Modelling of batch kinetics of aerobic carotenoid production using Saccharomyces cerevisiae

• Growth kinetics of genetically modified Saccharomyces cerevisiae were examined.
• Models were proposed to predict production of carotenoids and other metabolites.
• Local and global sensitivity were analyzed to determine quality of models.
• Models were able to accurately predict overflow metabolism of modified yeast strain.

Carotenes such as β-carotene have a positive impact in human health as a precursor of vitamin A. The structural complexity of these compounds makes chemical synthesis a difficult option, facilitating the need for their biological production. Reliable mathematical models for batch cultivation are developed to describe the glucose consumption, product formation and depletion, and β-carotene production of the Saccharomyces cerevisiae strain mutant SM14 with 20 g/L glucose as the carbon source. Parameter estimation for the models employ an objective function minimizing an expression that uses the coefficient of determination R2R2, which avoids the necessity of weighting or normalizing the equations. Comparison with experimental data shows that the developed models show a satisfactory prediction of the overflow metabolism that is happening in the cell. Additionally, local and global sensitivity analysis of the models with respect to the optimal parameters is also studied and further show that the models developed here accurately describe trends in the dynamic states of the bioreactor during batch fermentation.