Screening Of Cellulose-Degradation Bacteria For Pleurotus Eryngii Spent Substrate, Construction And Application Of Composite Microbial System

The study is performed to search efficient cellulose degrading microorganisms, set up complex bacteria and application to improve effect of microbial fermentation on spent substrate compost for promoting cyclic utilization of spent substrate of edible mushroom. The results were as follows:1. Samples were collected from spent substrates, four bacteria(FB7, CB1, BC11, BC12) were obtained according to the results of Congo red cellulose hydrolytic circle measurement, filter paper degradation test and activity assay of celluloses. The results of 16 s r DNA sequence analysis showed that FB7 and CB1 were Bacillus sp., BC12 was Comamonas_jiangduensis, and BC11 was Streptomyces albus. The cellulose activities of FB7 under liquid culture conditions were highest. The activities of four enzymes(FPA, CMCase, C1 enzyme and β-Gase) produced by FB7 cultured for 4 days were 22.81 U·g-1, 314.50 U·g-1, 2.78 U·g-1 and 188.09 U·g-1, respectively.2. FB7、CB1、BC11、BC12 were mixed at random, and complex bacteria(CB1+BC11+FB7) had highest filter paper degrading ability, degraded filter paper into paste within 6 days. The FPA activity of complex bacteria(CB1+BC11+FB7) was reached the maximum(31.98 U·g-1) in the 3-4 days, CMCase, C1, β-Gase activities of complex bacteria(CB1+BC11+FB7) were 133.61 U·g-1, 2.31U·g-1, 217.21 U·g-1.3. Commerial microbial agent(treatment A) and complex bacteria(treatment B) were added in the Pleurotus eryngiiat spent substrate compost, the compost temperature of treatment A and B were higher and little fluctuations than CK. FPA activities in treatment A and B were higher than CK. So, the results suggested that adding bacteria agent in compost can more effectively improve cellulose activity. The Agaricus bisporus production of treatment A, treatment B had a little higher than CK, but the difference was not significant.4. The analysis of microbial diversities in Pleurotus eryngiiat spent substrate compost indicated that the species richness was increased after microbial agents were added in the compost and the communities‘ structure was changed significantly. Shannon index of treatment A, B were higher than CK, it indicated that microbial diversity was more plentiful. Proteobacteria, Bacteroidetes, Acidobacteria, Verrucomicrobia, Planctomycetes and Actinobacteria were major bacteria in the compost, but the proportions of them in 3 treatments were absolutely different. The number of Actinobacteria, Bacteroidetes which related to cellulose degradation was bigger than CK. Different treatments had different predominant bacteria. The dominant bacteria in treatment A was Bacillus sp.、Candidatus_Nitrososphaera, the dominant bacteria in treatment B and CK were Pedobacter, Acinetobacter and Comamonas, Candidatus_Xiphinematobacter.