Anaerobic degradation of cellulose by rumen microorganisms at various pH values

Batch experiments were performed to investigate the anaerobic degradation of crystalline cellulose of 10 g l(-1) by rumen microorganisms at pH from 4.8 to 7.3. The degradation efficiency increased with pH and the highest value of about 78% was achieved at pH 6.8 and 7.3. Acetate and propionate were the major aqueous products at all pH values. With increasing pH, the molar percentage of acetate decreased, whereas that of propionate increased. A modified Gompertz equation was able to adequately model the fermentation of cellulose by rumen microorganisms. The results from this study might provide useful information for the application of rumen cultures for conversion of cellulosic wastes into value-added products. (C) 2004 Elsevier B.V. All rights reserved.