Biodetoxification of high amounts of malachite green by a multifunctional strain of Pseudomonas mendocina and its ability to metabolize dye adsorbed chicken feathers

•Biodetoxification of malachite green (MG) by Pseudomonas mendocina PM2 was evaluated.•Metabolism of chicken feathers by PM2 & MG sensitive Bacillus subtilis was studied.•MG adsorbed chicken feathers were toxic to B. subtilis but not to PM2.•Metabolism of MG adsorbed chicken feathers by both the strains was studied.•MG adsorbed chicken feathers were metabolized by PM2 and not by B. subtilis.

Malachite green (MG) is a highly toxic, and recalcitrant tri-phenyl methane dye, which can be adsorbed on surface of chicken feathers, a non toxic poultry waste. This interaction can affect metabolism of chicken feathers by microbes in the environment. In this study, decolorization/degradation of MG and metabolism of MG adsorbed chicken feathers by Pseudomonas mendocina strain PM2 has been evaluated. Decolorization of different concentrations of MG by strain PM2 was studied. Degradation of MG was studied by UV–vis/FTIR analysis. Enzyme activities of selected enzymes were evaluated in order to ascertain their role in MG degradation. Microbial/phytotoxocity studies on MG and its degraded metabolites were carried out to confirm detoxification of MG after degradation. MG was adsorbed on surface of chicken feathers and its toxicity on strain PM2 and MG sensitive strain of Bacillus subtilis MTCC 441 was evaluated. Metabolism of native and MG adsorbed chicken feathers by strain PM2 and MTCC 441 was studied. Results showed that strain PM2 could decolorize up to 1800 mg/L MG. UV–vis/FTIR studies indicated degradation of MG by strain PM2. Assay of enzyme activity indicated involvement of MG reductase, lignin peroxidase and manganese peroxidase during degradation. Microbial/phytotoxicity study confirmed biodetoxification of MG after degradation. MG adsorbed chicken feathers were toxic to MTCC 441 and non toxic to strain PM2. Further, strain PM2 was able to metabolize MG adsorbed chicken feathers whereas MTCC 441 could not metabolize MG adsorbed chicken feathers. This study clearly indicates that MG adsorbed chicken feathers are difficult to be metabolized by MG sensitive strains.