title: Removal of water-insoluble Sudan dyes by Shewanella oneidensis MR-1.
abstract: Decolorization of water-insoluble Sudan dyes was studied with Shewanella oneidensis MR-1, which removed 66.8%, 43.4%, 56.0% and 33.7% Sudan I-IV in 104 h, respectively and reduced Sudan I to aniline and 1-amino-2-naphthol. Lactate was identified as the most efficient electron donor for Sudan I reduction. Improved reduction performance was obtained in the presence of higher lactate or biomass concentration. The correlation between specific reduction rate and initial Sudan I concentration could be described with Michaelis-Menten kinetics (V(max)=1.8 mg Sudan I mg cell(-1) h(-1) and K(m)=5.3 mg l(-1)). The addition of anthraquinone-2-sulfonate stimulated the reduction significantly whereas the presence of 2-hydroxy-1,4-naphthoquinone had little enhancing effect. The main azoreductase activity was found with membrane-bound proteins of MR-1 and no reduction occurred when Sudan I was incubated with cell extracts. These data indicated for the first time that Shewanella could reduce solid-phase Sudan dye particles.
authors.affiliation: Key Laboratory of Industrial Ecology and Environmental Engineering, Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China.
authors.forename: Qiuyan
authors.initials: Q
authors.lastname: Ji
authors.forename: Guangfei
authors.initials: G
authors.lastname: Liu
authors.forename: Jiti
authors.initials: J
authors.lastname: Zhou
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.forename: Ruofei
authors.initials: R
authors.lastname: Jin
authors.forename: Hong
authors.initials: H
authors.lastname: Lv
mesh_terms: D001391:Azo Compounds / Q000302:isolation & purification / Q000378:metabolism*; D003116:Color; D004396:Coloring Agents / Q000302:isolation & purification / Q000378:metabolism*; D020592:Shewanella / Q000145:classification / Q000378:metabolism*; D013045:Species Specificity; D014874:Water Pollutants, Chemical / Q000302:isolation & purification / Q000378:metabolism*; D018508:Water Purification / Q000379:methods*
chemical_list: D001391:Azo Compounds; D004396:Coloring Agents; D014874:Water Pollutants, Chemical