Synthetic Biofilm Reactor with Independent Supply of Gas and Liquid Phase for Studying Chain Elongation with Immobilized <i>Clostridium kluyveri</i> at Defined Reaction Conditions
In this study, we explore the use of <i>C. kluyveri</i> in synthetic biofilms for the production of 1-butyrate and 1-hexanoate, investigating the impact of inoculation temperature during biofilm formation and the presence of yeast extract. Therefore, a novel synthetic biofilm reactor has...
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2025-04-01
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| Series: | Fermentation |
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| author | Josha Herzog Karlis Blums Simon Gregg Lukas Gröninger Johannes Poppe Verena Uhlig Qifei Wang Dirk Weuster-Botz |
| author_facet | Josha Herzog Karlis Blums Simon Gregg Lukas Gröninger Johannes Poppe Verena Uhlig Qifei Wang Dirk Weuster-Botz |
| author_sort | Josha Herzog |
| collection | DOAJ |
| description | In this study, we explore the use of <i>C. kluyveri</i> in synthetic biofilms for the production of 1-butyrate and 1-hexanoate, investigating the impact of inoculation temperature during biofilm formation and the presence of yeast extract. Therefore, a novel synthetic biofilm reactor has been designed and constructed. Prior to investigating synthetic biofilms in this reactor, we carried out preliminary batch experiments in anaerobic flasks containing an inoculated agar hydrogel fixed at the bottom and overlaid medium. For the operation of the novel synthetic biofilm reactor, specific volumes of inoculated agar hydrogel were dispensed into a cylindrical mold with a diameter of 102 mm, forming the synthetic biofilm with a height of 4 mm, which was then transferred into the biofilm reaction chamber onto the support grid. The biofilm support grid separates the gas phase (CO<sub>2</sub>, N<sub>2</sub>) above the synthetic biofilm from the aqueous phase (medium) below. Our results show that <i>C. kluyveri</i> remains metabolically active at biofilm preparation temperatures of up to 45 °C, with extended lag phases observed at 70 °C. The synthetic biofilm demonstrated efficient chain elongation in batch processes, converting ethanol and acetate into 1-butyrate and 1-hexanoate, with final concentrations of 2.7 g L<sup>−1</sup> and 10.1 g L<sup>−1</sup>, respectively, with yeast extract in the circulating liquid medium of the synthetic biofilm reactor setup. The maximum estimated space-time yields for 1-butyrate and 1-hexanoate, referenced to the biofilm volume, were 1.331 g L<sup>−1</sup> h<sup>−1</sup> and 4.947 g L<sup>−1</sup> h<sup>−1</sup>, respectively. Experiments without yeast extract lead to final concentrations of 2.0 g L<sup>−1</sup> 1-butyrate, and 7.3 g L<sup>−1</sup> 1-hexanoate and maximum estimated space-time yields, referenced to the biofilm volume, were 0.332 g L<sup>−1</sup> h<sup>−1</sup> and 1.123 g L<sup>−1</sup> h<sup>−1</sup>, respectively. The use of synthetic biofilms, even without yeast extract, eliminates the need for significant cell growth during chain elongation. However, product concentrations were lower without yeast extract. |
| format | Article |
| id | doaj-art-ddd58b78db42407bac947987bd2f3f33 |
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| language | English |
| publishDate | 2025-04-01 |
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| spelling | doaj-art-ddd58b78db42407bac947987bd2f3f332025-08-20T02:17:24ZengMDPI AGFermentation2311-56372025-04-0111420010.3390/fermentation11040200Synthetic Biofilm Reactor with Independent Supply of Gas and Liquid Phase for Studying Chain Elongation with Immobilized <i>Clostridium kluyveri</i> at Defined Reaction ConditionsJosha Herzog0Karlis Blums1Simon Gregg2Lukas Gröninger3Johannes Poppe4Verena Uhlig5Qifei Wang6Dirk Weuster-Botz7Chair of Biochemical Engineering, TUM School of Engineering and Design, Technical University of Munich, Boltzmannstraße 15, D-85748 Garching, GermanyChair of Biochemical Engineering, TUM School of Engineering and Design, Technical University of Munich, Boltzmannstraße 15, D-85748 Garching, GermanyChair of Biochemical Engineering, TUM School of Engineering and Design, Technical University of Munich, Boltzmannstraße 15, D-85748 Garching, GermanyChair of Biochemical Engineering, TUM School of Engineering and Design, Technical University of Munich, Boltzmannstraße 15, D-85748 Garching, GermanyChair of Biochemical Engineering, TUM School of Engineering and Design, Technical University of Munich, Boltzmannstraße 15, D-85748 