Engineered Microbial Systems (EMS) Lab, Industrial Biotechnology Section, Department of Biological and Chemical Engineering (BCE), Aarhus University, Aarhus, Denmark; Microbiology Section, Department of Biology, Aarhus University, Aarhus, Denmark.
Water Research Institute (IRSA), National Research Council (CNR), Monterotondo, Italy.
J Environ Manage. 2022 Aug 15;316:115244. doi: 10.1016/j.jenvman.2022.115244. Epub 2022 May 20.
The impact of piezosensitive microorganisms is generally underestimated in the ecology of underwater environments exposed to increasing hydrostatic pressure (HP), including the biodegradation of crude oil components. Yet, no isolated pressure-loving (piezophile) microorganism grows optimally on hydrocarbons, and no isolated piezophile at all has a HP optimum <10 MPa (e.g. 1000 m below sea water level). Piezosensitive heterotrophs are thus largely accountable for oil clean up < 10 MPa, however, they are affected by such a mild HP increase in ways which are not completely clear. In a first study, the application of a bioelectrochemical system (called "oil-spill snorkel") enhanced the alkane oxidation capacity in sediments collected at surface water but tested up to 10 MPa. Here, the fingerprint left on transcript abundance was studied to explore which metabolic routes are 1) supported by snorkels application and 2) negatively impacted by HP increase. Transcript abundance was comparable for beta-oxidation across all treatments (also at a taxonomical level), while the metabolism of acetyl-CoA was highly impacted: at either 0.1 or 10 MPa, snorkels supported acetyl-CoA oxidation within the TCA cycle, while in negative controls using non-conductive rods several alternative routes for acetyl-CoA were stimulated (including those leading to internal carbon reserves e.g. 2,3 butanediol and dihydroxyacetone). In general, increased HP had opposite effects as compared to snorkels, thus indicating that snorkels could enhance hydrocarbons oxidation by alleviating in part the stressing effects imposed by increased HP on the anaerobic, respiratory electron transport chain. 16S rRNA gene analysis of sediments and biofilms on snorkels suggest a crosstalk between oil-degrading, sulfate-reducing microorganisms and sulfur oxidizers. In fact, no sulfur was deposited on snorkels, however, iron, aluminum and phosphorous were found to preferentially deposit on snorkels at 10 MPa. This data indicates that a passive BES such as the oil-spill snorkel can mitigate the stress imposed by increased HP on piezosensitive microorganisms (up to 10 MPa) without being subjected to passivation. An improved setup applying these principles can further support this deep-sea bioremediation strategy.
在暴露于静水压力（HP）增加的水下环境（包括原油成分的生物降解）的生态学中，压电微生物的影响通常被低估。然而，没有孤立的嗜压（压电）微生物在烃类物质上最佳生长，也没有孤立的压电生物根本没有 HP 最佳值<10 MPa（例如，在海平面以下 1000 米处）。因此，压电敏感异养生物在<10 MPa 的范围内很大程度上负责清理油污，然而，它们受到 HP 适度增加的影响，其方式尚不完全清楚。在第一项研究中，应用生物电化学系统（称为“溢油 snorkel”）增强了从地表水收集的沉积物中烷烃的氧化能力，但测试压力最高可达 10 MPa。在这里，研究了转录丰度留下的指纹，以探索哪些代谢途径 1）受到 snorkel 应用的支持，2）受到 HP 增加的负面影响。在所有处理中（甚至在分类学水平上），β-氧化的转录丰度都相似，而乙酰辅酶 A 的代谢受到高度影响：在 0.1 或 10 MPa 时，snorkel 支持三羧酸循环中的乙酰辅酶 A 氧化，而在使用非导电棒的阴性对照中，几种乙酰辅酶 A 的替代途径被刺激（包括导致内部碳储备的途径，例如 2,3-丁二醇和二羟丙酮）。一般来说，增加的 HP 与 snorkel 的效果相反，这表明 snorkel 可以通过部分缓解增加的 HP 对厌氧、呼吸电子传递链施加的压力，从而增强碳氢化合物的氧化。对 snorkel 上沉积物和生物膜的 16S rRNA 基因分析表明，石油降解、硫酸盐还原微生物和硫氧化菌之间存在相互作用。事实上，snorkel 上没有沉积硫，但发现铁、铝和磷在 10 MPa 时优先沉积在 snorkel 上。这些数据表明，像溢油 snorkel 这样的被动 BES 可以减轻增加的 HP 对压电敏感微生物（高达 10 MPa）的压力，而不会被钝化。应用这些原则的改进设置可以进一步支持这种深海生物修复策略。
