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研究报告

Effects of organic load and temperature fluctuation on anaerobic microbial community and enzyme activity

摘要：基于太阳能辅热厌氧消化反应器进行餐厨垃圾半连续发酵试验，探究了温度波动和有机负荷调控（OLR=2.0、4.0、6.0、7.0 kg·m^-3·d^-1）对甲烷产量、酶活性变化和微生物群落结构的影响.结果表明，反应器可以在OLR为2.0 kg·m^-3·d^-1下稳定运行并在6.0 kg·m^-3·d^-1时实现最佳甲烷生产效率，虽然太阳能组比电能组减少了4倍能耗，但热辐射不稳定导致太阳能组发酵温度波动，甲烷平均产量比电能组减少21%.此外，蛋白酶在温度波动环境下表现出较高活性，但脂肪酶和淀粉酶活性却受到抑制.高通测序结果表明，低OLR阶段乙酸型产甲烷菌Methanosaeta活性较强，随着OLR递增氢营养型产甲烷菌Methanoregula和Methanospirillum相对丰度逐渐提高，而试验全过程中水解细菌Firmicutes相对丰度维持在62%~95%，占据主导地位.

Abstract：The semi-continuous fermentation experiment of food waste was carried out based on solar assisted heat anaerobic digestion reactor. The effects of temperature fluctuation and organic load regulation (OLR of 2.0, 4.0,6.0,7.0 kg·m^-3·d^-1) on methane production, enzyme activity and microbial community structure were studied.. The results show that the reactor can operate stably under the OLR of 2.0 kg·m^-3·d^-1 and achieve the best methane production efficiency at 6.0 kg·m^-3·d^-1. Although the energy consumption of solar energy group is 4 times lower than that of electric energy group, the instability of thermal radiation leads to the fluctuation of fermentation temperature of solar energy group, and the average yield of methane is 21% lower than that of electric energy group. In addition, protease showed high activity in the environment of temperature fluctuation, but the activities of lipase and amylase were inhibited. High-throughput test results showed that Methanosaeta in the low OLR stage had strong activity as an acetic acid methanogen, and the increase of OLR promoted the relative abundance of hydrogen trophic methanogenic bacteria Methanoregula and Methanospirillum, while the relative abundance of hydrolytic bacteria Firmicutes was maintained at 62%~95%, occupying a dominant position.

Key words：food waste organic load rate regulation temperature fluctuation enzyme activity microbial community structure