Asamba Micah Nyabiba, Mugendi Ezekiel Njeru, Oshule Paul Sifuna, Essuman Suliman, Chimbevo Lenny Mwagandi, Atego Norbert Adum
Department of Biochemistry, Microbiology and Biotechnology, Kenyatta University, Nairobi, Kenya.
Department of Medical Biochemistry, Mount Kenya University, Thika, Kenya.
Heliyon. 2022 Mar 24;8(3):e09176. doi: 10.1016/j.heliyon.2022.e09176. eCollection 2022 Mar.
Chlorpyrifos (CP) is an organophosphate widely used as an insecticide and acaricide. Extensive application of CP contaminates ecosystems, polluting the environment and food products, creating health complications to humans due to its neurotoxicity. The study evaluated CP bioremediation by bacteria isolated from dairy farm soils in Nakuru County, Kenya, through enrichment culture technique. The growth response of the bacteria and degradation of chlorpyrifos was monitored every five days using UV-VIS Spectrophotometer (600nm). Enrichment culture technique led to the isolation of eighteen (MA1-MA18) potential CP degraders belonging to the genera and The efficacy of four (4) strains was further investigated using Gas Chromatography-Mass Spectrometry (GC-MS) analysis. The results showed that all four strains significantly degraded chlorpyrifos in Minimum Salt Medium (MSM): (87.16 %), (82.04 %), (89.52 %), and (91.08 %) within 16 days, producing 2-Hydroxy-3, 5, 6-trichloropyridine (TCP) as the main metabolite. Therefore, these strains can be used to degrade chlorpyrifos in contaminated soil. There is a need for further studies to determine the possible mechanisms and other metabolites of chlorpyrifos degradation by the isolates obtained in the study. Besides, future studies should explore the efficacy and survival of the organisms in the contaminated environment.
毒死蜱（CP）是一种广泛用作杀虫剂和杀螨剂的有机磷酸酯。毒死蜱的广泛应用污染了生态系统，污染了环境和食品，因其神经毒性给人类带来健康问题。本研究通过富集培养技术，评估了从肯尼亚纳库鲁县奶牛场土壤中分离出的细菌对毒死蜱的生物修复作用。每隔五天使用紫外可见分光光度计（600nm）监测细菌的生长反应和毒死蜱的降解情况。富集培养技术导致分离出18株（MA1 - MA18）潜在的毒死蜱降解菌，它们属于不同的属。使用气相色谱 - 质谱联用仪（GC - MS）分析进一步研究了四株菌的降解效果。结果表明，在16天内，所有四株菌在最低盐培养基（MSM）中均能显著降解毒死蜱：MA1（87.16%）、MA3（82.04%）、MA5（89.52%）和MA15（91.08%），并产生2 - 羟基 - 3,5,6 - 三氯吡啶（TCP）作为主要代谢产物。因此，这些菌株可用于降解受污染土壤中的毒死蜱。有必要进一步研究以确定本研究中获得的分离菌株降解毒死蜱的可能机制和其他代谢产物。此外，未来的研究应探索这些生物体在受污染环境中的效能和存活情况。
