three bacteria are potential candidates for wastewater treatment through co-culture with microalgae.

      PubDate: 2018-02-03T14:13:46Z
      DOI: 10.1016/j.algal.2018.01.012
      Issue No: Vol. 31 (2018)
  • Carbon use efficiency diagnostics in Nannochloropsis salina
    • Authors: Tawanda Zidenga; Munehiro Teshima; George Perkins; Thom Rahn; Scott Twary; Jeffrey M. Heikoop
      Pages: 40 - 46
      Abstract: Publication date: April 2018
      Source:Algal Research, Volume 31
      Author(s): Tawanda Zidenga, Munehiro Teshima, George Perkins, Thom Rahn, Scott Twary, Jeffrey M. Heikoop
      Carbon dioxide (CO2) can be a significant resource input affecting the cost of algae biomass production on an industrial scale. Improvements in biofuel productivity therefore require characterization of CO2 use efficiency (CUE). RuBisCO saturation with CO2 is an important factor influencing biomass productivity. During CO2 fixation by RuBisCO, fractionation of carbon isotopes occurs, with preferential fixation of 12CO2, resulting in assimilation of the lighter isotope in algae. This photosynthetic discrimination (ΔDIC-algae), approximated by the difference between the δ13C of external medium and that of algae, is a function of the proportion of CO2 fixed relative to supply. ΔDIC-algae has been applied to the study of photosynthesis in algae over the past few decades and we have adopted the tool to characterize improvements in conditions optimized for biofuel productivity, such as controlled photobioreactors. We report the use of ΔDIC-algae as a tool for characterizing CO2 dynamics and RuBisCO saturation in Nannochloropsis salina CCMP 1776, a benchmark strain in algal biofuels research. We use ΔDIC-algae to describe the conditions under which RuBisCO saturation can be achieved to maximize biomass productivity. Our results suggest that determination of ΔDIC-algae can provide important feedback to support engineering and cultural improvements that can impact carbon use efficiency and biomass productivity.

      PubDate: 2018-02-14T00:20:43Z
      DOI: 10.1016/j.algal.2018.01.011
      Issue No: Vol. 31 (2018)
  • Cultivation of Emiliania huxleyi for coccolith production
    • Authors: I. Jakob; F. Weggenmann; C. Posten
      Pages: 47 - 59
      Abstract: Publication date: April 2018
      Source:Algal Research, Volume 31
      Author(s): I. Jakob, F. Weggenmann, C. Posten
      Graphical abstract image

      PubDate: 2018-02-14T00:20:43Z
      DOI: 10.1016/j.algal.2018.01.013
      Issue No: Vol. 31 (2018)
  • Effect of carbon dioxide on biomass and lipid production of Chlorella
           pyrenoidosa in a membrane bioreactor with gas-liquid separation
    • Authors: Lei Zhang; Yong-Zhong Wang; Shengwei Wang; Ke Ding
      Pages: 70 - 76
      Abstract: Publication date: April 2018
      Source:Algal Research, Volume 31
      Author(s): Lei Zhang, Yong-Zhong Wang, Shengwei Wang, Ke Ding
      In this work, an immobilized-cell biofilm photo-bioreactor, in which the CO2-rich gaseous phase was separated from the nutrient-rich liquid phase by a polytetrafluoroethylene membrane, was proposed to enhance the adsorption of CO2 by algal cells and the formation of biofilm on the membrane surface by reducing the disturbance from bubbles. The biomass productivity and biochemical composition, CO2 removal efficiency, and fatty acid profile were measured to evaluate effect of CO2 concentration on biomass and lipid production for biotechnological applications of the photo-bioreactor. The maximal biomass productivity (4.06 g/m2/d), lipid productivity (0.64 g/m2/d), and CO2 removal efficiency (52.5%) were obtained at 3% CO2 concentration, and C16–C18 fatty acids in this cultivated biofilm accounted for 96.28% to 98.61% of the total fatty acids in all runs. The results indicate that the productivities of lipid and biomass were significantly improved using the immobilized-cell cultivation method.

      PubDate: 2018-02-03T14:13:46Z
      DOI: 10.1016/j.algal.2018.01.014
      Issue No: Vol. 31 (2018)
  • A pilot-scale bioprocess to produce amphidinols from the marine microalga
           Amphidinium carterae: Isolation of a novel analogue
    • Authors: A. Molina-Miras; A. Morales-Amador; C.R. de Vera; L. López-Rosales; A. Sánchez-Mirón; M.L. Souto; J.J. Fernández; M. Norte; F. García-Camacho; E. Molina-Grima
      Pages: 87 - 98
      Abstract: Publication date: April 2018
      Source:Algal Research, Volume 31
      Author(s): A. Molina-Miras, A. Morales-Amador, C.R. de Vera, L. López-Rosales, A. Sánchez-Mirón, M.L. Souto, J.J. Fernández, M. Norte, F. García-Camacho, E. Molina-Grima
      Marine dinoflagellate microalgae belonging to the genus Amphidinium are a key source of an interesting group of polyketide metabolites with potent bioactivities, wide-ranging functional diversity and stereochemical complexity, but low natural availabilities. The feasibility of a microalgae dinoflagellate-based sustainable bioprocess for producing amphidinols (APDNs) by photoautotrophic culture of Amphidinium carterae in a pilot-scale LED-illuminated bubble column photobioreactor (PBR) was therefore investigated. A fed-batch culture mode with pulse feeding strategy provided a growth pattern strongly limited by the availability of phosphate content in the culture medium that stimulated the production of cellular APDNs. Since A. carterae was found to be much more shear-sensitive than other shear-tolerant non-dinoflagellate microalgae, the culture height and air flow rate were established to ensure the absence of damaging levels of hydrodynamic stress. The biomass capacity yielded by the PBR at the end of the culture (0.540 g d.w. L−1 equivalent to 1.70 × 106 cell mL−1) corresponded to that estimated stoichiometrically from the experimentally determined biomass P-molar formula (C329 O126 H732 N69 S3 P1) and the total phosphorus and nitrogen balances. The downstream processing section was initially conceived to recover APDNs excreted by cells into the supernatant. A dry APDN-enriched extract concentration of 49 mg per liter of supernatant was obtained. This purification process led to partitioning of the extract into several fractions and sub-fractions thereof. Only two sub-fractions were studied, yielding thereof highly pure (>95% pure) luteophanol D and lingshuiol A, and a new, roughly purified (>80% pure) APDN, namely amphidinol 20. The percentages of luteophanol D, lingshuiol A and amphidinol 20 by dry weight of the APDN-enriched extract obtained were 1%, 0.39% and 0.31%, respectively, thus representing a concentration in the culture supernatant of 490, 191 and 152 μg L−1, respectively.

