Modeling of Esterase from "Saccharomyces cerevisiae" and Evaluation of the Antimicrobial Activities of the Enzyme Products

The main objective of this work was to study the activity of esterase extracted from “Saccharomyces cerevisiae” and to predict the steady-state performance of kinetics in terms of conversion by using a mathematical model. We have demonstrated that esterification catalyzed by esterase followed a kinetic model based on Michaelis- Menten behavior and the kinetic constants experimentally determined were: Vmaxapp= 0.52 mM min-1mg-1 and Kmapp= 2 mM. A lumped model based on the Michaelis-Menten approach showed the fate of the reactants in the system. The antibacterial effects of two esterase products (the menthyl acetate and the ethyl hexanoate) have been also investigated in this work. The activities tested against Gram+ and Gram- bacteria have demonstrated that these molecules have inhibited the visible growth of the majority of tested bacteria. The growth of all tested bacteria and the bacteria (Escherichia.coli, Salmonella typhimurium, Klebsiella pneumonia, Staphylococcus aureus and Staphylococcus epidermis) has been inhibited by the respective use of menthyl acetate and ethyl hexanoate. These products could have a significant therapeutic effect due to their antimicrobial activity. They could also have a potential use as additive in food industry because of their activity against two food poisonous bacteria: “Salmonella typhimurium” and “Staphylococcus aureus”.