Synchronous microbial V(V) reduction and denitrification using corn straw as the sole carbon source

• Published in: The Science of the total environment 2022-09, Vol.839, p.156343-156343, Article 156343
• Main Authors: Wang, Haishuang, Chen, Nan, Feng, Chuanping, Deng, Yang
• Format: Article
• Language: English
• Subjects: Corn straw; Denitrification; Functional genes; Microorganisms; Vanadium
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2022.156343

The coexistence of nitrate and V(V) in groundwater aquifers poses potential threats to ecological environment and public health. However, much remains to be elucidated about how the complex microbial community coupled nitrate and V(V) simultaneous bio-reduction with carbon source oxidation. For the first time, it was demonstrated that denitrification and V(V) bio-reduction occur by using corn straw as the sole carbon and energy source. Corn straw was proved to have efficient denitrification and V(V) bio-reduction performance in various environments, especially at V(V) concentrations of 100 mg/L for optimal V(V) reduction rate (19.25 mg/L·d) and at pH of 11 with the best nitrate reduction rate (3.12 d−1). In addition, an interesting phenomenon was found that the release of V(V) occurred when the carbon source was insufficient and the competitive electron acceptor (NO3−-N) existed. Metagenomic analysis showed that the addition of corn straw increased the abundance of genes related to metal resistance, cytochrome and dimethyl sulfoxide, and increased the abundance of glycolytic process, which may play a vital role in facilitating the reduction of V(V). These findings can provide basic suggestions for improving the mechanism of V(V) reduction pathway and provide guidance for the remediation of groundwater polluted by nitrate and V(V). [Display omitted] •Corn straw achieved efficient simultaneous denitrificaion and V(V) bio-reduction.•Corn straw can attenuate the biological toxicity caused by V(V) at concentration of 100 mg/L.•V(IV)/V(V) redox couple reaction was found to be quasi-reversible.•Enterobacteriaceae carrying the encoding genes arsC and narG was responsible for V(V) reduction.•Genes related to metal resistance, cytochrome and DMSO functioned vitally in V(V) reduction.