Insights into high-solids anaerobic digestion of food waste enhanced by activated carbon via promoting direct interspecies electron transfer

•HS-AD of FW under high OLRs with the addition of PAC, GAC and CAC was examined.•PAC performed better than GAC and CAC in promoting methane yield at higher OLRs.•PAC enhanced the process stability via accelerating the propionate consumption.•Potential DIET microorganisms were selectively enriched with AC addition.•DIET contribution on methane yield was quantitively predicted with PAC addition.