Screening On The Cellulose-decomposing Microorganisms In Dairy Manure And Study Of Fermentation Conditions

In recent years, with the development of national economy and people's living standards, there is increasing demand for milk, which brings about rapid growth of cow cultivation. But traditional treatment of dairy manure can not meet the need of the current large-scale cultivation, and thus the pollution of dairy manure has become a focus of attention. Recently, people have been studying the cost-effective treatment of dairy manure and the microbial methods to deal with dairy manure have caught more and more attention at home and abroad. Dairy manure contain large amounts of cellulose. If we can use cellulose-decomposing microorganisms to degrade the dairy manure to produce reducing sugar, and furthermore to produce ethanol by fermentation, the pollution of dairy manure will be solved and ethanol as the clean energy will be produced, which is in line with the sustainable development strategy of our country. Aiming at the cellulose in the dairy manure, this paper screens the highly-active cellulose-decomposing microorganisms and studies the construction and fermentation conditions.In this study,19 cellulose degrading strains were isolated from the soil of water outlet of a dairy, forestland on the campus of the Southwest University and soil of a vegetable garden in the Meihua Village, including 5 actinomycete strains,2 bacteria strains and 12 fungi strains. Three fungi strains with relatively higher degradation rates were selected by the measurement of cellulose degradation rate in dairy manure and screening of filter paper, that is, F2, F3, and F9.The antagonistic reaction between each strain was tested. Results showed that the cellulose degradation rate of the F3-F9 pair accounts for 44.02%, which increases by 12.47% compared with single strain fermentation. Several single factors that can effect the cellulase activity was studied in this paper.The results showed that factors such as temperature, cultivation time, initial pH, S/L of medium, and addition of bran as well as nitrogen source etc have significant impact on cellulase productivity. Urea is added to the medium, S/L is 1:2 and the inoculum concentration is 5%.CMCase and FPase reach the maximum after three days cultivation. Whereas the ratio of wheat bran, initial pH and cultivation temperature have different influence on CMCase and FPase. CMCase and FPase come to the maximum activity value under different cultivation conditions.The orthogonal experiment showed that the optimal scheme was 24℃,0.1% urea and 40% bran are added to the medium and the initial pH is 7, CMCase and FPase were 1617.92U and 114.25U respectively.