Decolorization characteristics and mechanism of Victoria Blue R removal by Acinetobacter calcoaceticus YC210.

Acinetobacter calcoaceticus YC210 has been isolated and its ability to remove Victoria Blue R (VBR) from aqueous solution was assessed. The effects of various factors on decolorization efficiency were investigated in a batch system. The decolorization efficiency was found to be optimal within a pH of 5-7 and increased with VBR concentration up to 450 mg/l with high efficiency (94.5%) in a short time. The decolorization efficiency was significantly affected by cell concentrations. The decolorization of VBR by A. calcoaceticus YC210 followed first order kinetics. The apparent kinetic parameters of the Lineweaver-Burk equation, R(VBR,max) and K(m), were calculated as 6.93 mg-VBR/g-cell/h and 175.8 mg/l, respectively. Based on the biodegradation products, VBR degradation by A. calcoaceticus YC210 involves a stepwise demethylation process to yield partially dealkylated VBR species. To our knowledge, this is the first report using microbes to remove VBR. It clearly demonstrates the dealkylation pathway of VBR degradation.