Electrode as sole electrons donor for enhancing decolorization of azo dye by an isolated Pseudomonas sp. WYZ-2

Abstract

Pseudomonas sp. WYZ-2 was isolated from a biocathode which accelerating azo dye decolorization. When the electrode was polarized at -0.8 V (vs. SCE), WYZ-2 could exist on electrode, because the current of working electrode stabilized at -0.35 mA from -0.13 mA after inoculation. Moreover, cyclic voltammetry scanned an unidentified redox-active molecule which involved in the electron charge transfer potentially. On azo dye decolorization experiments by WYZ-2 modified electrode, electrochemical tests also indicated that the catalytic ability of WYZ-2 modified electrode was improved because charge transfer resistance decreased to 255 Ω from 720 Ω, azo dye reduction potential was shifted to -0.78 V from -0.89 V, and the maximum decolorization efficiency of azo dye was increased to 93.4% from 53.2%, comparing with unmodified electrode. Although numerous studies on azo dye decolorization employed biological agents, electrochemical activity bacteria accelerate the decolorization process using electrode as sole electron source has seldom been reported.

Keywords: Azo dye decolorization; Biocathode; Electroactive bacteria; Pseudomonas sp. WYZ-2.