      PubDate: 2018-02-03T14:13:46Z
      DOI: 10.1016/j.algal.2018.01.010
      Issue No: Vol. 31 (2018)
  • Bacterial community changes in an industrial algae production system
    • Authors: Scott P. Fulbright; Adam Robbins-Pianka; Donna Berg-Lyons; Rob Knight; Kenneth F. Reardon; Stephen T. Chisholm
      Pages: 147 - 156
      Abstract: Publication date: April 2018
      Source:Algal Research, Volume 31
      Author(s): Scott P. Fulbright, Adam Robbins-Pianka, Donna Berg-Lyons, Rob Knight, Kenneth F. Reardon, Stephen T. Chisholm
      While microalgae are a promising feedstock for production of fuels and other chemicals, a challenge for the algal bioproducts industry is obtaining consistent, robust algae growth. Algal cultures include complex bacterial communities and can be difficult to manage because specific bacteria can promote or reduce algae growth. To overcome bacterial contamination, algae growers may use closed photobioreactors designed to reduce the number of contaminant organisms. Even with closed systems, bacteria are known to enter and cohabitate, but little is known about these communities. Therefore, the richness, structure, and composition of bacterial communities were characterized in closed photobioreactor cultivations of Nannochloropsis salina in F/2 medium at different scales, across nine months spanning late summer – early spring, and during a sequence of serially inoculated cultivations. Using 16S rRNA sequence data from 275 samples, bacterial communities in small, medium, and large cultures were shown to be significantly different. Larger systems contained richer bacterial communities compared to smaller systems. Relationships between bacterial communities and algae growth were complex. On one hand, blooms of a specific bacterial type were observed in three abnormal, poorly performing replicate cultivations, while on the other, notable changes in the bacterial community structures were observed in a series of serial large-scale batch cultivations that had similar growth rates. Bacteria common to the majority of samples were identified, including a single OTU within the class Saprospirae that was found in all samples. This study contributes important information for crop protection in algae systems, and demonstrates the complex ecosystems that need to be understood for consistent, successful industrial algae cultivation. This is the first study to profile bacterial communities during the scale-up process of industrial algae systems.

      PubDate: 2018-02-25T00:56:52Z
      DOI: 10.1016/j.algal.2017.09.010
      Issue No: Vol. 31 (2018)
  • Influence of spectral light quality on the pigment concentrations and
           biomass productivity of Arthrospira platensis
    • Authors: Gustavo M. Lima; Pedro C.N. Teixeira; Cláudia M.L.L. Teixeira; Diego Filócomo; Celso L.S. Lage
      Pages: 157 - 166
      Abstract: Publication date: April 2018
      Source:Algal Research, Volume 31
      Author(s): Gustavo M. Lima, Pedro C.N. Teixeira, Cláudia M.L.L. Teixeira, Diego Filócomo, Celso L.S. Lage
      The species in the Arthrospira genus are cultured at a large scale throughout the world primarily for food supplements for human and animal diets. These species are valued for the rich composition of their biomass, which contains minerals, antioxidants, proteins and essential amino acids. This biomass can also be used for high-value product extraction, for example, the pigments chlorophyll a, β-carotene and phycocyanin as well as essential fatty acids. The use of LEDs is a solution for optimizing the productivity and biochemical composition of biomass produced by these microalgae. In this study, an innovative strategy for using LEDs was evaluated for Arthrospira platensis cultivation to increase its biomass productivity and high-value pigments (chlorophyll a, total carotenoids and phycocyanin). Microalgae suspensions were cultured in 250 mL Erlenmeyer flasks containing 120 mL of culture (George-modified Zarrouk's medium, pH 8.90) at 32 ± 1 °C with constant stirring and an initial biomass concentration of 0.03 g L−1. The biomass weights from ten lighting conditions consisting of blue and red LEDs of different compositions were evaluated in relation to the algal productivity and the chlorophyll a, total carotenoid and phycocyanin contents. The best results were obtained using LEDs that had a 70% red and 30% blue composition and a light intensity of 100 μE m−2 s−1, leading to an average biomass productivity of 0.148 g L−1d−1 and average concentrations of 21.35 μg mL−1, 5.45 μg mL−1 and 167.98 μg mL−1 of chlorophyll a, carotenoids and phycocyanin, respectively, in the given culture volume.

