Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, China.
The First Institute of Oceanography, State Oceanic Administration, Qingdao, 266061, China.
Mar Biotechnol (NY). 2018 Dec;20(6):803-812. doi: 10.1007/s10126-018-9850-4. Epub 2018 Sep 14.
In recent years, some marine microbes have been used to degrade diesel oil. However, the exact mechanisms underlying the biodegradation are still poorly understood. In this study, a hypothermophilous marine strain, which can degrade diesel oil in cold seawater was isolated from Antarctic floe-ice and identified and named as Rhodococcus sp. LH. To clarify the biodegradation mechanisms, a gas chromatography-mass spectrometry (GC-MS)-based metabolomics strategy was performed to determine the diesel biodegradation process-associated intracellular biochemical changes in Rhodococcus sp. LH cells. With the aid of partial least squares-discriminant analysis (PLS-DA), 17 differential metabolites with variable importance in the projection (VIP) value greater than 1 were identified. Results indicated that the biodegradation of diesel oil by Rhodococcus sp. LH was affected by many different factors. Rhodococcus sp. LH could degrade diesel oil through terminal or sub-terminal oxidation reactions, and might also possess the ability to degrade aromatic hydrocarbons. In addition, some surfactants, especially fatty acids, which were secreted by Rhodococcus into medium could also assist the strain in dispersing and absorbing diesel oil. Lack of nitrogen in the seawater would lead to nitrogen starvation, thereby restraining the amino acid circulation in Rhodococcus sp. LH. Moreover, nitrogen starvation could also promote the conversation of relative excess carbon source to storage materials, such as 1-monolinoleoylglycerol. These results would provide a comprehensive understanding about the complex mechanisms of diesel oil biodegradation by Rhodococcus sp. LH at the systematic level.
近年来，一些海洋微生物已被用于降解柴油。然而，生物降解的确切机制仍知之甚少。本研究从南极浮冰中分离出一株能在冷海水中降解柴油的嗜冷海洋菌株，并将其鉴定和命名为 Rhodococcus sp. LH。为了阐明生物降解机制，采用基于气相色谱-质谱（GC-MS）的代谢组学策略来确定 Rhodococcus sp. LH 细胞内与柴油生物降解过程相关的生化变化。借助偏最小二乘判别分析（PLS-DA），鉴定出 17 种具有可变重要性投影值（VIP）大于 1 的差异代谢物。结果表明，Rhodococcus sp. LH 对柴油的生物降解受到许多不同因素的影响。Rhodococcus sp. LH 可以通过末端或次末端氧化反应降解柴油，并且可能还具有降解芳烃的能力。此外，一些表面活性剂，特别是脂肪酸，由 Rhodococcus 分泌到培养基中，也可以帮助该菌株分散和吸收柴油。海水中缺乏氮会导致氮饥饿，从而抑制 Rhodococcus sp. LH 中的氨基酸循环。此外，氮饥饿还可以促进相对过量碳源向储存物质（如 1-单油酰基甘油）的转化。这些结果将在系统水平上提供对 Rhodococcus sp. LH 降解柴油的复杂机制的全面理解。
