Enhanced methane yield in anaerobic digestion of food waste by mixing Baijiu pit mud and anaerobic digester sludge as inoculum: Methane production enhancement and microbial mechanism

This study investigated the effect of two different inoculants, pit mud (PM) of baijiu and anaerobic digested sludge (ADS) from baijiu factory on the food waste of anaerobic digestion. 16S rDNA metabarcoding revealed that the domain of bacteria belonging to the phyla Firmicutes, Bacteroideta, Synergistota and Euryarchaeota in different ratio of PM:ADS. Network module analysis showed that unknown genera belong to Anaerolineaceae family is the center of the network. The abundance of hydrolysis and methanogenic related bacteria such as Aminobacterium, Petrimonas and Methanobrevibacter increased with the addition of PM. According to functional gene classification for Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, coenzyme F420 hydrogenase and Methane metabolism (ko00680) pathways were found in the PM:ASD ratio of 1:3, which play a key role in the CH4 production. Therefore, the food waste anaerobic digestion adding of PM could accelerate hydrolysis acidification and change the structure of microbial communities to promote an increase in CH4 production.