Fathepure Babu Z
Department of Microbiology and Molecular Genetics, Oklahoma State University Stillwater, OK, USA.
Front Microbiol. 2014 Apr 23;5:173. doi: 10.3389/fmicb.2014.00173. eCollection 2014.
Many hypersaline environments are often contaminated with petroleum compounds. Among these, oil and natural gas production sites all over the world and hundreds of kilometers of coastlines in the more arid regions of Gulf countries are of major concern due to the extent and magnitude of contamination. Because conventional microbiological processes do not function well at elevated salinities, bioremediation of hypersaline environments can only be accomplished using high salt-tolerant microorganisms capable of degrading petroleum compounds. In the last two decades, there have been many reports on the biodegradation of hydrocarbons in moderate to high salinity environments. Numerous microorganisms belonging to the domain Bacteria and Archaea have been isolated and their phylogeny and metabolic capacity to degrade a variety of aliphatic and aromatic hydrocarbons in varying salinities have been demonstrated. This article focuses on our growing understanding of bacteria and archaea responsible for the degradation of hydrocarbons under aerobic conditions in moderate to high salinity conditions. Even though organisms belonging to various genera have been shown to degrade hydrocarbons, members of the genera Halomonas Alcanivorax, Marinobacter, Haloferax, Haloarcula, and Halobacterium dominate the published literature. Despite rapid advances in understanding microbial taxa that degrade hydrocarbons under aerobic conditions, not much is known about organisms that carry out similar processes in anaerobic conditions. Also, information on molecular mechanisms and pathways of hydrocarbon degradation in high salinity is scarce and only recently there have been a few reports describing genes, enzymes and breakdown steps for some hydrocarbons. These limited studies have clearly revealed that degradation of oxygenated and non-oxygenated hydrocarbons by halophilic and halotolerant microorganisms occur by pathways similar to those found in non-halophiles.
许多高盐环境常常受到石油化合物的污染。其中，由于污染的范围和程度，世界各地的石油和天然气生产场地以及海湾国家较为干旱地区数百公里的海岸线备受关注。由于传统微生物过程在高盐度下无法良好运行，高盐环境的生物修复只能通过使用能够降解石油化合物的高耐盐微生物来实现。在过去二十年中，有许多关于中高盐度环境中碳氢化合物生物降解的报道。已经分离出许多属于细菌域和古菌域的微生物，并证明了它们在不同盐度下对各种脂肪族和芳香族碳氢化合物的系统发育和代谢能力。本文重点关注我们对在中高盐度条件下需氧环境中负责碳氢化合物降解的细菌和古菌的日益深入的理解。尽管已表明各种属的生物能够降解碳氢化合物，但嗜盐单胞菌属、食烷菌属、海杆菌属、嗜盐菌属、嗜盐碱杆菌属和嗜盐栖热菌属的成员在已发表的文献中占主导地位。尽管在理解需氧条件下降解碳氢化合物的微生物分类方面取得了快速进展，但对于在厌氧条件下进行类似过程的生物了解甚少。此外，关于高盐度下碳氢化合物降解的分子机制和途径的信息稀缺，直到最近才有一些报道描述了某些碳氢化合物的基因、酶和分解步骤。这些有限的研究清楚地表明，嗜盐和耐盐微生物对含氧和不含氧碳氢化合物的降解途径与非嗜盐微生物中的途径相似。
