Differential fate of metabolism of a disperse dye by microorganisms Galactomyces geotrichum and BrevibaciUus laterosporus and their consortium GG-BL

The present work aims to evaluate Brown 3 REL degrading potential of developed microbial consortium GG-BL using two microbial cultures, Galactomyces geotrichum MTCC 1360 （GG） and BrevibaciUus laterosporus MTCC 2298 （BL）. Microbial consortium GG-BL showed 100% decolorization of a dye Brown 3 REL, while individually G. geotrichum MTCC 1360 and B. laterosporus MTCC 2298 showed 26% and 86% decolorization under aerobic condition （shaking） respectively. Measurements of biochemical oxygen demand （BOD） （76%） and chemical oxygen demand （COD） （68%） were done after decolorization by consortium GG-BL. No induction in activities of oxidoreductive enzymes found in G. geotrichum while B. laterosporus showed induction of veratryl alcohol oxidase, Nicotineamide adenine dinucleotide-dichlorophenol indophenol （NADH-DCIP） reductase and riboflavin reductase indicating their role in dye metabolism. Consortium GG-BL showed induction in the activities of laccase, veratryl alcohol oxidase, tyrosinase, NADH-DCIP reductase and riboflavin reductase. Two different sets of induced enzymes from G. geotrichum and B. laterosporus work together in consortium GG-BL resulting in faster degradation of dye. The degradation of Brown 3 REL was analyzed using high performance thin layer chromatography （HPTLC）, high performance liquid chromatography （HPLC）, Fourier transform infrared spectroscopy （FT-IR） and gas chromatography mass spectroscopy （GC-MS）. Phytotoxicity study revealed that metabolites formed after degradation was significantly less toxic in nature.