Abstract: To explore inner mechanism of mixed anaerobic fermentation, an experiment was conducted to determine effects of glucose amendment rate and method on biogas production of wheat straw under batch anaerobic fermentation at (35±1)℃, using wheat straw as raw material and glucose as extraneous easily biodegradable organic carbon. Results show that in the initial period of the experiment, addition of glucose increased daily biogas yield, but when the glucose addition rate was too low, the effect was negligible, and when the rate was raised up to 6%of TS (total solid weight) of wheat straw, biogas yield per unit of TS of wheat straw was peaking to 303.13mL·g^-1. But further increase in glucose amendment rate affected reversely daily biogas yield. Once daily biogas yield began to decline, the amendment of glucose, either once for all or in several times, had no promoting effect on daily biogas yield.Only at the beginning the experiment, glucose amended at a rate of 6% of TS of the wheat straw would have some promoting effect on biogas production on wheat straw under anaerobic fermentation, raising the daily biogas yield per unit of TS by 9.24% as compared with CK. Addition of glucose did not have much effect on content of methane during the process of biogas production from anaerobic fermentation of wheat straw, but greatly raised mean concentration of cumulative biogas production, and the effect was more significant during the daily biogas yield declining period. However, such a promoting effect was not significant as compared with CK. To sum up, the amendment of glucose at a rate of 6% of TS of wheat straw once for all at the beginning of the experiment can achieve the highest biogas yield.

Key words: glucose, wheat straw, mixed anaerobic fermentation, biogas, methane