Azo dye decolorization with a mutant Escherichia coli strain

A recombinant Escherichia coli strain (E. coli NO3) containing genomic DNA fragments from ate-reducing wild-type Pseudomonas luteola strain decolorize d a reactive azo dye (C.I. Reactive Red 22) at approx. 17 mg dye h(-1) g ce ll. The ability to decolorize the azo dye probably did not originate from t he plasmid DNA. Acclimation in azo-dye-containing media gave a nearly 10% i ncrease in the decolorization rate of E. coli NO3. Growth with 1.25 g gluco se l(-1) completely stopped the decolorization activity. When the decoloriz ation metabolites from E. coli NO3 were analyzed by HPLC and MS, the result s suggested that decolorization of the azo dye map be due to cleavage of th e azo bond.