Stabilization of Nocardia EH1 epoxide hydrolase by immobilization

A partially purified epoxide hydrolase from Nocardia EH1 was stabilized by immobilization through ionic binding onto DEAE-cellulose. The biocatalyst showed more than twice the activity (225 %) of that of the free enzyme albeit at a marginal reduction in enantioselectivity. The addition of the nonionic detergent Triton X-100 during the immobilization further enhanced the stability as indicated by a dramatic shift in the temperature optimum from 35 to 45 degrees C. The stabilized immobilized biocatalyst could be successfully employed in repeated batch reactions (residual activity of 55 % after five cycles), which was not the case for whole cell reactions (residual activity less than or equal to 10%).