title: Mammalian cell-line based toxicological evaluation of paper mill black liquor treated in a soil microcosm by indigenous alkalo-tolerant Bacillus sp.
abstract: Organic pollutants present in the soil of a microcosm containing pulp and paper mill black liquor were extracted with hexane/acetone (1:1 v/v) to study the biodegradation and detoxification potential of a Bacillus sp. gas chromatography-mass spectroscopic (GC-MS) analysis performed after biodegradation showed formation of simpler compounds like p-hydroxyhydrocinnamic acid (retention time [RT] 19.3 min), homovanillic acid methyl ester (RT 21.6 min) and 3,5-dimethoxy-p-coumaric alcohol (RT 24.7 min). The methyltetrazolium (MTT) assay for cytotoxicity, 7-ethoxyresorufin-O-deethylase (EROD) assay for dioxin-like behavior and alkaline comet assay for genotoxicity were carried out in the human hepatocarcinoma cell line HuH-7 before and after bacterial treatment. Bioremediation for 15 days reduced toxicity, as shown by a 139-fold increase in black liquor's LC50 value, a 343-fold reduction in benzo(a)pyrene equivalent value and a 5-fold reduction in olive tail moment. The EROD assay positively correlated with both the MTT and comet assays in post biodegradation toxicity evaluation.
authors.affiliation: School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, 110 067, India, momis_biotech@yahoo.co.in.
authors.forename: Monika
authors.initials: M
authors.lastname: Mishra
authors.forename: Mihir Tanay
authors.initials: MT
authors.lastname: Das
authors.forename: Indu Shekhar
authors.initials: IS
authors.lastname: Thakur
mesh_terms: D001407:Bacillus / Q000378:metabolism*; D001673:Biodegradation, Environmental; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D020552:Comet Assay; D019363:Cytochrome P-450 CYP1A1 / Q000378:metabolism; D006801:Humans; D007220:Industrial Waste; D010209:Paper; D017382:Reactive Oxygen Species / Q000378:metabolism; D012989:Soil Pollutants / Q000378:metabolism* / Q000633:toxicity*
chemical_list: D007220:Industrial Waste; D017382:Reactive Oxygen Species; D012989:Soil Pollutants; D019363:Cytochrome P-450 CYP1A1