Experimental study and mathematical modeling of the pectinases production by Aspergillus flavipes FP-500 in an airlift bioreactor

Abstract

Mathematical models are indispensable for designing, optimizing, and controlling large-scale bioprocesses. In the present work, the production of pectinases was studied experimentally using an internal loop airlift bioreactor, pectin as a substrate, and Aspergillus flavipes FP-500 as a biocatalyst. The N-tanks-in-series (NTIS) model was implemented to predict the behavior of fungal growth, pectin and dissolved oxygen consumption, pectinases production, and the oxygen mass transfer rate from gas phase to liquid culture medium. A double Monod-Logistic kinetic model was used to describe the biomass growth rate as a function of biomass, pectin, and dissolved oxygen concentrations. In contrast, a Luedeking-Piret kinetic model was used to describe the production rate of endo and exo pectinases. A hydrodynamic model was utilized to estimate gas hold-ups, volumetric mass transfer coefficients, and air inflow velocities. Good agreement was observed between the experimental data and the theoretical results, demonstrating the predictive capacity of the NTIS model to describe pectinase production, the oxygen consumption rate, and the oxygen evolution in the gas phase. The model highlighted its robust capability to capture the critical parameters of aerobic fermentation processes. Therefore, it could be used as a tool for the scalability of the airlift bioreactors.