Studies On Screening Identification And Fermention Characters Of Oleaginous Yeasts By Utilizing Sugar Cane Bagasse Hemicellulose Hydrolysates

Lipid is one of the basic material and life-sustaining activities, as well as important industrial raw materials, a broad application value. Currently fats resources mainly come from animal and plant, with about microbial lipid in-depth study, using microbial fermentation fats, not only will it ease the animal and plant fats scarce resources situation, and oil could be abandoned microbial resources of the use of resources for fats provided a new way.This paper is based on these points. D-xylose is one of the most abundant pentose sugars in nature. To isolate oleaginous yeasts that can utilize xylose from diverse soil samples, we collected soils from a litchi orchard, a longan orchard, a carambola orchard, and woods, and isolated yeasts by the glycerol enrichment and measured their xylose assimilating capacity. A subset of these isolates was grown in nitrogen-limited media and then screened for their lipid contents by the Sudan Black B staining. Four colonies were selected. Then by fermentation xylose in shake flask, two oleaginous yeasts named H2-1 and J2-2 which had high performance in utilizing xylose were selected from four oleaginous yeasts. The lipid coefficient of two yeasts reached 14.56 and 10.73, respectively. H2-1 was identified as Rhodotorula minuta and J2-2 was identified as Rhodotorula glutinis based on physiological and biochemical characteristics and 26S rDNA sequence analysis. The effects of metal ions (Ca²⁺,Mn²⁺,Cu²⁺,Co²⁺) on lipid accumulation in the cells of strain J2-2 were investigated by fermenting in shaking flask. It revealed that certain quantity of Mn²⁺ and Cu²⁺ benefited lipid production, but Ca²⁺ and Co²⁺ inhibited accumulation of the lipid.With different culture conditions investigated in shake flasks, the results of experiments indicated that strain J2-2 was cultivated at 26℃for 144 hours with 200r/min at initial pH 10.0, the lipid production reached 3.85 g/L just 1.16 times as before, and the biomass reached 13 g/L just 1.04 times as before.The strain J2-2 producing lipids in utilizing sugar cane bagasse hemicellulose hydrolysates was preliminarily studied by fermenting in shaking flask. The lipid coefficients of J2-2 in utilizing sugar cane bagasse hemicellulose hydrolysates and xylose reached 10.23 and 10.73, respectively, showed similar transformation rate. Fatty acids analysis of microbial oil from sugar cane bagasse hemicellulose hydrolysates had fatty acid composition and proportion similar to normal vegetable oils.