Cloning of DNA from a Rhodococcus strain conferring the ability to decolorize sulfonated azo dyes.

Azo dyes are recalcitrant pollutants. Two sulfonated azo dyes, Orange II and Amido black, are effectively decolorized by certain nocardioform strains of the genus Rhodococcus. A mutant of one of these strains was isolated which had lost azo-dye decolorizing ability and the strain was used to clone DNA conferring this ability, by screening a BclI library constructed from DNA of a decolorizing strain. The relevant genetic information was located on a 6.3-kb fragment of DNA.