生物炭促进餐厨垃圾发酵产己酸效能及机理研究

研究了餐厨垃圾制备的水热炭和热解炭对餐厨垃圾发酵产己酸的影响,分析了生物炭的理化性质及微生物群落结构。结果表明:空白组己酸最大产量仅为1.65 g COD/L,投加5 g/L水热炭和热解炭对产己酸均有促进作用,己酸最大产量分别为3.64,24.24 g COD/L,为空白组的2.2,14.7倍;而过量水热炭和热解炭(10 g/L和20 g/L)反而对产己酸具有抑制效应。生物炭理化性质对比分析表明:热解炭可促进直接种间电子传递,比表面积更大的热解炭可为产己酸功能菌群提供更大面积的附着位点,富集己酸功能菌,促进乙醇和丁酸转化成己酸。微生物群落分析表明:5 g/L热解炭组产己酸功能菌Clostridium_sensu_stricto_12、Caproiciproducens和Clostridium_sensu_stricto_11的相对丰度分别为35.6%、2.0%和1.7%。

EFFECT OF BIOCHAR ON CAPROATE PRODUCTION DURING FOOD WASTE FERMENTATION AND THE MECHANISM

The effects of hydrochar and pyrochar prepared by food waste on the production of caproate from food waste fermentation were investigated. The physicochemical properties of the biochar and microbial community were analyzed. The results showed that the maximum production of caproate was only 1.65 g COD/L in the blank. The addition of 5 g/L hydrochar and pyrochar both promoted the production of caproate with the maximum production at 3.64 g COD/L and 24.24 g COD/L, which were 2.2 times and 14.7 times that in the blank respectively. While excess hydrochar and pyrochar (10 g/L and 20 g/L) inhibited the production of caproate. The comparative analysis of the physicochemical properties of the biochar showed that the pyrochar could promote direct interspecies electron transferring, and pyrochar with a larger specific surface area could provide more attachment sites for the functional microbes for caproate production and enrich its abundance, promoting the conversion of ethanol and butyrate into caproate. Microbial community analysis showed that the relative abundance of functional microbes for caproate production including Clostridium_sensu_stricto_12, Caproiciproducens and Clostridium_sensu_stricto_11 in the 5 g/L pyrochar was 35.6%, 2.0% and 1.7%, respectively.