赖氨酸芽孢杆菌产氨基甲酸乙酯水解酶的发酵条件优化

Optimization of the Fermentation Conditions for Producing Urethanase by Lysinibacillus fusiformis

DOI：10.3969/j.issn.1673-1689.2017.03.005

中文关键词: 氨基甲酸乙酯水解酶 发酵条件优化 芽孢杆菌 发酵食品

英文关键词: ethyl carbamate,single-factor optimization,Bacillus,fermented food

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中文摘要:

氨基甲酸乙酯是发酵酒精饮料及发酵食品中一种广泛存在的致癌物，酶法降解是解决氨基甲酸乙酯污染的重要途径之一。作者以一株来源于小鼠胃部具有水解氨基甲酸乙酯活性的菌株Lysinibacillus fusiformis SC02为出发菌株，通过摇瓶水平单因素实验对其产酶条件进行了优化。优化后的培养基组成为：半乳糖 25 g/L，大豆蛋白胨20 g/L，尿素4 g/L，硫酸铜 0.02 g/L，pH 6.0。最佳产酶的发酵条件为：发酵温度37 ℃，接种体积分数3 %，装液量20 mL/250 mL。在上述优化的培养基和培养条件下，产酶水平由900 U/L提高到4 500 U/L，提高了350%。在3 L发酵罐水平上初步探究了不同搅拌转速对菌株产酶的影响。当搅拌转速达到800 r/min，菌株最高酶活水平由4 500 U/L提高到7 066 U/L，提高了57%。

英文摘要:

Ethyl carbamate （EC） is a potential carcinogen which widely exists in alcohol beverage and fermented food. Enzyme degradation is one of the important routes to deal with the EC contamination. In this study，a bacteria Lysinibacillus fusiformis SC02 which was able to degrade EC was isolated from mice stomach as the starting strain. The condition of enzyme production was optimized by using single-factor test. The optimal fermentation medium components were as follows：galactose 25 g/L，soy peptone 20 g/L，urea 4 g/L，CuSO4 0.02 g/L，initial pH 6.0. The optimal conditions for enzyme-producing were as below：temperature 37 ℃，inoculum volume 3% and liquid volume in flask 20 mL/250 mL. Urethanase production level of the strain was improved from 900 U/L to 4 500 U/L after being cultured for 15 h under the conditions mentioned above，which was 350% higher than the one under the original conditions. After investigating the influences of different agitation speeds on the urethanase production at the fermentation tank level，800 r/min was chosen as the optimal agitation speed，and the urethanase activity can reach to 7066 U/L at this speed，which was 57% higher than before.

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