서종수 (국가독성과학연구소)

서종수 (국가독성과학연구소)

서종수 (국가독성과학연구소)

노영지 (국가독성과학연구소)

이정학 (국가독성과학연구소)

신민철 (국가독성과학연구소)

조승현 (국가독성과학연구소)

김종환 (국가독성과학연구소)

Polycyclic aromatic hydrocarbons (PAHs) are representative recalcitrant environmental pollutants generated by the incomplete combustion of organic matter. Due to their strong toxicity and carcinogenicity, they pose a serious threat to ecosystems and human health. In this study, the Delftia sp. strain KIT-007, which was isolated from the lower Nakdong River region samples, was used in degradation ability of fluoranthene, metabolic pathways, and physiological changes in metabolic mechanisms. The strain KIT-007 exhibited the best fluoranthene degradation ability at 35℃, pH 5-10, and salinity 0-1%, degrading more than 75% of 20 mg/L of fluoranthene within 5 days under these conditions. As a result of confirming the metabolites through GC-MS/MS analysis, it was confirmed that there are two pathways of degradation: one in which 7,8-dihydroxyfluoranthene is degraded into 1,8-naphththalic anhydride, and another in which 2,3-dihydroxyfluoranthene is degraded into 9-fluorenone-1-carboxylic acid, benzene-1,2,3-tricarboxylic acid, and citric acid. Using multi-omics (metabolomics, lipidomics) techniques, GC Orbitrap Exploris and LC Q Exactive Orbitrap were used to analyze how microorganisms alter metabolic pathways and exercise defense mechanisms to survive when exposed to the toxic organic pollutant fluoranthene. As a result, it was scientifically proven that the strain KIT-007 exposed to fluoranthene emitted oil-dissolving substances, firmly formed cell membranes to block toxicity, and cleared away the causes of oxidative stress and byproducts, while simultaneously producing large quantities of oxygenases using explosive energy obtained from burning fuel, thereby successfully surviving without dying, bioremediating pollutants, and increasing its population. By comprehensively elucidating not only the microbial degradation pathways of recalcitrant organic pollutants but also the omics-based physiological defense mechanisms, this study provides a scientific foundation for the future development of microbial-based bioremediation technologies.​