      PubDate: 2018-02-25T00:56:52Z
      DOI: 10.1016/j.algal.2018.02.012
      Issue No: Vol. 31 (2018)
  • High-throughput system for quantifying and characterizing homologous
           recombination in Chlamydomonas reinhardtii
    • Authors: Hussam Hassan Nour-Eldin; Elizabeth A. Specht; Joseph Ostrand; Kevin T.D. Hoang; Prema S. Karunanithi; Stephen P. Mayfield
      Pages: 167 - 172
      Abstract: Publication date: April 2018
      Source:Algal Research, Volume 31
      Author(s): Hussam Hassan Nour-Eldin, Elizabeth A. Specht, Joseph Ostrand, Kevin T.D. Hoang, Prema S. Karunanithi, Stephen P. Mayfield
      In the green alga Chlamydomonas reinhardtii, introduced DNA fragments predominantly insert randomly into the nuclear genome by non-homologous recombination (NHR), often resulting in highly variable phenotypes between transformants. Homologous recombination (HR) can occur in C. reinhardtii but at very low frequency, and is often accompanied by insertions, deletions, and/or rearrangements at the recombination site. To benchmark the frequency and characterize the nature of HR integrations in C. reinhardtii, we developed a system for detecting and characterizing HR events that includes three intact markers and one split marker as well a novel design element: utilizing a long intron as the homology region. In this study we demonstrate that this system meets the following criteria: accommodates high-throughput screening; provides a high-fidelity phenotype for detecting HR without false positives from reversion or locus heterogeneity; allows and captures both single- and double-crossover HR events; reports HR and NHR rates from a single transformation; and allows characterization of imprecise recombination or rearrangement at the integration site. Using this system we reproducibly determined the HR rate in our recipient strain of C. reinhardtii and characterized a number of recombinants by restriction digests and sequencing of PCR amplified recombination junctions to show that both double and single crossover events were recovered and that integration occurred both via perfect and imperfect (i.e. accompanied by insertions, deletions, and rearrangements) HR. This system is valuable for systematically testing approaches for increasing HR efficiency and accuracy.

      PubDate: 2018-02-25T00:56:52Z
      DOI: 10.1016/j.algal.2018.02.005
      Issue No: Vol. 31 (2018)
  • Overexpression of acetyl-CoA synthetase (ACS) enhances the biosynthesis of
           neutral lipids and starch in the green microalga Chlamydomonas reinhardtii
    • Authors: Rocío Rengel; Richard T. Smith; Richard P. Haslam; Olga Sayanova; Marta Vila; Rosa León
      Pages: 183 - 193
      Abstract: Publication date: April 2018
      Source:Algal Research, Volume 31
      Author(s): Rocío Rengel, Richard T. Smith, Richard P. Haslam, Olga Sayanova, Marta Vila, Rosa León
      Genetic engineering can be the solution to achieve the economically feasible production of microalgal based biofuels and other bulk materials. A good number of microalgal species can grow mixotrophically using acetate as carbon source. Moreover, experimental evidence suggests that the biosynthesis of acetyl-CoA could be a limiting step in the complex multifactor-dependent biosynthesis of acylglycerides and point to acetyl-CoA synthetase (ACS) as a key enzyme in the process. In order to test this hypothesis we have engineered the model chlorophyte Chlamydomonas reinhardtii to overexpress the endogenous chloroplastic acetyl-CoA synthetase, ACS2. Expression of the ACS2 encoding gene under the control of the strong constitutive RBCS2 promoter in nitrogen-replete cultures resulted in a 2-fold increase in starch content and 60% higher acyl-CoA pool compared to the parental line. Under nitrogen deprivation, the Cr-acs2 transformant shows 6-fold higher levels of ACS2 transcript and a 2.4-fold higher accumulation of triacylglycerol (TAG) than the untransformed control. Analysis of lipid species and fatty acid profiles in the Cr-acs2 transformant revealed a higher content than the parental strain in the major glycolipids and suggests that the enhanced synthesis of triacylglycerol in the transformant is not achieved at the expense of membrane lipids, but is due to an increase in the carbon flux towards the synthesis of acetyl-CoA in the chloroplast. These data demonstrate the potential of engineering the chloroplastic ACS to increase the carbon flux towards the synthesis of fatty acids as an alternative strategy to enhance the biosynthesis of lipids in microalgae.
      Graphical abstract image

      PubDate: 2018-02-25T00:56:52Z
      DOI: 10.1016/j.algal.2018.02.009
      Issue No: Vol. 31 (2018)
  • Growth rates and photon efficiency of Chlorella vulgaris in relation to
           photon absorption rates under different LED-types
    • Authors: Johannes Bialon; Thomas Rath
      Pages: 204 - 215
      Abstract: Publication date: April 2018
      Source:Algal Research, Volume 31
      Author(s): Johannes Bialon, Thomas Rath
      A general model was developed that depicts the long-term growth profiles of Chlorella vulgaris batch cultures under different light intensities of white LED light. The model equation reflects the growth with a time delay of second order at different light intensities by changing only one parameter of the entire equation. This model was applied to the data of short-term batch cultures at different incident light intensities of white, blue, green and red LEDs and growth rates were calculated. Models for the growth rates depending on the photon absorption rates for the different LED-types were developed. Photon absorption rates can be determined for other photobioreactor systems, hence the growth rates of Chlorella vulgaris in other reactor systems can be calculated using the newly developed models. At photon absorption rates up to 2.5 Einstein L−1 d−1, C. vulgaris yielded the highest growth rates under red LEDs. At higher photon absorption rates, white light led to the highest growth rates. Green and blue LEDs yielded similar growth rates which were consistently lower than the growth rates under white and red LEDs. Maximum photon efficiency of ~130 absorbed photons per fixed CO2 was reached under red LEDs.

