丝氨酸生产菌的筛选及静息细胞培养系统中L-丝氨酸的合成

从广西隆安县沼气池里的残渣中筛选到一株能以甲醇为唯一碳源生长的MB200菌株。根据常规形态特征、生理生化性状及16S rDNA基因序列分析将其鉴定为甲基杆菌属(M ethylobacteriumsp.)。其最佳生长条件为:温度32℃、pH值8.0、甲醇体积分数1.25%。建立了MB200生成L-丝氨酸的静息细胞培养系统。确定静息细胞培养的条件为:甘氨酸质量浓度为10 g.L-1,甲醇50 g.L-1,菌体质量浓度为30 g.L-1,pH8.9,于摇床250 r.m in-1,32℃静息培养48 h,L-丝氨酸产量为7.2 g.L-1。

Screening of L-Serine Producer and Biosynthesis of L-Serine in Resting Cell Culture System

A L-serine producing bacterium strain,named as MB200,was isolated from digester remainder in Longan,Guangxi.This strain can grow in the medium with methanol as sole carbon source.Traditional taxonomy,assays of its 16S rDNA sequence homology identified MB200 as Methylobacterium sp.The optimum culture conditions for the strain were:temperature32℃,pH8.0,methanol concentration 1.25%.Resting cells system was set up for producing Lserine by MB200.After optimizing the resting cells culture conditions,the optimum conditions were obtained: glycine 10 g·L~(-1),methanol 50 g·L~(-1), cell density 30 g·L~(-1),pH8.9,shaker speed 250 rpm,temperature32℃,resting cells incubation time 48 h.Under above conditions,7.2 g·L~(-1) L-serine was produced by this bacterium.