A natural isolate of Pseudomonas maltophila which degrades aromatic sulfonic acids.

A natural isolate, designated BSA56, which was originally selected for growth with benzene sulfonic acid as sole carbon and energy source, was identified as a strain of Pseudomonas maltophila. Strain BSA56 grew on a wide range of aromatic sulfonic acids and was shown to release sulfite from benzene sulfonic acid and 2-naphthalene sulfonic acid. Although it also grew on toluene sulfonic acid and pyridine sulfonic acid, no significant sulfite release was observed with these substrates. Release of sulfite from benzene sulfonic acid was greatly promoted by the presence of glycerol. The ability to release sulfite was induced by growth in the presence of benzene sulfonic acid and was repressed almost entirely by substrates allowing rapid growth such as acetate. Strain BSA56 grew better at 30 degrees C than 37 degrees C on most aromatic substrates, but the reverse was true for most aromatic sulfonates. Several mutants of BSA56 were isolated with defects in benzoate, salicylate, or gentisate metabolism. However, all these mutants retained the ability to degrade the aromatic sulfonates.