Metabolomic and kinetic investigations on the electricity-aided production of butanol by Clostridium pasteurianum strains

Engineering in Life Sciences published by Wiley-VCH GmbH In this contribution, we studied the effect of electro-fermentation on the butanol production of Clostridium pasteurianum strains by a targeted metabolomics approach. Two strains were examined: an electrocompetent wild type strain (R525) and a mutant strain (dhaB mutant) lacking formation of 1,3-propanediol (PDO). The dhaB-negative strain was able to grow on glycerol without formation of PDO, but displayed a high initial intracellular NADH/NAD ratio which was lowered subsequently by upregulation of the butanol production pathway. Both strains showed a 3–5 fold increase of the intracellular NADH/NAD ratio when exposed to cathodic current in a bioelectrochemical system (BES). This drove an activation of the butanol pathway and resulted in a higher molar butanol to PDO ratio for the R525 strain. Nonetheless, macroscopic electron balances suggest that no significant amount of electrons derived from the BES was harvested by the cells. Overall, this work points out that electro-fermentation can be used to trigger metabolic pathways and improve product formation, even when the used microbe cannot be considered electroactive. Accordingly, further studies are required to unveil the underlying (regulatory) mechanisms.

Schlagworte

BES

butanol production

Clostridium pasteurianum

electro-fermentation

redox metabolism

DDC Class

570: Biowissenschaften, Biologie

Projekt(e)

Publikationsfonds 2020

Publikationsfonds 2021

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Metabolomic and kinetic investigations on the electricity-aided production of butanol by Clostridium pasteurianum strains