出芽短梗霉产脂肪酶培养基的响应面优化

Statistical Optimization of Culture Medium for Enhanced Lipase Production by Aureobasidium pullulans Using Response Surface Methodology

通过单因素试验,Plackett-Burrman设计,最陡爬坡试验和响应面设计相结合的试验方法,优化出芽短梗霉产脂肪酶的培养基成分。由单因素试验优化得到初始发酵培养基中相对较好的碳源(蔗糖)、氮源(酵母提取物)、诱导物(葵花籽油)、表面活性剂(阿拉伯胶)和无机盐(K_2HPO_4·3H_2O,KH_2PO_4,NaCl)。在此基础上,经Plackett-Burrman设计筛选到对脂肪酶产量影响较为显著的3个因素——蔗糖、葵花籽油、NaCl。根据试验结果拟合上述3个因素与发酵液脂肪酶酶活的一阶线性模型。以该一阶线性模型为依据进行最陡爬坡试验,确定3个显著因素在响应面试验中的中心点水平。经响应面优化得出蔗糖、葵花籽油、NaCl的最佳含量分别为2.14%,4.24%,5.15 mmol/L。优化后的产酶培养基中脂肪酶酶活为31.75 U/m L,比初始酶活9.30 U/m L提高3.41倍。

A lipase producing strain, Aureobasidium pullulans S4, was isolated in privious study. To enhance the extracellular lipase production by A. pullulans, response surface methodology（RSM） was used to optimize fermentation culture medium. Firstly, a Placett-Burman design was employed to evaluate the effects of different culture medium components, which were selected by optimization experiments of preliminary single variable. Among the seven variables, sucrose, sunflower oil and Na Cl were found to have significant effects on lipase production. The concentrations of these three variables were optimized using a central composite design. The optimum culture medium containing 2.14% sucrose,4.24% sunflower oil（V/V） and 0.03% NaCl led to 3.41-fold increase in lipase production（31.75 U/m L） compared with the original medium.