The Electrochemical Character During the Decolorization Processes of Azo Dyes by a Halomonas sp. GYW

This work was conducted to study the changing characteristics of the oxidation-reduction potentials (ORP) during the processes of the biological decolorization of azo dyes, knowledge of which would be useful for prediction of the decolorization capacity of oxidative and reductive biocatalysts. Reduction of these azo dyes did not occur under aeration conditions, and azo dyes were reduced by microorganisms only when the Oxidation-Reduction Potential (ORP) values decreased the certain limits (<-93 mV) during the decolrization processes. At the same time, sulfate salt, anthnaquinone (AQ) and 1-amino-4-bromo-2- anthraquinonesulfonic acid (BAA) were tested to assess the effects on the change of ORP during the decolorization processes. These studies with a Halomonas sp. GYW indicated that the reduction of azo dyes might be influenced by the chemical nature of the azo compound and redox mediators.