Fig. 3. Dynamic control of population composition in a microbial consortium.

a Setup for two reactor control. Cells harbouring the original differentiation system were continuously cultured at fixed but different cell densities in two reactors simultaneously. The first reactor was kept in the dark as a reservoir of non-differentiated cells. The output of this vessel was connected to the second ‘control’ reactor. The control culture was set to a target level of differentiation and continuously monitored via automated flow cytometry measurements that were analysed online. The system state was estimated from analysed data and sent to the model predictive control (MPC) module. The MPC module provided an optimized light sequence to maintain the culture at the desired set point (Supplementary Note 5). b Control of consortium composition. Cultures were targeted to 10–80% differentiation. Control started at t = 0. Circles signify differentiated fractions. Each colour corresponds to a different control experiment and the dashed line reflects the target set point. Note that the figure is composed of independent experiments of different lengths. Data were removed when the OD, either in the reservoir or the control reactor, could not be maintained at the desired target. Light signals are provided in Supplementary Fig. 17. c Bidirectional control of consortium composition. Cultures were targeted to 40 and 80% differentiation. Data are represented as in (b). The target was changed at t = 60 h to 80% and 40%, respectively.