Differences in Microbial Diversity, Composition and Function During V(V) Release and Reduction in Co-Contaminated Water by Nitrate and V(V) Under Liquid Carbon Sources

Abstract

With the increase of nitrate and V(V) pollution globally, microbial-driven pollutant reduction and its interaction have attracted more and more attention. In this study, the explicit vanadium release and reduction processes were distinguished in a complex contaminated system with liquid-carbon-source as external carbon source, while the microbial driving mechanism regarding this part has not been explored. Herein, we conducted experiments containing three liquid-carbon-sources, and obtained the concurrent changes of nitrate and V(V) under anaerobic conditions. Student’s T test and PcoA analysis showed that microorganisms were the driving force to distinguish vanadium release from vanadium reduction. ANOSIM analysis revealed that the microbial composition was affected by the type of pollutants, especially the release of V(V) caused by the addition of nitrate. The genus of Desulfosarcinaceae , LNR_A2-18 , Anaerocella and Flavobacterium had fermentation ability, which were conducive to the release of V(V). In the process of V(V) reduction, the genus of metal resistant and reduction with increased abundance were recognized as important candidates. Taken together, our findings provide a promising bioremediation strategy for the combined pollution of nitrate and V(V), and an in-depth study on the mechanisms of microbial action will help to improve the technological innovation in the remediation of co-contaminated groundwater.

Keywords: Nitrate, V(V) release, V(V) reduction, Microbial indicators, Liquid carbon source