Soil and Environmental Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Pakistan; Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad, Pakistan.
Soil and Environmental Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Pakistan; Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad, Pakistan.
J Hazard Mater. 2019 Mar 15;366:1-9. doi: 10.1016/j.jhazmat.2018.11.054. Epub 2018 Nov 16.
Metribuzin (MB) is used for control of weeds in crops like potato, maize and sugarcane. Its extensive and unjudicial use has resulted in various environmental issues; hence it is very critical to remediate this herbicide at the respective point source. Plant associated, MB degrading bacterial strains, Rhodococcus rhodochrous sp. AQ1, Bacillus tequilensis sp. AQ2, Bacillus aryabhattai sp. AQ3 and Bacillus safensis sp. AQ4 were isolated, and a consortium MB3R was developed. For degradation of MB by the consortium MB3R, various parameters i.e., pH, temperature, inoculum density and pesticide concentration were optimized by using Taguchi design of experiment (DOE). MB degradation was dependent upon all the four factors. The contribution of each factor on MB degradation was according to the order: temperature > inoculum density > pH > pesticide concentration. Fitness of Taguchi DOE in forecasting the optimum response, was confirmed experimentally by using optimized levels of the four factors i.e., pH 7.0, temperature 30 °C, pesticide concentration 45 mg l and an inoculum density of 5.0 × 10 CFU ml whereby 98.63% MB degradation was observed. Appearance and subsequent degradation of three MB metabolites, desamino-metribuzin (DA), diketo-metribuzin (DK) and desamino-diketo-metribuzin (DADK) during biodegradation by the consortium was observed.
苯达松（MB）用于控制马铃薯、玉米和甘蔗等作物中的杂草。它的广泛和不公正使用导致了各种环境问题；因此，在相应的源头修复这种除草剂非常关键。从植物中分离出与苯达松降解相关的细菌菌株，如 Rhodococcus rhodochrous sp. AQ1、Bacillus tequilensis sp. AQ2、Bacillus aryabhattai sp. AQ3 和 Bacillus safensis sp. AQ4，并开发了一个细菌混合体 MB3R。为了使细菌混合体 MB3R 降解 MB，通过 Taguchi 实验设计（DOE）优化了各种参数，如 pH 值、温度、接种密度和农药浓度。MB 的降解依赖于这四个因素。每个因素对 MB 降解的贡献按以下顺序排列：温度>接种密度>pH 值>农药浓度。通过使用四个因素的优化水平（即 pH 值 7.0、温度 30°C、农药浓度 45mg/L 和接种密度 5.0×10^8CFU/ml）实验证实了 Taguchi DOE 在预测最佳响应方面的适用性，在此条件下观察到 98.63%的 MB 降解。在细菌混合体的生物降解过程中，观察到三种 MB 代谢物的出现和随后的降解，即去氨基苯达松（DA）、二酮苯达松（DK）和去氨基二酮苯达松（DADK）。
