Use of flow cytometry for growth structured kinetic model development: Application to Candida bombicola growth

Flow cytometry (FC) has been used for the measurement of intracellular compound contents, such as nucleic acids, proteins and lipids, during the growth of Candida bombicola, yeast able to synthesise sophorolipids, molecules with important tensioactive properties. For obtaining quantitative results, FC measurements must be calibrated with other technique. In this work, spectrofluorymetry (SFM) has been used for calibration of nucleic acids (NAs) and proteins (IP) and spectrophotometry/UV (SPM) for calibration of intracellular triglycerides (TGs). According to the experimental measurements of the compounds quoted above, biomass growth can be described as production rates of those intracellular compounds (NA, IP and TG). Structured kinetic models can be formulated with these data, following two main steps: first, a simplified reaction scheme (or the simplified metabolic pathway) must be proposed, according to the experimental data of production rates of intracellular compounds; second, kinetic equations for each one of the reactions involved in the reaction scheme must also be proposed. For this complex task, FC becomes a very useful technique, as shown in this work. The experimental results can be well described according to this kinetic model type. In this case, experimental results of C. bombicola growth are very well-fitted by the kinetic model proposed.