Revealing formate production from carbon monoxide in wild type and mutants of Rnf‐ and Ech‐containing acetogens, Acetobacterium woodii and Thermoanaerobacter kivui

  • Acetogenic bacteria have gained much attraction in recent years as they can produce different biofuels and biochemicals from H2 plus CO2 or even CO alone, therefore opening a promising alternative route for the production of biofuels from renewable sources compared to existing sugar‐based routes. However, CO metabolism still raises questions concerning the biochemistry and bioenergetics in many acetogens. In this study, we focused on the two acetogenic bacteria Acetobacterium woodii and Thermoanaerobacter kivui which, so far, are the only identified acetogens harbouring a H2‐dependent CO2 reductase and furthermore belong to different classes of ‘Rnf’‐ and ‘Ech‐acetogens’. Both strains catalysed the conversion of CO into the bulk chemical acetate and formate. Formate production was stimulated by uncoupling the energy metabolism from the Wood–Ljungdahl pathway, and specific rates of 1.44 and 1.34 mmol g−1 h−1 for A. woodii ∆rnf and T. kivui wild type were reached. The demonstrated CO‐based formate production rates are, to the best of our knowledge, among the highest rates ever reported. Using mutants of ∆hdcr, ∆cooS, ∆hydBA, ∆rnf and ∆ech2 with deficiencies in key enzyme activities of the central metabolism enabled us to postulate two different CO utilization pathways in these two model organisms.

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Author:Fabian M. SchwarzGND, Sarah Ciurus, Surbhi JainORCiDGND, Christoph Baum, Anja WiechmannORCiD, Mirko BasenORCiD, Volker MüllerORCiD
Pubmed Id:
Parent Title (German):Microbial biotechnology
Place of publication:Oxford
Document Type:Article
Date of Publication (online):2020/09/21
Date of first Publication:2020/09/21
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2020/12/09
Page Number:13
First Page:2044
Last Page:2056
Institutes:Biowissenschaften / Biowissenschaften
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 57 Biowissenschaften; Biologie / 570 Biowissenschaften; Biologie
Licence (German):License LogoCreative Commons - Namensnennung 4.0