(291d) Lipid Production from Acid Hydrolysate of Lignocellulosic Biomass Using Rhodotorula Glutinis

The ability of the oleaginous yeast Rhodotorula Glutinis (ATCC 15125) to accumulate lipid and the fatty acid profile of these triglycerides when grown on acid hydrolysate from lignocellulosic biomass was investigated. In the experiments, two acid hydrolysates to lipid processes have been considered. In the first process, yeasts were continuously grown in a low nitrogen content medium with acid hydrolysate as source of carbon and energy. The other process is a two-stage culture system. In this process, yeasts were grown initially in a nitrogen-rich medium. The cells were harvested by centrifugation once the culture had reached the stationery phase. These yeasts were transferred to a fresh nitrogen free medium containing acid hydrolysate for the lipid accumulation phase. In the single stage process, the effect of culture conditions, especially nitrogen/carbon (N/C) ratio and temperature, on lipid production and triglyceride profile was studied. For the two-stage process, effect of temperature and initial cell mass concentration in the second culture was experimented. The lipid content in cell of yeast was determined by gravimetrical measurements of Bligh/Dyer extracts. The dry lipid content of the cells was as high as 27.6%. The triglyceride composition of lipid was characterized by high temperature gas chromatography. According to the gas chromatography spectra of lipid samples, the majority contents of triglycerides were of C16~C20. The lipid production based on sugar was also calculated.