Flash devolatilization was applied to incorporate an enzyme into a polymer matrix, which created a novel and highly active biocatalytic composite suitable for use in both aqueous and organic media. Enzymes were codissolved in toluene with commercial, high-molecular-weight polymers, and the solvent was then rapidly removed by injecting the mixture into a vacuum chamber. Subsequent cross-linking of the enzyme with glutaraldehyde resulted in stable entrapped enzyme within the polymeric matrices. For example, an composite of alpha -chymotrypsin and low-density polyethylene showed no significant los of enzymatic activity in aqueous buffer over a period of one month. The normalized activity of this biocatalytic material in organic solvents was 3-13 times higher than that of native alpha -chymotrypsin lyophilized from aqueous buffer. Washing the composite material with aqueous buffer increased the activity in isooctane an additional ten fold. The composites of alpha -chymotrypsin and polyethylene demonstrated the feasibility of obtaining active and stable biocatalytic materials via the application of compositional quenching to a biological system.