title: Biotransformation of Direct Blue 1 by a moderately halophilic bacterium Marinobacter sp. strain HBRA and toxicity assessment of degraded metabolites.
abstract: The ability of halophiles to survive in the extreme salt concentrations has gained them the importance of being used in the treatment of industrial waste waters. A moderately halophilic bacterial strain with the ability to degrade the complex azo dye Direct Blue-1 (DB-1) was isolated from sea water and identified as Marinobacter sp. strain HBRA. Complete decolorization of DB-1 (100 mg L(-1)) was achieved in 6h at 37 °C, pH 8 and with 70 g L(-1) NaCl. Decolorization was analyzed by UV-vis spectrophotometer. The FT-IR spectrum revealed that Marinobacter sp. strain HBRA specifically targeted azo bond (NN) at 1631 cm(-1) to break down Direct Blue-1. Formation of metabolites at different retention times in HPLC indicated degradation. Biotransformation pathway for DB-1 was proposed based on LC-MS. Phytotoxicity study revealed the less toxic nature of the metabolites compared to the dye. Genotoxicity with Allium cepa confirmed the cytotoxic nature of DB-1 by inducing several chromosomal abnormalities compared to the negligible effects of degraded metabolites. The current study is the first report on the detoxification of DB-1 by Marinobacter sp. strain HBRA.
authors.affiliation: Division of Environmental Biotechnology, School of Biosciences and Technology, VIT University, Vellore, India.
authors.forename: A S
authors.initials: AS
authors.lastname: Arun Prasad
authors.forename: V S V
authors.initials: VS
authors.lastname: Satyanarayana
authors.forename: K V
authors.initials: KV
authors.lastname: Bhaskara Rao
mesh_terms: D000490:Allium / Q000187:drug effects / Q000235:genetics; D003116:Color; D004396:Coloring Agents / Q000378:metabolism*; D007887:Fabaceae / Q000187:drug effects / Q000254:growth & development; D053520:Marinobacter / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D012329:RNA, Bacterial / Q000032:analysis; D012336:RNA, Ribosomal, 16S / Q000032:analysis; D012623:Seawater / Q000382:microbiology; D045868:Sorghum / Q000187:drug effects / Q000254:growth & development; D014343:Trypan Blue / Q000378:metabolism*; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D004396:Coloring Agents; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D014874:Water Pollutants, Chemical; C009000:pontamine sky blue; D014343:Trypan Blue
keywords: Biotransformation; Direct Blue-1; Marinobacter sp. strain HBRA; Toxicity