From an extremophilic community to an electroautotrophic production strain: identifying a novel Knallgas bacterium as cathodic biofilm biocatalyst.

Bibliographic Details
Title: From an extremophilic community to an electroautotrophic production strain: identifying a novel Knallgas bacterium as cathodic biofilm biocatalyst.
Authors: Reiner, Johannes Eberhard, Geiger, Katharina, Hackbarth, Max, Fink, Marielle, Lapp, Christian Jonas, Jung, Tobias, Dötsch, Andreas, Hügler, Michael, Wagner, Michael, Hille-Reichel, Andrea, Wilcke, Wolfgang, Kerzenmacher, Sven, Horn, Harald, Gescher, Johannes
Source: ISME Journal: Multidisciplinary Journal of Microbial Ecology; May2020, Vol. 14 Issue 5, p1125-1140, 16p
Abstract: Coupling microbial electrosynthesis to renewable energy sources can provide a promising future technology for carbon dioxide conversion. However, this technology suffers from a limited number of suitable biocatalysts, resulting in a narrow product range. Here, we present the characterization of the first thermoacidophilic electroautotrophic community using chronoamperometric, metagenomic, and 13C-labeling analyses. The cathodic biofilm showed current consumption of up to −80 µA cm−2 over a period of 90 days (−350 mV vs. SHE). Metagenomic analyses identified members of the genera Moorella, Desulfofundulus, Thermodesulfitimonas, Sulfolobus, and Acidianus as potential primary producers of the biofilm, potentially thriving via an interspecies sulfur cycle. Hydrogenases seem to be key for cathodic electron uptake. An isolation campaign led to a pure culture of a Knallgas bacterium from this community. Growth of this organism on cathodes led to increasing reductive currents over time. Transcriptomic analyses revealed a distinct gene expression profile of cells grown at a cathode. Moreover, pressurizable flow cells combined with optical coherence tomography allowed an in situ observation of cathodic biofilm growth. Autotrophic growth was confirmed via isotope analysis. As a natural polyhydroxybutyrate (PHB) producer, this novel species, Kyrpidia spormannii, coupled the production of PHB to CO2 fixation on cathode surfaces. [ABSTRACT FROM AUTHOR]
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Database: Complementary Index
More Details
ISSN:17517362
DOI:10.1038/s41396-020-0595-5
Published in:ISME Journal: Multidisciplinary Journal of Microbial Ecology
Language:English