      PubDate: 2018-02-25T00:56:52Z
      DOI: 10.1016/j.algal.2018.02.007
      Issue No: Vol. 31 (2018)
  • Selection of microalgae with potential for cultivation in
           surfactant-stabilized foam
    • Authors: María Vázquez; Juan L. Fuentes; Adriana Hincapié; Inés Garbayo; Carlos Vílchez; María Cuaresma
      Pages: 216 - 224
      Abstract: Publication date: April 2018
      Source:Algal Research, Volume 31
      Author(s): María Vázquez, Juan L. Fuentes, Adriana Hincapié, Inés Garbayo, Carlos Vílchez, María Cuaresma
      Recently, microalgal cultivation in liquid foams has been developed. Compared to the traditional systems, this concept is expected to offer advantages such as increased mass transfer and reduced biomass harvesting costs and water consumption. However, there is limited information, thus far, on the microalgal performance in foam-bed photobioreactors. Therefore, this study was aimed at comparing the foaming properties of six algal strains to identify the criteria that could be broadly employed for assessing the microalgal potential for cultivation in a foam-bed photobioreactor. The microalgal strains investigated were selected based on their different nature and potential uses. All the microalgal strains could not naturally produce stable foam, thus necessitating the use of a surfactant. To investigate the differences in the foaming properties of the selected microalgae, the natural surfactant, bovine serum albumin, was employed. Factors such as culture age, algal hydrophobicity, and biomass concentration differently influenced the key foaming properties (foamability, microalgal partitioning, and foam stability) depending on the microalgal strain. In conclusion, the assessment of the foaming properties of microalgal strains together with their inherent growth characteristics revealed large differences in the potentiality of microalgae to be cultivated in a foam-bed photobioreactor. In particular, among the microalgal strains tested, the commercial strains Chlorella sorokiniana, Nannochloropsis gaditana, and Scenedesmus obliquus showed the highest potentiality for cultivation in foam. Overall, the following criteria could be broadly applied to select suitable microalgae for cultivation in a foam-bed photobioreactor: high or moderate foamability of the microalga-surfactant suspension, and microalgal partitioning, stability of the foam formed, and robustness and fast growth of the strains.
      Graphical abstract image

      PubDate: 2018-02-25T00:56:52Z
      DOI: 10.1016/j.algal.2018.02.006
      Issue No: Vol. 31 (2018)
  • Light-dependent kinetic model for microalgae experiencing
           photoacclimation, photodamage, and photodamage repair
    • Authors: Levi Straka; Bruce E. Rittmann
      Pages: 232 - 238
      Abstract: Publication date: April 2018
      Source:Algal Research, Volume 31
      Author(s): Levi Straka, Bruce E. Rittmann
      Microalgae naturally are exposed to changing light conditions. While a higher light intensity can promote a faster growth rate, it also can cause photodamage that leads to a temporary or semi-permanent decline in growth rate. We developed a model of photosynthetic growth including photoacclimation, reversible photodamage to photosystem II (PSII), and more severe photodamage to photosystem I (PSI). Phototrophic biomass optimizes its photosynthetic machinery to the light intensity it is experiencing; this is captured in the model by photoacclimation, in which photodamage to PSII caused by absorbed light is balanced by repair. However, repair of PSII photodamage can be overwhelmed by increases of light outside the photoacclimated condition, and this leads to severe PSII photodamage that slows the cells' specific growth rate. Furthermore, very large increases in light intensity can lead to photodamage to PSI, which is semi-permanent in that it can take days to weeks to repair. Our model captures all these phenomena. Example model outputs demonstrate the importance of each phenomenon for increases and decreases in light intensity from the photoacclimated state.
      Graphical abstract image

      PubDate: 2018-02-25T00:56:52Z
      DOI: 10.1016/j.algal.2018.02.022
      Issue No: Vol. 31 (2018)
  • Evaluation of secretion reporters to microalgae biotechnology: Blue to red
           fluorescent proteins
    • Authors: João Vitor Dutra Molino; João Carlos Monteiro de Carvalho; Stephen Mayfield
      Pages: 252 - 261
      Abstract: Publication date: April 2018
      Source:Algal Research, Volume 31
      Author(s): João Vitor Dutra Molino, João Carlos Monteiro de Carvalho, Stephen Mayfield
      Efficient protein secretion could potentially be exploited for improving the performance of heterologous protein expression system. However, efficient protein secretion depends on numerous factors that are not always known, and rapid development of protein secretion depends on efficient reporters. This study aimed to compare the secretion efficiency of seven fluorescent proteins (FPs)—mTagBFP, mCerulean, Emerald, CrGFP, cOFP, tdTomato, and mCherry—which are photoactive across the visible light spectrum in the microalgal expression system, Chlamydomonas reinhardtii. To fully compare the efficiency of FPs, three expression vectors—a non-secreting vector used as a control and two secreting vectors employing arylsulfatase 1 (ARS1) signal peptide—were used. Up to 94 transformants for each construct were evaluated to better determine the secretion detection efficiency and variability of each FP construct. Fluorescence measurements of all FPs in the whole culture and supernatant were conducted using a microplate reader. Furthermore, we observed fluorescence of six FPs, among the seven tested, in the secretory pathway by confocal fluorescence microscopy. The results indicated that orange and red FPs are the most suitable for this photosynthetic pigment-rich organism, but the FP reporter for secretion should be selected carefully, since some may be deleteriously modified, as observed in the case of tdTomato, in our study. Overall, cOFP and mCherry performed admirably with a high fluorescence signal to noise ratio (S/N > 6) for all constructs as compared to that of the wild type auto-fluorescence, and showed a high positive rate of transformants (>75%). This FP may play an important role in protein secretion studies, supporting the development of this potential expression system based on microalgae.
      Graphical abstract image

