莓实假单胞菌产低温胆固醇酯酶发酵条件优化

为了提高莓实假单胞菌（Pseudomonas fragi）Q-06产低温胆固醇酯酶的能力，在单因素试验基础上，结合Plackett-Burman设计和最陡爬坡试验确定影响酶活的3个显著影响因子为葡萄糖添加量、摇瓶装液量、培养温度，确定最优发酵培养基配方为葡萄糖3.0%，酵母粉1.3%，（NH4）2SO4 0.010%，MgSO4·7H2O 0.050%，KH2PO4 0.400%，运用Design-Expert软件Box-Behnken试验设计对P. fragi Q-06发酵产生甾醇酯酶的培养基条件和发酵条件进行优化。结果表明，最适发酵条件为温度28 ℃，转速180 r/min，接种量4%，初始pH 7.5，装液量80 mL/250 mL。在此最佳条件下，甾醇酯酶酶活由优化前360.00 U/L提高至479.64 U/L，是优化前的1.33倍。海洋微生物发酵甾醇酯酶工业化生产有望创造可观的经济效益，具有潜在的研究开发价值。

Fermentation conditions optimization of Pseudomonas fragi for low temperature cholesterol esterase production

In order to improve the yield of low-temperature cholesterol esterase by Pseudomonas fragi Q-06, the three significant factors affecting the enzyme activity including glucose addition, shaker loading volume and culture temperature were determined on the basis of single factor tests, combined with Plackett-Burman design and the steepest ascent tests. The results showed that the optimum fermentation medium formula was glucose 3.0%, yeast powder 1.3%, （NH4）2SO4 0.010%, MgSO4·7H2O 0.050%, and KH2PO4 0.400%. The medium and fermentation conditions of P. fragi Q-06 for sterol esterase production was optimized by Box-Behnken experiments design and the results showed that the optimal fermentation conditions were temperature 28 ℃, rotation speed 180 r/min, inoculum 4%, initial pH 7.5, and loading volume 80 ml/250 ml. Under the optimal conditions, the sterol esterase activity increased from 360.00 U/L to 479.64 U/L, which was 1.33 times that of before optimization. The industrial production of sterol esterase produced by marine microorganisms was expected to create considerable economic benefits and had good research and development value.