Degradation of the Neonicotinoid Insecticide Acetamiprid via the N-Carbamoylimine Derivate (IM-1-2) Mediated by the Nitrile Hydratase of the Nitrogen-Fixing Bacterium Ensifer meliloti CGMCC 7333

Abstract

The metabolism of the widely used neonicotinoid insecticide acetamiprid (ACE) has been extensively studied in plants, animals, soils, and microbes. However, hydration of the N-cyanoimine group in ACE to the N-carbamoylimine derivate (IM-1-2) by purified microbes, the enzyme responsible for this biotransformation, and further degradation of IM-1-2 have not been studied. The present study used liquid chromatography–mass spectrometry and nuclear magnetic resonance spectroscopy to determine that the nitrogen-fixing bacterium Ensifer meliloti CGMCC 7333 transforms ACE to IM-1-2. CGMCC 7333 cells degraded 65.1% of ACE in 96 h, with a half-life of 2.6 days. Escherichia coli Rosetta (DE3) overexpressing the nitrile hydratase (NHase) from CGMCC 7333 and purified NHase converted ACE to IM-1-2 with degradation ratios of 97.1% in 100 min and 93.9% in 120 min, respectively. Interestingly, IM-1-2 was not further degraded by CGMCC 7333, whereas it was spontaneously hydrolyzed at the N-carbamoylimine group to the derivate ACE-NH, which was further converted to the derivative ACE-NH2. Then, ACE-NH2 was cleaved to the major metabolite IM-1-4. IM-1-2 showed significantly lower insecticidal activity than ACE against the aphid Aphis craccivora Koch. The present findings will improve the understanding of the environmental fate of ACE and the corresponding enzymatic mechanisms of degradation.

Biodegradation of the neonicotinoid insecticide acetamiprid in surface water by the bacterium Variovorax boronicumulans CGMCC 4969 and its enzymatic mechanism

“…AAP degradation tted rst-order dissipation kinetics (R ¼ 0.99) with a half-life of 182 h. In contrast, AAP was barely degraded in control water without bacterial inoculation. We previously isolated an E. meliloti CGMCC 7333, which could degrade 65.1% of 500 mg L À1 AAP in 96 h with a half-life of 63 h. 16 However, this strain showed weak AAP degradation in surface water samples (data not shown). E. meliloti (formerly Sinorhizobium meliloti) is a symbiotic nitrogen-xing bacterium, and is usually limited by application of microbes-plants combined remediation.…”

Pigmentiphaga sp. Strain D-2 Uses a Novel Amidase To Initiate the Catabolism of the Neonicotinoid Insecticide Acetamiprid

“…Microbiological degradation plays key roles in the dissipation of acetamiprid from the environment, as well as in the detoxification of acetamiprid. Many prokaryotic and eukaryotic microorganisms have been reported to be capable of degrading acetamiprid (17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28). Strain D-2, previously isolated in our laboratory, could degrade over 99% of 0.22 mM acetamiprid in 3 days, showing that it possesses a very high degradation capability.…”

“…The environmental fate of acetamiprid has attracted considerable attention, and microbial degradation is the key means for the dissipation of acetamiprid from the environment (15,16). In recent years, several microbial strains capable of degrading acetamiprid have been isolated, and the catabolic pathways of acetamiprid have been extensively studied (17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28). Four catabolic pathways of acetamiprid are illustrated in Fig.…”

“…Although the catabolic pathways of acetamiprid have been studied in detail, the molecular mechanisms underlying its biodegradation have not been systematically investigated. Nitrile hydratase is the only enzyme reported to be involved in acetamiprid degradation (26,27), and the enzyme responsible for the biotransformation of acetamiprid into its main intermediate, IM 1-4, has not been elucidated. In our previous study, a bacterial strain, Pigmentiphaga sp.…”

Co‐transport of Pesticide Acetamiprid and Silica Nanoparticles in Biochar‐Amended Sand Porous Media

“…Hydrolysis and photolysis of acetamiprid should also be minor in the biochar‐amended sand because the experimental conditions are similar. A number of studies (Liu et al, 2011; Wang et al, 2013a, 2013b; Yang et al, 2013; Zhou et al, 2014b) showed that the primary degradation pathway for the acetamiprid is aerobic soil metabolism. The microorganisms in the biochar likely induced biodegradation of acetamiprid.…”