Metabolism of sulfoacetate by environmental Aureobacterium sp. and Comamonas acidovorans isolates

Abstract

Newly isolated environmental strains of Comamonas acidovorans and Aureobacterium sp. were found to mineralize sulfoacetate at concentrations up to at least 50 mM. Transient sulfite release was detected during growth on sulfoacetate, with essentially quantitative accumulation of sulfate. Cell-free conversion of sulfoacetate could not be obtained, but resting-cell studies indicated that cleavage of the C-S bonds of both sulfoacetate and sulfoacetaldehyde was induced only when sulfoacetate was the sole carbon and energy source. A sulfite-oxidizing activity was also induced under these conditions. Sulfoacetaldehyde sulfo-lyase activity was demonstrated by in vitro assay and by gel zymography in extracts of cells grown on sulfoacetate as sole carbon source. This activity was not present in acetate-grown cells, or in cells grown on sulfoacetate as sole sulfur source. Results suggest that sulfoacetate mineralization in both isolates may proceed by a novel pathway which involves an initial reduction to sulfoacetaldehyde and subsequent cleavage of the C-S bond to yield sulfite and acetate. The proposed pathway may be of environmental significance in the mineralization of plant sulfolipid.