Kinetic model of Clostridium beijerinckii's Acetone-Butanol-Ethanol fermentation considering metabolically diverse cell types

• Published in: Journal of biotechnology 2021-12, Vol.342, p.1-12
• Main Authors: Rivas-Astroza, Marcelo, Paredes, Iván, Guerrero, Karlo, Mau, Silvia, Quintero, Julián, Gentina, Juan Carlos, Conejeros, Raúl, Aroca, Germán
• Format: Article
• Language: English
• Subjects: ABE fermentation; Clostridium beijerinckii; Fermentation modelling; Flux balance analysis
• ISSN: 0168-1656; 1873-4863
• DOI: 10.1016/j.jbiotec.2021.09.021

Clostridium beijerinckii population branches into metabolically diverse cell types in batch cultures. Here, we present a new kinetic model of C. beijerinckii’s Acetone-Butanol-Ethanol fermentation that considers three cell types: producers of acids (acidogenic), consumer of acids and producers of solvents (solventogenic), and spores cells. The model accurately recapitulates batch culture data. Also, the model estimates cell type-specific kinetic parameters, which can be helpful to improve the operation of the ABE fermentation and give a framework to study acidogenic and solventogenic metabolic pathways. To exemplify the latter, we used a constraint-based model to study how the ABE pathways are used among acidogenic and solventogenic cell types. We found that among both cell types, glycolytic production of ATP and consumption of NAD+ varies widely during the fermentation, with their maximum production/consumption rates happening when acidogenic and solventogenic growth rates were at their highest. However, acidogenic cells use the ABE pathway to contribute with an extra 12.5% of the total production of ATP, whereas solventogenic cell types use the ABE pathway to supply more than 75% of the demand for NAD+, alternating between the production of lactate and butyrate, being both coupled to the production of NAD+. •A novel kinetic model of ABE fermentation that considers various cell types.•The model simulates complex temporal trends of acids and solvents in ABE fermentation.•This approach combines experimental measurements with in silico metabolic and kinetic modeling.•Estimation of cell type-specific exchange rates allows studying how glycolytic production of ATP and consumption of NAD+ vary during fermentation.