Park Chulwoo, Park Woojun
Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul, South Korea.
Front Microbiol. 2018 May 25;9:1081. doi: 10.3389/fmicb.2018.01081. eCollection 2018.
Many petroleum-polluted areas are considered as extreme environments because of co-occurrence of low and high temperatures, high salt, and acidic and anaerobic conditions. Alkanes, which are major constituents of crude oils, can be degraded under extreme conditions, both aerobically and anaerobically by bacteria and archaea of different phyla. Alkane degraders possess exclusive metabolic pathways and survival strategies, which involve the use of protein and RNA chaperones, compatible solutes, biosurfactants, and exopolysaccharide production for self-protection during harsh environmental conditions such as oxidative and osmotic stress, and ionic nutrient-shortage. Recent findings suggest that the thermophilic sulfate-reducing archaeon uses a novel alkylsuccinate synthase for long-chain alkane degradation, and the thermophilic anaerobically oxidizes butane via alkyl-coenzyme M formation. In addition, gene expression data suggest that extremophiles produce energy via the glyoxylate shunt and the Pta-AckA pathway when grown on a diverse range of alkanes under stress conditions. Alkane degraders possess biotechnological potential for bioremediation because of their unusual characteristics. This review will provide genomic and molecular insights on alkane degraders under extreme conditions.
由于低温与高温、高盐以及酸性和厌氧条件同时存在，许多石油污染地区被视为极端环境。作为原油主要成分的烷烃，在极端条件下可被不同门类的细菌和古菌进行好氧和厌氧降解。烷烃降解菌拥有独特的代谢途径和生存策略，包括在诸如氧化应激、渗透应激和离子营养短缺等恶劣环境条件下，利用蛋白质和RNA伴侣、相容性溶质、生物表面活性剂以及胞外多糖的产生来进行自我保护。最近的研究结果表明，嗜热硫酸盐还原古菌利用一种新型的烷基琥珀酸合酶进行长链烷烃降解，嗜热菌通过烷基辅酶M的形成厌氧氧化丁烷。此外，基因表达数据表明，极端微生物在应激条件下以多种烷烃为生长底物时，通过乙醛酸循环和磷酸转乙酰酶-乙酸激酶途径产生能量。由于其独特的特性，烷烃降解菌在生物修复方面具有生物技术潜力。本综述将提供关于极端条件下烷烃降解菌的基因组和分子层面的见解。
