PDF(Pubmed)
Abstract：
The environmental and economic impact of an oil spill can be significant. Biotechnologies applied during a marine oil spill involve bioaugmentation with immobilised or encapsulated indigenous hydrocarbonoclastic species selected under laboratory conditions to improve degradation rates. The environmental factors that act as stressors and impact the effectiveness of hydrocarbon removal are one of the challenges associated with these applications. Understanding how native microbes react to environmental stresses is necessary for effective bioaugmentation. Herein, Micrococcus luteus and M. yunnanensis isolated from a marine oil spill mooring system showed hydrocarbonoclastic activity on Maya crude oil in a short time by means of total petroleum hydrocarbons (TPH) at 144 h: M. luteus up to 98.79 % and M. yunnanensis 97.77 % removal. The assessment of Micrococcus biofilms at different temperature (30 °C and 50 °C), pH (5, 6, 7, 8, 9), salinity (30, 50, 60, 70, 80 g/L), and crude oil concentration (1, 5, 15, 25, 35 %) showed different response to the stressors depending on the strain. According to response surface analysis, the main effect was temperature > salinity > hydrocarbon concentration. The hydrocarbonoclastic biofilm architecture was characterised using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Subtle but significant differences were observed: pili in M. luteus by SEM and the topographical differences measured by AFM Power Spectral Density (PSD) analysis, roughness was higher in M. luteus than in M. yunnanensis. In all three domains of life, the Universal Stress Protein (Usp) is crucial for stress adaptation. Herein, the uspA gene expression was analysed in Micrococcus biofilm under environmental stressors. The uspA expression increased up to 2.5-fold in M. luteus biofilms at 30 °C, and 1.3-fold at 50 °C. The highest uspA expression was recorded in M. yunnanensis biofilms at 50 °C with 2.5 and 3-fold with salinities of 50, 60, and 80 g/L at hydrocarbon concentrations of 15, 25, and 35 %. M. yunnanensis biofilms showed greater resilience than M. luteus biofilms when exposed to harsh environmental stressors. M. yunnanensis biofilms were thicker than M. luteus biofilms. Both biofilm responses to environmental stressors through uspA gene expression were consistent with the behaviours observed in the response surface analyses. The uspA gene is a suitable biomarker for assessing environmental stressors of potential microorganisms for bioremediation of marine oil spills and for biosensing the ecophysiological status of native microbiota in a marine petroleum environment.
摘要：
石油泄漏对环境和经济的影响可能很大。在海洋溢油过程中应用的生物技术涉及在实验室条件下选择的固定或封装的本地破烃物种进行生物增强，以提高降解率。作为压力源并影响烃去除效率的环境因素是与这些应用相关的挑战之一。了解天然微生物对环境压力的反应对于有效的生物增强是必要的。在这里，从海洋溢油系泊系统中分离出的黄牛微球菌和云南芥在144h时通过总石油烃（TPH）在短时间内对玛雅原油显示出碳氢化合物活性：黄牛达98.79％，云南芥达97.77％。在不同温度（30°C和50°C）下评估微球菌生物膜，pH（5，6，7，8，9），盐度（30、50、60、70、80g/L），原油浓度（1、5、15、25、35％）对压力源的反应不同。根据响应面分析，主要影响是温度>盐度>烃浓度。使用扫描电子显微镜（SEM）和原子力显微镜（AFM）表征了烃碎屑生物膜结构。观察到细微但显着的差异：通过SEM观察黄体菌毛和通过AFM功率谱密度（PSD）分析测量的地形差异，黄牛的粗糙度高于云南黄牛。在生命的三个领域，通用应激蛋白（Usp）对于应激适应至关重要。在这里，在环境胁迫下，分析了微球菌生物膜中uspA基因的表达。uspA表达在30°C时在黄牛分枝杆菌生物膜中增加高达2.5倍，在50°C时为1.3倍。在50°C的云南芥生物膜中记录到最高的uspA表达，分别为2.5和3倍，盐度分别为50、60和80g/L，碳氢化合物浓度分别为15％、25％和35％。当暴露于恶劣的环境压力源时，云南M.生物膜比黄体生物膜表现出更大的复原力。云南M.生物膜比黄牛生物膜厚。通过uspA基因表达对环境应激源的两种生物膜响应与响应面分析中观察到的行为一致。uspA基因是评估潜在微生物的环境应激源的合适生物标志物，用于生物修复海洋溢油和生物传感海洋石油环境中天然微生物群的生态生理状态。
