Polyphenol rewiring of the microbiome reduces methane emissions

Area of Science:

• Microbiology
• Environmental Science
• Biogeochemistry

Background:

• Methane (CH4) emissions are a major driver of global warming, with microbial sources contributing approximately 40% of total emissions.
• Current strategies to suppress methanogens (methane-producing microbes) lack detailed microbiome insights, limiting their effectiveness across diverse ecosystems.
• Peatlands are significant sources of atmospheric methane, necessitating effective mitigation approaches.

Purpose of the Study:

• To investigate the impact of the proposed methane inhibitor catechin on greenhouse gas emissions in high-methane-emitting peatlands.
• To elucidate the microbial pathways and mechanisms by which catechin influences methane production.

Main Methods:

• Utilized genome-resolved metatranscriptomics and metabolomics to analyze microbial community responses to catechin treatment in peatland microcosms.
• Conducted longitudinal sampling to reconstruct microbial degradation pathways of catechin and assess gene expression changes.
• Quantified methane emissions and analyzed the expression of genes involved in methanogenesis and hydrogen metabolism.

Main Results:

• Catechin treatment drastically reduced methane emissions by 72%-84% compared to control microcosms.
• Reconstructed a catechin degradation pathway involving Actinomycetota, Clostridium, and Pseudomonas_E, highlighting microbial breakdown of the inhibitor.
• Observed decreased gene expression in hydrogenotrophic and methylotrophic methanogens, alongside reduced expression in syntrophic partners, suggesting hydrogen availability was limited.

Conclusions:

• Catechin acts as a potent methane inhibitor by redirecting microbial metabolism and reducing hydrogen availability to methanogens.
• The findings suggest catechin is a promising tool for methane mitigation in various environments, including ruminants, landfills, and wetlands.
• Understanding microbiome-centered insights is crucial for developing effective and translatable strategies for greenhouse gas reduction.