      PubDate: 2018-02-25T00:56:52Z
      DOI: 10.1016/j.algal.2018.02.018
      Issue No: Vol. 31 (2018)
  • Metabolic engineering of fatty acid biosynthesis in Chlorella vulgaris
           using an endogenous omega-3 fatty acid desaturase gene with its promoter
    • Authors: Md Nor Norashikin; Saw Hong Loh; Ahmad Aziz; Thye San Cha
      Pages: 262 - 275
      Abstract: Publication date: April 2018
      Source:Algal Research, Volume 31
      Author(s): Md Nor Norashikin, Saw Hong Loh, Ahmad Aziz, Thye San Cha
      This study demonstrated the overexpression of omega-3 fatty acid desaturase (ω-3 FAD) gene under the control of its endogenous promoter and to elucidate its effect on fatty acid biosynthesis pathway in transgenic Chlorella vulgaris. Two stable transgenic lines (Ch-TL1 and Ch-TL2) were selected and cultured under nitrate-replete and nitrate-deficient BBM culture conditions, respectively to determine the growth, biomass production, total oil content, fatty acid composition and the expression level of four fatty acid biosynthetic genes of the transgenic C. vulgaris. Results revealed that both transgenic lines and wild-type displayed similar growth patterns. Higher biomass production and total oil content were recorded for both transgenic lines that were cultured under nitrate-deficient condition. The ω-3 FAD gene expression was consistently up-regulated in Ch-TL2 in all culture conditions which led to higher α-linolenic acid (C18:3n3) content. Similarly, the expression of β-ketoacyl ACP synthase I (KAS I), stearoyl-ACP desaturase (SAD) and omega-6 desaturase (ω-6 FAD) genes were also up-regulated in Ch-TL2. However, the accumulation of palmitic (C16:0), stearic (C18:0), oleic (C18:1) and linoleic (C18:2) acids were found to be differentially regulated at either transcriptional or post-transcriptional levels. PCR-base genome walking of Ch-TL2 genomic DNA successfully elucidated the integration sites and flanking regions of the inserted vector cassette. These findings provide valuable insight that could pave way for further genetic improvement of the C. vulgaris for various downstream applications.

      PubDate: 2018-02-25T00:56:52Z
      DOI: 10.1016/j.algal.2018.02.020
      Issue No: Vol. 31 (2018)
  • Heterogeneous expression of human PNPLA3 triggers algal lipid accumulation
           and lipid droplet enlargement
    • Authors: Xiang Wang; Wei Wei; Nian-Jing Li; Wasiqi Yuan; Yu Ding; Wei-Dong Yang; Jie-Sheng Liu; Srinivasan Balamurugan; Hong-Ye Li
      Pages: 276 - 281
      Abstract: Publication date: April 2018
      Source:Algal Research, Volume 31
      Author(s): Xiang Wang, Wei Wei, Nian-Jing Li, Wasiqi Yuan, Yu Ding, Wei-Dong Yang, Jie-Sheng Liu, Srinivasan Balamurugan, Hong-Ye Li
      Microalgal metabolic engineering holds great promise for algal biofuels. However, identification of the key lipid metabolic target remains challenging due to its complex regulation. In this study, we advocated an alternative strategy that potentially rewired lipid metabolism by unprecedented mechanisms. PNPLA3, a human protein associated with non-alcoholic fatty liver disease (NAFLD), was firstly tested in microalgae for enhancing lipid accumulation. HsPNPLA3 was synthesized with a site mutation (I148M) and expressed in a model diatom Phaeodactylum tricornutum. Heterogeneous HsPNPLA3-I148M was successfully integrated, transcribed and expressed. Lipidomic analyses revealed that HsPNPLA3-I148M significantly elevated TAG content by 1.55-fold in algae, while algal growth and photosynthetic rate were not impaired. Fatty acid profile showed that content of C16:0, C18:1 and C20:4 was increased by 1.43-, 4.18- and 4.3-fold, respectively, which implied that HsPNPLA3-I148M might regulate the fatty acid substrate preference. Overall, the findings demonstrated that human PNPLA3 played a potential role in elevating TAG accumulation by regulating lipogenic enzymes and provide unprecedented insights into its functional significance.

