黑曲霉ZD利用棉花秸秆固体发酵产纤维素酶条件优化

【目的】以棉花秸秆作为发酵基质,优化黑曲霉(Aspergillus niger)ZD固体发酵产纤维素酶的发酵条件。【方法】以固体发酵条件(棉花秸秆和玉米粉的比例、发酵时间、接种率、含水量和pH值)为优化因素,通过单因素试验和Plackett-Burman试验,确定主要影响因素;再由最陡爬坡试验确定优化中心点,最后通过 Box-Behnken中心组合设计确定主要影响因素及其交互作用对固体发酵产酶的影响,并对其进行回归分析。【结果】由单因素试验和Plackett-Burman试验确定碳氮比,接种量和含水率为主要影响因素;最陡爬坡试验确定棉花秸秆与玉米粉的比例4∶1,接种量10%和含水率60%为中心点;Box-Behnken中心组合试验确定最佳发酵条件:棉花秸秆和玉米粉的比例为4.4∶1,接种量8.12%,含水率60%,发酵时间40 d,pH为4,此条件下羧甲基纤维素钠酶活最高,为310.885 U/mL;比未优化条件下的酶活207.496 U/mL提高了49.8%。【结论】确定黑曲霉ZD利用棉花秸秆固体发酵产纤维素酶的最优条件,为利用该菌制备棉花秸秆发酵饲料,降解棉花秸秆纤维素含量,提供了理论依据和工艺参数。

Optimization of cellulase production by Aspergillus niger ZD using solid fermentation of cotton straw

【Objective】 Optimization of cellulase production by Aspergillus niger ZD using solid fermentation, using cotton straw as a fermentation substrate.【Method】Identify the main influencing factors by single factor test and Plackett-Burman test, as optimization factor of the ratio of cotton straw and corn flour, fermtation time, inoculation rate, water content and pH value under solid fermentation conditions. Then determines the optimization center point through the steepest climbing test, finally the influence of main influencing factors and their interactions on enzyme production was determined by Box-Behnken center combination design under solid fermentation, and regression analysis of the main influences.【Result】Identify the main influences of the ratio of cotton straw and corn flour, inoculation rate and water content by single factor test and Plackett-Burman test; dedetermines the optimization center point of 4∶1 of cotton straw-corn flour ratio, 10% of inoculation rate, 60% of water content; the optimal fermentation conditions was 4.4∶1 of cotton straw-corn flour ratio, 8.12% of inoculation rate, 65% of water content by Box-Behnken center combination tests.The maximum carboxymethylcellulose sodium enzyme activity under this condition was 310.885 U/mL, which was 49.8% higher than the enzyme activity 207.496 U/mL under unoptimized conditions. 【Conclusion】In conclusion, the optimal fermentation conditions of cellulase production by Aspergillus niger ZD using cotton straw solid fermentation was obtain. The results can be used to make cotton straw fermented feed using bacteria mixed, to degradate cellulose content of cotton straw and provide theoretical basis and process parameters.