Technological watch

AbstractThere is an increasing interest in biocatalysis to perform chemical reactions in biphasic systems, consisting of an aqueous phase and a water immiscible organic solvent or ionic liquid. In most cases, the hydrophobic phase is used as reservoir for poorly water?soluble substrates or for in situ product removal. However, many enzymes are solvent?sensitive and cannot be used in such systems. In this study, we exemplarily protected the solvent?sensitive enzyme mandelate racemase from the organic phase by its entrapment in (crosslinked) polymersomes. The covalent crosslinking of the individual chains of the block copolymer poly(2?methyloxazoline)15?poly(dimethylsiloxane)68?poly(2?methyloxazoline)15 via terminal methacrylates led to enhanced membrane stability. This effect was especially pronounced for long?time incubation in the presence of organic solvents and ionic liquids. By using a gentle polymerization initiator at its minimal necessary concentration, the prior encapsulated enzymes remained intact during crosslinking. Although the insertion of natural channel proteins into the membrane improved the mass transport into the vesicles, it was non?essential. Mandelate racemase in (crosslinked) polymersomes remained active in different highly dispersed biphasic systems for more than 24 h. The free enzyme, on the other hand, got completely inactivated within 1 h, thus illustrating the potential of polymersomes as nanoreactors in biphasic reaction setups.This article is protected by copyright. All rights reserved