Isolation and characterization of an abamectin-degrading Burkholderia cepacia-like GB-01 strain

Abstract

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.

Monensin biodegradation pathway and role of epoxide hydrolase in Stenotrophomonas maltophilia DM‐2

“…In addition, the degradation of monensin was significantly correlated with the density of bacteria from 10 to 50 °C, indicating that temperature affects the degradation of monensin mainly by altering the density of bacterial cells. This result is consistent with previously reported results …”

Phenotypic and phylogenetic characterization of an abamectin-degrading bacterial strain isolated from a citrus orchard

“…Strain GB-01, isolated from abamectin-contaminated soils, was revived from our laboratory stock (Ali et al, 2010). The bacterium was maintained on mineral salt medium (MSM) (1.0 g L 1 NaCl, 1.0 g L 1 NH 4 NO 3 , 1.5 g L 1 K 2 HPO 4 , 0.5 g L 1 KH 2 PO 4 , 0.1 g L 1 MgSO 4 7H 2 O and pH 7.0) agar plates supplemented with abamectin (analytical standard, purity 97.1%, Sigma Aldrich) as the sole carbon source for growth.…”

“…Extensive use of abamectin has raised questions about its persistence in the environment and potential toxicity to non-target organisms (Kolar et al, 2008). Keeping in view the importance of pesticide toxicity issues, an abamectin-degrading bacterial strain, GB-01, was isolated from contaminated soil as a potential bioremediation agent and preliminary identified as a Burkholderia cepacia-like species (Ali et al, 2010(Ali et al, , 2012. Keeping in view the problems hampering the identification of a Burkholderia species, the purpose of this study was to conclude the exact classification of strain GB-01, because nomenclature and identification must be based on correct classification and extensive information.…”

Studies revealing bioremediation potential of the strain Burkholderia sp. GB-01 for abamectin contaminated soils

“…GB-01, was revived from our lab stock culture (Ali et al 2010). Minimal medium (MSM) (1.0 g L -1 NaCl, 1.0 g L -1 NH 4 NO 3 , 1.5 g L -1 K 2 HPO 4 , 0.5 g L -1 KH 2 PO 4 , 0.1 g L -1 MgSO 4 Á7H 2 O and pH 7.0) was used to characterize the growth conditions of bacterium for large scale inoculum production.…”

“…Wide spread use of abamectin in agriculture and veterinary has promoted research on abamectin-degrading microorganism to develop efficient bioremediation strategies for abamectin polluted sites aiming to reduce contamination to safe levels and to quickly prevent the dispersion of this insecticide to non-agricultural environment. Until now, merely few bacterial strains capable of degrading abamectin are reported (Zhang et al 2004;Li et al 2008;Ali et al 2010).…”