Photo-biodegradation of imidacloprid under blue light-emitting diodes with bacteria and co-metabolic regulation

• Published in: Environmental research 2021-10, Vol.201, p.111541, Article 111541
• Main Authors: Elumalai, Punniyakotti, Yi, Xiaohui, Cai, Tingting, Xiang, Wei, Huang, Chaoguang, Huang, Mingzhi, Ying, Guang-Guo
• Format: Article
• Language: English
• Subjects: Biodegradation; Blue-LEDs; Imidacloprid; Photo-biodegradation; Photodegradation
• ISSN: 0013-9351
• DOI: 10.1016/j.envres.2021.111541

Imidacloprid (IMI) is existence in the soil environment with a half-life habitually more than hundred days. This study targets to determine, identify and characterize photo-biodegradation bacteria from neonicotinoids (NEOs) contaminated agricultural field soils. The sub-surface soil had a higher level contamination of NEOs, in specifically greater concentration of IMI (3445.2 ± 0.09 μg/g) and thiacloprid (4084.4 ± 0.09 μg/g) has been found. Three bacteria Ralstonia pickettii (PBMS-2), Bacillus cereus (PBMS-3) and Shinella zoogloeoides (PBMS-4) was identified from soil-free stable enrichment cultures. The biodegradability of IMI (50 mg L−1) by three bacteria under different colors of light-emitting diodes (LEDs) with a constant 12 V power supply was tested and found that the blue-LEDs had greatest efficiency in supporting biodegradation of IMI which is called photo-biodegradation. In specific, the rate of photo-biodegradation of IMI by Ralstonia pickettii (87%), Bacillus cereus (80%) and Shinella zoogloeoides (80%) was measured. Besides this study also tested the effect of aeration (rpm), pH, and temperature on photo-biodegradation of IMI. There were seven intermediate metabolites were measured as biodegradation products of IMI under photo-biodegradation conditions and they are; IMI-urea, IMI-desnitro, 6-chloronicotinic acid, 6-hydroxy nicotinic acid, IMI- aminoguanidine, IMI-nitrosoguanidine and 4,5-hydroxy IMI, these metabolites are may non-toxic to the environment. •Neonicotinoids insecticide such as imidacloprid in the soil environment had greater half-life.•The agricultural field sub-surface soil had a higher concentration of IMI (3445.2 ± 0.09 μg/g).•Photo-biodegradation performance is greater than separate photo degradation and biodegradation.•The bacteria of Ralstonia pickettii with blue-LEDs enhanced IMI degradation rate.