脂肪酶生产菌株的筛选及其发酵条件优化

为获得具有高产脂肪酶能力的菌株，以橄榄油为唯一碳源进行富集，再经过维多利亚蓝B平板初筛和两次摇瓶复筛，从自然界中筛选得到一株具有较高酶活的革兰氏阴性短杆菌G1。通过提取16S rDNA进行同源比对，确定该菌属于伯克霍尔德氏菌属。该菌经紫外和ARTP复合诱变得诱变株G1-7-4，酶活较原始菌株提高了51.87%。在单因素试验考察各因素对脂肪酶酶活的影响的基础上采用响应面法对影响酶活的重要因素进一步优化，得到最佳发酵条件：玉米油33.09 mL/L，酵母膏31.90 g/L，初始pH 6.67。该条件下酶活最高达到80.62 U/mL，为初始条件下的24.81倍。该脂肪酶的最适pH为8.0，在30~80 ℃范围内均具有较高酶活，最适反应温度为50 ℃。
A gram-negative short rhabdoid bacillus G1 with the high enzymatic activity to produce lipase was first obtained by the enrichment using olive oil as the sole carbon，Victoria blue B plate screening and shaking culture re-screening. Homology search by 16S rDNA showed that the strain belonged to Burkholderia. The enzymatic activity of the resulting mutant G1-7-4 through the composite mutation of UV and ARTP was increased by 51.87%. Base on the response surface methodology，the optimal fermentation conditions were determined as 33.09 mL/L of corn oil，31.90 g/L of yeast extract and initial pH 6.67. With these parameters，the lipase activity reached 80.62 U/mL，which was 24.81 times compared to that in the initial condition. The resulting lipase had the optimal pH 8.0，the active temperature range of 30-80 ℃ and the optimal temperature of 50 ℃