Anaerobic digestion is one of the most effective bioprocess practices used for maximum utilization of organic wastes to produce methane, a renewable energy source. In this study, the optimum loading ratio of lignocellulosic biomass (LCB), food waste (FW) and animal manure (AM) in an anaerobic digester for sustainable methane production is determined. An efficient lignocellulose-degrading acclimated culture (AC) was developed for bioaugmentation of an anaerobic digester fed with pretreated lignocellulose, AM and anerobic digested sludge (ADS) for 80 days. The potential of co-digestion and bioaugmentation to increase biogas production was investigated in a continuous reactor (20 L) under mesophilic and thermophilic conditions. The key parameters including temperature, pH, organic loading rate (OLR), hydraulic retention time (HRT), C:N ratio, alkalinity, and volatile fatty acid (VFA) concentration were measured and their effects on the stability of the co-digestion process were analyzed. Higher methane production and shorter lag phase were observed in the acclimatized continuous reactors, while longer lag phase and incomplete substrate utilization were observed in unacclimatized reactors. Thermophilic continuous reactors operated for 70 days showed higher cumulative methane production (405.78 L) than mesophilic reactors (388.88 L). Degradation of long-chain fatty acids (LCFAs) was enhanced in the presence of AC, and degradation of up to 99% LCFAs was observed. Multi-omics analysis showed that <i>Methanosaeta</i> and <i>Methanosarcina</i> were abundant and enhanced metabolic pathways specific for carbohydrate and lipid metabolism.

Methanogenic performance and multi-omics analysis of a continuous anaerobic co-digester under mesophilic and thermophilic conditions

ACS Spring 2022

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