Screening Of High-efficiency Degrading Microbes Of The Cow Excrement And Fermentation By Mixed Microorganism

Thirty four mid-temperature cellulose degrading strains were isolated and screened from the compost, cow excrement, and soil. They consist of thirty-one bacteria strains, five fungi strains, and four actinomycetes strains. Together with six reference strains, the ability of degrading cellulose of these strains was determined using the cow excrement as specific substrate. Seven effective strains with high ability of degrading cow excrement were obtained and were used to degrade cow excrement. The results of the taxonomic tests show that four bacteria strains belong to different genus; b3 is genus of Cellulomonas, b25 and b29 are genus of Pseudomonas, and b27 is genus of Curtobacterium. Two strains belong to fungi; f1 and f3 belong to genus of Penicillium and Trichoderma, respectively. Strain s4 belong to genus of Sterptomyces.The fermentation experiments show that the highest rate of cow excrement degrading by single strain can reach 43.9% (strain f3). Furthermore, the antagonistic reaction between each strain was tested; the results show that there is no antagonism existed except strains b3 and s4. Compared with single strain fermentation, the degrading rate of cellulose by the mixture of double strains is higher; the highest rate is 71.3% (the mixed inoculants of strains fl and f3), which is 27.4% higher than that degraded by the most efficient single strain. The efficient strain combinations were found to be fl b25 , flb27, f3b3, f3b25, f3b29, f3s4 and flf3, which may decompose the cow excrement well. After 12-days' fermentation, the average rate of degraded cellulose by inoculating double strain mixture is 50.8% higher than that of CK, and is 26.8% higher than that inoculated single strain.The optimum culturing condition of mixed strains was performed by the orthogonal experiment and the results show that the optimum conditions to get a high cellulase activity of the mixed strains are: a wheat bran and straw ratio of 3:7, 7% nitrogenous fertilizer (brewery sludge), and a material and water ratio of 1:1.5 with pH7.0.The outdoor fermentation experiments show that the physical states are different at the end of composting process. As for the smell aspect, the fetid odor of all the treatments almost disappeared except CK (no inoculants used during the fermentation); and the compost inoculated strain mixture was much looser than the other treatments. After35-days' fermentation treated by mixed microbes, the average water content, the average cellulose quantity, the average ember content, and the average fattiness content of compost are 52.64%, 20.93%, 49.2%, and 4.53%, respectively; And the average seed-germination ratio treated by compost effluent is 108.48%, which indicates that the effect of degrading cow excrement by mixed microbes is much better.