Unravelling the Syntrophic Relationships in Anaerobic Digestion for Biomethane Production

Biological biogas upgrading (BBU) is a process that offers a solution to the increasing demand for energy and the need to reduce greenhouse gas emissions. The technology relies on the microbial communities involved in syntrophic relationships. The study aimed to understand the mechanisms behind these interactions and the impact of feeding conditions and exogenous factors on biogas production and quality. In the current work, genome-centric metagenomics and metatranscriptomics were used to analyse the microbial communities fed with hydrogen (H2) and carbon dioxide (CO2). A combination of amino acids were used to corroborate the hypothesis of their key role as metabolites in syntrophic interactions. The addition of antibiotics alone hindered the growth of the microbial community, however, the presence of amino acids allowed the archaeal population to survive and continue producing methane. Additionally, the amino acids addition had improved the stability of the process and the total production of methane. The outcomes of this research provide a fresh perspective on the pivotal metabolic pathways of CO2 methanation in microbial ecosystems and emphasise the significance of syntrophic relationships in the BBU process. These findings have the potential to inform the development of more efficient and sustainable biogas upgrading technologies in the future.