Variation of photoautotrophic fatty acid production from a highly CO2 tolerant alga, Chlorococcum littorale, with inorganic carbon over narrow ranges of pH

• Published in: Biotechnology progress Vol. 31; no. 4; pp. 1053 - 1057
• Main Authors: Ota, Masaki, Takenaka, Motohiro, Sato, Yoshiyuki, Smith Jr, Richard L., Inomata, Hiroshi
• Format: Journal Article
• Language: English
• Published: United States Blackwell Publishing Ltd 01.07.2015; Wiley Subscription Services, Inc
• Subjects: algal oil; Biofuels; biomass; Carbon Dioxide - metabolism; Chlorophyta - metabolism; Fatty Acids - metabolism; green algae; Hydrogen-Ion Concentration; microalgae; Microalgae - metabolism; microalgae; biomass; biofuels; green algae; algal oil
• ISSN: 8756-7938; 1520-6033
• DOI: 10.1002/btpr.2099

Photoautotrophic fatty acid production of a highly CO2‐tolerant green alga Chlorococcum littorale in the presence of inorganic carbon at 295 K and light intensity of 170 µmol‐photon m−2 s−1 was investigated. CO2 concentration in the bubbling gas was adjusted by mixing pure gas components of CO2 and N2 to avoid photorespiration and β‐oxidation of fatty acids under O2 surrounding conditions. Maximum content of total fatty acid showed pH‐dependence after nitrate depletion of the culture media and increased with the corresponding inorganic carbon ratio. Namely, [HCO3−]/([CO2]+n[ CO32−]) ratio in the culture media was found to be a controlling factor for photoautotrophic fatty acid production after the nitrate limitation. At a CO2 concentration of 5% (vol/vol) and a pH of 6.7, the fatty acid content was 47.8 wt % (dry basis) at its maximum that is comparable with land plant seed oils. © 2015 American Institute of Chemical Engineers Biotechnol. Prog., 31:1053–1057, 2015