Electron shuttles stimulate the reductive dissolution of jarosite by Acidiphilium cryptum

González, Ernesto; Hernández, L. A.; Muñoz, J.A.; Blázquez, M.L.; Ballester, A.; González, F.

doi:10.1016/j.hydromet.2020.105351

Cited by 5 publications

(9 citation statements)

References 48 publications

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“…These experiments were performed using a potentiostat (Gamry 1000B) connected to a conventional three‐electrode cell, which used a pencil graphite electrode as working electrode, platinum wire as counter electrode and Ag/AgCl (3 mol L −1 KCl) as reference electrode. The pencil graphite electrode (Staedtler® Mars micro carbon, HB 0.5 mm) was made and pretreated as described elsewhere 21 . Neutral red solutions (10 mmol L −1 ) were prepared using wide range citrate–phosphate buffers, purged with N 2 , and analyzed at 100 mV s −1 .…”

Section: Methodsmentioning

confidence: 99%

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Butanol production by Clostridium acetobutylicumATCC 824 using electro‐fermentation in culture medium supplemented with butyrate and neutral red

Guerrero

Gallardo

González

et al. 2021

J of Chemical Tech & Biotech

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BACKGROUND Butanol is a versatile chemical that can be used as fuel, solvent or intermediate in chemical synthesis. Several strategies have been used to increase the availability of reducing power in Clostridium sp. with the aim of maximizing the production of butanol, the use of electron carriers being one of the most effective. Moreover, electrons from an external power source can be transferred to cells through electron carriers such neutral red, or directly reducing NAD+. From a previous metabolic analysis, we hypothesized that adding butyrate to the culture medium and using an external electron source as a co‐reducing agent, along with glucose‐derived reducing power (electro‐fermentation), would result in an increase in the specific butanol productivity. RESULTS Butyrate caused a decrease in the maximum concentration of butanol reached at the concentration used (6 g L−1). The supplementation of neutral red to the culture medium by itself and along with electro‐fermentation were effective in stimulating the production of butanol. The mean specific rate of butanol production obtained for electro‐fermentation in medium supplemented with butyrate and neutral red was 307% and 156% higher than that recorded using medium supplemented with butyrate, or butyrate and neutral red, respectively, this value being even 113% higher than that recorded for the non‐supplemented medium. CONCLUSIONS The presence of butyrate and absence of neutral red in the electro‐fermentation were detrimental for the microorganism. The electro‐fermentation in medium supplemented with neutral red led to an increase in both volumetric and specific productivities of butanol. © 2021 Society of Chemical Industry (SCI).

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Section: Methodsmentioning

confidence: 99%

“…The pencil graphite electrode (Staedtler® Mars micro carbon, HB 0.5 mm) was made and pretreated as described elsewhere. 21 Neutral red solutions (10 mmol L −1 ) were prepared using wide range citratephosphate buffers, purged with N 2 , and analyzed at 100 mV s −1 .…”

Section: Methodsmentioning

confidence: 99%

Butanol production by Clostridium acetobutylicumATCC 824 using electro‐fermentation in culture medium supplemented with butyrate and neutral red

Guerrero

Gallardo

González

et al. 2021

J of Chemical Tech & Biotech

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“…Acidianus manzaensis anaerobically dissolved jarosites via Fe(III) reduction coupled to sulfur oxidation (Zhang et al 2020a , b ). Also demonstrated has been a reductive dissolution of jarosite by the heterotrophic bacterium Acidiphilium cryptum (e.g., González et al 2020 ). Cu extraction from mine tailings was achieved by a combination of oxidative and reductive bioleaching (Falagán et al 2017 ) as an approach for tailings reprocessing.…”

Section: Acid and Reductive Bioleaching Of Laterite Oresmentioning

confidence: 99%

Progress in bioleaching: part B, applications of microbial processes by the minerals industries

Roberto

Schippers

2022

Appl Microbiol Biotechnol

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This review provides an update to the last mini-review with the same title pertaining to recent developments in bioleaching and biooxidation published in 2013 (Brierley and Brierley). In the intervening almost 10 years, microbial processes for sulfide minerals have seen increased acceptance and ongoing but also declining commercial application in copper, gold, nickel and cobalt production. These processes have been applied to heap and tank leaching, nowadays termed biomining, but increasing concerns about the social acceptance of mining has also seen the re-emergence of in situ leaching and quest for broader applicability beyond uranium and copper. Besides metal sulfide oxidation, mineral dissolution via reductive microbial activities has seen experimental application to laterite minerals. And as resources decline or costs for their exploitation rise, mine waste rock and tailings have become more attractive to consider as easily accessible resources. As an advantage, they have already been removed from the ground and in some cases contain ore grades exceeding that of those currently being mined. These factors promote concepts of circular economy and efficient use and valorization of waste materials. Key points • Bioleaching of copper sulfide ore deposits is producing less copper today • Biooxidation of refractory gold ores is producing more gold than in the past • Available data suggest bioleaching and biooxidation processes reduce carbon emissions

