Sulfoacetaldehyde is excreted quantitatively by Acinetobacter calcoaceticus SW1 during growth with taurine as sole source of nitrogen

Abstract

Eighteen enrichment cultures with taurine (2-aminoethanesulfonate) as the sole source of combined nitrogen under aerobic conditions were all successful, and 24 pure cultures were obtained. Only three of the cultures yielded an inorganic product, sulfate, from the sulfonate moiety of taurine, and the others were presumed to yield organosulfonates. Sulfoacetate, known from Rhodopseudomonas palustris CGA009 under these conditions, was not detected in any culture, but sulfoacetaldehyde (as a hydrazone derivative) was tentatively detected in the outgrown medium of nine isolates. The compound was stable under these conditions and the identification was confirmed by MALDI-TOF-MS. Most sulfoacetaldehyde-releasing isolates were determined to be strains of Acinetobacter calcoaceticus, and a representative organism, strain SW1, was chosen for further work. A quantitative enzymic determination of sulfoacetaldehyde and its bisulfite addition complex was developed: it involved the NAD-coupled sulfoacetaldehyde dehydrogenase from R. palustris. A. calcoaceticus SW1 utilized taurine quantitatively and concomitantly with growth in, for example, an adipate-salts medium, and the release of sulfoacetaldehyde was stoichiometric. The deamination reaction involved a taurine dehydrogenase. Enrichment cultures to explore the possible release of organophosphonates from the analogous substrate, 2-aminoethanephosphonate, led to 33 isolates, all of which released inorganic phosphate quantitatively.