New paper: Degradation of a green-fodder-derived sulfosugar by cow rumen bacteria

Sulfoquinovose is a sulfur-containing glucose derived from specialized lipids in green plants and algae. It is degraded by specialized gut microbes, generating metabolites such as acetate, butyrate, and hydrogen sulfide that can influence both human and animal health. Together with an international team of scientists, Julia Krasenbrink and Alexander Loy now show how sulfoquinovose is processed by the cow rumen microbiota and describe previously uncharacterized bacterial species involved in this pathway. Their study demonstrates that sulfoquinovose-degrading bacteria in the cow rumen differ markedly from those in the human and mouse gut: they are more diverse, largely belong to uncultivated taxa, and employ distinct metabolic pathways. The researchers further reveal that microbial cross-feeding of a key intermediate, isethionate, links sulfoquinovose degradation to sulfite respiration and sulfide formation in the rumen. These findings highlight sulfoquinovose degradation as a fundamental metabolic process in the rumen and broaden our understanding of sulfur cycling in complex microbiomes. Importantly, the study also points to potential applications in reducing methane emissions from ruminants. Increased sulfite respiration is associated with decreased activity of methane-producing archaea, suggesting that this pathway may naturally suppress methane formation. Future research will determine whether sulfoquinovose-containing lipids, such as those found in algae-based feed additives, contribute to their reported anti-methanogenic effects.