title: Identification of the Amidase BbdA That Initiates Biodegradation of the Groundwater Micropollutant 2,6-dichlorobenzamide (BAM) in Aminobacter sp. MSH1.
abstract: 2,6-dichlorobenzamide (BAM) is a recalcitrant groundwater micropollutant that poses a major problem for drinking water production in European countries. Aminobacter sp. MSH1 and related strains have the unique ability to mineralize BAM at micropollutant concentrations but no information exists on the genetics of BAM biodegradation. An amidase-BbdA-converting BAM to 2,6-dichlorobenzoic acid (DCBA) was purified from Aminobacter sp. MSH1. Heterologous expression of the corresponding bbdA gene and its absence in MSH1 mutants defective in BAM degradation, confirmed its BAM degrading function. BbdA shows low amino acid sequence identity with reported amidases and is encoded by an IncP1-β plasmid (pBAM1, 40.6 kb) that lacks several genes for conjugation. BbdA has a remarkably low KM for BAM (0.71 μM) and also shows activity against benzamide and ortho-chlorobenzamide (OBAM). Differential proteomics and transcriptional reporter analysis suggest the constitutive expression of bbdA in MSH1. Also in other BAM mineralizing Aminobacter sp. strains, bbdA and pBAM1 appear to be involved in BAM degradation. BbdA's high affinity for BAM and its constitutive expression are of interest for using strain MSH1 in treatment of groundwater containing micropollutant concentrations of BAM for drinking water production.
authors: Division of Soil and Water Management, KU Leuven , Kasteelpark Arenberg 20, 3001 Leuven, Belgium.
authors: Jeroen
authors: J
authors: T'Syen
authors: Division of Soil and Water Management, KU Leuven , Kasteelpark Arenberg 20, 3001 Leuven, Belgium.
authors: Raffaella
authors: R
authors: Tassoni
authors: Department of Biology, University of Copenhagen , Universitetsparken 15, 2100 København, Denmark.
authors: Lars
authors: L
authors: Hansen
authors: Department of Biology, University of Copenhagen , Universitetsparken 15, 2100 København, Denmark.
authors: Søren J
authors: SJ
authors: Sorensen
authors: Department of Proteomics and Microbiology, Research Institute for Biosciences, University of Mons , Place du Parc 20, 7000 Mons, Belgium.
authors: Baptiste
authors: B
authors: Leroy
authors: Division of Soil and Water Management, KU Leuven , Kasteelpark Arenberg 20, 3001 Leuven, Belgium.
authors: Aswini
authors: A
authors: Sekhar
authors: Department of Proteomics and Microbiology, Research Institute for Biosciences, University of Mons , Place du Parc 20, 7000 Mons, Belgium.
authors: Ruddy
authors: R
authors: Wattiez
authors: Centre of Microbial and Plant Genetics, KU Leuven , Kasteelpark Arenberg 20, 3001 Leuven, Belgium.
authors: René
authors: R
authors: De Mot
authors: Division of Soil and Water Management, KU Leuven , Kasteelpark Arenberg 20, 3001 Leuven, Belgium.
authors: Dirk
authors: D
authors: Springael
mesh_terms: D000581:Amidohydrolases / Q000235:genetics / Q000378:metabolism*; D001549:Benzamides / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002723:Chlorobenzoates / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D016680:Genome, Bacterial; D060587:Groundwater / Q000737:chemistry*; D007700:Kinetics; D059127:Phyllobacteriaceae / Q000201:enzymology* / Q000235:genetics; D010802:Phylogeny; D010957:Plasmids / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D017422:Sequence Analysis, DNA; D013696:Temperature; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D001549:Benzamides; D002723:Chlorobenzoates; D011994:Recombinant Proteins; D014874:Water Pollutants, Chemical; C057454:2,6-dichlorobenzamide; D000581:Amidohydrolases; C019665:amidase