MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, School of Water Resources and Environment, China University of Geosciences Beijing, Beijing 100083, PR China.
MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, School of Water Resources and Environment, China University of Geosciences Beijing, Beijing 100083, PR China.
Water Res. 2024 Jun 15;257:121747. doi: 10.1016/j.watres.2024.121747. Epub 2024 May 7.
Contamination of aquifers by a combination of vanadate [V(V)] and nitrate (NO) is widespread nowadays. Although bioremediation of V(V)- and nitrate-contaminated environments is possible, only a limited number of functional species have been identified to date. The present study demonstrates the effectiveness of V(V) reduction and denitrification by a denitrifying bacterium Acidovorax sp. strain BoFeN1. The V(V) removal efficiency was 76.5 ± 5.41 % during 120 h incubation, with complete removal of NO within 48 h. Inhibitor experiments confirmed the involvement of electron transport substances and denitrifying enzymes in the bioreduction of V(V) and NO. Cyt c and riboflavin were important for extracellular V(V) reduction, with quinone and EPS more significant for NO removal. Intracellular reductive compounds including glutathione and NADH directly reduce V(V) and NO. Reverse transcription quantitative PCR confirmed the important roles of nirK and napA genes in regulating V(V) reduction and denitrification. Bioaugmentation by strain BoFeN1 increased V(V) and NO removal efficiency by 55.3 % ± 2.78 % and 42.1 % ± 1.04 % for samples from a contaminated aquifer. This study proposes new microbial resources for the bioremediation of V(V) and NOcontaminated aquifers, and contributes to our understanding of coupled vanadium, nitrogen, and carbon biogeochemical processes.
如今，地下水同时受到钒酸盐[V(V)]和硝酸盐(NO)污染的情况非常普遍。尽管可以对受 V(V)和硝酸盐污染的环境进行生物修复，但迄今为止，只有有限数量的功能物种被鉴定出来。本研究证明了一种反硝化菌 Acidovorax sp. strain BoFeN1 还原 V(V)和反硝化的有效性。在 120 h 的孵育过程中，V(V)的去除效率为 76.5 ± 5.41%，48 h 内可完全去除 NO。抑制剂实验证实了电子传递物质和反硝化酶参与 V(V)和 NO 的生物还原。细胞色素 c 和核黄素对于细胞外 V(V)还原很重要，而醌和 EPS 对于 NO 的去除更为重要。包括谷胱甘肽和 NADH 在内的细胞内还原化合物可直接还原 V(V)和 NO。反转录定量 PCR 证实了 nirK 和 napA 基因在调节 V(V)还原和反硝化过程中的重要作用。通过 BoFeN1 菌株的生物增强作用，受污染含水层样本的 V(V)和 NO 去除效率分别提高了 55.3%±2.78%和 42.1%±1.04%。本研究为受 V(V)和 NO 污染的含水层的生物修复提供了新的微生物资源，并有助于我们理解耦合钒、氮和碳的生物地球化学过程。
