Theoretical and Experimental Studies of Enzyme- Catalyzed Isoamyl Acetate Synthesis with Ionic Liquid at the Microreactor Scale P. Žnidaršič-Plazl, A. Pohar, I. Plazl University of Ljubljana, Faculty of Chemistry and Chemical Technology Aškerčeva 5, SI-1000 Ljubljana, Slovenia igor.plazl@fkkt.uni-lj.si In this work, a lipase-catalyzed synthesis of isoamyl acetate, which is one of the most employed flavours in food industry, was studied in a microreactor. Synthesis of isoamyl acetate from acetic anhydride and isoamyl alcohol, and simultaneous extraction in organic phase was performed in microreactors of different geometries using 1-Butyl-3- methylpyridinium dicyanamide/n-heptane two-phase system. Experimental data, obtained at different process conditions have demonstrated good esterification yields in the chosen system. 1. Introduction Enzymatic production of esters used in food, cosmetic and pharmaceutical industry is of high importance since such products can be labeled as “natural”. Isoamyl acetate is one of the most employed esters used in food, cosmetic and pharmaceutical industries due to its characteristic banana flavour. Lipases (EC 3.1.1.3.) of different origin, which can catalyze hydrolysis in aqueous environment, as well as esterifications in organic solvents, are generally employed in the production of flavours and fragrances (Krings and Berger, 1998, Hasan et al., 2006). Ionic liquids (ILs) have received an increased attention as "green" solvents for organic synthesis in general and catalytic processes in particular. Recently, the use of ionic liquids as reaction media has been extended to enzymatic catalysis (Rantwijk et al., 2003) and whole cells biotransformations (Pfruender et al., 2004). Some ILs have been shown to be by far the best non-aqueous media for biocatalytic processes due to their positive influences on the enzyme stability and activity, as well as on the enantioselectivity of the reactions catalyzed by them. Just recently, a study on different ionic liquid-alcohol biphasic systems for the enzymatic production of isoamyl acetate was reported (Fehér et al., 2008). However, their use in industrial processes is restricted due to high prices at the market, so the development of the processes with these solvents at microscale is suggested here as a promising alternative. Microtechnology has opened completely new scientific challenges and useful solutions in a broad range of areas, from electronic industry, medical technology, fuel production and processing, to biotechnology, chemical industry, environmental protection and process safety. Microstructured devices have demonstrated several advantages in (bio)chemical processes, due to the very large surface-area-to-volume ratio connected