Brevibacillus laterosporus MTCC 2298: A potential azo dye degrader

Abstract

Aims: To evaluate the potential of Brevibacillus laterosporus MTCC 2298 for the decolourization of different textile azo dyes including methyl red, mechanism of biotransformation and the toxicity of products. Methods and Results: Brevibacillus laterosporus showed decolourization of thirteen different azo dyes including methyl red. Decolourization of methyl red was faster (93% within 12 h) under static condition at the concentration 0·2 g l -1. Induction in the activities of lignin peroxidase, laccase, aminopyrine N-demethylase, NADH-DCIP reductase and malachite green reductase was observed in the cells obtained after decolourization. Fourier transform infra-red spectral analysis of products indicated conversion of methyl red into secondary aryl amines and nitrosamines, which further transformed into the aromatic nitro compounds. Gas chromatography-mass spectroscopy analysis suggested conversion of methyl red into high molecular weight complex derivatives. The heterocyclic substituted aryl amine (m/z 281), p-(N,N di formyl)-substituted para-di amino benzene derivative (m/z 355) and p-di-amino benzene derivative (m/z 282) are the mainly elected biotransformation products. Microbial and phytotoxicity studies suggested nontoxic nature of the biotransformation products. Conclusions: Brevibacillus laterosporus has potential for the decolourization of different textile azo dyes. Significance and Impact of the Study: Brevibacillus laterosporus decolourized different azo dyes including methyl red and can be utilized for textile dye decolourization. © 2009 The Authors.