Synthetic Crossfeeding Cocultures in Yeast: Computational Model of Autoregulation and Design of a Tryptophan Export Device

Figure 2

Dynamics of the crossfeeding model. Numerical simulation of a coculture seeded with cells/mL of each strain. and are and amino acids⋅cell⁻¹⋅hr⁻¹, respectively. See text for values of the model parameters. (a) Time evolution of the strains. Lag time was operationally defined as the time at which the line tangent to the inflexion point of the growth curve intersects the horizontal line of the basal level of the culture (grey dashed lines). (b) Amino acid concentrations. Horizontal dashed gray lines mark the values of and , respectively, and the vertical dashed line the lag time as defined in (a). (c) Growth lag time in hours as a function of relative (normalized to the experimental parameter , -axis) and initial cell populations (-axis). The dashed black lines are contour curves of value 0.1, 0.31, 1, 3.1, 10, 31, and 100 hours. The gray region corresponds to cultures with no growth after 300 hours. The thick black line is the boundary defined in the supplementary material. The black point represents the parameters used in (a) and (b).