Modeling metabolic overload effects in bacterial growth rate in synthetic biology

Modeling growth in bacterial cells is a major issue in systems and synthetic biology. Despite several growth rate functions are proposed in literature, most of them focus on nutrients composition, without explicitly counting for possible perturbation provided by the expression of recombinant genes, an effect called metabolic load or burden. In this work, some already published growth functions are evaluated, highlighting possible disagreements with the biological knowledge, which allow to reject some of them. Furthermore, some alternative functions based on biological evidences are proposed and tested as well, specifically oriented on metabolic load effects. The final aim is to identify a growth rate function that can be applied to models with different levels of complexity, leading to coherent results, which also account for the addition of metabolic burden, decoupled from nutrient composition.