Isolation And Degradation Characterization Of Cellulose-degrading Microorganisms Under Low Temperature

With the rapid development of social economy and the increase of population, environmental pollution and energy crisis are becoming serious problem. So seeking an effective method becomes more and more important. Cellulose is a renewable resource. Its storage is the most abundant on the earth. Cellulose can be degraded by cellulose and their product can be transformed into energy. And it also can be used to degrade some pollutant in environmental pollution. Low temperature cellulase has more benefits than thermophilic or ordinary temperature cellulase in the application process. For example, it can shorten treatment time, reduce cost and save more energy. The annual mean temperature in Inner Mongolia is low. Therefore, it is necessary to research low temperature soil microorganisms in Inner Mongolia, which can produce low temperature cellulase and may provide a new powerful tool to solve the energy crisis and environmental problems.In this paper, we studied low temperature soil cellulose-degrading microorganisms in Inner Morgolia by the pure culture and mixed enrichment culture methods. The results showed that55strains were isolated by the pure culture method under10℃. The similarities of16S rRNA gene sequences of the isolates were analyzed. The results indicated that the bacterial groups composed of γ-Proteobacteria (30.90%), Formicates (27.27%), Actinobacteria (16.36%), Bacteroidetes (18.18%) and β-Proteobacteria (7.27%). Their cellulase of optimum temperature is22℃. In these strains, the strain CF11had the highest relative enzyme activity under10℃. Optimization conditions for cellulase-producing of strain CF11were the incubation time10days, pH value6.5, and yeast extract as nitrogen source, and the relative enzyme activity is58.091IU. In the enrichment culture experiments, we found that uncrushed straw had the least degradation amount. And the relative enzyme activity increased with successive transfer cultures. In this paper, microbial community structure of enrichment cultures were revealed by DGGE. The results indicated that microorganism community were composed of α-Proteobacteria, Firmicutes, Bacteroidetes, y-Proteobacteria and β-Proteobacteria.