藏灵菇源干酪乳杆菌KL1高产胆盐水解酶发酵条件的优化研究

Study on the Optimization of the Fermentation Conditions of Bile Salt Hydrolase by Lactobacillus casei KL1 from Tibetan Kefir

利用从藏灵菇中筛选的产胆盐水解酶的干酪乳杆菌Lactobacillus casei KL1研究影响胆盐水解酶酶活力的环境因素和超声波细胞破碎条件,探讨产酶能力的检测方法;采用四因素三水平[L9(34)]正交试验研究胆盐水解酶的优化发酵条件,利用完全交叉组合试验研究超声波细胞破碎的最适条件,并应用牛津杯试验定性检测KL1菌株产胆盐水解酶的能力;优化发酵条件:葡萄糖添加量为2%、大豆蛋白胨添加量为2%、发酵温度为37℃、接种量为2%;细胞破碎最适条件:超声波功率为700W,3s间歇,5s工作,持续工作15min,控制温度范围0～6℃。在优化发酵条件下,胆盐水解酶的活力是优化前的7.4倍;在超声波细胞破碎最适条件下,细胞破碎率能达到80%的要求,并可检出胆盐水解酶活性;牛津杯试验结果表明Lactobacillus casei KL1菌株产生的胆盐水解酶具有降低胆固醇的功效。

Lactobacillus casei KL1,isolated from Tibetan Kefir,was studied the environment factors,ultrasound cytoclasis conditions and detection method which influenced the enzyme activity of bile salt hydrolase,Four factors and three levels orthogonal test were chosen to study fermentation conditions.The completely cross combination testing was utilized to research ultrasound cytoclasis condition,and Oxford cup experiment was used to detect the producing enzyme ability of KL1,Optimize fermentation conditions were glucose 2%,soy peptone 2%,fermentation temperature 37 ℃ and inoculums size 2% ,Optimize cytoclasis conditions were ultrasonic power 700W,3 s intermission,5 s task,non-stop working 15 min,and the temperature range from 0 ℃ to 6 ℃Under the optimize fermentation conditions,the enzyme activity of bile salt hydrolase was 7.4 times bigger than before.The cytoclasis rate achieved 80% under the ultrasound cytoclasis optimum condition,and bile salt hydrolase＇s activity could be check out.The results of Oxford cup experiment indicated that the bile salt hydrolase of Lactobacillus casei KL1 had the function of reducing cholesterol.