Kinetic Modeling for Cellulosic Butanol Production Based on Multi-Omics Analysis

Butanol has a higher energy density and lower volatility than gasoline and is similarly compatible with existing energy infrastructure. Furthermore, butanol can be produced using a Clostridium cellulovorans biomass conversion platform. This study utilized a platform overexpressing heterologous acetaldehyde/alcohol dehydrogenase (adhE2) gene allowing for cellulose to butanol conversion. Using this platform, we have previously produced butanol with >3 g/L, a yield of >0.14 g/g, and a selectivity of >3 g/g from corn residues. To achieve a high butanol production, this study integrated fermentation data and the multi-Omics experimental data through two types of mathematic model. A static model based on end product yields was created to simulate flux balance analysis of carbon using fermentation data. A dynamic model was created to additionally incorporate intracellular metabolite concentrations to correct for fermentation end product yields. Resultantly, the dynamic model successfully simulated the intracellular metabolite fluctuation from pyruvate to butanol. Important results included carbon flux distribution reduction from C2 to C4 in the mutant with cellulose substrate. Key regulators for metabolic engineering were evaluated and strategies for improved butanol production were proposed.