Hydrogen is a key intermediate element in microbial electrosynthesis as a mediator of the reduction of carbon dioxide (CO) into added value compounds. In the present work we aimed at studying the biological production of hydrogen in biocathodes operated at - 1.0 V vs. Ag/AgCl, using a highly comparable technology and CO as carbon feedstock. Ten bacterial strains were chosen from genera Rhodobacter, Rhodopseudomonas, Rhodocyclus, Desulfovibrio and Sporomusa, all described as hydrogen producing candidates. Monospecific biofilms were formed on carbon cloth cathodes and hydrogen evolution was constantly monitored using a microsensor. Eight over ten bacteria strains showed electroactivity and H production rates increased significantly (two to eightfold) compared to abiotic conditions for two of them (Desulfovibrio paquesii and Desulfovibrio desulfuricans). D. paquesii DSM 16681 exhibited the highest production rate (45.6 ± 18.8 µM min) compared to abiotic conditions (5.5 ± 0.6 µM min), although specific production rates (per 16S rRNA copy) were similar to those obtained for other strains. This study demonstrated that many microorganisms are suspected to participate in net hydrogen production but inherent differences among strains do occur, which are relevant for future developments of resilient biofilm coated cathodes as a stable hydrogen production platform in microbial electrosynthesis.
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http://dx.doi.org/10.1038/s41598-020-76694-y | DOI Listing |
Nat Commun
December 2024
Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China.
The emergence of single-atom catalysts offers exciting prospects for the green production of hydrogen peroxide; however, their optimal local structure and the underlying structure-activity relationships remain unclear. Here we show trace Fe, up to 278 mg/kg and derived from microbial protein, serve as precursors to synthesize a variety of Fe single-atom catalysts containing FeNO (1 ≤ x ≤ 4) moieties through controlled pyrolysis. These moieties resemble the structural features of nonheme Fe-dependent enzymes while being effectively confined on a microbe-derived, electrically conductive carbon support, enabling high-current density electrolysis.
View Article and Find Full Text PDFBiotechnol Bioeng
December 2024
Department of Biological and Chemical Engineering, Aarhus University, Aarhus, Denmark.
Acetogenic bacteria play an important role in various biotechnological processes, because of their chemolithoautotrophic metabolism converting carbon dioxide with molecular hydrogen (H) as electron donor into acetate. As the main factor limiting acetogenesis is often H, insights into the H consumption kinetics of acetogens are required to assess their potential in biotechnological processes. In this study, initial H consumption rates at a range of different initial H concentrations were measured for three different acetogens.
View Article and Find Full Text PDFJ Ind Microbiol Biotechnol
December 2024
Department of Biology, Washington University in St. Louis, St. Louis, MO, USA.
In this review, we focus on how purple non sulfur bacteria (PNSB) can be leveraged for sustainable bioproduction to support the circular economy (CE). We discuss the state of the field with respect to the use of purple bacteria for energy production, their role in wastewater treatment, as a fertilizer, and as a chassis for bioplastic production. We explore their ability to serve as single cell protein and production platforms for fine chemicals from waste materials.
View Article and Find Full Text PDFFoods
November 2024
College of Food Science and Engineering, Qingdao Agricultural University, Qingdao 266109, China.
Utilizing (), this study constructed a dual-chamber microbial electrosynthesis system, based on microbial electrolysis cells, that was capable of producing lycopene. Cultivation within the electrosynthesis chamber yielded a lycopene concentration of 282.3722 mg/L when the optical density (OD) reached 0.
View Article and Find Full Text PDFTrends Biotechnol
December 2024
Institute of Technical Microbiology, Hamburg University of Technology (TUHH), Kasernenstraße 12 (F), 21073 Hamburg, Germany. Electronic address:
Autotrophic microbial electrosynthesis (MES) processes are mainly based on organisms that rely on carbon dioxide (CO) as an electron acceptor and typically have low biomass yields. However, there are few data on the process and efficiencies of oxic MES (OMES). In this study, we used the knallgas bacterium Kyrpidia spormannii to investigate biomass formation and energy efficiency of cathode-dependent growth.
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