A synthetic pyrethroid (SP)-degrading bacterium, designated pyd-1, was isolated from SPcontaminated soil. Based on its phenotypic and genotypic properties, the strain was identified as Ochrobactrum tritici. Strain pyd-1 was able to degrade a wide range of SPs, and its degradation efficiencies were dependent on the molecular structure of the SP. Interestingly, the strain degraded cisand trans-permethrin (cypermethrin) at nearly the same rate and possessed approximately equal hydrolysis activities toward the two enantiomers of fenpropathrin. These results suggest that different isomers of SPs are degraded with equal efficiency by strain pyd-1. We studied the metabolic pathway of fenpropathrin degradation in strain pyd-1 by metabolite identification and enzymatic analysis. Fenpropathrin is degraded by hydrolysis of the carboxylester linkage to yield 2,2,3,3-tetramethylcyclopropanecarboxylic acid and 3-phenoxybenzaldehyde, which is converted to 3-phenoxybenzoic acid (PBA). PBA is further metabolized to 4-hydroxy-3-phenoxybenzoic acid (4-hydroxy-PBA). 4-Hydroxy-PBA is oxidized to protocatechuate and p-hydroquinone. Protocatechuate is further oxidized through an ortho-cleavage pathway, and p-hydroquinone is degraded via 1,2,4-benzenetriol.

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A series of novel metal–organic frameworks (MOFs) have been assembled from PbII and 2,3,5,6-tetrachloro-1,4-benzenedicarboxylic acid (H2BDC-Cl4) by simply adding different alkali metal ions as templates. When only lead nitrate is used, a robust 3D open framework [Pb(BDC-Cl4)(MeOH)2] n (1) with pts topology can be obtained. Incorporating the lighter LiI or NaI ions into the above PbII/BDC-Cl4 system results in two unique isostructural 3D PbII–LiI and PbII–NaI heterometallic frameworks, {[PbLi2(BDC-Cl4)(μ2-OH)2](H2O)} n (2) and [PbNa2(BDC-Cl4)(μ2-OH)2] n (3), which are built from the combination of a 3D rod-packing PbII-carboxylate framework and a 3D NaI–BDC-Cl4 (or LiI–BDC-Cl4) network. When the heavier KI ion is applied, the similar reaction affords a 3D MOF [Pb2(BDC-Cl4)2(DMF)3] n (4), which represents the first pillar-layered PbII coordination network with a (3,5)-connected gra topology. The results illustrate the powerful effect of the alkali-metal templates in MOFs assemblies. The solid-state properties such as thermal stability and luminescence of 1–4 have also been studied.

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Abamectin is widely used in agriculture as an insecticide and in veterinary as an anti-parasitic agent, and has caused great environmental pollution by posing potential risk to non-target soil invertebrates and nearby aquatic systems. A bacterium designated GB-01, which was capable of degrading abamectin, was isolated from soil by enrichment culture method. On the basis of morphological, physiological and biochemical characteristics, combined with phylogenetic analysis of 16S rRNA gene, the bacterium GB-01 was identified as Burkholderia cepacia-like species. The bacterium GB-01 was able to utilize abamectin as its sole carbon source for growth, and could degrade more than 90% of abamectin at initial concentrations of 50 and 100 mg l(-1) in mineral salt medium in 30 and 36 h, respectively. The longer degradation cycle was observed with abamectin concentrations higher than 100 mg l(-1). Optimal growth temperatures and pH values with highest degradation rate were 30-35 degrees C and 7-8, respectively. Two new degradation products were identified and characterized by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) based mass spectral data and a plausible partial degradation pathway of abamectin was proposed. This is the first report in which an abamectin-degrading Burkholderia species isolated from soil was identified and characterized.

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