Microbial co-culturing of Chlorella sp. And Rhodotorula toruloides for the enhanced microbial lipid production

A microbial co-culture system composed of Chlorella sp. and Rhodotorula. toruloides was established to improve the microbial lipid production in this study. Within this mixed culture, Chlorella sp. acts as oxygen emitters to provide a constant supply of oxygen and regulate the pH, leading to higher biomass and lipid production. Subsequently, a series of culture conditions were optimized to improve the suitability and stability of the cocultivation system, including the C/N ratio, temperature, inoculation time and inoculation ratio. Under the optimal conditions, the accumulation of biomass and lipid content was improved 26.9 g/L and 70.94%, which was 1.8-fold and 2.13-fold than that of pure culture, respectively. Interestingly, the composition of fatty acids was significantly changed under different temperatures in mixed culture systems. The enhancement of unsaturated fatty acids will contribute to high value-added applications. In addition, the highest biomass of 31.9 g/L was obtained from molasses, indicating the great potential for industrial application.