L-瓜氨酸生产菌株的筛选及鉴定

Screening and identification of L-citrulline producing strains

通过选择性培养基初筛(利用精氨酸双水解酶筛选培养基)和复筛(高效液相色谱法测定L-瓜氨酸质量浓度),从杭州市勾庄地区西瓜大棚的土壤中筛选获得45株产L-瓜氨酸菌株。其中一株细菌(菌株编号11)转化L-精氨酸生产L-瓜氨酸的能力最强,产生的L-瓜氨酸浓度最高,0.344 g湿菌,在60 m L转化体系中转化一天,可将20 g/L的底物L-精氨酸转化为9.31g/L的L-瓜氨酸。对11号菌株分别进行形态学观察,生理生化试验及分子生物学鉴定,初步鉴定该菌株为粪肠球菌(Enterococcus faecalis)。

Forty-five L-citrulline producing strains were preliminarily screened from Hangzhou watermelon greenhouse soil using arginine dihydrolase selective medium and their productivities were determined by HPLC. The strain of NO.11 had the highest ability to convert L-arginine to Lcitrulline. 20 g/L L-arginine was converted into 9.31 g/L L-citrulline in 60 m L reaction mixture in one day with 0.344 g wet cells. The strain was identified as Enterococcus faecalis by morphology observation, physiological and biochemical characterization and molecular biological identification.