Co-culture of Chlorella pyrenoidosa and Cutaneotrichosporon oleaginosum with enhanced biomass, lipid yield, and lipid productivity for micro-biodiesel production

The current microalgae/yeast co-culture consortia suffer from relatively low lipid yield and lipid productivity, which impedes the techno-economics of the technology. Herein, a novel co-culture combination containing the oleaginous microalga Chlorella pyrenoidosa and the oleaginous yeast Cutaneotrichosporon oleaginosum was firstly described for lipid production. Algal mono-culture merely yielded 3.21 g/L of biomass and 0.56 g/L of lipid, whereas these values were 10.35 g/L and 3.98 g/L for the yeast mono-culture. Interestingly, lipid concentration (7.87 g/L) via the co-culture was dramatically higher than the sum of mono-cultures. The co-culture system successfully realized pH self-regulation and nutrients synergism for enhanced lipid yield and productivity. The mixed fermentation medium (MM) was valuable to improve cell growth and lipogenesis of both C. pyrenoidosa and C. oleaginosum. When the co-culture was held in the MM containing 80 g/L of glucose, the total biomass, lipid concentration, lipid content, lipid yield, and lipid productivity reached 33.16 g/L, 18.15 g/L, 54.72 %, 0.23 g/g, and 4.03 g/L/d, respectively. The co-culture system was successfully expanded to cassava starch hydrolysate. The fatty acid composition and the estimated biodiesel properties of lipid samples obtained from co-culture indicated the feasibility for biodiesel production. This study provides a high-efficient microalga-yeast microbial consortium for lipogenesis.