Samples collected from various effluent-contaminated soils in the vicinities of dyestuff manufacturing units of Ahmedabad, India, were studied for screening and isolation of organisms capable of decolorizing textile dyes. A novel bacterial consortium was selected on the basis of rapid decolorization of Direct Red 81 (DR 81), which was used as model dye. The bacterial consortium exhibited 90% decolorization ability within 35 h. Maximum rate of decolorization was observed when starch (0.6 g l )1 ) and casein (0.9 g l )1 ) were supplemented in the medium. Decolorization of DR 81 was monitored by high performance thin layer chromatography, which indicated that dye decolorization was due to its degradation into unidentified intermediates. The optimum dye-decolorizing activity of the culture was observed at pH 7.0 and incubation temperature of 37°C. Maximum dye-decolorizing efficiency was observed at 200 mg l )1 concentration of DR 81. The bacterial consortium had an ability to decolorize nine other structurally different azo dyes.

Solid state fermentation of wheat straw was attempted with P. chrysosporium MTCC 787 for production of MnP at 39ºC. Fermented residue was extracted with 0.2 M sodium tartarate buffer (pH 3) and was subjected to ammonium sulfate precipitation. Precipitates obtained were subjected to MnP assay, upon dialysis, using MBTH and DMAB as substrate. Optimum pH and temperature were reported to be pH 4.5 and 30ºC respectively. Km and Vmax of MnP for MBTH were found to be 0.05 mM and 25 U/mg, respectively. Enzyme kinetics were also assessed against Reactive Black B (RBB), a widely used textile diazo dye, as substrate. Km and Vmax of MnP for RBB were reported as 0.2 mM and 7 U/mg, respectively. These findings suggest enormous potential of MnP of P. chrysosporium MTCC 787 for its application in treatment of RBB containing wastewater.

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