      PubDate: 2018-02-25T00:56:52Z
      DOI: 10.1016/j.algal.2018.02.019
      Issue No: Vol. 31 (2018)
  • Life history determinants of the susceptibility of the blood alga
           Haematococcus to infection by Paraphysoderma sedebokerense
    • Authors: Céline C. Allewaert; Noreen Hiegle; Martina Strittmatter; Reinhoud de Blok; Tiago Guerra; Claire M.M. Gachon; Wim Vyverman
      Pages: 282 - 290
      Abstract: Publication date: April 2018
      Source:Algal Research, Volume 31
      Author(s): Céline C. Allewaert, Noreen Hiegle, Martina Strittmatter, Reinhoud de Blok, Tiago Guerra, Claire M.M. Gachon, Wim Vyverman
      Haematococcus pluvialis is currently cultivated at large scale for its ability to produce high amounts of the high value keto-carotenoid astaxanthin when encysted. Mass cultivation of this species is threatened by the destructive blastocladialean fungus, Paraphysoderma sedebokerense Boussiba, Zarka and James, responsible for the fast collapse of Haematococcus populations. Given the difficulty of maintaining pathogen-free production systems and the lack of treatment options, the selection and development of resistant Haematococcus strains could potentially present an effective and efficient method to control infection. In the present work, we examined the host specificity of P. sedebokerense (strain PS1) through quantitative phenotyping of 44 Haematococcus strains in a laboratory-controlled infectivity assay. We determined the growth and photosynthetic activity of strains in the presence and absence of PS1 over time (using Chl a in vivo fluorescence) and quantified the degree of infection through the intensity of fluorescence after staining with Wheat Germ Agglutinin (WGA)-Fluorescein, which labels PS1 without interfering with Haematococcus. The measurements were converted into three infectivity proxies, allowing comparisons amongst strains. Eventually, microscopy was performed to check the life stage of Haematococcus upon infection. Strains of Haematococcus clearly exhibited different levels of susceptibility against PS1 as determined by the three proxies. These were not related to phylogenetic background, nor the sampling origin of the strains. Amongst ten strains with low susceptibility, five occurred as flagellated state cultures, while others were palmelloid and/or aplanospore dominated. In addition, in a long-term selection experiment, we showed that susceptibility to PS1 of a highly sensitive H. pluvialis strain decreased through the dominance of flagellated phenotypes over several generations of infection. While providing considerable expansion of the relation between PS1 and Haematococcus our study opens the possibility for selection and development of resistant strains.

      PubDate: 2018-02-25T00:56:52Z
      DOI: 10.1016/j.algal.2018.02.015
      Issue No: Vol. 31 (2018)
  • Over-accumulation of astaxanthin in Haematococcus pluvialis through
           chloroplast genetic engineering
    • Authors: Janeth I. Galarza; Javier A. Gimpel; Verónica Rojas; Bertha O. Arredondo-Vega; Vitalia Henríquez
      Pages: 291 - 297
      Abstract: Publication date: April 2018
      Source:Algal Research, Volume 31
      Author(s): Janeth I. Galarza, Javier A. Gimpel, Verónica Rojas, Bertha O. Arredondo-Vega, Vitalia Henríquez
      The carotenoid biosynthesis pathway of Haematococcus pluvialis has been genetically modified to overproduce astaxanthin, a red pigment of high commercial value. The endogenous phytoene desaturase coding sequence (pds) has been codon optimized and overexpressed in the chloroplast of H. pluvialis under the control of the psbA promoter/UTR. After biolistic transformation and selection, PDS mRNA and protein were detected in transformants. Astaxanthin accumulated up to 67% higher in transformed strains than in wild-type upon induction with high light intensity and nitrogen depletion. This is the first report of plastid transformation of a microalgae with its endogenous pds nuclear gene.

      PubDate: 2018-02-25T00:56:52Z
      DOI: 10.1016/j.algal.2018.02.024
      Issue No: Vol. 31 (2018)
  • Identification of harmful protozoa in outdoor cultivation of Chlorella and
           the use of ultrasonication to control contamination
    • Authors: Yao Wang; Yingchun Gong; Lili Dai; Milton Sommerfeld; Chengwu Zhang; Qiang Hu
      Pages: 298 - 310
      Abstract: Publication date: April 2018
      Source:Algal Research, Volume 31
      Author(s): Yao Wang, Yingchun Gong, Lili Dai, Milton Sommerfeld, Chengwu Zhang, Qiang Hu
      Contaminating organisms in mass cultivation present one of the major challenges that must be overcome for successful commercialization of algal biofuels. The present study identified a range of contaminating organisms in Chlorella cultures cultivated in outdoor raceway ponds at the Arizona Center for Algae Technology and Innovation (Mesa, AZ). Nineteen organisms or Operational Taxonomic Units (OTU) in the Chlorella culture were identified by a combination of microscopic observation and 18S rRNA denaturing gradient gel electrophoresis (DGGE). More detailed analyses identified these contaminating organisms as 2 fungi, 7 flagellates, 3 amoebae, 4 ciliates, 1 rotifer, and 2 large insects. Among them Poterioochromonas sp., a small flagellate, appeared to be one of the most harmful causing culture collapse. In order to control Poterioochromonas sp., various operational parameters and application strategies of ultrasonic treatment were investigated. During sixteen-day consecutive Chlorella cultivation in batch mode, the ultrasonication conditions of 6 L min−1 flow rate with the power of 495 W at 100% amplitude and a treatment frequency of once for 1 h every day, was proven to be the most effective in preventing Poterioochromonas outbreak in Chlorella culture with volume of 60 L. The above ultra-sonication method was also effective at destroying an unknown fungus, an amoeba (Acanthocystis sp.), and ciliates (a member of the family Orchitophryidae). Our findings can serve as a technical foundation for the application of ultrasonication to control some of the contaminating microorganisms in mass cultivation of microalgae including Chlorella.

