Use of polyvinyl alcohol cryogels for the compartmentation of biocatalyzed reactions in non-aqueous media

Abstract

Separation into stable aqueous compartments is a promising concept to enable the synthetic application of biocatalysts in unfavourable non-aqueous media, and might provide the key for successful application of complex multistep synthesis. This study describes and evaluates the practical utility of polyvinyl alcohol (PVA) cryogels as a matrix for such compartmentation. The protocol for enzyme entrapment in the gels was highly efficient, giving an immobilization yield of >99% and a total loss of material less than 10%. The resulting gel compartments were between 2.2 and 4 mm in size and had high mechanical strength. Shrinking occurred in solvents with the ability for water uptake. The matrix enabled the synthetic use of benzaldehyde lyase and alcohol dehydrogenase in hexane, in which equilibrium concentrations were comparable to a conventional two-phase system. The results suggest a general suitability of PVA gels for the compartmentation of biocatalyzed reactions in non-aqueous media.