Producing of Microbial Oil by Mixed Culture of Microalgae and Oleaginous Yeast Using Sugarcane Molasses as Carbon Substrate

Abstract

The oleaginous microorganisms involving yeasts and microalgae have the potential to generate significant quantities of biomass and oil suitable for conversion to biodiesel. Compared to microbial oil production, little work has been performed for mixed culture of microalgae and yeast. In this work, microbial oil production from mono and mixed cultures of microalgae Chlorella sp. KKU-S2 and yeast Toluraspora maleeae Y30, Toluraspora globosa YU5/2 under mixotrophic cultivation using sugarcane molasses as carbon substrate was demonstrated. In monoculture, a biomass of 5.23g/L with lipid yield of 0.31g/L, 9.43g/L of biomass with lipid yield of 0.20g/L, 3.3g/L with lipid yield of 0.12g/L was obtained from T. maleeae Y30, T. globosa YU5/2 and Chlorella sp. KKU-S2, respectively. In mixed culture of microalgae Chlorella sp. KKU-S2 and T. maleeae Y30, a biomass of 5.47g/L and lipid yield of 0.25g/L were obtained. A biomass of 6.90g/L with lipid yield of 0.33g/L was obtained for a mixed culture of T. globosa YU5/2 with Chlorella sp. KKU-S2. Maximum process product yield (Y P/S) of 0.03g/L and maximum volumetric lipid production rate (Q P) of 0.041 were obtained in mixed culture of T. globosa YU5/2 with Chlorella sp. KKU-S2. The results obtained from this study shows that mixed culture of the oleaginous yeast with microalgae is a desirable cultivation process for enhance of microbial oil production. Index Terms-Microbial lipid, microalgae, oleaginous yeast, mixed culture.