To avoid complex procedures in measurement of lipid content of oleaginous yeast especially for that can accumulate microbial lipid in lignocellulosic hydrolysates, fluorescent method using Nile Red as fluorescent dye was applied to measure lipid content of oleaginous yeast Trichosporon dermatis. The fluorescent method was built by fitting of lipid content identified by both conventional gravimetric method and fluorescence intensity of oleaginous yeast. Within the range of lipid content measured, the fitting curves showed linear relationship with good correlation coefficient (R2=0.95), showing this method is suitable for measuring lipid content of T. dermatis in the simulated medium. To evaluate the applicability of this method for lipid fermentation using lignocellulosic acid hydrolysates as substrate, T. dermatis was cultured in corncob acid hydrolysate and rice straw acid hydrolysate and then its lipid content measured by both fluorescent method and gravimetric method were compared. The results showed that the lipid content measured by these two methods were close, therefore, this method was promising for the application in lipid fermentation in lignocellulosic acid hydrolysates.

Cheng Zhao, Qing-Song Yao, Can Wang, Mu-Tan Luo, Chao Huang, Xue-Fang Chen, Lan-Lan Tian, Qian-Lin Huang, Lian Xiong, Hai-Long Li, Xin-De Chen