Screening, identification and enzyme production conditions optimization of cellulose-degrading bacteria from the cow and sheep manure

The cellulose-degrading bacteria were isolated and screened from the cow and sheep manure in Qinghai natural pasturehe by Congo red staining method and filter paper strip disintegration method, and the screened strains were identified by morphological observation and molecular biological technique. Using carboxymethyl cellulose (CMC) activity as the screening index, the enzyme production conditions were optimized by single factor tests and response surface tests, and its degradation effect on different stalks was evaluated. The results showed that a strain BC-4 with high cellulase activity was identified as Bacillus sonorensis. The results of single factor and response surface tests showed that the optimal enzyme production conditions of the strain BC-4 were initial pH 8, inoculum 2% and fermentation temperature 35 ℃. Under these optimal conditions, the activity of carboxymethyl cellulose produced by the strain BC-4 was 93.7 U/ml. The strain BC-4 had good degradation effect on different stalks, and the degradation rate of Jerusalem artichoke straw was 26.3%.