Functional Characterization of a Novel Amidase Involved in Biotransformation of Triclocarban and its Dehalogenated Congeners in Ochrobactrum sp. TCC-2

• DOI: 10.1021/acs.est.6b04885
• Publication Date: 2016-11-30T16:58:34Z
• Authors: Hui Yun; Bin Liang; Jiguo Qiu; Long Zhang; Youkang Zhao; Jiandong Jiang; Aijie Wang
• Keywords: Triclocarban; Biotransformation; Amidase

Haloaromatic antimicrobial triclocarban (3,4,4′-trichlorocarbanilide, TCC) is a refractory contaminant which frequently detected in various aquatic and sediment environments globally. However, few TCC-degrading communities or pure cultures have been documented, functional enzymes involved TCC biodegradation hitherto not yet characterized. In this study, bacterial strain, Ochrobactrum sp. TCC-2, capable of degrading under both aerobic anaerobic conditions was isolated from sample. A novel amidase gene (tccA), responsible for the hydrolysis two amide bonds its dehalogenated congeners 4,4′-dichlorocarbanilide (DCC) carbanilide (NCC) to more biodegradable chloroaniline aniline products, cloned TccA shares low amino acid sequence identity (27 38%) with other biochemically characterized amidases contains conserved catalytic triad (Ser-Ser-Lys) signature enzyme family. stable over pH range 5.0 10.0 at temperatures lower than 60 °C, it constitutively expressed strain TCC-2. contrast halogenated DCC, nonchlorinated NCC preferred substrate TccA. also had activity broad spectrum herbicides, insecticides, chemical intermediates. The constitutive expression suggested TCC-2 may be potentially useful bioremediation applications.