title: Detoxification of benzidine-based azo dye by E. gallinarum: time-course study.
abstract: Direct black 38 (DB38) dye is a well-established toxic and carcinogenic compound. Present investigation reports isolation of an Enterococcus gallinarum strain capable of decolorizing and degrading it. Changes in toxicity and mutagenicity of DB38 and its metabolites were also determined using a battery of carefully selected tests (cytotoxicity, respiration inhibition test and Ames test). Toxicity assays were carried out on E. gallinarum itself as this also gave information about suitability of this strain for the dye decolorization operation. The strain was found to reduce both toxicity and mutagenicity of DB38 metabolites. Benzidine and 4-aminobiphenyl (4-ABP) were identified as the DB38 metabolites, responsible for its toxic and mutagenic properties, by HPLC-MS analysis. Further degradation of benzidine and 4-ABP was found to result in the decrease in toxicity and mutagenicity.
authors.affiliation: Environmental Biotechnology Division, National Environmental Engineering Research Institute (NEERI), Nagpur 440020, India.
authors.forename: Amit
authors.initials: A
authors.lastname: Bafana
authors.forename: Tapan
authors.initials: T
authors.lastname: Chakrabarti
authors.forename: Pradeep
authors.initials: P
authors.lastname: Muthal
authors.forename: Gajanan
authors.initials: G
authors.lastname: Kanade
mesh_terms: D000611:Aminobiphenyl Compounds / Q000032:analysis / Q000378:metabolism; D001391:Azo Compounds / Q000032:analysis / Q000378:metabolism* / Q000633:toxicity; D001560:Benzidines / Q000032:analysis / Q000378:metabolism; D001673:Biodegradation, Environmental; D002851:Chromatography, High Pressure Liquid; D004396:Coloring Agents / Q000032:analysis / Q000378:metabolism* / Q000633:toxicity; D016983:Enterococcus / Q000378:metabolism*; D008658:Inactivation, Metabolic; D013058:Mass Spectrometry; D009152:Mutagenicity Tests; D012486:Salmonella typhimurium / Q000187:drug effects / Q000235:genetics
chemical_list: D000611:Aminobiphenyl Compounds; D001391:Azo Compounds; D001560:Benzidines; D004396:Coloring Agents; C006757:4-biphenylamine; C029876:benzidine; C015844:direct black 3