Metabolic and Biochemical Pathways for Anaerobic Digestion

The entirety of anaerobic digestion (AD) is deliberated as an intricate microbial process that produces methane from organic matter through various chemical and biological reactions encompassed using hydrolysis, acidogenesis, acetogenesis, and methanogenesis, respectively. Enzymatic pathways, including hydrolases and pyruvate metabolism, facilitate this conversion. Syntrophic interactions among microorganisms drive efficient biogas production. The methanogenesis occurs through acetoclastic, hydrogenotrophic, and methylotrophic pathways, relying on microbial cooperation. Metagenomic studies reveal Firmicutes, Bacteroidetes, Proteobacteria, and Actinobacteria as dominant phyla, with methanogens comprising a small fraction (<20%). Substrate type and operational conditions, such as temperature and pH, shape microbial communities. Despite advancements in metagenomics, many microorganisms in AD remain unidentified. Dedicated databases like KEGG PATHWAY and MetaCyc elucidate AD metabolic pathways. Understanding microbial interactions and functions is critical for optimizing AD processes.