Process maps with metabolic constraints for bioethanol production by continuous fermentation

This paper presents a method of preparing process maps for the bioethanol production process by con-tinuous fermentation. The proposed method of process map construction is based on the nonlinear analysis of bioreactor steady states and the metabolic interpretation method of the steady state branches. The nonlinear analysis of bioreactor steady states was performed relative to the dilution rate and the mass recirculation coefficient. It revealed the presence of nonlinear phenomena in the system, such as Hopf bifurcation points and limit points. The use of the qualitative interpretation method of bifurcation diagrams allowed the detection of metabolic change points and multiple steady state areas in which the metabolic activity of biomass cells undergoes changes. Taking this information into account together with the determined gradient profile of bioethanol concentrations has made it possible to construct a process map with metabolic constraints. (c) 2020 Elsevier Ltd. All rights reserved.