State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Provincial Key Laboratory of Agricultural & Rural Pollution Abatement and Environmental Safety, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, 510642, China; Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China; Department of Microbiology, G. B Pant University of Agriculture and Technology, Pantnagar, U. S Nagar, 263145, India.
Department of Water Supply, Sanitation and Environmental Engineering, IHE Delft Institute for Water Education, Westvest 7, 2601DA Delft, the Netherlands.
Environ Res. 2022 Sep;212(Pt A):113137. doi: 10.1016/j.envres.2022.113137. Epub 2022 Mar 29.
Cypermethrin is a toxic pyrethroid insecticide that is widely used in agricultural and household activities. One of the most serious issues is its persistence in the environment, because it is easily transported to the soil and aquatic ecosystem. The biodegradation of cypermethrin is emerging as an environmentally friendly method for large-scale treatment. This study examined the application of a novel binary bacterial combination-based (Bacillus thuringiensis strain SG4 and Bacillus sp. strain SG2) approach used for the enhanced degradation of cypermethrin from the environment. The bacterial strains degraded cypermethrin (80% and 85%) in the presence of external nitrogen sources (KNO and NaNO). Furthermore, when immobilized in agar disc beads, the co-culture degraded cypermethrin (91.3%) with a half-life (t) of 4.3 days compared to 4.9 days using sodium alginate beads. Cereal straw, farmyard manure, press mud compost, fresh cow dung, and gypsum were used as organic amendments in the soil to stimulate cypermethrin degradation. Cereal straw promoted the fastest cypermethrin degradation among the different organic amendments tested, with a t of 4.4 days. The impact of cypermethrin-degrading bacterial consortium on cypermethrin rhizoremediation was also investigated. Bacterial inoculums exhibited beneficial effects on plant biomass. Moreover, Zea mays and the bacterial partnership substantially enhanced cypermethrin degradation in soil. Six intermediate metabolites were detected during the degradation of cypermethrin, indicating that cypermethrin could be degraded first by the hydrolysis of its carboxyl ester bond, followed by the cleavage of the diaryl linkage and subsequent metabolism. Our findings highlight the promising potential and advantages of the bacterial consortium for the bioremediation of a cypermethrin-contaminated environment.
氯菊酯是一种有毒的拟除虫菊酯杀虫剂，广泛应用于农业和家庭活动。其中一个最严重的问题是它在环境中的持久性，因为它很容易被运输到土壤和水生生态系统中。氯菊酯的生物降解作为一种大规模处理的环保方法正在兴起。本研究探讨了一种新型二元细菌组合（苏云金芽孢杆菌菌株 SG4 和芽孢杆菌菌株 SG2）在增强环境中氯菊酯降解中的应用。在存在外部氮源（KNO 和 NaNO）的情况下，细菌菌株降解氯菊酯（80%和 85%）。此外，当固定在琼脂圆盘珠中时，与用海藻酸钠珠固定的情况相比，共培养物降解氯菊酯（91.3%）的半衰期（t）为 4.3 天，为 4.9 天。麦秆、厩肥、压泥堆肥、新鲜牛粪和石膏被用作土壤中的有机改良剂，以刺激氯菊酯降解。在测试的不同有机改良剂中，麦秆促进氯菊酯降解最快，半衰期为 4.4 天。还研究了氯菊酯降解细菌菌剂对氯菊酯根际修复的影响。细菌接种剂对植物生物量表现出有益的影响。此外，玉米和细菌伙伴关系大大增强了土壤中氯菊酯的降解。在氯菊酯降解过程中检测到 6 种中间代谢物，表明氯菊酯首先可以通过其羧酸酯键的水解进行降解，然后是二芳基键的断裂和随后的代谢。我们的研究结果突出了细菌菌剂在受氯菊酯污染环境的生物修复方面的潜在优势。
