Decolourization of synthetic dyes by a newly isolated strain of Serratia marcescens

A novel dye-decolourizing strain of the bacterium Serratia marcescens efficiently decolourized two chemically different dyes Ranocid Fast Blue (RFB) and Procion Brilliant Blue-H-GR (PBB-HGR) belonging respectively to the azo and anthraquinone groups. Extracellular laccase and manganese peroxidase (MnP) activity were detected during dye decolourization. The involvement of MnP activity was found in the decolourization of both dyes. More than 90% decolourization of PBB-HGR and RFB was obtained on days 8 and 5, respectively at 26 degreesC under static conditions at pH 7.0. MnP activity was increased by the addition of Mn2+. At 50 muM Mn2+, high MnP (55.3 U/ml) but low laccase activity (8.3 U/ml) was observed. Influence of oxalic acid on MnP activity was also observed.