Optimization of Enzyme Production Conditions of High-yielding Cellulase Engineering Strains
In order to improve the efficiency of cellulase production,the fermentation medium and culture conditions of Bacillus subtilis engineered strains C36,CM,KF and GH5 were optimized by single factor test and orthogonal test.The results showed that the enzyme production efficiency of engineered strains C36,CM,KF and GH5 was significantly improved under the optimal fermentation conditions.After optimizing the fermentation conditions,the cellulase activity of the engineered strain CM was the highest.Under the conditions of 7%of aged tobacco leaves,0.8%of peptone,pH 6.1,fermentation temperature 37℃,rotation speed 220 r·min-1,liquid medium volume 40 mL and fermentation for 96 h,the enzyme activities of carboxymethylcellulose(CMC)and filter paper activity(FPA)of the engineered strain CM were 504.95 and 222.11 U·mL-1,respectively.After optimizing the fermentation conditions,the increase of cellulase activity of the engineered strain GH5 was the highest.Under the conditions of 6%of aged tobacco leaves,0.9%of peptone,pH 6.1,fermentation temperature 37℃,rotation speed 220 r·min-1,liquid medium volume 40 mL and fermentation for 96 h,the enzyme activities of CMC and FPA was 28.55 and 9.68 times higher than that before optimization.
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