Enhanced lipid production with undetoxified corncob hydrolysate by Rhodotorula glutinis using a high cell density culture strategy

• Rhodotorula glutinis had high tolerance to the inhibitors in corncob hydrolysate.
• R. glutinis can utilize undetoxified hydrolysate directly for lipid production.
• Acetic acid, furfural and 5-HMF could be metabolized prior to xylose.
• Biomass and lipid production was enhanced obviously with high cell density culture.
• High biomass and lipid concentration was obtained by two-stage feeding strategy.

In recent years, energy crisis and environmental issues such as greenhouse effect, global warming, etc. has roused peoples’ concern. Biodiesel, as renewable energy, has attracted much attention to deal with such problems. This work studied the lipid production by Rhodotorula glutinis with undetoxified corncob hydrolysate. The results indicated that R. glutinis had high tolerance to the inhibitors in corncob hydrolysate and it could utilize undetoxified corncob hydrolysate directly for lipid production. The cell grew well with undetoxified hydrolysate in the batch culture of 5 L fermentor with the optimized C/N ratio of 75, lipid titer and lipid content reached 5.5 g/L and 36.4%, respectively. High cell density culture with two-stage nitrogen feeding strategy was studied to enhance the lipid production, biomass, lipid concentration and lipid content of 70.8, 33.5 g/L and 47.2% were obtained. The results indicated the potential application for lipid production by R. glutinis with corncob hydrolysate directly.