Methane Valorization to Antioxidant Polysaccharides by Methanotrophic Bacteria

Bioconversion of methane into functional polysaccharides presents a promising strategy for mitigating methane-induced greenhouse gas emissions and addressing the limitations of plant-derived polysaccharide and sugar-based microbial polysaccharides production. In this study, the novel methane-derived polysaccharide (MePS) was obtained from a newly isolated methanotrophic bacterium Alkalicoccus glycogenes WONF2802. Structural characterization found that MePS is a branched-chain glucan with a weight-average molecular weight of 283.2 kDa. Additionally, MePS exhibited considerable antioxidant capacities in both in vitro biochemical assays and the H₂O₂-induced oxidative stress cell model. This work establishes a potential pathway for polysaccharide production, reducing reliance on plant and sugar-based feedstocks, while offering a new strategy for methane emission reduction.