Methane fermentation of xylan by mesophilic and thermophilic methane sludges

Abstract

The degradation of xylan during methane fermentation proceeded as a first-order reaction. The rate constants were calculated to be 0.40–0.09 day⁻¹ at 37° C and 0.341 day⁻¹ at 55° C. From calculations based on the experimental data, K _A and C _A values in the expression of the velocity of xylose consumption changed as the fermentation progressed. In the mesophilic fermentation, the degradation of xylan slowed down after 2 days of incubation, but the rate of consumption of xylose increased between days 3 and 4 of incubation and slow again at the 5th day of incubation. In the thermophilic fermentation, the degradation of xylan proceeded at a constant rate and the rate of consumption of xylose increased slightly on the 3rd day of incubation. When the velocity of gas evolution was determined, the C _G value for acetate at 55° C was about 1.8 times larger than the value at 37° C.