Microbial reduction of metal-organic frameworks enables synergistic chromium removal

Abstract

Redox interactions between electroactive bacteria and inorganic materials underpin many emerging technologies, but commonly used materials (e.g., metal oxides) suffer from limited tunability and can be challenging to characterize. In contrast, metal-organic frameworks exhibit well-defined structures, large surface areas, and extensive chemical tunability, but their utility as microbial substrates has not been examined. Here, we report that metal-organic frameworks can support the growth of the metal-respiring bacterium Shewanella oneidensis, specifically through the reduction of Fe(III). In a practical application, we show that cultures containing S. oneidensis and reduced metal-organic frameworks can remediate lethal concentrations of Cr(VI) over multiple cycles, and that pollutant removal exceeds the performance of either component in isolation or bio-reduced iron oxides. Our results demonstrate that frameworks can serve as growth substrates and suggest that they may offer an alternative to metal oxides in applications seeking to combine the advantages of bacterial metabolism and synthetic materials.

Face Masks in the New COVID-19 Normal: Materials, Testing, and Perspectives

“…MOFs, as an emerging new class of antimicrobials, are superior compared with metals due to their high surface area, uniform distribution of metal active sites, and adjustable porous structures [ 191 , 192 ]. There has been rapid progress in recent years on the research of antimicrobial behavior of MOFs, along with the antimicrobial application of MOFs and their composites [ 191 , 193 ]. The antimicrobial mechanism of MOFs is mainly accredited to the inherent biocidal nature from their metal ions and may also be from the antimicrobial organic ligands [ 191 , 193 – 195 ].…”

Extracellular Electron Transfer Enables Cellular Control of Cu(I)-catalyzed Alkyne-Azide Cycloaddition

“…This pathway allows S. oneidensis to use oxidized metal ions, including organometallic catalysts, as terminal electron acceptors under anaerobic conditions [18][19][20] . Indeed, bacterial reduction of metals including iron(III) and copper(II) by E. coli and S. oneidensis have previously been used to perform atom-transfer radical polymerization (ATRP) [21][22][23] , and transcriptional regulation of specific EET proteins in S. oneidensis has enabled dynamic control over metal reduction and resulting catalysis [24][25] .…”

“…Among these approaches EET is particularly advantageous because it provides a tunable protein bridge between central carbon metabolism and extracellular redox reactions, including those controlled via metal catalysts. Specifically, EET in the model electroactive bacterium Shewanella oneidensis (wild-type MR-1) is regulated through a set of well-defined heme-containing cytochromes in the Mtr-pathway (metal-reducing pathway) 15-17 .This pathway allows S. oneidensis to use oxidized metal ions, including organometallic catalysts, as terminal electron acceptors under anaerobic conditions [18][19][20] . Indeed, bacterial reduction of metals including iron(III) and copper(II) by E. coli and S. oneidensis have previously been used to perform atom-transfer radical polymerization (ATRP) [21][22][23] , and transcriptional regulation of specific EET proteins in S. oneidensis has enabled dynamic control over metal reduction and resulting catalysis [24][25] .…”

MIL-88A Metal-Organic Framework as a Stable Sulfur-Host Cathode for Long-Cycle Li-S Batteries

“…MIL-88A is a metal-organic framework based on Fe (III) trimers, octahedrally interconnected through the dicarboxylates of fumaric acid [48]. MIL88-A has been considered as an electronic semiconductor material showing this ability for electronic conduction in photocatalytic [49] or in microbial reduction processes [50]. Some investigations of this material have already been reported in the field of Li-ion batteries, showing highly promising performances and improvements in electrochemical activity due to its high porosity which allows greater contact surface between electrode-electrolyte and an increase in the number of active reaction sites [51][52][53][54].…”