Ionic liquids are considered as an alternative to organic solvents for catalysis. The literature in this field is reviewed with focus on advantageous use of ionic liquids in biocatalysis and biotransformations. The overview reveals that the exploration and mapping of ionic liquids with respect to biocatalysis is still sketchy. It is apparent that advantages can be gained in view of activity, stability and selectivity. Furthermore, integration of reaction and separation has a high potential in the field. The review presents quantitative data on the productivities, space-time yields, as well as stability as far as they can be extracted from the literature.

Utilizing the biphasic system water/CO 2 as a reaction and extraction medium is of rising importance, because of its advantages as a green solvent combination. The problem of predictable pH control in the aqueous phase has to be addressed in view of optimized reaction conditions. The control is possible up to a pH of approximately 6 by means of buffer salts, and the resulting pH can be predicted by an algebraic equation.

Enantioselective sulfoxidation was carried out by cascade reaction of Pd(0) catalysed formation of H 2 O 2 and enzymatic oxidation using chloroperoxidase from Caldariomyces fumago. Supercritical carbon dioxide (scCO 2 ) was used as medium for in situ generation of H 2 O 2 directly from H 2 and O 2 using Pd-catalysts. Subsequently, H 2 O 2 was utilised by the chloroperoxidase as an oxidant for the asymmetric sulfoxidation in the aqueous phase. This chemo-enzymatic cascade transformation exemplifies the potential of compartmentalisation of catalytic processes in multiphase systems.