Fast Measurement of Lipid Content of Oleaginous Yeast Trichosporon dermatis Cultured in Lignocellulosic Hydrolysates Using Fluorescent Method

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.

Fast Measurement of Lipid Content of Oleaginous Yeast Trichosporon dermatis Cultured in Lignocellulosic Hydrolysates Using Fluorescent Method

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.

Fast Measurement of Lipid Content of Oleaginous Yeast Trichosporon dermatis Cultured in Lignocellulosic Hydrolysates Using Fluorescent Method

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.

Screening of a highly inhibitor-tolerant bacterial strain for 2,3-BDO and organic acid production from non-detoxified corncob acid hydrolysate

Fermentation of chemicals from lignocellulose hydrolysate is an effective way to alleviate environmental and energy problems. However, fermentation inhibitors in hydrolysate and weak inhibitor tolerance of microorganisms limit its development. In this study, atmospheric and room temperature plasma mutation technology was utilized to generate mutant strains of Enterobacter cloacae and screen for mutants with high inhibitor tolerance to acid hydrolysate of corncobs. A highly inhibitor-tolerant strain, Enterobacter cloacae M22, was obtained after fermentation with non-detoxified hydrolysate, and this strain produced 24.32 g/L 2,3-butanediol and 14.93 g/L organic acids. Compared with that of the wild-type strain, inhibitor tolerance was enhanced twofold with M22, resulting in improvement of 2,3-butanediol and organic acid production by 114% and 90%, respectively. This work presents an efficient method to screen for highly inhibitor-tolerant strains and evidence of a novel strain that can produce 2,3-butanediol and organic acids using non-detoxified acid hydrolysate of corncobs.