title: Effects of redox mediators on azo dye decolorization by Shewanella algae under saline conditions.
abstract: Azo dye decolorization by Shewanella algae (SAL) in the presence of high concentrations of NaCl and different quinones or humic acids was investigated to reveal the effects of redox mediator under saline conditions. Growth of SAL and the other two marine Shewanella strains coupled to anthraquinone-2,6-disulfonate (AQDS) reduction was observed in a wide range of NaCl concentrations (0-7%). AQDS showed the best enhancing effects, whereas some other quinones demonstrated poorer stimulating or even inhibiting effects on acid red 27 (AR27) decolorization. Different humic acids could also enhance the decolorization. The correlation between specific AQDS-mediated reduction rate and initial AR27 concentration could be described with Michaelis-Menten kinetics (Km=0.2 mM and Vmax=9.3 μmol mg cell(-1) h(-1)). AQDS reduction by SAL was determined to be the rate-limiting step of mediated reduction. Mediated decolorization products of AR27 were determined to be less phytotoxic aromatic amines.
authors.affiliation: Key Laboratory of Industrial Ecology and Environmental Engineering, Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Linggong Road 2, Dalian 116024, China.
authors.forename: Xianming
authors.initials: X
authors.lastname: Meng
authors.forename: Guangfei
authors.initials: G
authors.lastname: Liu
authors.forename: Jiti
authors.initials: J
authors.lastname: Zhou
authors.forename: Q Shiang
authors.initials: QS
authors.lastname: Fu
mesh_terms: D000548:Amaranth Dye; D000880:Anthraquinones / Q000494:pharmacology*; D001391:Azo Compounds / Q000378:metabolism* / Q000633:toxicity; D001673:Biodegradation, Environmental / Q000187:drug effects; D018533:Biomass; D003116:Color; D004396:Coloring Agents / Q000378:metabolism*; D007700:Kinetics; D012275:Oryza / Q000187:drug effects; D010084:Oxidation-Reduction / Q000187:drug effects; D027805:Phaseolus / Q000187:drug effects; D020592:Shewanella / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D012965:Sodium Chloride / Q000494:pharmacology*
chemical_list: D000880:Anthraquinones; D001391:Azo Compounds; D004396:Coloring Agents; C408124:anthraquinone-2,6-disulfonate; D012965:Sodium Chloride; D000548:Amaranth Dye
keywords: Decolorization; Humic acids; Redox mediator; Saline; Shewanella