title: Ionic polymer-coated laccase with high activity and enhanced stability: application in the decolourisation of water containing AO7.
abstract: Eliminating dyes in environmental water purification remains a formidable challenge. Laccase is a unique, environmentally friendly and efficient biocatalyst that can degrade pollutants. However, the use of laccase for the degradation of pollutants is considerably limited by its susceptibility to environmental changes and its poor reusability. We fabricated a novel biocatalyst (LacPG) by coating polyethylenimine onto the native laccase (Lac) followed by crosslinking with glutaraldehyde. The stability of the resulting LacPG was highly enhanced against pH variations, thermal treatments and provided better long-term storage with a negligible loss in enzymatic activity. Compared to Lac, LacPG exhibited significantly higher decolourisation efficiency in the degradation of a representative azo dye, acid orange 7 (AO7), which resulted from the electrostatic attraction between the coating and AO7. LacPG was separated from the AO7 solution using an ultrafiltration unit. The increased size and modified surface chemistry of LacPG facilitated ultrafiltration and reduced membrane fouling. LacPG exhibited enhanced stability, high catalytic activity and favourable properties for membrane separation; therefore, LacPG could be continuously reused in an enzymatic membrane reactor with a high efficiency for decolourising water containing AO7. The developed strategy appears to be promising for enhancing the applicability of laccase in practical water treatment.
authors: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, P.R. China.
authors: Xiaolin
authors: X
authors: Zhang
authors: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, P.R. China.
authors: Ming
authors: M
authors: Hua
authors: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, P.R. China.
authors: Lu
authors: L
authors: Lv
authors: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, P.R. China.
authors: Bingcai
authors: B
authors: Pan
mesh_terms: D001391:Azo Compounds / Q000737:chemistry; D001557:Benzenesulfonates / Q000737:chemistry; D004396:Coloring Agents / Q000737:chemistry; D004789:Enzyme Activation; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D007477:Ions / Q000737:chemistry*; D042845:Laccase / Q000737:chemistry* / Q000378:metabolism*; D011108:Polymers / Q000737:chemistry*; D013696:Temperature; D013816:Thermodynamics; D018508:Water Purification / Q000379:methods
chemical_list: D001391:Azo Compounds; D001557:Benzenesulfonates; D004396:Coloring Agents; D007477:Ions; D011108:Polymers; D042845:Laccase; C014722:2-naphthol orange
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