Nano zero-valent iron: A pH buffer, electron donor and activator for chain elongation

Xindi Fu; Xi Jin; Rong Ye; Wenjing Lu

doi:10.1016/j.biortech.2021.124899

Nano zero-valent iron: A pH buffer, electron donor and activator for chain elongation

Bioresour Technol. 2021 Jun:329:124899. doi: 10.1016/j.biortech.2021.124899. Epub 2021 Mar 2.

Authors

Xindi Fu¹, Xi Jin¹, Rong Ye¹, Wenjing Lu²

Affiliations

¹ School of Environment, Tsinghua University, 100084 Beijing, China.
² School of Environment, Tsinghua University, 100084 Beijing, China. Electronic address: luwenjing@tsinghua.edu.cn.

PMID: 33677422
DOI: 10.1016/j.biortech.2021.124899

Abstract

Chain elongation produce medium chain carboxylates, which are important precursors to many pharmaceuticals, antimicrobials and biofuels. Results in the presented investigations show that the supply of nano zero-valent iron (NZVI) can enhance caproate production. The highest caproate concentration achieved amounted to 27.2 mmol/L when 5 g/L NZVI were added, which was about 100% higher than the control. The study also showed increase of ethanol oxidation and decrease of butyrate and butanol with NZVI addition. Mechanism study showed NZVI can stimulate caproate production by preventing pH to fall below 5.4 through displacement reaction. Electron balance analysis displayed that NZVI provides extra electron by promoting ethanol oxidation and its dissolution. H₂ was the potential electron shuttle between NZVI and chain elongators; High throughput sequencing showed function of NZVI on reshaping of microbial communities, especially enriching Oscillibacter Marseille-P3260, a kind of chain elongator and Corynebacterium which possesses fatty acid biosynthesis and iron utilization.

Keywords: Chain elongation; Electron donor; Ferredoxin; Nano zero-valent iron; pH buffer.

MeSH terms

Biofuels
Electrons
Hydrogen-Ion Concentration
Iron*
Water Pollutants, Chemical*

Substances

Biofuels
Water Pollutants, Chemical
Iron