Modelagem e simulação da produção de hidromel em biorreator em batelada utilizando a levedura Saccharomyces Cerevisiae.

Abstract

Mead is an alcoholic beverage obtained from fermentation, using honey as substrate. In these processes, knowledge of kinetics is of great importance, for the understanding of cell growth rates, substrate consumption and product generation. The kinetic parameters associated with modeling and experimental planning allow simulations to be performed and the best operating conditions are determined. Therefore, the present work aimed to obtain a mathematical model that could represent the kinetic behavior in the production of mead, in batch and applying the yeast Saccharomyces cerevisiae. The objective was also to perform the simulation for different initial concentrations of cells and substrate, aiming at the achievement of optimal conditions. A mathematical model was applied, unstructured and unsegregated, starting from a mass balance for each species present in the bioreactor, and a set of differential equations was generated that was solved using polymath® software. After adjusting the model to the studied data, the simulation was performed using the central composite planning to define the initial operating conditions. Among the models tested for cell growth, Levenspiel presented better fit in relation to substrate and product concentrations, and kinetic parameters used cell yields per substrate, YC/S = 0.0087 g/g, and product per substrate, YP/S = 0.44 g/g, maximum specific growth speed, μ max = 0.00153 h-1, and Monod constant, Ks = 165 g.L-1. After the simulation, it was found that the highest substrate conversion, 95.78%, and the highest yield in product, 74.46%, were achieved when starting the process with 2.4 g.L-1 of cells and 90 g.L-1 of substrate. Thus, it is concluded that the applied model made it possible to evaluate the substrate and product concentrations, making it possible to define which initial conditions can produce better results in product generation and substrate consumption, avoiding raw material waste and higher yield, within the specifications contained in the current beverage standard.