What is the Role of Individual Species within Bidirectional Electroactive Microbial Biofilms: A Case Study on <i>Desulfarculus baarsii</i> and <i>Desulfurivibrio alkaliphilus</i>

Izadi, Paniz; Schröder, Uwe

doi:10.1002/celc.202101116

Cited by 12 publications

(3 citation statements)

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“…Notably, the direct electron transfer-based bi-directional EET is reported only for Geobacter sp., Shewanella sp. (Xie et al, 2021), and Desulfurivibrio alkaliphilus (Izadi and Schröder, 2022). Moreover, most bi-directional EET studies have been conducted in BESs with non-extreme microorganisms and with the electrode serving as either an electron donor or acceptor source and barely with natural insoluble electron donors and acceptors, such as Fe and Mn elemental and oxide forms (Jiang and Zeng, 2019;Xie et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

The bidirectional extracellular electron transfer process aids iron cycling by Geoalkalibacter halelectricus in a highly saline-alkaline condition

Yadav,

Sadhotra,

Patil

2023

Appl Environ Microbiol

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Bidirectional extracellular electron transfer (EET) is crucial to upholding microbial metabolism with insoluble electron acceptors or donors in anoxic environments. Investigating bidirectional EET-capable microorganisms is desired to understand the cell-cell and microbe-mineral interactions and their role in mineral cycling besides leveraging their energy generation and conversion, biosensing, and bio-battery applications. Here, we report on iron cycling by haloalkaliphilic Geoalkalibacter halelectricus via bidirectional EET under haloalkaline conditions. It efficiently reduces Fe 3+ oxide (Fe 2 O 3 ) to Fe 0 at a 0.75 ± 0.08 mM/mg protein /d rate linked to acetate oxidation via outward EET and oxidizes Fe 0 to Fe 3+ at a 0.24 ± 0.03 mM/mg protein /d rate via inward EET to reduce fumarate. Bioelectrochemical cultivation confirmed its outward and inward EET capabilities. It produced 895 ± 23 µA/cm 2 current by linking acetate oxidation to anode reduction via outward EET and reduced fumarate by drawing electrons from the cathode (‒2.5 ± 0.3 µA/cm 2 ) via inward EET. The cyclic voltammograms of G. halelectricu s biofilms revealed redox moieties with different formal potentials, suggesting the involvement of different membrane components in bidirectional EET. The cyclic voltammetry and GC-MS analysis of the cell-free spent medium revealed the lack of soluble redox mediators, suggesting direct electron transfer by G. halelecctricu s in achieving bidirectional EET. By reporting on the first haloalkaliphilic bacterium capable of oxidizing and reducing insoluble Fe 0 and Fe 3+ oxide, respectively, this study advances the limited understanding of the metabolic capabilities of extremophiles to respire on insoluble electron acceptors or donors via bidirectional EET and invokes the possible role of G. halelectricu s in iron cycling in barely studied haloalkaline environments. IMPORTANCE Bidirectional extracellular electron transfer (EET) appears to be a key microbial metabolic process in anoxic environments that are depleted in soluble electron donor and acceptor molecules. Though it is an ecologically important and applied microbial phenomenon, it has been reported with a few microorganisms, mostly from nonextreme environments. Moreover, direct electron transfer-based bidirectional EET is studied for very few microorganisms with electrodes in engineered systems and barely with the natural insoluble electron acceptor and donor molecules in anoxic conditions. This study advances the understanding of extremophilic microbial taxa capable of bidirectional EET and its role in barely investigated Fe cycling in highly saline-alkaline environments. It also offers research opportunities for understanding the membrane components involved in the bidirectional EET of G. halelectricus . The high rate of Fe 3+ oxide reduction activity by G. halelectricus suggests its possible use as a biocatalyst in the anaerobic iron bioleaching process under neutral-alkaline pH conditions.

