Enhancing HAP3 mediated xylose metabolism and acetic acid metabolism promotes lipid production from lignocellulosic hydrolysate fermented by Candida glycerinogenes.

Enhanced Candida glycerinogenes xylose metabolism as well as acetic acid metabolism for lipid production from undetoxified lignocellulosic hydrolysate. The C. glycerinogenes after overexpression of HAP3 increased the xylose assimilation capacity and the xylitol production decreased by 66.7%. HAP3 could bind to the upstream activation sequence of XYL2 promoter and promote the expression of XYL2. The transcription factor HAP3 enhanced xylose metabolism and increased lipid production in undetoxified lignocellulosic hydrolysate. By enhancing the metabolism of acetic acid, the ability of acetic acid to produce lipids was improved. The use of acetic acid as a carbon source produced 4.1 g/L of lipid, representing 44.7% of the weight of the dried cells. The final lipid titer in the undetoxified lignocellulosic hydrolysate reached 5.3 g/L, and the lipid content accounted for 43.9% of the dry cell weight. Candida glycerinogenes engineered strains can rapidly ferment undetoxified lignocellulosic hydrolysates for lipid production and provide a reference for converting lignocellulosic biomass.