title: Laccase-catalyzed removal of diphenylamine from synthetic wastewater.
abstract: The priority pollutant lists of both the U.S. Environmental Protection Agency (U.S. EPA) and the European Union (EU) include diphenylamine (DPA), a contaminant found in wastewater of various industries. This work demonstrates the potential of using enzymatic treatment to remove DPA from buffered synthetic wastewater. This treatment method includes oxidative polymerization of DPA using laccase from Trametes villosa, followed by removal of those polymers via adsorptive micellar flocculation (AMF) using sodium lauryl sulfate (SDS) and alum. Researchers investigated the effects of pH, laccase concentration, molecular mass, and concentration of polyethylene glycol (PEG) in continuously stirred batch reactors to achieve 95% substrate conversion in three hours. Treatment of 0.19 mM DPA was best at pH 7 and an enzyme concentration from 0.0025 to 0.0075 standard activity unit/mL. Except for PEG400 optimum enzyme and PEG concentrations decreased with an increase in PEG molecular mass. Optimum AMF conditions were pH 3.0 to 6.5, 200 mg/L of SDS, and 150 mg/L of alum.
authors.affiliation: Department of Civil & Environmental Engineering, University of Windsor, Ontario, Canada.
authors.forename: Beeta
authors.initials: B
authors.lastname: Saha
authors.forename: K E
authors.initials: KE
authors.lastname: Taylor
authors.forename: J K
authors.initials: JK
authors.lastname: Bewtra
authors.forename: N
authors.initials: N
authors.lastname: Biswas
mesh_terms: D000327:Adsorption; D000534:Alum Compounds / Q000737:chemistry; D055162:Biocatalysis; D001673:Biodegradation, Environmental; D019149:Bioreactors; D004159:Diphenylamine / Q000302:isolation & purification* / Q000378:metabolism; D005427:Flocculation; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste; D042845:Laccase / Q000737:chemistry / Q000378:metabolism*; D010084:Oxidation-Reduction; D011092:Polyethylene Glycols / Q000737:chemistry; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D013997:Time Factors; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000302:isolation & purification* / Q000378:metabolism; D018508:Water Purification / Q000379:methods*
chemical_list: D000534:Alum Compounds; D007220:Industrial Waste; D014874:Water Pollutants, Chemical; C041524:aluminum sulfate; D012967:Sodium Dodecyl Sulfate; D011092:Polyethylene Glycols; D004159:Diphenylamine; D042845:Laccase