title: Removal of the insect repellent N,N-diethyl-m-toluamide (DEET) by laccase-mediated systems.
abstract: Numerous efforts have been made to remove emerging trace organic contaminants, such as pharmaceuticals and personal care products (PPCPs). This study examined the removal of N,N-diethyl-m-toluamide (DEET) by Trametes versicolor laccase and its laccase-mediator systems. Experimental results showed that DEET was poorly removed by laccase alone. The poor removal efficiency of DEET by laccase may be attributed to the presence of strong withdrawing electron group (-CO-N [CH2-CH3]2) in the chemical structure of DEET. Experimental results also indicated that DEET might be indirectly oxidized by laccase-mediator systems. More than 50% initial DEET amount was removed by laccase in the presence of a redox mediator, such as 2,2'-azino-bis[3-ethylbenzothiazoline-6-sulphonic acid] (ABTS) or 1-hydroxybenzotriazole (HBT). However, laccase activity was considerably decreased in the presence of a redox mediator (ABTS or HBT). Further studies on identification of degradation byproducts and degradation pathways are recommended.
authors.affiliation: Department of Civil and Environmental Engineering, Faculty of Engineering, National University of Singapore, 1 Engineering Drive 2, Singapore 117576, Singapore. Electronic address: ceetnh@nus.edu.sg.
authors.forename: Ngoc Han
authors.initials: NH
authors.lastname: Tran
authors.affiliation: Department of Civil and Environmental Engineering, Faculty of Engineering, National University of Singapore, 1 Engineering Drive 2, Singapore 117576, Singapore.
authors.forename: Jiangyong
authors.initials: J
authors.lastname: Hu
authors.affiliation: School of Bioscience and Biotechnology, Tokyo University of Technology, Katakura 1404-1, Hachioji, Tokyo 192-0982, Japan.
authors.forename: Taro
authors.initials: T
authors.lastname: Urase
mesh_terms: D002851:Chromatography, High Pressure Liquid; D003671:DEET / Q000302:isolation & purification*; D007302:Insect Repellents / Q000302:isolation & purification*; D042845:Laccase / Q000378:metabolism*; D010084:Oxidation-Reduction; D053719:Tandem Mass Spectrometry; D062065:Wastewater
chemical_list: D003671:DEET; D007302:Insect Repellents; D042845:Laccase; D062065:Wastewater
keywords: DEET; Degradation; Fungal laccase; Redox mediators; Wastewater