title: Characterization of a cypermethrin-degrading Methylobacterium sp. strain A-1 and molecular cloning of its carboxylesterase gene.
abstract: A novel mesophilic bacterial strain, designated A-1, was isolated from microbially contaminated biopolymer microcapsules. The bacterium was able to withstand and grow in liquid cultures supplemented with the pyrethroid cypermethrin in concentrations up to 400 mg L(-1) . Furthermore, strain A-1 could use cypermethrin as sole carbon source and could degrade >50% of it in 12 h. Based on phenotypic and chemotaxonomic characterization, and phylogenetic analysis of 16S rRNA gene sequence, the strain A-1 was identified as Methylobacterium sp., which is the first reported cypermethrin degrader of methylotrophic bacteria. A role for esterase activity in cypermethrin biodegradation was presumed. Therefore, the carboxylesterase gene mse1 was amplified from the Methylobacterium sp. strain A-1 genome and the resulting 1 kb amplicon cloned into E. coli. Sequence analysis of the mse1-DNA insert revealed an open reading frame of 633 bp encoding for a putative carboxylesterase of 210 amino acid residues with a predicted molecular mass of 22 kDa. The amino acid sequence of the deduced enzyme MsE1 with the catalytic triad Ser106 , Asp156 , and His187 was found to be similar to that of α/β-hydrolase fold proteins. The active site Ser106 residue is located in the consensus pentapeptide motif Gly-X-Ser-X-Gly that is typical of esterases.
authors.affiliation: Department of Chemical Engineering and Biotechnology, Hochschule Darmstadt, University of Applied Sciences, Darmstadt, Germany.
authors.forename: Corinna
authors.initials: C
authors.lastname: Diegelmann
authors.affiliation: Department of Chemical Engineering and Biotechnology, Hochschule Darmstadt, University of Applied Sciences, Darmstadt, Germany.
authors.forename: Joachim
authors.initials: J
authors.lastname: Weber
authors.affiliation: Department of Chemical Engineering and Biotechnology, Hochschule Darmstadt, University of Applied Sciences, Darmstadt, Germany.
authors.forename: Regina
authors.initials: R
authors.lastname: Heinzel-Wieland
authors.affiliation: Department of Chemical Engineering and Biotechnology, Hochschule Darmstadt, University of Applied Sciences, Darmstadt, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Kemme
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D043182:Carboxylesterase / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D004926:Escherichia coli; D020580:Methylobacterium / Q000201:enzymology* / Q000235:genetics* / Q000302:isolation & purification; D016366:Open Reading Frames; D010802:Phylogeny; D011722:Pyrethrins / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D011722:Pyrethrins; D012336:RNA, Ribosomal, 16S; C017160:cypermethrin; D043182:Carboxylesterase
keywords: Biodegradation; Carboxylesterase; Cypermethrin; Methylobacterium; Pyrethroid