Screening of a strain of Bacillus velezensis and its degradation effect on corn DDGS crude fiber
The experiment aims to screen for strains with efficient cellulose-degrading capabilities to degrade the crude fiber content of dried distillers'grains with solubles(DDGS),providing high-quality strains for the efficient resource utilization of corn DDGS.The experiment used the plate separation method to isolate a strain Q1 with cellulose-degrading ability from rural honey,and identified Q1 as Bacillus velezensis through morphological observation and 16S rDNA sequence analysis.Using corn DDGS as the raw material and the cellulose degradation rate as the index,the experiment investigated the effects of inoculum amount,liquid-to-solid ratio,and fermentation time on the crude fiber degradation rate through single-factor experiments.On the basis of single-factor experiments,the response surface method was used to optimize each factor.The results showed that the optimal fermentation conditions were an inoculum amount of 4.8％,a liquid-to-solid ratio of 0.5 mL/g,and a fermentation time of 75 hours,with a crude fiber degradation rate of 28.31％after fermentation.Moreover,the crude protein and ash content in the fermented corn DDGS were significantly higher than before fermentation(P＜0.05),and the crude fiber content was significantly lower than before fermentation(P＜0.05).The study indicates that strain Q1 has good cellulose-degrading capabilities and can improve the degradation rate of crude fiber in corn DDGS,providing a reference for increasing the use of corn DDGS in feed.
cellulose degrading bacteriacorn DDGSsolid state fermentation
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