Strategic mixed substrate cultivation of microalgae: productivity, respiration, yield, and lipid quality

Mixotrophic cultivation of three microalgae species, Chlorella sorokiniana, Scenedesmus obliquus and Scenedesmus abundans, was carried out with a mixed substrate containing glucose and acetate (1:1) under indoor and outdoor conditions. For indoor cultivation, the highest biomass productivities for C. sorokiniana, S. obliquus and C. abundans were 331 ± 11.5, 317 ± 3.5, and 130.7 ± 3.1 mg L−1 day−1, respectively. The key result showed that the highest lipid productivities (29.8–36.2 mg L−1 day−1) were obtained for C. sorokiniana for the cases in which acetate was added on day 1 in glucose-mediated cultures. Lipid accumulation was higher (27–36% of dry weight) for S. obliquus and S. abundans. The highest amount of lipid was accumulated for the strategies in which acetate was added on day 1 in glucose-mediated culture. C. sorokiniana showed the highest biomass yields of 0.39 g g−1 as compared to the other two species. For outdoor cultivation, the biomass and lipid productivity values for C. sorokiniana and S. obliquus were 172.8 ± 4.2 and 183.9 ± 6.8 mg L−1 day−1 and 30.5 ± 2.2 and 26.9 ± 3.1 mg L−1 day−1, respectively.