Genome-centric metagenomic analysis unveils the influence of temperature on the microbiome in anaerobic digestion

Abstract

Temperature plays a crucial role in shaping microbial ecosystems during anaerobic digestion. However, the specific microbial communities and their functions across a wide temperature range still remain elusive. This study employed a genome-centric metagenomic approach to explore microbial metabolic pathways and synergistic networks at temperatures of 35℃, 44℃, 53℃, 55℃, and 65℃. A total of 84 metagenome assembled genomes (MAGs) were assembled, with over 65% of these MAGs corresponding to novel bacterial and archaeal species (including Firmicutes, Chloroflexota, Bacteroidia and Methanobacteriota), greatly enhancing our current comprehension anaerobic digestion process. Notably, functional annotation identified that 44_bin.2 (Methanothrix_A sp.001602645) harbors enzymes associated with hydrogenotrophic metabolism. Additionally, this microorganism exhibited diverse metabolic capabilities at 44℃, a temperature commonly employed in industrial practice yet less explored in bench studies. Consequently, it implies a promising potential for conducting anaerobic digestion at a moderate thermophilic temperature, as opposed to the conventional mesophilic range. The microorganism exhibited a variety of metabolic capabilities at 44℃, a temperature frequently employed in industrial applications but underexplored in laboratory investigations. The findings suggest that anaerobic digestion carried out at moderate thermophilic temperatures may have a higher potential for methane production.