Marine Bioresource and Environment Research Center, Key Laboratory of Marine Eco-Environmental Science and Technology, First Institute of Oceanography, Ministry of Natural Resources of China, Qingdao, 266061, People's Republic of China.
Marine Bioresource and Environment Research Center, Key Laboratory of Marine Eco-Environmental Science and Technology, First Institute of Oceanography, Ministry of Natural Resources of China, Qingdao, 266061, People's Republic of China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, People's Republic of China.
Chemosphere. 2023 Jul;329:138647. doi: 10.1016/j.chemosphere.2023.138647. Epub 2023 Apr 8.
Cycloalkanes pose a tremendous environmental risk due to their high concentration in petroleum hydrocarbons and hazardous effects to organisms. Numerous studies have documented the biodegradation of acyclic alkanes and aromatic hydrocarbons. However, insufficient attention has been paid to studies on the microbial degradation of cycloalkanes, which might be closely linked to psychrophilic microbes derived from low-temperature habitats. Here we show that endemic methylcyclohexane (MCH, an abundant cycloalkane species in oil) consumers proliferated in seawater samples derived from the Antarctic surface water (AASW). The MCH-consuming bacterial communities derived from AASW exhibited a distinct species composition compared with their counterparts derived from other cold-water habitats. We also probed Colwellia and Roseovarius as the key active players in cycloalkane degradation by dilution-to-extinction-based incubation with MCH as sole source of carbon and energy. Furthermore, we propose two nearly complete MCH degradation pathways, lactone formation and aromatization, concurrently in the high-quality metagenome-assembled genomes of key MCH consumer Roseovarius. Overall, we revealed that these Antarctic microbes might have strong interactions that enhance the decomposition of more refractory hydrocarbons through complementary degradation pathways.
环烷烃由于其在石油碳氢化合物中的高浓度和对生物体的有害影响，构成了巨大的环境风险。大量研究已经记录了无环烷烃和芳烃的生物降解。然而，对于环烷烃的微生物降解研究关注不足，这可能与低温生境来源的嗜冷微生物密切相关。在这里，我们表明，源自南极地表水 (AASW) 的海水样本中，丰富的环烷烃（甲基环己烷，MCH）消费者大量繁殖。与来自其他冷水生境的样本相比，源自 AASW 的 MCH 消耗细菌群落具有明显不同的物种组成。我们还通过以 MCH 作为唯一碳源和能源的稀释至灭绝培养，探究了 Colwellia 和 Roseovarius 作为环烷烃降解的关键活性因子。此外，我们提出了两条几乎完整的 MCH 降解途径，内酯形成和芳构化，同时在关键 MCH 消费者 Roseovarius 的高质量宏基因组组装基因组中。总体而言，我们揭示了这些南极微生物可能具有强烈的相互作用，通过互补的降解途径增强对更难分解的碳氢化合物的分解。
