Microbial community dynamics and biogas optimization in full-scale anaerobic digesters across South Korea

Abstract

Optimizing microbial communities in anaerobic digesters is essential to improving biogas production for sustainable energy. This study utilized high-throughput 16S rRNA gene sequencing to profile microbial communities from 18 full-scale biogas plants across South Korea, revealing key microbial patterns linked to performance. The bacterial consortia were dominated by Firmicutes, Bacteroidetes, Cloacimonetes, and Proteobacteria, with feedstock type exerting a marked influence on community composition. Firmicutes predominated in FW-fed digesters that exhibited high methane yields (≥ 1 m3 CH m-3 day-1), whereas Proteobacteria prevailed in activated sludge-fed systems characterized by lower methane production. Among archaeal families, Methanosarcinaceae, Methanomassiliicoccaceae, and Methanobacteriaceae were especially abundant in high-performing plants. Co-occurrence network analysis revealed a strong positive association between Firmicutes and Methanosarcinaceae in these reactors, indicative of synergistic metabolic interactions that enhance methane generation. Conversely, low-yield plants showed prominent co-occurrence patterns between Proteobacteria and Methanosaetaceae, suggesting alternative or less efficient pathways of methanogenesis. Overall, our findings underscore the critical role of feedstock-dependent microbial networks in determining biogas plant performance, highlighting specific bacterial and archaeal groups as potential biomarkers for monitoring and optimizing anaerobic digestion. These insights also lay a foundation for computational modeling aimed at predicting metabolic outcomes based on microbiome data, ultimately contributing to more effective and sustainable biogas production.