Anaerobic Co-Digestion Changes Microbial Community and Synergistically Increases Biogas Production in Municipal Digesters

摘要

Co-digestion of certain wastes (i.e., synergistic wastes) has been observed to produce morebiogas than predicted based on the additional COD of the co-digestate alone. The objectives ofthis study were to determine the influence of co-digestion on microbial community structure andactivity and quantify performance of full-scale anaerobic co-digestion using primary sludge andacid whey from cheese production. Biochemical methane potential tests were performed toidentify the co-digestion outcomes. Methanogenic activity was determined using standardspecific methanogenic activity (SMA) assays against acetate, propionate and H_2. Denaturinggradient gel electrophoresis (DGGE) and quantitative PCR (qPCR) analyses were performed onthe methyl coenzyme M reductase (mcrA) gene to compare methanogen communities. SMAincreased when co-digestion was practiced. The increased SMA in co-digesters was putativelydue to changes in the relative number of different methanogens present in co-digesters (i.e., themicrobial community structure), and not due to an increase in the total number of allmethanogens. The increased abundance of Methanospirillum, an H_2-utilizing methanogengenus, played a significant role in higher methanogenic activity of co-digesters. Full scale codigestionof acid whey with primary sludge synergistically increased CH_4 production. Codigestionof synergistic wastes is one method to increase biogas yield by changing methanogencommunity and enhancing microbial activity.