Microbial oil production from rice straw hydrolysate by Trichosporon fermentans

Microbial oil production from sulphuric acid treated rice straw hydrolysate (SARSH) by Trichosporon fermentans was performed for the first time. Fermentation of SARSH without detoxification gave a poor lipid yield of 1.7 g/l, which was much lower than the result with glucose or xylose as the single carbon source (13.6 g/l or 9.9 g/l). The detoxification pretreatment, including overliming, concentration, and adsorption by Amberlite XAD-4 improved the fermentability of SARSH significantly by removing the inhibitors in SARSH. A total biomass of 28.6 g/l with a lipid content of 40.1% (corresponding to a lipid yield of 11.5 g/l) could be achieved after cultivation of T. fermentans on the detoxified SARSH for 8 days. Moreover, besides SARSH, T. fermentans could also utilize mannose, galactose, or cellobiose, in hydrolysates of other natural lignocellulosic materials as the single carbon source to grow and accumulate lipid with a high yield (at least 10.4 g/l). Hence, it is a promising strain for microbial oil production and thus biodiesel preparation from agro-industrial residues, especially lignocellulosic materials.