产脂肪酶菌株的筛选鉴定及产酶条件优化

以橄榄油为唯一碳源，采用油脂同化平板从食堂废弃物中筛选出一株产脂肪酶菌株HFE722。通过测定与分析该菌株16S rRNA基因序列，鉴定该菌株为芽孢杆菌（Bacillus sp.）。菌株HFE722在初始条件（发酵温度30 ℃，接种量为1%，自然pH，装液量为100 mL/250 mL，摇床转速为200 r/min）下培养36 h，测得发酵液上清液脂肪酶酶活为2.17 U/mL。优化后所得菌株HFE722产酶的最适发酵条件为：发酵温度30 ℃，发酵周期为36 h，接种量为1%（V/V），初始pH 7.0，装液量为50 mL/250 mL，摇床转速为160 r/min。在最佳发酵条件下，发酵液上清液酶活可达到5.8 U/mL，酶活较优化前提高了167.28%。

Screening and identification of lipase-producing strains and optimization of fermentation conditions

Using olive oil as unique carbon source, a lipase-producing strain HFE722 was isolated from the waste of canteen by screening plates. Through 16S rRNA gene sequence determination and analysis, results showed that strain HFE722 was identified as a Bacillus sp. Strain HFE722 was incubated for 36 h in the initial fermentation condition(fermentation temperature 30 ℃, inoculum 1%, natural pH, loading volume 100 ml/250 ml, shaking speed 200 r/min), the lipase activity of the fermentation broth was 2.17 U/ml. Single-factor method was used for optimizing the fermentation conditions, and then the optimum lipase production conditions were determined as follows: fermentation temperature 30 ℃, time 36 h, inoculum 1%(v/v), initial medium pH 7.0, loading volume 50 ml/250 ml, and shaking speed 160 r/min. Under these fermentation conditions, the lipase activity of fermentation broth of strain HFE722 reached 5.8 U/ml, which was 167.28% higher than that of before optimization.