Genome sequences of Arthrobacter spp. that use a modified sulfoglycolytic Embden-Meyerhof-Parnas pathway

Background Sulfoglycolysis pathways enable the breakdown of the sulfosugar sulfoquinovose and environmental recycling of its carbon and sulfur content. Several pathways exist for the breakdown of sulfoquinovose that usually lead to production of C3-sulfonates (sulfolactate and 2,3-dihydroxypropanesulfonate) that are excreted and sustain secondary bacterial communities. The prototypical sulfoglycolytic pathway is a variant of the classical Embden-Meyerhof-Parnas pathway that has been described in gram-negative Escherichia coli and results in production of 2,3-dihydroxypropanesulfonate. Results We used enrichment cultures to discover new sulfoglycolytic bacteria from Australian soil samples. Two gram-positive Arthrobacter spp. were isolated that produced sulfolactate as the metabolic end-product. Genome sequences identified a modified sulfoglycolytic Embden-Meyerhof-Parnas (sulfo-EMP) gene cluster that retained the core sulfoglycolysis genes encoding metabolic enzymes, but featuring the replacement of the gene encoding sulfolactaldehyde (SLA) reductase with SLA dehydrogenase, and the absence of sulfoquinovosidase and sulfoquinovose mutarotase genes. The gene clusters were broadly conserved across a range of other sequenced Actinobacteria. Conclusions We report the first gram-positive soil bacteria that utilize sulfo-EMP pathways to metabolize SQ. Excretion of sulfolactate is consistent with an aerobic saprophytic lifestyle. This work broadens our knowledge of the sulfo-EMP pathway to include soil bacteria.