黄曲霉YZC产纤维素酶的固态发酵条件优化

为了提高黄曲霉YZC固态发酵所产纤维素酶的酶活力,采用单因素试验分别研究了碳源、氮源、氮源质量浓度、培养温度、培养时间、初始p H值、接种量对纤维素酶酶活的影响。优化后的固态发酵条件为：碳源为质量比3∶2的稻草粉与麸皮,氮源为NH4Cl,其质量浓度为10 g/L,培养温度为30℃,培养时间为7 d,初始p H值为4.0,接种量为20%。在此基础上,采用响应曲面法对影响纤维素酶活的3个因素包括氮源NH4Cl的质量浓度、培养时间、初始p H值进行优化,以期提高纤维素酶酶活。通过响应曲面分析得到滤纸酶活力与这三个因素的最优回归方程,确定滤纸酶活力最大时的最佳组合为NH4Cl质量浓度为8.5 g/L、培养时间为6.5 d、初始p H值为4.5,该条件下滤纸酶活力为10.87 IU/m L,是优化前的2.39倍,并与响应曲面拟合所得方程的预测值10.50 IU/m L符合良好。

Optimization of Solid-state Fermentation Conditions for Cellulase Production with Aspergillusflavus YZC

To improve the cellulase activity produced by Aspergillus flavus YZC, the effects of different factors such as carbon, nitrogen, nitrogen concentration, etc., on this cellulase activity were explored. On the basis, response surface methodology was applied to optimize the effects of three factors （NH4Cl concentration, fermentation time and initial pH） on the cellulase activity. The optimal conditions of the three factors were as follows： 8.5 g/L of NH4Cl concentration, 6.5 d of fermentation time and 4.5 of initial pH. Under the optimized conditions, the cellulase activity was 10.87 IU/mL, 2.39 times of the unoptimized and in good agreement with the predicted value （10.50 IU/mL ）.