Microbial lipids for biofuel production have recently attracted increasing attention because of their advantages over plant oils such as fast growth, year-round production, less demand on space, and easy scale-up. Particularly, microbes are able to utilize a variety of carbon sources (glucose, xylose, glycerol, starch, and lignocellulose) for the production of cell mass and lipids, which greatly improves the flexibility of microbial lipid based biofuel production. Among these carbon sources, lignocellulose, the most abundant and renewable source in nature, is considered as an ideal raw material for microbial lipid production. Some oleaginous microbes (those can accumulate more than 20% of intracellular lipid), such as Mortierella isabellina, Rhodotorula glutinis, and Candida curvata etc., are able to uptake both glucose and xylose from lignocellulose and accumulate a relatively large amount of lipid in the cell. Despite their promise, the full potential of lignocellulose for microbial lipid fermentation has yet to be unlocked because of the challenges associated with its decomposition into fermentable sugars and low fermentation efficiency due to inhibitors generated from thermal/chemical pretreatment. In addition, liquid-solid separation, water usage, and low xylan utilization are other major issues impeding commercial microbial lignocellulose based lipid production. In response to addressing the aforementioned issues, the novel biological process of combined hydrolysis, which based on our co-hydrolysis process, was developed in the current study to efficiently release mono-sugars and acetate from lignocelluloses, and satisfy the need of fungal fermentation to accumulate lipids. Besides that, little is known about the effect of inhibitors from lignocellulose hydrolysis on oleaginous fungal cell growth and lipid production, so their individual and synergistic effects were studied as well. 13C isotope traced experiment was carried on to illustrate the carbon utilization regarding cell growth and lipid accumulation in the presence of inhibitors such as furfural and HMF. This study would play an important role in terms of microbial lipid fermentation from lignocellulose using oleaginous fungal fermentation platform.
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