Zhou Yumiao, Wang Ying, Yang Likun, Kong Qiang, Zhang Huanxin
College of Geography and Environment, Shandong Normal University, Jinan, 250000, China.
College of Marine Life Sciences, Ocean University of China, Qingdao, 266100, China.
Environ Pollut. 2023 May 1;324:121420. doi: 10.1016/j.envpol.2023.121420. Epub 2023 Mar 9.
Petroleum hydrocarbons are significant new persistent organic pollutants for marine oil spill risk areas. Oil trading ports, in turn, have become major bearers of the risk of offshore oil pollution. However, studies on the molecular mechanisms of microbial degradation of petroleum pollutants by natural seawater are limited. Here, an in situ microcosm study was conducted. Combined with metagenomics, differences in metabolic pathways and in the gene abundances of total petroleum hydrocarbons (TPH) are revealed under different conditions. About 88% degradation of TPH was shown after 3 weeks of treatment. The positive responders to TPH were concentrated in the genera Cycloclasticus, Marivita and Sulfitobacter of the orders Rhodobacterales and Thiotrichales. The genera Marivita, Roseobacter, Lentibacter and Glaciecola were key degradation species when mixing dispersants with oil, and all of the above are from the Proteobacteria phylum. The analysis showed that the biodegradability of aromatic compounds, polycyclic aromatic hydrocarbon and dioxin were enhanced after the oil spill, and genes with higher abundances of bphAa, bsdC, nahB, doxE and mhpD were found, but the photosynthesis-related mechanism was inhibited. The dispersant treatment effectively stimulated the microbial degradation of TPH and then accelerated the succession of microbial communities. Meanwhile, functions such as bacterial chemotaxis and carbon metabolism (cheA, fadeJ and fadE) were better developed, but the degradation of persistent organic pollutants such as polycyclic aromatic hydrocarbons was weakened. Our study provides insights into the metabolic pathways and specific functional genes for oil degradation by marine microorganisms and will help improve the application and practice of bioremediation.
石油烃是海洋溢油风险区域中重要的新型持久性有机污染物。而石油贸易港口则成为近海石油污染风险的主要承载者。然而，关于天然海水对石油污染物微生物降解分子机制的研究较为有限。在此，开展了一项原位微观研究。结合宏基因组学，揭示了不同条件下总石油烃（TPH）代谢途径和基因丰度的差异。处理3周后TPH降解率达88%左右。对TPH有正向响应的集中在红杆菌目和硫发菌目的环裂菌属、海生菌属和硫杆菌属。海生菌属、玫瑰杆菌属、缓生根瘤菌属和嗜冷杆菌属在油与分散剂混合时是关键降解物种，以上所有属均来自变形菌门。分析表明，溢油后芳香族化合物、多环芳烃和二噁英的生物降解性增强，发现bphAa、bsdC、nahB、doxE和mhpD等基因丰度较高，但光合作用相关机制受到抑制。分散剂处理有效刺激了TPH的微生物降解，进而加速了微生物群落演替。同时，细菌趋化作用和碳代谢（cheA、fadeJ和fadE）等功能得到更好发展，但多环芳烃等持久性有机污染物的降解减弱。我们的研究为海洋微生物降解石油的代谢途径和特定功能基因提供了见解，将有助于改进生物修复的应用和实践。
