Oleaginous fungal lipid fermentation on combined acid- and alkali-pretreated corn stover hydrolysate for advanced biofuel production

• A novel combined hydrolysis was developed for fungal lipid fermentation.
• Detoxification and pH adjustment were minimized for lignocellulosic biofuel production.
• Lipid accumulation on hydrolysate had a comparable performance with the control.

A combined hydrolysis process, which first mixed dilute acid- and alkali-pretreated corn stover at a 1:1 (w/w) ratio, directly followed by enzymatic saccharification without pH adjustment, has been developed in this study in order to minimize the need of neutralization, detoxification, and washing during the process of lignocellulosic biofuel production. The oleaginous fungus Mortierella isabellina was selected and applied to the combined hydrolysate as well as a synthetic medium to compare fungal lipid accumulation and biodiesel production in both shake flask and 7.5 L fermentor. Fungal cultivation on combined hydrolysate exhibited comparable cell mass and lipid yield with those from synthetic medium, indicating that the integration of combined hydrolysis with oleaginous fungal lipid fermentation has great potential to improve performance of advanced lignocellulosic biofuel production.