Isolation Of Effective Cellulytic Anaerobic Bacteria,Construction Microbial Agent And Application On Biogas Fermentation

In China, biogas plays a key role on the energy construction and the new rural construction due to the advantages of its low costs and fits rural areas. However, anaerobic digestion was severely restricted by the low temperature that greatly limites the popularization of the anaerobic digestion in the cold regions. Besides, the efficiency of biogas production is also affected by the degradation and conversion efficiency of cellulosic material. Thus, it is significantly important to obtain highly efficient cellulose degrading bacterium that suitable for low temperature. In this study, we analyze the microbial community of frozen soil and materials for biogas production, then the highly efficient bacteria strains for cellulose degradation were obtained and microbial agents were prepared. The main conclusions are as follows:1.264anaerobic fiber degrading bacterium were isolated from8samples by Hungate technique. Under35℃,191bacterium were isolated, which were consisted of Acetivibrio, Clostridium and Ruminococcus genus. The other bacterium were isolated under15℃and were consisted of Clostridium and Bacteroides genus. The microbial community structure and number was variable between samples. In general, the diversity and the structure were low and simple, respectively.2.15highly efficient cellulose degrading bacterium were obtained. Fore these bacterium, the efficiency of filter paper degradation and enzyme activity of CMC were18.51%higher and higher than0.0116U. The effect of filter paper degradation of YBJ-301351was the best, the efficiency of filter paper degradation and the enzyme activity of CMC were52.69%and0.033U, respectively.3. Two microbial agents (C14and C15) of cellulose degradation were obtained by Orthogonal User Pairing Scheduling. The enzyme activity were124%and60%higher than that of YBJ-301351, respectively, and the efficiency of filter paper degradation were65.5%and25.9%higher than that of YBJ-301351, respectively.4. The microbial agents C14could significantly improve the biogas production and degradation of corn stover under35℃and15℃. Under35℃, the start-up of anaerobic digestion was accelerated by C14, the total biogas and methane productions were increased by27.3%and21.5%, respectively. However, under15℃, the daily biogas production of control and C14were unstable, and the total biogas and methane productions were27.3%and21.5%higher than that of the control.These results not only enrich the resources of cellulose degrading bacteria strains, but also lay theoretical foundations for the improvement of biogas production in cold regions.