Abstract：
The coexistence of heavy metals (HMs) and petroleum hydrocarbons (PHs) exacerbates ecotoxicity and impair the drivers of eco-functionalities that stimulate essential nutrients for the productivity of the impacted environment. Profiling the bacteria that stem the ecological impact via HMs sequestration and PHs catabolism with nitrogen fixation is imperative to bioremediation of the polluted sites. The sediment of site that was consistently contaminated with industrial wastewaters was analysed for ecological toxicants and the bacterial strains that combined HMs resistance with PHs catabolism in a nitrogen-limiting system were isolated from the sediment and characterized. The geochemistry of the samples revealed the co-occurrence of the above-benchmark concentrations of HMs with the derivatives of hydrocarbons. Notwithstanding, nickel and mercury (with 5% each of the total metal concentrations in the polluted site) exhibited probable effect concentrations on the biota and thus hazardous to the ecosystem. Approx. 31% of the bacterial community, comprising unclassified Planococcaceae, unclassified Bradyrhizobiaceae, Rhodococcus, and Bacillus species, resisted 160 µmol Hg2+ in the nitrogen-limiting system within 24 h post-inoculation. The bacterial strains adopt volatilization, and sometimes in combination with adsorption/bioaccumulation strategies to sequester Hg2+ toxicity while utilizing PHs as sources of carbon and energy. Efficient metabolism of petroleum biomarkers (> 87%) and Hg2+ sequestration (≥ 75% of 40 µmol Hg2+) displayed by the selected bacterial strains portend the potential applicability of the bacilli for biotechnological restoration of the polluted site.
摘要：
重金属（HM）和石油烃（PH）的共存加剧了生态毒性，并损害了生态功能的驱动因素，这些驱动因素刺激了受影响环境的生产力。对通过HMs固存和PHs分解代谢以及固氮来阻止生态影响的细菌进行分析，对于污染地点的生物修复至关重要。分析了一直被工业废水污染的站点的沉积物中的生态毒物，并从沉积物中分离出了在氮限制系统中将HMs抗性与PHs分解代谢相结合的细菌菌株并进行了表征。样品的地球化学揭示了上述基准浓度的HM与碳氢化合物衍生物的共存。尽管如此,镍和汞（污染场地中总金属浓度分别为5％）对生物群具有可能的影响浓度，因此对生态系统有害。大约。31%的细菌群落，包括未分类的植物科，未分类的缓生根瘤菌科，红球菌,和芽孢杆菌属物种，在接种后24小时内，在氮限制系统中抵抗了160µmolHg2。细菌菌株采用挥发，有时与吸附/生物积累策略相结合，以隔离Hg2毒性，同时利用PHs作为碳和能源。所选细菌菌株显示的石油生物标志物（>87％）和Hg2固存（≥40µmolHg2的75％）的有效代谢预示着杆菌对污染部位的生物技术修复的潜在适用性。
