Using rice straw hydrolysate for microbial oil production by Trichosporon fermentans HWZ004
发酵性丝孢酵母HWZ004利用水稻秸秆水解液发酵产油脂

To efficiently use both cellulose and hemicellulose for lipid production, rice straw was hydrolyzed by a two-step process including dilute acid pretreatment and then enzymatic hydrolysis, and the hydrolysate was used as carbon source for lipid fermentation by Trichosporon fermentans HWZ004. After a simple overliming, the concentrations of acetic acid, furfural and 5-hydroxymethyl-furfural were 0.4 g/L, 0.1 g/L and 0.05 g/L, respectively. The hydrolysate could be used for lipid fermentation with T. fermentans HWZ004 without adding other nutrients except for a small amount of nitrogen source and trace CuSO4?5H2O. The optimum inoculum size, initial pH and temperature were 5.0%, 7.0 and 25 °C, respectively. A total biomass of 26.4 g/L with a lipid content of 52.2% (corresponding to a lipid yield of 13.8 g/L) was achieved after cultivation of T. fermentans HWZ004 under the above-mentioned conditions for 7 days. The lipid coefficient (lipid yield on substrate consumed) is 17.0, which is much higher than the corresponding one (11.9) obtained on detoxified rice straw hemicullulose hydrolysate by original yeast T. fermentans CICC 1368. The fatty acid composition of the lipid was found to be similar to that of vegetable oil and its unsaturated fatty acid content was over 70%, thus the lipid is a promising material for biodiesel production.