Production of 2-phenylethanol in hybrid system using airlift reactor and immersed hollow fiber membrane module

To minimize capital and operative costs in many bioproductions of chemical specialities, where the product inhibits the bioreaction, a hybrid system based on the application of membrane extraction integrated in the bioreactor to remove the product is a suitable solution. Integration can be done by an external module for membrane extraction or, as a more effective solution, by an extraction membrane module immersed directly in the bioreactor. In this second case, it is not necessary to use microfiltration to prevent membrane fouling or to use another pump for shell flow in the membrane module. Moreover, the system is very compact, highly effective, resistant to failures and its mathematic simulation is also possible. These statements are proved in this paper where a hybrid system consisting of an airlift reactor and immersed extraction hollow fiber membrane module was used for the biotransformation of l-phenylalanine to the desired rose-like aroma, 2-phenylethanol, by yeasts Saccharomyces cerevisiae. Two biotransformation experiments were carried out using different feeding and aeration strategies. In both experiments, high conversion of l-phenylalanine (up 100%) and high volumetric production of 2-phenylethanol (up 18.6 g L−1) were reached. Both biotransformation experiments were mathematically predicted with good agreement between experimental data and simulations.