Mixotrophic culture of Monoraphidium braunii using glucose on the increase of biomass, protein, and lipid productivity

In this study, the effect of exogenous addition of glucose on the growth, biomass, pigment content, protein, and lipid productivity of green microalgae M. braunii under mixotrophic culture was investigated.The microalgae were cultivated in a batch system under four different glucose concentrations, including 0 g L -1 (photoautotrophic conditions, control), 0.1 g L -1 , 0.3 g L -1 , and 0.5 g L -1 (mixotrophic conditions).The light intensity of 200 µmol photon m -2 s -1 under constant illumination was applied in this study.The obtained findings indicated that glucosesupplemented cultures under mixotrophic conditions produced higher growth and biomass productivity than the photoautotrophic culture.The maximum specific growth rate (0.64 d -1 ) and biomass productivity (188.94mg L -1 d -1 ) were attained at 0.5 g L -1 glucose, which was 66.7% and 22.4% higher than the glucose-free cultures.The highest Chl a+b content was observed at 0.3 g L -1 , while carotenoid and protein content increased along with glucose concentration.The maximum protein productivity of 64.13 mg L -1 d -1 and lipid productivity of 33.92 mg L -1 d -1 were obtained at 0.5 g L -1 glucose, which was 1.5-and 1.3-times higher than the control.This study demonstrates that glucose supply under mixotrophic systems is an effective strategy to enhance the protein and lipid productivity of M. braunii, which could potentially be applied for large-scale cultivation.