Biological decolorization of dye solution containing malachite green by Pandoraea pulmonicola YC32 using a batch and continuous system

In our study, we have isolated a relatively newly identified bacteria species, Pandoraea pulmonicola YC32, and first assessed its capability to treat malachite green (MG). 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 7-10 and it increased, with increasing initial MG concentration up to 100mg/l. The relationship between the decolorization rate and MG concentration agreed with Lineweaver-Burk equation. The apparent kinetic parameters, R-MG,R-max and K-m, were 6.23 mg-MG/g-cell/h and 153.4mg/l. respectively. The initial step in the biodegradation pathway of MG by A pulmonicola YC32 was a reduction or N-demethylation reaction. We achieved a decolorization efficiency of 85.2% with 50 mg/l MG in the immobilized A pulmonicola YC32 continuous column system. This is the first report on the application of a continuous column system to decolorize MG using a microorganism. (C) 2009 Elsevier B.V. All rights reserved.