Intensification of 2-phenylethanol production in fed-batch hybrid bioreactor: Biotransformations and simulations

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2-Phenylethanol is a well-known rose-like aroma widely applied in the cosmetic, perfume and food industries. It can be produced by microbial bioconversion of L-phenylalanine to 2-phenylethanol using Saccharomyces cerevisiae. This biotransformation is connected with the growth of biomass and is strongly limited by product inhibition which allows reaching the maximum concentration of 2-phenylethanol, 4gL−1, in an ordinary batch, fed-batch or chemostat bioreactor. The main aim of the presented work is to study the possible yield increase of 2-phenylethanol using membrane separation techniques such as microfiltration and membrane extraction interconnected with the bioreactor in one hybrid system, which was used to remove 2-phenylethanol from the fermentation medium and thus to overcome the inhibition of biotransformation. In this paper, mathematical model of such a hybrid system is presented. Two fed-batch biotransformations with product removal were carried out at different conditions and they provided higher efficiency of the hybrid system over the classical 2-phenylethanol production. Biotransformation performed in an air-lift reactor was compared with the predictions of the mathematical model with quite good accuracy of the simulated and experimental data. Finally, a sensitivity study of the membrane extraction efficiency in hybrid system under different operation conditions was carried out.