Communal action of microbial cultures for Red HE3B degradation

The consortium PMB11 consisting of three bacterial species, originally isolated from dye contaminated soil was identified as Bacillus odysseyi SUK3, Morganella morganii SUK5 and Proteus sp. SUK7. The consortium possessed the ability to decolorize various textile dyes as well as mixtures of dyes. PMB11 could decolorize Red HE3B (50 mg l−1) with 99% of decolorization within 12 h in nutrient broth, while in mineral medium it could decolorize up to 97% within 24 h. Induction in the activities of various oxidative and reductive enzymes indicates the involvement of these enzymes in decolorization. Biodegradation of the dye was monitored using UV-vis spectroscopy, HPLC and FTIR analysis. The Red HE3B degradation pathway was proposed by GC-MS analysis. Various metabolites formed after the degradation were identified as 2,5-diaminobenzene 6-aminotriazine, aniline 2-sulfate, aniline 3-sulfate, 2-amino 5-chlorotriazine and naphthalene. Phytotoxicity studies revealed that metabolites formed after degradation were significantly less toxic in nature.