The Evolution of Microbial Community during Acclimation for High Sodium Food Waste Anaerobic digestion

Abstract

Anaerobic digestion is a promising method for treating the rapidly increasing food wastes. However, the high level of sodium salt in food waste significantly inhibited the anaerobic digestion process. In this study, acclimation was conducted to adapt to the high sodium food waste. The evolution of microbial community during acclimation process was characterized by high-throughput sequencing based on the 16S rRNA gene. The results revealed that the predominant phyla were Bacteroidetes, Firmicutes, Thermotogae, Chloroflexi, Proteobacteria and Synergistetes. The increase of functional genera Kosmtoga, Levilinea and Longilinea during the process potentially promoted the biodegradation of organics. As for the archaea community, the mixotrophic methanogens Methanosaricina was almost replaced by hydrogenotrophic methanogens Methanobacterium and Methanocorpusculum. The variations of pH and volatile fatty acid during acclimation provided additional information on the adaptation of microorganisms to the high sodium environment. The biogas production of food waste inoculated with acclimated sludge was increased by 63.6% compared with the raw sludge. The evolutions of bacterial and archaea communities during acclimation at the phylum level