Abstract The study focuses on the biodegradation kinetics of organophosphate pesticides (OPs), chlorpyrifos and dichlorvos by enriched cultures and its application in pesticide transport models. Pseudomonas aeruginosa and Taonella mepensis were the species identified in dichlorvos enriched culture (DEC) while Pseudomonas aeruginosa and Methylobacterium zatmanii were present in chlorpyrifos enriched culture (CPEC). DEC readily degraded dichlorvos as the sole carbon source at higher concentrations up to 1000 mg/L while CPEC rapidly degraded chlorpyrifos up to 100 mg/L. On addition of 1 g/L C of dextrose, dichlorvos degradation efficiency significantly increased only at higher pesticide concentrations while there was no effect on chlorpyrifos degradation. Cross-feed and mixed-feed studies highlighted that, CPEC degraded dichlorvos as a sole substrate and a mixture of both the pesticides effectively when compared to DEC. Edward inhibition and Haldane inhibition models satisfactorily simulated the biodegradation kinetics of dichlorvos and chlorpyrifos by DEC and CPEC respectively. The biokinetic parameters; maximum specific growth rate (µmax), half saturation constant (KC), yield coefficient (Y) and inhibition concentration (Ki) for the selected pesticides were thus estimated from the best fit biokinetic models. Further, batch determined biokinetic parameters were successfully applied to pesticide transport model and used to simulate breakthrough curves (BTCs) from flow-through pesticide soil column studies. The results indicated that the enriched microbes are promising candidates for insitu bioremediation of contaminated waters and soils. In addition, the estimated biokinetic constants can be used to assess the biodegradation capabilities of the enriched cultures and act as input parameters for transport models.

中文翻译：

---

农业土壤中富集细菌培养物对敌敌畏和毒死蜱的生物降解动力学

摘要 本研究的重点是有机磷农药 (OPs)、毒死蜱和敌敌畏通过富集培养的生物降解动力学及其在农药运输模型中的应用。Pseudomonas aeruginosa 和 Taonella mepensis 是敌敌畏富集培养 (DEC) 中鉴定的物种，而毒死蜱富集培养 (CPEC) 中存在绿脓杆菌和扎特曼甲基杆菌。DEC 在高达 1000 mg/L 的较高浓度下很容易降解作为唯一碳源的敌敌畏，而 CPEC 可以快速降解高达 100 mg/L 的毒死蜱。添加 1 g/LC 葡萄糖后，敌敌畏降解效率仅在较高农药浓度下显着提高，而对毒死蜱降解没有影响。交叉饲料和混合饲料研究强调，与 DEC 相比，CPEC 可有效降解敌敌畏作为唯一底物和两种农药的混合物。Edward 抑制和 Haldane 抑制模型分别令人满意地模拟了 DEC 和 CPEC 对敌敌畏和毒死蜱的生物降解动力学。生物动力学参数；所选农药的最大比生长速率 (µmax)、半饱和常数 (KC)、产量系数 (Y) 和抑制浓度 (Ki) 是根据最佳拟合生物动力学模型估算的。此外，批次确定的生物动力学参数已成功应用于农药传输模型，并用于模拟流通农药土壤柱研究的突破曲线 (BTC)。结果表明，富集的微生物是受污染水体和土壤原位生物修复的有希望的候选者。