黑曲霉β-葡萄糖苷酶发酵培养基的优化

Optimization of Culture Medium for Producing β-glucosidase by Aspergillus Niger ZJ1

用响应面方法对黑曲霉(Aspergillusniger)ZJ1生产β-葡萄糖苷酶的培养基进行了优化。首先用部分因子设计对培养基组分稻草粉、麦麸、大麦粉、(NH4)2SO4及pH对β-葡萄糖苷酶活性的影响进行了评价,并找出主要影响因子为稻草粉和(NH4)2SO4,两者均为负影响,其它组分对酶活没有显著影响;再用最陡爬坡路径逼近最大响应区域;最后用中心组合设计及响应面分析确定主要影响因子的最佳浓度。经响应面分析获得的优化培养基组成(g/L)为:稻草粉7.02,麦麸16.65,大麦粉16.65,(NH4)2SO42.44,KH2PO40.5,MgSO4·7H2O0.5。经优化后,β-葡萄糖苷酶酶活性达到403.7U/mL。

Response surface methodology was used to optimize a medium for β-glucosidase production of Aspergillus niger ZJ1. In the first optimization step, the influence of straw powder, barley flour, wheat bran, （NH4）2SO4 and pH on β-glucosidase production was evaluated using a fractional factorial design. Straw powder and （NH4）2SO4 had negative effect on β-glucosidase production, while other components had no significant effect on β-glucosidase production. The path of steepest ascent was used to approach the optimal region of the medium composition. In the third step, the opti- mal concentrations of straw powder and （NH4）2SO4 were determined by a central composite design and response surface analysis. The optimized composition of fermentation medium was （g/L）： straw powder 7.02, wheat bran 16.65, barley flour 16.65, （NH4）2SO4 2.44, KH2PO4 0.5, MgSO4·7H2O 0.5. The maximum enzyme activity predicted was 403.7U/mL under the optimized cultivation medium composition.