外源葡萄糖对麦秸厌氧发酵产沼气的影响

摘要

为进一步阐释混合厌氧发酵的内在机制，在中温（35±1）℃条件下，以麦秸为原料，以葡萄糖为外源易分解有机碳，采用批式发酵方式，进行了葡萄糖不同添加量和不同添加方式对秸秆厌氧发酵产沼气影响试验。结果表明，在试验初始添加葡萄糖可提高日产气量，但葡萄糖添加量太少对提高秸秆总固体（ TS）产气量无促进作用，当葡萄糖添加量为秸秆TS质量的6％时获得最大秸秆TS产气量，为303�13 mL·g－1，继续增加葡萄糖添加量，秸秆TS产气量反而降低；在秸秆厌氧发酵日产气量下降阶段一次性或者分次添加葡萄糖对促进秸秆厌氧发酵产沼气均无效果，仅在试验初始一次性添加秸秆TS质量6％的葡萄糖时对秸秆厌氧发酵产沼气有促进作用，秸秆TS产气量较对照提高9�24％；添加葡萄糖对秸秆厌氧发酵过程产气中甲烷含量无明显影响，但提高累积产气中甲烷平均含量，且在日产气量下降后添加葡萄糖的效果更好，但这种促进效果与对照间差异并不显著。综合以上结果，在试验初始一次性添加秸秆TS质量6％的葡萄糖可以获得最佳的产气效果。%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�13 mL·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 of the experiment, glucose a⁃mended at a rate of 6% of TS of the wheat straw would have some promoting effect on biogas production on wheat straw un⁃der anaerobic fermentation, raising the daily biogas yield per unit of TS by 9�24% as compared with CK. Addition of glu⁃cose 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.