CHARACTERISTICS OF CELLULOSE-DEGRADING MICROBES IN ANAEROBIC CO-DIGESTION OF SWINE MANURE WITH CORN STOVER FOR BIOGAS PRODUCTION

Anaerobic co-digestion of swine manure and corn stover for biogas production has been studied in completely;mixed and semi-continuously fed reactors. Preliminary results indicate that corn stover has been substantially degraded to methane in anaerobic co-digestion with swine manure. Corn stover contains mainly cellulose, hemicelluloses; and lignin. Among. which, cellulose is the main and pioneer carbon source contributor most probably available for the microbes in co-digesters. So cellulose-degrading microorganisms must have played an important role in the anaerobic co-digestion. One of the main objectives of this study was to analyze the cellulose-degrading microorganisms and their activities in the digestion. In our experiment, filter paper (FP) degradation test and. Congo red-dyed cellulose-enriched cultivation have been conducted to analyze the activities of cellulose-degrading microorganisms. The activities of cellulose-degrading microbes in the anaerobic cultures from the digester treating swine manure alone and the co-digester treating both swine manure and corn stover have been compared to determine the metabolism and the pathways of carbon utilization in the anaerobic co-digestion. Results of FP degradation test show that dry weight loss (DWL) of FP with cultures from the digester and the co-digester under anaerobic cultivation at 35 degrees C and 120 rpm for 34 days are 43% and 62.5%, respectively, Biogas yields are 200 ml and 350 ml, respectively. Congo red-dyed cellulose-enriched cultivation test indicates that.cellulase activity of microbes from the co-digester are approximately 3 times higher than that from the digester treating swine manure alone. Microscopic observation shows that the dominant bacteria are G(+) spore-forming Clostridium and micrococcus.