title: In silico analysis of Clostridium acetobutylicum ATCC 824 metabolic response to an external electron supply.
abstract: The biological production of butanol has become an important research field and thanks to genome sequencing and annotation; genome-scale metabolic reconstructions have been developed for several Clostridium species. This work makes use of the iCAC490 model of Clostridium acetobutylicum ATCC 824 to analyze its metabolic capabilities and response to an external electron supply through a constraint-based approach using the Constraint-Based Reconstruction Analysis Toolbox. Several analyses were conducted, which included sensitivity, production envelope, and phenotypic phase planes. The model showed that the use of an external electron supply, which acts as co-reducing agent along with glucose-derived reducing power (electrofermentation), results in an increase in the butanol-specific productivity. However, a proportional increase in the butyrate uptake flux is required. Besides, the uptake of external butyrate leads to the coupling of butanol production and growth, which coincides with results reported in literature. Phenotypic phase planes showed that the reducing capacity becomes more limiting for growth at high butyrate uptake fluxes. An electron uptake flux allows the metabolism to reach the growth optimality line. Although the maximum butanol flux does not coincide with the growth optimality line, a butyrate uptake combined with an electron uptake flux would result in an increased butanol volumetric productivity, being a potential strategy to optimize the production of butanol by C. acetobutylicum ATCC 824.
authors.affiliation: Escuela de Ingeniería Bioquímica, Pontificia Universidad Católica de Valparaíso, Av. Brasil, 2085, Valparaíso, Chile.
authors.forename: Roberto
authors.initials: R
authors.lastname: Gallardo
authors.affiliation: Escuela de Ingeniería Bioquímica, Pontificia Universidad Católica de Valparaíso, Av. Brasil, 2085, Valparaíso, Chile.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Acevedo
authors.affiliation: Escuela de Ingeniería Bioquímica, Pontificia Universidad Católica de Valparaíso, Av. Brasil, 2085, Valparaíso, Chile.
authors.forename: Julián
authors.initials: J
authors.lastname: Quintero
authors.affiliation: Escuela de Ingeniería Bioquímica, Pontificia Universidad Católica de Valparaíso, Av. Brasil, 2085, Valparaíso, Chile.
authors.forename: Ivan
authors.initials: I
authors.lastname: Paredes
authors.affiliation: Escuela de Ingeniería Bioquímica, Pontificia Universidad Católica de Valparaíso, Av. Brasil, 2085, Valparaíso, Chile.
authors.forename: Raúl
authors.initials: R
authors.lastname: Conejeros
authors.affiliation: Escuela de Ingeniería Bioquímica, Pontificia Universidad Católica de Valparaíso, Av. Brasil, 2085, Valparaíso, Chile. german.aroca@pucv.cl.
authors.forename: Germán
authors.initials: G
authors.lastname: Aroca
mesh_terms: D046969:Clostridium acetobutylicum / Q000378:metabolism*; D003198:Computer Simulation; D004583:Electrons; D008954:Models, Biological
keywords: Available reducing capacity; Butanol; Clostridium acetobutylicum; Electron supply; Flux balance analysis