Differences in microbial diversity, composition and function during V(v) release and reduction in nitrate–V(v) co-contaminated water from liquid carbon sources

Abstract

With the increase of nitrate and V(V) pollution globally, microbially-driven pollutant reduction has attracted more and more attention. In this study, the explicit vanadium release and reduction processes were distinguished in a complex contaminated system with a liquid carbon source as an external carbon source, although the microbial driving mechanism regarding this part has not been explored. Here, we performed experiments containing three liquid carbon sources and obtained the variation of nitrate and V(V) under anaerobic conditions. Student's t-test and PcoA showed that microorganisms might be the driving force to distinguish these two processes. ANOSIM tests revealed that the microbial composition was affected by the types of pollutants, especially the release of V(V) caused by the addition of nitrate. The genera Desulfosarcinaceae, LNR_A2-18, Anaerocella and Flavobacterium had fermentation ability, and were conducive to the release of V(V). In the process of V(V) reduction, the metal resistant and reducing genera 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.