Analysis of reaction kinetics during chemostat cultivation of Saccharomyces cerevisiae using a multiphase microreactor

• Aerobic yeast chemostat cultivation was studied in multiphase microbioreactor.
• Reaction kinetics was analysed using stationary balance equations.
• Yield coefficients were determined from plots of qS and qP = f(D).
• Kinetic reaction model was in good agreement with microscale experimental data.
• Micro- and macroscale data were of the same order (differing by factor of 50,000).

This paper presents the determination of reaction kinetic parameters and the kinetic analysis of a chemostat cultivation performed using a multiphase microreactor (mMR). Saccharomyces cerevisiae was cultivated aerobically in continuous chemostat mode using an mMR. Steady-state biomass, substrate and ethanol concentrations were determined at dilution rates between 0.14 ≤ D ≤ 0.42 h−1 with a glucose-feed concentration of 10 g L−1. Modelling the aerobic chemostat culture was based on stationary balance equations. Maximal specific growth rate and Monod constant were determined using different linearization methods. The aerobic yeast metabolism was considered using two validity ranges of the model: (a) with purely oxidative metabolism in which glucose was converted into biomass or was used for maintenance metabolism, and no ethanol was generated; (b) with oxido-reductive metabolism employing an active Crabtree effect, in which ethanol was generated at the expense of biomass production. The different yield coefficients could be determined using the plots of the specific substrate consumption rate qS = f(D) and the specific product formation rate qP = f(D), respectively. Using this model, the reaction kinetic parameters were determined from the stationary concentrations of the biomass, glucose and ethanol that were determined during aerobic cultivation in the mMR. Finally, the kinetic parameters were compared with those reported in the literature that had been obtained using laboratory-scale reactors.