Syngas fermentation studies with Clostridium ragsdalei for enhanced alcohol production

Luis Guilherme Sampaio de Oliveira, doctoral thesis Technical University of Munich, 2023

One goal of the syngas fermentation is the shift from acid to alcohol production. Continuously gassed batch processes with Clostridium ragsdalei  in a controlled stirred-tank bioreactor showed that lowering the pH to pH 5.5 as well as lowering the process temperature to 32 °C was beneficial for alcohol production (ethanol and 2,3-butandiol). The combination with an appropriate sulfide feed resulted in a substantial shift from acid to alcohol production, leading to an alcohol to acetate mass ratio of > 17.

Publications

• Oliveira L, Rückel A, Nordgauer L, Schlumprecht P, Hutter E, Weuster-Botz D (2022): Comparison of syngas-fermenting Clostridia in stirred-tank bioreactors and the effects of varying syngas impurities. Microorganisms 10: 681.
• Oliveira L, Röhrenbach S, Holzmüller V, Weuster-Botz D (2022): Continuous sulfide supply enhanced autotrophic production of alcohols with Clostridium ragsdalei. Bioresources Bioprocessing 9: 15.