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“…34,35 Finally, with using this tool, inner sphere electron transfer mechanisms can be evidenced and studied without risking RFB electrode materials. 35 Inspired by the ability of gallocyanine (GAL) to act as a redox mediator (undergoing two reversible electron transfers) in enzymatic and biological reduction processes, 26,29 and because it is a commercially available PXZ-based derivative that is also decorated with OH and COOH groups around its structure, here we examined and discussed its use as a negolyte electrolyte in an alkaline flow cell, also presenting a set of chemical and electrochemical reactions for reducing GAL deprotonated species (GAL ox RFB electrolytes are typically characterized by cyclic voltammetry at low analyte concentrations (close to 0.001 mol L −1 ) and scan rates (e.g., 0.1 V s −1 ). Based on this approach, a two-electron reduction process for GAL compound dissolved in 1 mol L −1 KOH (Figure 1A, black line) was identified when comparing its voltammetric peak current intensities to the ones measured from the singleelectron reduction voltammetric wave (Figure 1A, gray line) of 1,1′-bis(3-sulfonatepropyl)-4,4′-bipyridinium structure used as a reference system, 5,32 and considering the reported information on similar PXZ-based structures.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Phenoxazines and its derivatives are heterocyclic compounds that are widely used as broad-spectrum antibiotics, serve as dye-sensitizers of solar cells and light-emitting diodes, and are efficient scaffolds in catalysis and spintronic applications. , These molecules have been used as redox shuttles and as p-type redox centers in organic battery cathode materials. , As a highlight, a phenoxazine-based skeleton can be functionalized with heteroatoms at the para position (with respect to the N group) to prepare aqueous soluble structures of two electron storage capacity ( PXZ ). The resulting PXZ systems become pH dependent and can undergo one or two reversible reduction reactions in cyclic voltammetry experiments, , exhibiting marginal molecular structure reorganizations and faster electrode kinetics than phenothiazine derivatives . Within this framework, structure PXZ becomes a new promising skeleton for preparing and investigating aqueous negolytes of two-electron storage capacity.…”

Section: Introductionmentioning

confidence: 99%

Reversible Redox Chemistry in a Phenoxazine-Based Organic Compound: A Two-Electron Storage Negolyte for Alkaline Flow Batteries

Martínez‐González

Amador‐Bedolla

Ugalde‐Saldívar

2022

ACS Appl. Energy Mater.

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Finding two-electron storage aqueous organic negolytes is crucial for increasing the charge storage capacity in next-generation flow batteries. Inspired by the ability of gallocyanine compound (GAL) to act as an efficient two-electron transfer mediator in biology, we investigated its reduction process by cyclic voltammetry at alkaline conditions, detecting ion pairing (with Na+, K+, or Li+ ions) and H+ transfer pathways in electrogenerated species. The voltammetric responses obtained were dependent on the concentrations of analyte and supporting electrolyte and exhibited values of peak-to-peak potential distance (ΔE p) close to the limiting value established in flow battery protocols for screening irreversible systems (>200/n mV). The results presented in this work can not be explained by irreversible mechanisms. This atypical behavior was related to the evolution of a mixed and reversible process of adsorption and diffusion pathways, where GAL species near the electrode first attach to the electroactive surface without passivating it, so at high concentrations of GAL compound, the reactions can take place by a mainly diffusive process (at the modified electrode). The reversible redox chemistry in compound studied was corroborated by testing a flow cell of 0.83 V composed of a GAL-KOH system and the posolyte ferrocyanide-KOH solution. The cell exhibited a Coulombic efficiency close to 100% and retained 87% of its capacity after 200 charge–discharge cell cycles. This is the first report concerning the use of a phenoxazine-based derivative for storing two electrons per molecule in an aqueous flow cell.

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Electron shuttles stimulate the reductive dissolution of jarosite by Acidiphilium cryptum

Cited by 5 publications

References 48 publications

Butanol production by Clostridium acetobutylicumATCC 824 using electro‐fermentation in culture medium supplemented with butyrate and neutral red

Butanol production by Clostridium acetobutylicumATCC 824 using electro‐fermentation in culture medium supplemented with butyrate and neutral red

Progress in bioleaching: part B, applications of microbial processes by the minerals industries

Reversible Redox Chemistry in a Phenoxazine-Based Organic Compound: A Two-Electron Storage Negolyte for Alkaline Flow Batteries

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