Lee HyunWoo, Fitamo Temesgen M, Nesbø Camilla L, Guilford Nigel G H, Kanger Kärt, Yang Minqing Ivy, Edwards Elizabeth A
Department of Chemical Engineering and Applied Chemistry and BioZone, University of Toronto, 200 College Street, Toronto, Ontario, Canada, M5S 3E5.
Faculty of Science and Technology, University of Tartu, Vanemuise 46, Tartu 51003, Estonia.
FEMS Microbiol Ecol. 2023 Feb 28;99(3). doi: 10.1093/femsec/fiad017.
A 50-kg scale, high solids anaerobic digester (AD) comprising six sequentially fed leach beds with a leachate recirculation system was operated at 37°C for 88 weeks. The solid feedstock contained a constant fibre fraction (a mix of cardboard, boxboard, newsprint, and fine paper) and varying proportions of food waste. Previously, we reported on the stable operation of this digestion system, where significantly enhanced methane production from the fibre fraction was observed as the proportion of food waste increased. The objective of this study was to identify relationships between process parameters and the microbial community. Increasing food waste led to a large increase in the absolute microbial abundance in the circulating leachate. While 16S rRNA amplicons for Clostridium butyricum were most abundant and correlated with the amount of FW in the system and with the overall methane yield, it was more cryptic Candidatus Roizmanbacteria and Spirochaetaceae that correlated specifically with enhanced methane from the fiber fraction. A faulty batch of bulking agent led to hydraulic channeling, which was reflected in the leachate microbial profiles matching that of the incoming food waste. The system performance and microbial community re-established rapidly after reverting to better bulking agent, illustrating the robustness of the system.
一个50千克规模的高固体厌氧消化器（AD），由六个顺序进料的渗滤液回流系统的渗滤床组成，在37°C下运行88周。固体原料包含恒定的纤维部分（由硬纸板、箱板纸、新闻纸和细纸混合而成）和不同比例的食物垃圾。此前，我们报道了该消化系统的稳定运行情况，即随着食物垃圾比例的增加，纤维部分的甲烷产量显著提高。本研究的目的是确定工艺参数与微生物群落之间的关系。食物垃圾的增加导致循环渗滤液中微生物绝对丰度大幅增加。虽然丁酸梭菌的16S rRNA扩增子最为丰富，且与系统中食物垃圾的量和总甲烷产量相关，但与纤维部分甲烷产量增加具体相关的是更为神秘的“罗伊兹曼氏菌属候选菌”和螺旋体科。一批有问题的膨胀剂导致了水力通道的形成，这反映在渗滤液微生物图谱与进入的食物垃圾相匹配。在恢复使用更好的膨胀剂后，系统性能和微生物群落迅速恢复，说明了该系统的稳健性。
