Mechanism for the disparity of the lipid production by Trichosporon fermentans grown on different sweetpotato vines hydrolysates.

摘要

The enzymatic hydrolysate of sweetpotato vines (SVH) has been proved to be an effective substrate for lipid production of Trichosporon fermentans. This study proposed that the lipid production efficiencies could be remarkably different among different SVHs, although these SVHs were prepared from the samples of the same species. The plant samples for producing SVH-1 and SVH-2 belong to the same species but were harvested in 2011 and 2012, respectively. However, the maximum lipid yield was 9.6 g l-1 by using SVH-1 but only 5.6 g l-1 by using SVH-2. eSVH-2 was prepared from a hot water extracted sweetpotato vines of 2012. Although the maximum lipid yields in all the SVH-1, SVH-2 and eSVH-2 treatments increased after glucose addition, the promoting effects of glucose addition on the lipid accumulation were not effective in the SVH-2 and eSVH-2 treatments. Combined analysis of the SVHs composition and the different biochemical behaviors of T. fermentans suggested that different levels of carbon and nitrogen in the SVHs were the main causes for the disparity of lipid production. The water extractable fraction of sweetpotato vines was also essential for the promoting effect of SVHs. The removal of water extract resulted in the lack of active components that can stimulate the lipid accumulation. This work provides valuable information about the effects of composition of SVHs on lipid production, which is helpful for the optimization of lipid fermentation from sweetpotato vines.