嗜盐四联球菌的分离及其精氨酸代谢

嗜盐四联球菌是存在于酱醪发酵中后期的嗜盐乳酸菌，其代谢精氨酸的特性与氨基甲酸乙酯前体物瓜氨酸的积累存在密切关系。为了降低酱油发酵过程中氨基甲酸乙酯前体物瓜氨酸的积累，研究采用选择性培养基以及groEL基因特异性对嗜盐四联球菌进行了分离和筛选，得到一株Tetragenococcus halophilus R23。对该菌株在不同培养温度和盐浓度下的精氨酸代谢特性进行了考察。结果表明：在30 ℃，180 g/L NaCl培养条件下，嗜盐四联球菌R23消耗精氨酸和瓜氨酸能力最强，消耗量分别为100.0%和64.3%。其中，代谢精氨酸的培养基中未检测到瓜氨酸的积累。这一特性对降低酱油发酵过程中氨基甲酸乙酯前体物瓜氨酸的积累具有重要意义。
The Tetragenococcus halophilus species is a halophilic lactic acid bacteria （LAB） exhibiting in the later fermentation of soy sauce moromi. The arginine metabolism of this species is closely related to the accumulation of citrulline which is the main ethyl carbamate precursor in soy sauce. A Tetragenococcus halophilus strain R23 was isolated from moromi by selective medium cultivation and PCR （targeting on the groEL gene） screening. The arginine metabolism of the strain was investigated under different cultivation temperature and salt concentration. A highest utilization of arginine and citrulline for T. halophilus R23 was observed at 30 ℃ in the presence of 180 g/L NaCl，with degradation rate of 100.0% and 64.3%，respectively. In addition，there was no citrulline detected with in arginine consumption of R23，which provided a potential application of citrulline reduction in soy sauce during fermentation process