School of Water Resources and Environment, MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing, 100083, PR China.
School of Water Resources and Environment, MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing, 100083, PR China.
Water Res. 2021 Feb 1;189:116664. doi: 10.1016/j.watres.2020.116664. Epub 2020 Nov 22.
Mackinawite (FeS), a widely-distributed natural reducing mineral, can donate electron for various (bio)processes. However, little is known about mackinawite-driven chemoautotrophic bioreduction of toxic vanadate [V(V)] in aquifer. This study demonstrates that V(V) is successfully bioreduced by mackinawite under anaerobic condition via 150-d operation of constructed aquifer. Complete V(V) removal was achieved at the initial concentration of 10 mg/L and flow rate of 0.125 mL/min. Fluctuant hydrochemistry and hydrodynamics affected V(V) removal performance. Biotic activity was identified as the major contribution to V(V) transformation (76.4 ± 1.01%). Chemoautotrophic genera (e.g., Thiobacillus) could oxidize FeS coupled to direct V(V) reduction independently. Heterotrophic V(V) reducers (e.g., Pseudomonas and Spirochaeta) could also achieve V(V) detoxification by utilizing metabolic intermediates synthesized by autotrophic Fe(II) oxidizers (e.g., Thiobacillus) and S(-II) oxidizing genera (e.g., Sulfuricurvum). Gene abundance and enzymatic activity tests confirmed that nitrate reductase gene napA functioned crucially in chemoautotrophic V(V) reduction by Fe(II) and S(-II) donating electron. V(V) was reduced to insoluble V(IV) while elements in mackinawite were oxidized to Fe(III) and SO. This study reveals the coupling of iron, sulfur and vanadium in biogeochemical cycling, and offers a promising strategy for remediation of V(V)-polluted aquifer.
磁黄铁矿（FeS）是一种广泛分布的天然还原矿物，可为各种（生物）过程提供电子。然而，人们对含水层中磁黄铁矿驱动的有毒五价钒[V(V)]的化学生物还原过程知之甚少。本研究表明，通过构建含水层 150 天的运行，在厌氧条件下，V(V)可被磁黄铁矿成功还原。在初始浓度为 10 mg/L 和流速为 0.125 mL/min 的条件下，可实现完全去除 V(V)。波动的水化学和水动力会影响 V(V)的去除性能。生物活性被认为是 V(V)转化的主要贡献者（76.4±1.01%）。化能自养菌（如硫杆菌）可以氧化耦合的 FeS，独立地直接还原 V(V)。异养 V(V)还原剂（如假单胞菌和螺旋体）也可以通过利用自养 Fe(II)氧化剂（如硫杆菌）和 S(-II)氧化菌（如硫矿硫化叶菌）合成的代谢中间产物来实现 V(V)解毒。基因丰度和酶活性测试证实，硝酸盐还原酶基因 napA 在 Fe(II)和 S(-II)供电子的化学生物还原 V(V)中起着至关重要的作用。V(V)被还原为不溶性 V(IV)，而磁黄铁矿中的元素被氧化为 Fe(III)和 SO。本研究揭示了铁、硫和钒在生物地球化学循环中的耦合，并为污染含水层中 V(V)的修复提供了一种有前景的策略。
