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Biogeneration of Volatile Organic Compounds in Microalgae-Based Systems
Published in Gokare A. Ravishankar, Ranga Rao Ambati, Handbook of Algal Technologies and Phytochemicals, 2019
Pricila Nass Pinheiro, Karem Rodrigues Vieira, Andriéli Borges Santos, Eduardo Jacob-Lopes, Leila Queiroz Zepka
Some microalgae are mixotrophic and can simultaneously drive phototrophy and heterotrophy to utilize both inorganic (CO2) and organic carbon substrates, thus leading to an additive or synergistic effect of the two processes that enhance the productivity of biomass and consequently a production of volatile compounds (Bhatnagar et al. 2011). CO2 is fixed through photosynthesis, which is influenced by illumination, while organic compounds are assimilated through aerobic respiration, which is affected by the availability of organic carbon. Several species are able to switch between photoautotrophic and heterotrophic growth (Perez-Garcia and Bashan 2015).
Brevetoxin
Published in Dongyou Liu, Handbook of Foodborne Diseases, 2018
While about half of living dinoflagellate species are autotrophs possessing chloroplasts, the other half are nonphotosynthesizing heterotrophs. In addition, some dinoflagellate species are mixotrophic, combining photosynthesis with phagotrophy (i.e., ingestion of prey such as other protozoa). Some dinoflagellates produce resting stages, called dinoflagellate cysts or dinocysts, as part of their life cycles. Further, dinoflagellate species K. brevis, K. mikimotoi, and Karlodinium micrum have acquired fucoxanthin pigments through endosymbiosis.
Neurotransmitters in Marine and Freshwater Algae
Published in Akula Ramakrishna, Victoria V. Roshchina, Neurotransmitters in Plants, 2018
Kathryn L. Van Alstyne, Richard L. Ridgway, Timothy A. Nelson
Algae are a phylogenetically diverse assemblage of organisms ranging from single-celled plankton to giant kelps. The term algae itself is neither unequivocally defined nor taxonomically useful. Algae are sometimes characterized as eukaryotic, aquatic, photosynthetic, and lacking a sterile jacket of cells around their reproductive structures. However, some authors consider prokaryotic cyanobacteria to be algae (Lee 1999). Other algae have lost the ability to conduct photosynthesis, as also seen in parasitic embryophytes (i.e., land plants), and live as parasites, saprophytes, or predators (e.g., dinoflagellates). A number are mixotrophic, capable of both feeding and photosynthesizing. Terrestrial algae are common in humid microclimates or live symbiotically within or on terrestrial organisms (e.g., lichens). Some Charophytes, traditionally included as green algae (errantly in Division Chlorophyta historically), protect their reproductive cells within sterile jackets (Graham et al. 2008).
Current advances in the algae-made biopharmaceuticals field
Published in Expert Opinion on Biological Therapy, 2020
Sergio Rosales-Mendoza, Karla I. Solís-Andrade, Verónica A. Márquez-Escobar, Omar González-Ortega, Bernardo Bañuelos-Hernandez
The group headed by Mayfield is performing seminal studies on the large scale production of algae-made biopharmaceuticals. Bovine Milk Amyloid A (MAA) has been produced in C. reinhardtii grown under greenhouse conditions using 100-L plastic bags; leading to concentrations up to 2.27 mg∙L−1 of culture (1.39% of TSP), nonetheless these concentrations varied depending on the differential light irradiation caused by the position of the bags in the greenhouse [46]. Some authors have focused on optimizing culture light conditions to enhance protein and biomass yields. Carrera-Pacheco et al. [62] reported the effect of continuous light versus light/dark cycles; as well as light intensity on the expression of two recombinant proteins: GFP and a bacterial lysin-GFP fusion protein (GFP-PlyGBS). Optimized protein production conditions were determined for photoautotrophic, mixotrophic, and heterotrophic conditions. Protein yields were influenced by the light period (6–24 h∙d−1), light intensity (0–450 μE∙m−2⋅s−1), and trophic condition. Heterotrophic conditions showed lower yields of both recombinant proteins due to reduced growth rates, despite having high protein accumulation per cell. Mixotrophic conditions exhibited the highest yields for GFP (4 mg∙L−1·d−1) under constant light at 35 μE∙m−2⋅s−1 and GFP-PlyGBS (0.4 mg∙L−1·d−1) under a light period of 15 h∙d−1 and 35 μE∙m-2⋅s−1. For GFP-PlyGBS the maximum increase in cellular protein accumulation was ~24-fold and ~10-fold higher in total protein yield when compared to constant light conditions (~200 μE∙m-2⋅s−1). The highest yields under photoautotrophic conditions were obtained under a 9 h∙d−1 light period, with a GFP yield of 1.2 mg·L−1·d−1 and a GFP-PlyGBS yield of 0.42 mg·L−1·d−1. This represented a ~ 5-fold increase in cellular protein accumulation for GFP-PlyGBS in comparison to constant light conditions (~200 μE∙m-2⋅s−1). This report highlights that, besides genetic engineering approaches, the upstream processing is critical to enhance productivity. Similarly, some authors have proposed using Chlorella sorokiniana UTEX 1230 as model; using mixotrophic conditions and a fed-batch strategy to increase biomass productivity. A 3-fold increase in biomass yield was observed when mixotrophic conditions were applied, whereas the fed-batch approach increased the yield by 50% [63].