产脂肪酶菌株的筛选、鉴定及发酵培养基优化

该研究从自然界筛选出一株脂肪酶产生菌株，鉴定其种属并对其发酵培养条件进行研究。采集富油水样，利用罗丹明B培养基进行初筛，结合形态观察、生理生化试验和16S rDNA序列分析进行菌种鉴定，建立系统发育树。结果表明，筛选出一株产脂肪酶的细菌U5，经鉴定为枯草芽孢杆菌（Bacillus subtilis）。通过单因素试验和响应面试验设计对发酵培养基中三丁酸甘油酯、葡萄糖、尿素添加量进行发酵优化。结果表明，最佳的发酵培养基组分为：三丁酸甘油酯2.0%（V/V），葡萄糖9 g/L，尿素8 g/L。在此优化条件下，粗脂肪酶酶活为4.3 U/mL，比优化前的酶活提高了16.22%。

Screening and identification of lipase producing strain and optimization of the fermentation medium

A lipase-producing strain was screened from nature, the species was identified and the fermentation conditions were studied. The oil-rich water samples were collected and the strain was screened by rhodamine B medium. The strain was identified by morphological observation, physiological and biochemical test and 16S rDNA sequence analysis, and the phylogenetic tree were established. The results showed that a lipase-producing bacterium U5 was selected and identified as Bacillus subtilis. The fermentation medium formula was optimized by single factor and response surface methodology as follows: tributyrin 2.0% (V/V), glucose 9 g/L and urea 8 g/L. Under the condition, the lipase activity was 4.3 U/ml, which was 16.22% higher than that of before optimization.