SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, School of Environment, South China Normal University, Guangzhou, 510006, PR China.
SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, School of Environment, South China Normal University, Guangzhou, 510006, PR China; South China Intelligence Environment Tecnology (Qingyuan) Co.,Ltd, SCNU Qingyuan Institute of Science and Technology Innovation Co., Ltd, Qingyuan 511517, PR China.
Environ Pollut. 2022 Aug 1;306:119452. doi: 10.1016/j.envpol.2022.119452. Epub 2022 May 10.
The social and ecological influence of Neonicotinoids (NEOs) usage in agriculture sector is progressively higher. There are seven NEOs insecticides widely used for the insects control. Among the NEOs, thiacloprid (THD) was extensively used for insect control during crop cultivation. This study targets to analyse the contamination levels of NEOs in agricultural soil and identify photo-biodegradation of THD degradation using pure isolates and mixed consortium. The photo degradation (PD), biodegradation (BD) and photo-biodegradation (PBD) of THD were compared. The corn field agricultural soils were polluted by four NEOs, among them THD had greater contamination level (surface soil: 3901.2 ± 0.04 μg/g) and (sub-surface soil: 3988.6 ± 0.05 μg/g). Three soil free enriched bacterial strains following Bacillus atrophaeus (PB-2), Priestia megaterium (PB-3) (formerly known as Bacillus megaterium), and Peribacillus simplex (PB-4) (formerly known as Bacillus simplex) were identified by microbiological and molecular 16s rRNA gene sequencing. The PD, BD and PBD of THD were conducted and degradation rate was detected by instrument UPLC-MS-MS. The PBD process with blue-LEDs showed better THD degradation efficiency than PD and BD, where the specific THD degradation rate was 85 ± 0.2%, 87 ± 0.5%, and 89 ± 0.3%, respectively for PB-2, PB-3 and PB-4. Then, the photo-biodegradation performance is greater at 150, 175, 200 rpm, pH 7.0-9.0, and temperature 30-35 °C. After the PBD system deliver four intermediate metabolites, the THD degradation process maybe through nitro reduction, hydroxylation and oxidative cleavage pathway.
农业领域中使用新烟碱类（NEOs）的社会和生态影响越来越大。有七种新烟碱类杀虫剂被广泛用于控制昆虫。在这些新烟碱类杀虫剂中，噻虫啉（THD）在作物种植期间被广泛用于控制虫害。本研究旨在分析农业土壤中 NEOs 的污染水平，并利用纯分离物和混合菌丛来鉴定噻虫啉的光降解。比较了 THD 的光降解（PD）、生物降解（BD）和光生物降解（PBD）。四种 NEOs 污染了玉米田土壤，其中噻虫啉的污染水平更高（表层土壤：3901.2±0.04μg/g；次表层土壤：3988.6±0.05μg/g）。通过微生物学和分子 16s rRNA 基因测序，鉴定出三种土壤自由富集细菌菌株，分别为萎缩芽孢杆菌（PB-2）、巨大芽孢杆菌（PB-3）（原名巨大芽孢杆菌）和简单芽孢杆菌（PB-4）（原名简单芽孢杆菌）。进行了 THD 的 PD、BD 和 PBD，并通过仪器 UPLC-MS-MS 检测降解率。与 PD 和 BD 相比，蓝光 LEDs 下的 PBD 过程显示出更好的 THD 降解效率，其中 PB-2、PB-3 和 PB-4 的特定 THD 降解率分别为 85±0.2%、87±0.5%和 89±0.3%。然后，在 150、175、200rpm、pH 7.0-9.0 和 30-35°C 的条件下，光生物降解性能更大。在 PBD 系统产生四个中间代谢物后，THD 降解过程可能通过硝基还原、羟化和氧化裂解途径进行。
