Assessment of imidacloprid degradation by soil-isolated Bacillus alkalinitrilicus

Abstract

Imidacloprid is extensively used on a broad range of crops worldwide as seed dressing, soil treatment, and foliar application. Hence, the degradation potential of bacterial strains from sugarcane-growing soils was studied in liquid medium for subsequent use in bioremediation of contaminated soils. The microbe cultures degrading imidacloprid were isolated and enriched on Dorn's broth containing imidacloprid as sole carbon source maintained at 28 °C and Bacillus alkalinitrilicus showed maximum potential to degrade imidacloprid. Clay loam soil samples were fortified with imidacloprid at 50, 100, and 150 mg kg(-1) along with 45 × 10(7) microbe cells under two opposing sets of conditions, viz., autoclaved and unautoclaved. To study degradation and metabolism of imidacloprid under these two conditions, samples were drawn at regular intervals of 7, 14, 28, 35, 42, 49, and 56 days. Among metabolites, three metabolites were detected, viz., 6-chloronicotinic acid, nitrosimine followed by imidacloprid-NTG under both the conditions. Total imidacloprid residues were not found to follow the first-order kinetics in both types of conditions. This paper reports for the first time the potential use of pure cultures of soil-isolated native bacterium B. alkalinitrilicus and also its use along with natural soil microflora for remediation of imidacloprid-contaminated soils.

Zero-Valent Aluminum as Reducer in Sodium Carbonate Solution for Degradation of Imidacloprid

“…Guanidine IMI is formed by the loss of the –NO 2 group after H + attacking the position of N–NO 2 of IMI. This intermediate is also found in the biodegradation, photodegradation, and heterogeneous electro‐Fenton degradation processes for IMI treatment . The guanidine lacks insecticidal properties, but shows higher mammalian toxicity than the parent compound.…”

“…Physical methods such as ultrasonic irradiation and UV irradiation suffer from drawbacks such as low degradation rate, long degradation time, and secondary pollution. While the diverse microorganisms may potentially degrade the insecticide, they are nonfunctional for IMI degradation due to its high toxicity. Chemical oxidation such as advanced oxidatoion processes (AOPs) can efficiently degrade recalcitrant organics via the intermediate of hydroxyl radicals (·OH) .…”

Partitioning the roles of CYP6G1 and gut microbes in the metabolism of the insecticide imidacloprid in Drosophila melanogaster

“…Nitro-reduction of IMI is a biotransformation mechanism commonly found in soil bacteria 28 , 29 . In testing the hypothesis that the IMI-NH and IMI-NNO metabolites previously observed in D .…”

Partitioning the roles of insect and microbial enzymes in the metabolism of the insecticide imidacloprid inDrosophila melanogaster

“…Nitro-reduction of IMI is a biotransformation mechanism commonly found in soil bacteria 26,27 . In testing the hypothesis that the IMI-NH and IMI-NNO metabolites previously observed in D. melanogaster 35 are produced by gut microbes, we examined the levels of these metabolites in axenic and non-axenic control larvae.…”