Lipid Production By Mixed Culture Of Oleaginous Yeasts Using Lignocellulose Hydrolysates

Microbial oils can be used as raw materials for biodiesel and other oil-based chemicals.It is of great significance to produce microbial oils in cheap raw materials,it can reduce production costs and increase oil production.This study studied the oil production of oleaginous yeasts using cheap lignocellulosic hydrolysates and the work focused on the fermentation process of mixed culture.Three oleaginous yeasts,Rhodotorula graminis,Trichosporon cutaneum and Rhodosporidium toruloides were used to produce oil from lignocellulosic hydrolysates.The equations of biomass-absorbance and number of cells-absorbance were established.The results showed that the growth rate of T.cutaneum and R.toruloides was faster than that of R.graminis,and the oil accumulation ability of three oleaginous yeasts was compared in nitrogen-limited glucose medium,showed that R.toruloides>T.cutaneum>R.graminis;The fatty acid composition of three oleaginous yeasts was analyzed by GC-MS.Among them,the fatty acids of R.toruloides are the most diversified,and the fatty acids composition of three oleaginous yeasts were mainly C16 and C18,which could be used as raw materials of biodiesel.The biomass and oil accumulation of three oleaginous yeasts under pure and mixed culture conditions in lignocellulosic hydrolysate were studied.1.Compared with pure culture the utilization rate of reducing sugar increased by 37.01%,the biomass increased by 18.27% and the oil yield reached 2.68 g/L by mixed culture of R.graminis and R.toruloides;2.The utilization rate of substrate increased by 10.10% and oil production increased by 13.42% by mixed culture of three oleaginous yeasts.The mixed culture of oleaginous yeasts has potential for development in efficiently converting lignocellulosic resources to produce microbial oils.