      PubDate: 2018-02-25T00:56:52Z
      DOI: 10.1016/j.algal.2018.02.002
      Issue No: Vol. 31 (2018)
  • Exploring the potential of high-density cultivation of cyanobacteria for
           the production of cyanophycin
    • Authors: Luca Lippi; Lars Bähr; Arne Wüstenberg; Annegret Wilde; Ralf Steuer
      Pages: 363 - 366
      Abstract: Publication date: April 2018
      Source:Algal Research, Volume 31
      Author(s): Luca Lippi, Lars Bähr, Arne Wüstenberg, Annegret Wilde, Ralf Steuer
      Photoautotrophic cyanobacteria and microalgae offer significant potential for the renewable synthesis of high-value products. As yet, however, the productivity of phototrophic cultures is limited due to the low cell densities that are typically obtained in current pilot scale photobioreactors. Here, we explore the use of ultrahigh-density cultivation of cyanobacteria for the production of cyanophycin, a non-ribosomally synthesized biopolymer of high biotechnological interest. We demonstrate that ultrahigh-density cultivation using a two-tier vessel with membrane-mediated CO2 supply yields a cyanophycin content per cellular dry weight similar to previously reported values, while the volumetric productivity per culture volume is significantly increased. Already after 96 h of cultivation, the engineered production strain BW86 reached up to 1 g cyanophycin per liter culture, approximately a 4-fold increase over the previously reported maximal yield obtained after 12 days of cultivation. Under phosphate-limiting growth conditions, the wild-type strain Synechcocystis sp. PCC 6803 accumulates up to 0.6 g cyanophycin per L culture. Our results demonstrate that ultrahigh-density cultivation is a suitable strategy towards the development of viable phototrophic production processes for cyanophycin and possibly other products of interest.

      PubDate: 2018-03-06T12:34:47Z
      DOI: 10.1016/j.algal.2018.02.028
      Issue No: Vol. 31 (2018)
  • Microalgae for biobutanol production – Technology evaluation and
           value proposition
    • Authors: Tong Kai Yeong; Kailin Jiao; Xianhai Zeng; Lu Lin; Sharadwata Pan; Michael K. Danquah
      Pages: 367 - 376
      Abstract: Publication date: April 2018
      Source:Algal Research, Volume 31
      Author(s): Tong Kai Yeong, Kailin Jiao, Xianhai Zeng, Lu Lin, Sharadwata Pan, Michael K. Danquah
      The depletion of petroleum and fossil fuels and the escalating problem of climate change motivate and compel an ongoing effort focusing on the development of renewable energy in the form of biofuels. Biobutanol is one such potent biofuel, attributing to similar characteristics as of gasoline, which manifests in easier public distribution based on the current oil and gas infrastructure. Also, the development of the third-generation biofuels sourced from cultivation of microalgae seems an outright promising prospect for renewable energy sources. This is mainly because of its inherent advantages in comparison to the previous methods of biofuel production from crops and plant waste. However, in spite of the ongoing efforts, the research targeting towards biobutanol production utilizing microalgal resources is insufficient. Working on the strengths of both may provide the much needed boost for the thriving biofuel industry, ultimately aiding to cope with global energy demand and reduce CO2 emissions. In this review, the design and selection of a complete industrial scale biobutanol production plant, using microalgae as the feedstock, have been proposed. Advances in bioprocess technologies for biobutanol production via fermentation and biobutanol recovery methods are described. In addition, comparative analyses of biobutanol versus petroleum diesel and biodiesel, and strategies for biobutanol cum lipid and methane gas manufacturing are also discussed.
      Graphical abstract image

      PubDate: 2018-04-15T04:40:39Z
      DOI: 10.1016/j.algal.2018.02.029
      Issue No: Vol. 31 (2018)
  • Marine macroalgal nursery: A model for sustainable production of seedlings
           for large scale farming
    • Authors: Vishal Gupta; Nitin Trivedi; Silvano Simoni; C.R.K. Reddy
      Pages: 463 - 468
      Abstract: Publication date: April 2018
      Source:Algal Research, Volume 31
      Author(s): Vishal Gupta, Nitin Trivedi, Silvano Simoni, C.R.K. Reddy
      Innovative technologies in seaweed aquaculture are the need of the hour for sustaining the emerging global market demands. The supply of seedlings for year-round sea farming has remained as a major challenge for large-scale production of seaweeds. This study describes a simple innovative model integrating the designing of a prototype with an effective protocol for seedling production and their propagation for the continuous production of seedlings from seaweeds. The novelty of this model includes its design enabling maximum seedlings production and demonstration of reusability of enzyme employed for protoplast (seedlings) production for five times without compromising over the protoplast yield and viability. The laboratory test trials conducted to assess the effectivity of this model in the production of seedlings from protoplasts with Ulva yielded seedling biomass of 0.25 kg fresh wt. (>200 folds of initial biomass) in 44 days culture period over 0.33 m2 surface area. The present prototype is simple, scalable and facilitates a consistent production of a large number of quality seedlings from relatively a small sample size. A concept layout for scale-up production of seedlings in an outdoor facility is also proposed based on prototype tested in this study. The findings reported in this study collectively not only promote the concept for establishing the macroalgal nursery for large-scale production of quality seedlings suitable for extraction of pharmaceutical and nutraceutical grade products but also provide an option for rapid restoration of species, if found under threat.
      Graphical abstract image

