Biodegradation of xenobiotics

A bacterium capable to grow on sulfanilic acid as sole carbon, nitrogen and sulfur source has been isolated. A unique feature of this strain is that it contains the full set of enzymes necessary for the biodegradation of sulfanilic acid. Taxonomical analysis determined our isolate as Sphingomonas subarctica sp. The biodegradation pathway of sulfanilic acid was investigated at the molecular level. Screening the substrate specificity of the strain disclosed its capability to completely degrade six analogue aromatic compounds and oil contamination. Sphingomonas sp. seemed to use distinct enzyme cascades to utilize these molecules, since alternative enzymes were induced in cells grown on various substrates. However, the protein patterns appearing upon induction by sulfanilic acid and sulfocatechol were very similar to each other indicating common pathways for the degradation of these substrates. From the soluble fraction the enzyme capable to oxidize 4-sulfocatechuate could be partially purified and characterized.