Microbial Lipid Production By Cofermentation Of Glucose And Xylose With Lipomyces Starkeyi 2～#

Biodiesel, chemically defined as mixture of long chain fatty acid esters, is generally believed as an ideal replacement of diesel. Lipid is a basic material for life-sustaining activities, as well as important industrial raw materials with a broad application value. Currently, fats resources mainly come from animal and plant. With the research development of microbial lipid, microbial fermentation to produce fats not only will it ease the scarce resources situation of animal and plant fats, but also provide a new way to reuse abandoned resources in industry and agriculture.Lignocellulosic materials represent the largest reservoir of potentially fermentable carbohydrates. In an ideal case, the hydrolysate of lignocellulose contains about 50% glucose and 25% xylose.This paper is based on these points. Firstly, Microbial lipid production by cofermentation of glucose and xylose with oleaginous yeast Lipomyces starkeyi 2~# was examined. When cultivated by shaking flask at 30℃with glucose (70 g/L) or xylose (70 g/L) as sole carbon source for 96 h, over 90% substrate was consumed. Cellular biomass and lipid content were 14.1 g/L and 55.7% for glucose culture, and 13.1 g/L and 52.6% for xylose culture. Then glucose and xylose with the ratio of 2 to 1 were used as carbon source in the medium, and the medium composition with mixed sugar for lipid production was optimized by L. starkeyi 2~# through RSM (Response surface methodology). The optimal condition was mixed sugar 79.8 g/L,yeast extract 8.9 g/L,FeSO4 8.0 mg/L,KH2PO4 7 g/L,Na2HPO4 2 g/L,MgSO4 1 g/L,and NH4Cl 0.5 g/L. In the shaking flask fermentation, the biomass, lipid concentration and the lipid content reached 18.0 g/L,10.9 g/L and 60.6% respectively. In the batch fermentation experiment, the biomass,lipid concentration and lipid content reached to 27 g/L,15.8 g/L and 58.8% respectively.