title: Metabolism of azo dyes by Lactobacillus casei TISTR 1500 and effects of various factors on decolorization.
abstract: Lactobacillus casei TISTR 1500 was isolated from soil of a dairy wastewater treatment plant and selected as the most active azo dye degrader of 19 isolates. Growing cells and freely suspended cells of this strain completely degraded methyl orange, thereby decolorizing the medium. The strain stoichiometrically converted methyl orange to N,N-dimethyl-p-phenylenediamine and 4-aminobenzenesulfonic acid, which were identified by HPLC, GC, and GC-MS analyses. The enzyme activity responsible for the cleavage of the azo bond of methyl orange was localized to the cytoplasm of cells grown on modified MRS medium containing methyl orange. The effect of sugars, oligosaccharides, organic acids, metal ions, pHs, oxygen and temperatures on methyl orange decolorization by freely suspended cells was investigated. The optimal conditions for the decolorization of methyl orange by the Lactobacillus casei TISTR 1500 are incubation at 35 degrees C and pH 6 with sucrose provided as the energy source.
authors.affiliation: Faculty of Agro-industry, Department of Biotechnology, Chiang Mai University, Chiang Mai 50100, Thailand.
authors.forename: Phisit
authors.initials: P
authors.lastname: Seesuriyachan
authors.forename: Shinji
authors.initials: S
authors.lastname: Takenaka
authors.forename: Ampin
authors.initials: A
authors.lastname: Kuntiya
authors.forename: Srikarnjana
authors.initials: S
authors.lastname: Klayraung
authors.forename: Shuichiro
authors.initials: S
authors.lastname: Murakami
authors.forename: Kenji
authors.initials: K
authors.lastname: Aoki
mesh_terms: D001391:Azo Compounds / Q000378:metabolism*; D001673:Biodegradation, Environmental; D004396:Coloring Agents / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste; D007780:Lacticaseibacillus casei / Q000378:metabolism*; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism; D009601:Nitroreductases; D012722:Sewage; D013379:Substrate Specificity; D013696:Temperature; D014865:Waste Disposal, Fluid; D014874:Water Pollutants, Chemical / Q000378:metabolism; D018508:Water Purification
chemical_list: D001391:Azo Compounds; D004396:Coloring Agents; D007220:Industrial Waste; D012722:Sewage; D014874:Water Pollutants, Chemical; C100258:methyl orange; D009247:NADH, NADPH Oxidoreductases; D009601:Nitroreductases; C021106:azoreductase