单因子-响应面法优化白地霉Y162产脂肪酶条件

对白地霉Y162液体发酵产脂肪酶的条件进行了优化。首先采用单因子实验筛选出最适碳源为橄榄油，氮源为黄豆粉和NH4Cl，无机盐为BaCl2和MgCl2。在此基础上，利用Plackett-Burman设计对影响产酶因素的效应进行评价，筛选出具有显著效应的橄榄油、BaCl2和NH4Cl三个最显著的因素。用最陡爬坡路径逼近最大产酶区域后，利用响应面中心组合设计对显著因素进行优化，得出橄榄油、BaCl2和NH4Cl最佳浓度分别为2.35％，0.36％，1.35％。优化后液体发酵液中脂肪酶活力提高到31.85 U/mL，比初始酶活力14.16 U/mL提高了2.25倍，表明单因子-响应面结合法可显著优化白地霉Y162液体发酵产脂肪酶条件。

Optimization of lipase production conditions by Geotrichum candidum Y162 using single factor-response surface methodology

The fermentation conditions of lipase production by Geotrichum candidum Y162 were optimized. Initially, the most suitable carbon olive oil, nitrogen source soybean flour and NH4Cl, salt BaCl2 and MgCl2 were selected according to single factorial experiments respectively. Based on the result, screening methodology Plackett-Burman design was used to evaluate the effects of twelve factors related to lipase production and three statistically significant factors olive oil, BaCl2 and NH4Cl were selected. The path of steepest ascent was used to approach the optimal region of lipase production subsequently. Then, the optimal combined concentration for maximum enzyme activity were further optimized by response surface methodology and determined as follows: olive oil 2.35%, BaCl2 0.36%,and NH4Cl 4.69%.The optimization of culture conditions of G.candidum Y162 led to a 2.25-fold increase in lipase production relative to initial result 14.16 U/ml, which indicate that single factor in combination with response surface methodology is an effective method for optimization of lipase production conditions by G.candidum Y162.