Aerobic Biodegradation of Malachite Green and Methyl Red by Klebsiella pneumonia KP 13 Isolated from Soil Contaminated with Laboratory Effluent

Synthetic dyes are widely used in the textile, food, cosmetic, and paper printing industry. Due to their recalcitrance and persistence in the environment they pose a threat to environmental health.The current study was carried out to study decolorization of two such environmental pollutants, Methyl red, an azo dye and Malachite green, a triphenylmethane dye by Klebsiella pneumonia KP 13 which was isolated from laboratory effluent contaminated soil of our college. Identification of the potent isolate was authenticated by 16S r DNA method. Klebsiella pneumonia KP 13 was capable of utilizing Methyl red and Malachite green as sole source of carbon in a medium containing 200 mgL-1 of di- ammonium hydrogen phosphate and 1000 mgL-1 yeast extract at optimum pH 7, temperature 37°C and under shaking conditions. Extent of decolorization of Malachite green and Methyl red was to the extent of 85% and 93% respectively in 24 hours. Presence of nitrites in the decolorized samples of Methyl red confirmed aerobic mode of biodegradation thus ruling out formation of toxic aromatic amines.