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Section: Introductionmentioning

confidence: 99%

The bidirectional extracellular electron transfer process aids iron cycling by Geoalkalibacter halelectricus in a highly saline-alkaline condition

Yadav,

Sadhotra,

Patil

2023

Appl Environ Microbiol

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“…Not much is known about the electrochemical activity of isolated species. Only Desulfurivibrio alkaliphillus has been shown to be electrochemically active in pure culture 27 . However, many of the occurring species have been detected in electrochemically active biofilms or planktonic cultures, such as Thioalkalivibrio sulfidophilus , Acholeplasma sp.…”

Section: Resultsmentioning

confidence: 99%

“…Only Desulfurivibrio alkaliphillus has been shown to be electrochemically active in pure culture. 27 However, many of the occurring species have been detected in electrochemically active biofilms or planktonic cultures, such as Thioalkalivibrio sulfidophilus, Acholeplasma sp. and Bacteroidales GZKB119 15,20,[28][29][30] (Table 3).…”

Section: Biomass Composition Of Sulphide Shuttling Communitiesmentioning

confidence: 99%

Electric discharge by sulphide shuttling bacteria

Linssen,

ter Heijne

2023

J of Chemical Tech & Biotech

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BACKGROUNDIn biodesulphurisation processes, sulphide oxidising bacteria (SOB) convert toxic sulphide to sulphur. Haloalkalophilic SOB are known to anaerobically remove sulphide from solution and release electrons when subsequently exposed to an electrode. This makes SOB able to spatially decouple sulphide removal and current production, thereby acting as sulphide shuttles. Little is known about the kinetics of electron release by sulphide shuttling SOB. To gain more insight into the sulphide shuttling mechanism and electron release, current production of abiotic sulphide and sulphide shuttling SOB was compared.RESULTSSOB communities dominated by Thioalkalivibrio sulfidophilus were incubated with sulphide in batch experiments. After sulphide was removed, SOB were discharged in an electrochemical cell. Anode potential, sulphide load and biomass concentration were varied. Current was produced at potentials of −0.2 V versus Ag/AgCl and higher, and at a potential of 0.1 V a coulombic efficiency of 70% was reached in 30 min. The maximum charge recovered from biologically stored sulphide was 4900 ± 810 mC mgN−1. Discharge kinetics were not affected by biomass concentration or degree of sulphide removal and kinetics of biotic and abiotic current production were similar.CONCLUSIONCurrent production of sulphide shuttling SOB and abiotic sulphide was highly similar. This implies that sulphide shuttling is based on sorption to the biomass, and that shuttled sulphide converts to sulphur directly at the electrode surface. Therefore, the sulphide shuttling strategy is not sufficient to prevent electrode passivation, and different strategies need to be applied in the design of a sulphur‐producing bioelectrochemical desulphurisation process. © 2023 Society of Chemical Industry.

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Desulfurivibrionaceae

Sorokin,

Merkel

2023

Bergey's Manual of Systematics of Archaea and Bacteria

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De.sul.fu.ri.vi.bri.o.na.ce'ae. N.L. masc. n. Desulfurivibrio , type genus of the family; L. fem. pl. n. suff. ‐aceae , ending to denote a family; N.L. fem. pl. n. Desulfurivibrionaceae , the family of the genus Desulfurivibrio . Thermodesulfobacteria / Desulfobulbia / Desulfobulbales / Desulfurivibrionaceae The family Desulfurivibrionaceae includes obligately anaerobic, moderately salt‐tolerant, and obligately alkaliphilic chemolithoautotrophic bacteria with a unique energy metabolism consisting of elemental sulfur disproportionation. H 2 or formate can also serve as additional electron donors for sulfur reduction, while nitrate can be ammonified with either sulfide or formate as the electron donors. The cultured representatives are found exclusively in saline soda lakes. The family consists of a single genus Desulfurivibrio with the type species D. alkaliphilus and a second yet undescribed species “ D. dismutans .” DNA G + C content (mol%) : 60.0–60.3 (whole‐genome sequences). Type genus : Desulfurivibrio Sorokin et al. 2008, VL123.

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What is the Role of Individual Species within Bidirectional Electroactive Microbial Biofilms: A Case Study on Desulfarculus baarsii and Desulfurivibrio alkaliphilus

Cited by 12 publications

References 34 publications

The bidirectional extracellular electron transfer process aids iron cycling by Geoalkalibacter halelectricus in a highly saline-alkaline condition

The bidirectional extracellular electron transfer process aids iron cycling by Geoalkalibacter halelectricus in a highly saline-alkaline condition

Electric discharge by sulphide shuttling bacteria

Desulfurivibrionaceae

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