High-solids anaerobic co-digestion performances and microbial community dynamics in co-digestion of different mixing ratios with food waste and highland barley straw

High-solids anaerobic co-digestion (HSACoD) performances and microbial community dynamics were investigated. Food waste (FW) and highland barley straw (HBS) were used as co-digestion substrates with mixing ratios of 1:1, 1:3, 1:5, 5:1, and 3:1 (FW: HBS) in an anaerobic digestion (AD) system with 20% total solids. The results showed that the highest methane yield was 509.5 mLN/gVS for FH51, which was 129.8% higher than that of the single HBS. Synergistic effects contributed 20.4%–30.9% to improving methane yields in the first 25 days. The HSACoD system displayed excellent buffer capacity. Fastidiosipila, Gallicola, Proteiniphilum, Aminobacterium, Syntrophaceticus, and W5053 were dominant genera. Methanobacterium, Methanosphaera, Methanoculleus, and Methanosarcina were the key methanogens, displaying high relative abundance. Functional profiling indicated a relative abundance of metabolic pathways of 36.9%–39.6%, with the next most prevalent pathways being cellular processes and signaling, and information storage and processing. Therefore, HSACoD of FW and HBS can enhance AD speed in the early phase of AD and improve system stability.