title: A new polymer-based laccase for decolorization of AO7: long-term storage and mediator reuse.
abstract: To address the bottlenecks of laccase-based catalysis, i.e., poor long-term stability and potential secondary pollution caused by synthetic mediator, we fabricated a new biocatalyst (N-PS-Lac) through adsorption of laccase onto polystyrene anion exchangers (N-PS) binding quaternary ammonium groups. After 2-year storage, the residual activity of N-PS-Lac remained as high as 101.7%, while that for native laccase was only 14.6%. Also, N-PS-Lac exhibited improved durability against pH variation and thermal treatment at 60°C. Gaussian curve fitting of FT-IR spectra indicated that laccase conformation of N-PS-Lac was rigidified, possibly because of the host geometric restriction and the host-laccase electrostatic attraction. A two-step method, i.e., adsorption of an azo dye AO7 by N-PS and then ectopic degradation by the immobilized laccase, was proposed to reuse the mediator HOBT for seven cyclic runs, where N-PS-Lac kept the constant decolorization efficiency. AO7 solution was detoxified completely after decolorization by the two-step method.
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China.
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China. Electronic address: bcpan@nju.edu.cn.
authors.forename: Bingcai
authors.initials: B
authors.lastname: Pan
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China.
authors.forename: Bing
authors.initials: B
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China.
authors.forename: Weiming
authors.initials: W
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China.
authors.forename: Lu
authors.initials: L
authors.lastname: Lv
mesh_terms: D000837:Anion Exchange Resins / Q000737:chemistry; D001391:Azo Compounds / Q000378:metabolism* / Q000633:toxicity; D001557:Benzenesulfonates / Q000378:metabolism* / Q000633:toxicity; D001673:Biodegradation, Environmental; D003116:Color; D006863:Hydrogen-Ion Concentration; D042845:Laccase / Q000378:metabolism*; D012275:Oryza / Q000187:drug effects; D011137:Polystyrenes / Q000737:chemistry*; D059027:Recycling; D012639:Seeds / Q000187:drug effects; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D013997:Time Factors; D018675:Toxicity Tests
chemical_list: D000837:Anion Exchange Resins; D001391:Azo Compounds; D001557:Benzenesulfonates; D011137:Polystyrenes; D042845:Laccase; C014722:2-naphthol orange
keywords: Degradation; Laccase; Long-term stability; Phytotoxicity; Polystyrene composite