Optimization of fermentation condition about extropolysaccharide by Bacillus sp.

An oligotrophic bacteria(Bacillus sp.) was isolated from oligotrophic environment(Luobupo desert) in Xingjiang.In this paper,the relationship between the yield of extropolysaccharide and main factors by carrying on the experiment of single factor and orthogonal experiment.The results showed that hydrolysis of wheat bran and soybean were optimal carbon and nitrogen source.The best medium for flask fermentation was wheat bran 4%,soybean 1.5%,K2HPO4 0.15%,MgSO4 0.06%,NaCl 0.2%,inoculum size 5%,liquid volume 50 mL /500 mL,initial pH7.0 and fermentation time 48 h.The yield of extropolysaccharide was 4.33 g/L,which was 125.4% times more than the yield under original conditions.