Groundwater co-contaminated by vanadium (V) (V(V)) and nitrate requires efficient remediation to prevent adverse environmental impacts. However, little is known about simultaneous bio-reductions of V(V) and nitrate supported by gaseous electron donors in aquifers. This study is among the first to examine microbial V(V) reduction and denitrification with hydrogen as the sole electron donor. V(V) removal efficiency of 91.0 ± 3.2% was achieved in test bioreactors within 7 d, with synchronous, complete removal of nitrate. V(V) was reduced to V(IV), which precipitated naturally under near-neutral conditions, and nitrate tended to be converted to nitrogen, both of which processes helped to purify the groundwater. Volatile fatty acids (VFAs) were produced from hydrogen oxidation. High-throughput 16S rRNA gene sequencing and metagenomic analyses revealed the evolutionary behavior of microbial communities and functional genes. The genera Dechloromonas and Hydrogenophaga promoted bio-reductions of V(V) and nitrate directly coupled to hydrogen oxidation. Enriched Geobacter and denitrifiers also indicated synergistic mechanism, with VFAs acting as organic carbon sources for heterotrophically functional bacteria while reducing V(V) and nitrate. These findings are likely to be useful in revealing biogeochemical fates of V(V) and nitrate in aquifer and developing technology for removing them simultaneously from groundwater.

钒（V）（V（V））和硝酸盐共污染的地下水需要有效补救，以防止对环境造成不利影响。但是，对于含水层中气态电子供体支持的V（V）和硝酸盐的同时生物还原知之甚少。这项研究是最早研究以氢作为唯一电子给体的微生物V（V）还原和反硝化的方法之一。在测试生物反应器中，在7 d内实现了V（V）的V（V）去除效率达到91.0±3.2％，同时同步，完全去除了硝酸盐。V（V）还原为V（IV），V（IV）在接近中性的条件下自然沉淀，硝酸盐趋于转化为氮，这两个过程均有助于净化地下水。挥发性脂肪酸（VFA）是由氢氧化产生的。高通量16S rRNA基因测序和宏基因组分析揭示了微生物群落和功能基因的进化行为。属Dechloromonas和Hydrogenophaga促进了V（V）和硝酸盐与氢氧化直接偶联的生物还原。富集的土细菌和反硝化剂也表明了协同机制，VFA充当异养功能细菌的有机碳源，同时降低了V（V）和硝酸盐。这些发现可能对揭示含水层中V（V）和硝酸盐的生物地球化学命运以及开发从地下水中同时去除它们的技术很有用。