Hydrocarbon and salt contamination of surface and groundwater resources often co-occur from oil production activities. However, salt is often considered as a potential inhibitor of microbial activity. The feasibility of microbiome-based biotechnologies to treat the hydrocarbon contamination is contingent on the ability of the indigenous community to adapt to saline conditions. Here, we demonstrate enhanced hydrocarbon biodegradation in soil slurries under saline conditions of up to ~1 M (5%) compared to non-saline systems and the underlying causes. The mineralization extent of hexadecane was enhanced by salinity in the absence of nutrients. Salinity, similar to nutrients, enhanced the mineralization but through ecological selection. Microbial community analysis indicated a significant enrichment of Actinobacteria phylum and an increase in the absolute abundance of the hydrocarbon-degrading Dietzia genus, but a decrease in the total population size with salinity. Moreover, the in situ expression of alkane hydroxylases genes of Dietzia was generally increased with salinity. The data demonstrate that indigenous halotolerant hydrocarbon degraders were enriched, and their hydrocarbon degradation genes upregulated under saline conditions. These findings have positive implications for engineered biotreatment approaches for hydrocarbons in saline environments such as those affected with produced waters and oil sands tailing ponds.

地表和地下水资源的碳氢化合物和盐污染通常与石油生产活动同时发生。然而，盐通常被认为是微生物活动的潜在抑制剂。基于微生物组的生物技术处理碳氢化合物污染的可行性取决于土著社区适应咸水条件的能力。在这里，我们证明了与非盐分系统相比，在高达约 1 M (5%) 的盐分条件下，土壤泥浆中的碳氢化合物生物降解能力和潜在原因得到了增强。在没有养分的情况下，盐度提高了十六烷的矿化程度。盐度，类似于营养物，通过生态选择增强了矿化作用。微生物群落分析表明放线菌显着富集门和碳氢化合物降解Dietzia属的绝对丰度增加，但总种群规模随着盐度的增加而减少。此外，Dietzia烷烃羟化酶基因的原位表达通常随着盐度的增加而增加。数据表明，本地耐盐烃降解剂富集，并且它们的烃降解基因在盐水条件下上调。这些发现对盐水环境中碳氢化合物的工程生物处理方法具有积极意义，例如受采出水和油砂尾矿池影响的环境。