Evolution of Microbial Community Structure and Diversity Analysis during Acclimation for High-oil Food Waste Anaerobic Digestion

Abstract

Abstract Anaerobic digestion is one of the most promising options for dealing with biodegradable food waste. However, the relatively high content of oil in food waste inhibits the conversion efficiency of anaerobic digestion because of the accumulation of long-chain fatty acids (LCFA). In this study, the activated anaerobic sludge was acclimated to accommodate the high-oil condition. The shift of the microbial communities during the acclimation period was represented by high-throughput sequencing based on the 16S rRNA gene. The results indicated that Bacteroidetes, Firmicutes, Chloroflexi and Proteobacteria were the dominant bacteria at the phylum level. The relative abundances of Anaerolinea, Clostridium and Longilinea at the genus level improved during the acclimation period, likely triggered by the degradation of LCFA. Among the archaea communities, the hydrogenotrophic methanogen Methanobacterium nearly supplanted the acetotrophic methanogen Methanosaeta. The fluctuations of pH and volatile fatty acids during the period provide extra evidence for the effectiveness of the acclimation. The methane yield of high-oil food waste digested by the acclimated sludge was 24.9% higher than with the raw sludge.