      PubDate: 2018-04-15T04:40:39Z
      DOI: 10.1016/j.algal.2018.02.032
      Issue No: Vol. 31 (2018)
  • The impact of wastewater characteristics, algal species selection and
           immobilisation on simultaneous nitrogen and phosphorus removal
    • Authors: Matthew Kube; Bruce Jefferson; Linhua Fan; Felicity Roddick
      Pages: 478 - 488
      Abstract: Publication date: April 2018
      Source:Algal Research, Volume 31
      Author(s): Matthew Kube, Bruce Jefferson, Linhua Fan, Felicity Roddick
      Nutrient removal from wastewater reduces the environmental impact of its discharge and provides opportunity for water reclamation. Algae can accomplish simultaneous nitrogen and phosphorus removal while also adding value to the wastewater treatment process through resource recovery. The application of algae to wastewater treatment has been limited by a low rate of nutrient removal and difficulty in recovering the algal biomass. Immobilising the algal cells can aid in overcoming both these issues and so improve the feasibility of algal wastewater treatment. Trends for nutrient removal by algal systems over different wastewater characteristics and physical conditions are reviewed. The impact that the selection of algal species and immobilisation has on simultaneous nutrient removal as well as the interdependence of nitrogen and phosphorus are established. Understanding these behaviours will allow the performance of algal wastewater treatment systems to be predicted, assist in their optimisation, and help to identify directions for future research.

      PubDate: 2018-04-15T04:40:39Z
      DOI: 10.1016/j.algal.2018.01.009
      Issue No: Vol. 31 (2018)
  • Enhanced biomass production by Phaeodactylum tricornutum overexpressing
           phosphoenolpyruvate carboxylase
    • Authors: Seungbeom Seo; Hancheol Jeon; Kwang Suk Chang; EonSeon Jin
      Pages: 489 - 496
      Abstract: Publication date: April 2018
      Source:Algal Research, Volume 31
      Author(s): Seungbeom Seo, Hancheol Jeon, Kwang Suk Chang, EonSeon Jin
      Phaeodactylum tricornutum is an extensively studied model diatom and a promising candidate for biochemical and biotechnological engineering aimed at increasing biomass production. Phosphoenolpyruvate carboxylase (PEPCase), which converts phosphoenolpyruvate (PEP) to oxaloacetate (OAA) using bicarbonate, is a key metabolic enzyme of the tricarboxylic acid (TCA) cycle and the C4 photosynthetic pathway. Two transgenic P. tricornutum lines overexpressing PtPEPCase1 (PtPEPC1, JGI protein ID: 27976) were constructed and their photosynthetic productivity, cell growth, and biomass were characterized. The levels of PtPEPC1 mRNAs in the two transgenic lines were increased by 2.3 and 11.2-fold and the amounts of the PEPCase protein by 1.3 and 2.3-fold, respectively. PtPEPC1 was targeted to mitochondria. Addition of bicarbonate to the P. tricornutum culture increased biomass of the transformants by about 12% compared to wild type, and their maximum specific growth rate in exponential phase was about 10% greater than that of wild type. The transformants also exhibited higher photosynthetic productivity. We conclude that overexpression of mitochondrial PtPEPC1 enhanced both photosynthetic productivity and TCA cycle activity in P. tricornutum, thereby enhancing biomass production in the presence of dissolved inorganic carbon. Our findings suggest that P. tricornutum overexpressing PtPEPC1 can be used to mitigate rising atmospheric CO2 levels or for sustainable microalgal biomass production.

      PubDate: 2018-04-15T04:40:39Z
      DOI: 10.1016/j.algal.2017.08.017
      Issue No: Vol. 31 (2018)
  • Mild cell disruption methods for bio-functional proteins recovery from
           microalgae—Recent developments and future perspectives
    • Authors: Win Nee Phong; Pau Loke Show; Tau Chuan Ling; Joon Ching Juan; Eng-Poh Ng; Jo-Shu Chang
      Pages: 506 - 516
      Abstract: Publication date: April 2018
      Source:Algal Research, Volume 31
      Author(s): Win Nee Phong, Pau Loke Show, Tau Chuan Ling, Joon Ching Juan, Eng-Poh Ng, Jo-Shu Chang
      Bio-functional proteins from microalgae have numerous biological properties with health-promoting effects. However, efficient harnessing of bio-functional proteins from microalgae is still in its infancy. One of the major obstacles that hinder the mass production of bio-functional proteins is the presence of resistant cell wall that diminishes the liberation of cell contents. As the bio-functional proteins are very sensitive to denaturation, selecting a mild disruption method to rupture the cell wall, while preserving their bioactivity and functionality, is of vital importance in downstream processing. To ensure the future development of efficient mild disruption methods for maximum recovery of bio-functional proteins from microalgae, this review provides useful information on various mild disruption approaches, current status, potential technologies that are still under development, as well as their advantages and constraints. In particular, those potential technologies that require further attention in the future (namely, explosive decompression, microfluidization, pulsed arc technology and cationic polymer coated membranes) are also discussed in this review.
      Graphical abstract image

      PubDate: 2018-04-15T04:40:39Z
      DOI: 10.1016/j.algal.2017.04.005
      Issue No: Vol. 31 (2018)
  • Inside Front Cover - Editorial Board Page/Cover image legend if applicable
    • Abstract: Publication date: April 2018
      Source:Algal Research, Volume 31

      PubDate: 2018-04-15T04:40:39Z
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