Explication of structural variations in the bacterial and archaeal community of anaerobic digestion sludges: An insight through metagenomics

Anaerobic digestion (AD) is a biological process, encompasses the treatment and stabilization of complex organic matter to extract renewable biomethane fuel through microbial interaction in the digester. The main aim of the current study is to investigate the microbial community of anaerobic digestion sludge (ADS), collected at different periods from a mesophilic operating anaerobic digester. The core group of bacteria in ADS including Firmicutes, Bacteroidetes, and Proteobacteria represented more than 60% of the core bacterial community. In ADS (I), the supremacy of Cloacimonetes (18%) was also observed. In ADS (II), the dominance of Anaerobacter (8%) showed the effect of substrate composition on the microbial structure. However, 91% relative abundance of Firmicutes was observed in ADS (III). The hydrogenotrophic methanogens belonging to order Methanomicrobiales and Methanobacteriales exhibited dominance in all three ADSs (> 60%). No specific variations in the archaeal community might be attributed to the presence of beneficial bacterial species. This study provides all the detailed functional roles of microbes involved in AD which can further be used for additional environmental applications.

Automated summary

The study investigated the microbial community of anaerobic digestion sludge (ADS) collected at different periods and found the relative abundance and dominant microbes in different bacterial groups. Hydrogenotrophic methanogens were dominant in all three ADSs, while there were no specific variations in the archaeal community.