SEBASTIEN ELGUE^1,2,*, ANNELYSE CONTE*¹, ALAIN MARTY^3,4,5, JEAN-STEPHANE CONDORET²
*Corresponding authors
1. MEPI – Plate-forme SAFRAN-HERAKLES, Chemin de la Loge, CS 27813, 31078 Toulouse Cedex 4, France
2. Laboratoire de Génie Chimique, INP Toulouse, 4 allée Emile Monso, BP 842342, 31432 Toulouse Cedex 4, France
3. Université de Toulouse; INSA, UPS, INP; LISBP, 135 Avenue de Rangueil, F-31077 Toulouse, France
4. NRA, UMR792 Ingénierie des Systèmes Biologiques et des Procédés, F-31400 Toulouse, France
5. CNRS, UMR5504, F-31400 Toulouse, France

Abstract

Developing continuous enzymatic process, especially when a two-phase medium is required, remains nowadays a great challenge. So, there is a need to provide a technical solution for generating highly controlled interfacial area. In this study, three types of reactors, conventionally used for chemical process intensification, were tested for continuous lipase-catalysed esterification in two-phase medium. On the single criterion of mass transfer performance that is considered here, the Nitech oscillating reactor proved to be the more efficient to transform the input mechanical power into mass transfer while proposing easily adjustable residence time. Nevertheless Corning and Chart flow reactors were shown to be very suitable candidates even if mass transfer performances are dependant on the flow-rate and therefore are not uncoupled from the residence time. This results in a less convenient choice of operating conditions. Also, it has been shown here that the model reaction could also be a simple way to characterize mass transfer performance of these technologies.

INTRODUCTION 

Operation of enzymatic reactions in two-phase medium, i.e. oil-water dispersions, is very common when hydrophobic reactants are concerned, as for instance in the case of hydrolysis of lipids (1-2). Moreover, enzymatic reactions,, such as esterification, can be effective in two-phase media using free enzymes (3). Indeed, even in a two-phase system with a water activity close to unity, esterification can be effective due to a shift of the thermodynamic equilibrium by maintaining a low ester activity. After preliminary studies, when industrial development is envisaged, continuous operation must be considered in order to increase productivity and economic viability. But, at present time, it is not possible to propose a realistic continuous liquid-liquid reactor where controlled contact area and steady operation is insured, while this would greatly simplify the development of the process. So, usually, to overcome this technical difficulty and make the more efficient and economic use of the biocatalyst, this latter is used as an immobilized biocatalyst packed in a tubular reactor (1, 4, 5). Therefore, there is a need for a technical solution whi ...