Study on screening of high-yield cellulase strains in the fermented grains and its enzymatic properties

Cellulase has broad application prospects, and has respective characteristics according to the different sources. The cellulase microbes were screened from Luzhou-flavor fermented grains, and further plan to use for the degradation and utilization of cellulose in distiller's grains. Sodium carboxymethyl cellulose culture medium containing Congo red was used to screen for producing enzyme strains, a highly cellulose-secreted strain XWS-1 was obtained. The strain was identified as Bacillus subtilis.The optimum conditions in 1% CMC-Na medium were as follows: 35 ℃, initial pH5.5, cultivate 72 h. The enzymatic activity properties of XWS-1 strains was further studied.The results showed that the optimum reaction temperature of crude enzyme fluid was 40 ℃, and the optimum reaction pH was 5.5. In summary, the cellulase produced by XWS-1 is a medium-temperature and acidic cellulase, which is suitable for the degradation of acidic cellulosesuch as distiller's grains.This work not only provide a foundation for degradation of cellulose in distiller's grains, but also provide a genetic material for recombinant complex cellulasethatcan using degradation of cellulose in distiller's grains.