Microbial lipid production by oleaginous yeast in d-xylose solution using a two-stage culture mode

Abstract

The economical production of biodiesel from lignocellulose hydrolysates requires a robust D-xylose fermentation path. The present work found that Lipomyces starkeyi AS 2.1560 and Rhodosporidium toruloides AS 2.1389 could produce micro-lipid effectively from D-xylose solution by a two-stage culture mode. Results demonstrated that both L. starkeyi and R. toruloides could achieve high lipid production in xylose solution. High cell density fermentation was carried out by a feed-batch fermentation mode. After fermentation for 48 h in a bioreactor using unsterile xylose solution by L. starkeyi, the biomass, lipid and lipid content reached 97.4 g L⁻¹, 63.9 g L⁻¹, and 65.5%, respectively. Accordingly, the lipid productivity reached 1.3 g L⁻¹ h⁻¹ in the second stage. And the overall lipid productivity was 0.55 g L⁻¹ h⁻¹. Therefore, L. starkeyi and R. toruloides are highly effective D-xylose-fermenting oleaginous yeasts for lipid production in xylose solution. The two-stage culture method should provide a new opportunity to make the industrial production of biodiesel possible in the future.