Asymmetric synthesis of an (R)-cyanohydrin using enzymes entrapped in lens-shaped gels

[GRAPHICS] A novel synthesis of (R)-cyanohydrins is described which is based on the us e of cross-linked and subsequently poly(vinyl alcohol)-entrapped (R)-oxynit rilases, These immobilized lens-shaped biocatalysts have a well-defined mac roscopic size in the mm range, show no catalyst leaching, and can be recycl ed efficiently, Furthermore, this immobilization method is cheap and the en trapped (R)-oxynitrilases gave similar good results compared with those of free enzymes. The (R)-cyanohydrin was obtained in good yields and with high enantioselectivities of up to > 99% ee.