Garching, GermanyChair of Biochemical Engineering, TUM School of Engineering and Design, Technical University of Munich, Boltzmannstraße 15, D-85748 Garching, GermanyChair of Biochemical Engineering, TUM School of Engineering and Design, Technical University of Munich, Boltzmannstraße 15, D-85748 Garching, GermanyChair of Biochemical Engineering, TUM School of Engineering and Design, Technical University of Munich, Boltzmannstraße 15, D-85748 Garching, GermanyIn this study, we explore the use of <i>C. kluyveri</i> in synthetic biofilms for the production of 1-butyrate and 1-hexanoate, investigating the impact of inoculation temperature during biofilm formation and the presence of yeast extract. Therefore, a novel synthetic biofilm reactor has been designed and constructed. Prior to investigating synthetic biofilms in this reactor, we carried out preliminary batch experiments in anaerobic flasks containing an inoculated agar hydrogel fixed at the bottom and overlaid medium. For the operation of the novel synthetic biofilm reactor, specific volumes of inoculated agar hydrogel were dispensed into a cylindrical mold with a diameter of 102 mm, forming the synthetic biofilm with a height of 4 mm, which was then transferred into the biofilm reaction chamber onto the support grid. The biofilm support grid separates the gas phase (CO<sub>2</sub>, N<sub>2</sub>) above the synthetic biofilm from the aqueous phase (medium) below. Our results show that <i>C. kluyveri</i> remains metabolically active at biofilm preparation temperatures of up to 45 °C, with extended lag phases observed at 70 °C. The synthetic biofilm demonstrated efficient chain elongation in batch processes, converting ethanol and acetate into 1-butyrate and 1-hexanoate, with final concentrations of 2.7 g L<sup>−1</sup> and 10.1 g L<sup>−1</sup>, respectively, with yeast extract in the circulating liquid medium of the synthetic biofilm reactor setup. The maximum estimated space-time yields for 1-butyrate and 1-hexanoate, referenced to the biofilm volume, were 1.331 g L<sup>−1</sup> h<sup>−1</sup> and 4.947 g L<sup>−1</sup> h<sup>−1</sup>, respectively. Experiments without yeast extract lead to final concentrations of 2.0 g L<sup>−1</sup> 1-butyrate, and 7.3 g L<sup>−1</sup> 1-hexanoate and maximum estimated space-time yields, referenced to the biofilm volume, were 0.332 g L<sup>−1</sup> h<sup>−1</sup> and 1.123 g L<sup>−1</sup> h<sup>−1</sup>, respectively. The use of synthetic biofilms, even without yeast extract, eliminates the need for significant cell growth during chain elongation. However, product concentrations were lower without yeast extract.https://www.mdpi.com/2311-5637/11/4/200anaerobic<i>Clostridia</i>immobilizationagar hydrogelbiofilm reactorsynthetic biofilm |
| spellingShingle | Josha Herzog Karlis Blums Simon Gregg Lukas Gröninger Johannes Poppe Verena Uhlig Qifei Wang Dirk Weuster-Botz Synthetic Biofilm Reactor with Independent Supply of Gas and Liquid Phase for Studying Chain Elongation with Immobilized <i>Clostridium kluyveri</i> at Defined Reaction Conditions Fermentation anaerobic <i>Clostridia</i> immobilization agar hydrogel biofilm reactor synthetic biofilm |
| title | Synthetic Biofilm Reactor with Independent Supply of Gas and Liquid Phase for Studying Chain Elongation with Immobilized <i>Clostridium kluyveri</i> at Defined Reaction Conditions |
| title_full | Synthetic Biofilm Reactor with Independent Supply of Gas and Liquid Phase for Studying Chain Elongation with Immobilized <i>Clostridium kluyveri</i> at Defined Reaction Conditions |
| title_fullStr | Synthetic Biofilm Reactor with Independent Supply of Gas and Liquid Phase for Studying Chain Elongation with Immobilized <i>Clostridium kluyveri</i> at Defined Reaction Conditions |
| title_full_unstemmed | Synthetic Biofilm Reactor with Independent Supply of Gas and Liquid Phase for Studying Chain Elongation with Immobilized <i>Clostridium kluyveri</i> at Defined Reaction Conditions |
| title_short | Synthetic Biofilm Reactor with Independent Supply of Gas and Liquid Phase for Studying Chain Elongation with Immobilized <i>Clostridium kluyveri</i> at Defined Reaction Conditions |
| title_sort | synthetic biofilm reactor with independent supply of gas and liquid phase for studying chain elongation with immobilized i clostridium kluyveri i at defined reaction conditions |
| topic | anaerobic <i>Clostridia</i> immobilization agar hydrogel biofilm reactor synthetic biofilm |
| url | https://www.mdpi.com/2311-5637/11/4/200 |
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