Biodegradation of p-toluenesulphonamide by a Pseudomonas sp.

A bacterium capable of utilising p-toluenesulphonamide was isolated from ac tivated sludge, The isolated strain designated PTSA was identified as a Pse udomonas sp. using chemotaxonomic and genetic studies. Pseudomonas PTSA gre w on p-toluenesulphonamide in a chemostat with approximately 90% release of sulphate and 80% release of ammonium. The isolate was also able to grow on 4-carboxybenzenesulphonamide and 3,4-dihydroxybenzoate but did not grow on p-toluenesulphonate. The transient appearance of 4-hydroxymethylbenzenesul phonamide and 4-carboxybenzenesulphonamide during p-toluenesulphonamide deg radation proves oxidation of the methyl group is the initial attack in the biodegradation pathway. Both metabolites of p-toluenesulphonamide degradati on were identified by high-performance liquid chromatography-mass spectrome try. 4-Carboxybenzenesulphonamide is probably converted into 3,4-dihydroxyb enzoate and amidosulphurous acid. The latter is a chemically unstable compo und in aqueous solutions and immediately converted into sulphite and ammoni um. Both sulphite and ammonium were formed during degradation of 4-carboxyb enzenesulphonamide. (C) 2001 Federation of European Microbiological Societi es. Published by Elsevier Science B.V. All rights reserved.