Clues for the existence of two different epoxide hydrolase activities in the fungus Beauveria bassiana

Epoxide hydrolase activity was produced during the exponential and stationary growth phases of the fungus Beauveria bassiana ATCC 7159. It was completely cell-associated. After cell disruption epoxide hydrolase activity was recovered in both the cell debris (EH “A”) and the soluble fraction (EH “B”), but not in the membrane fraction. Activity assays of these fractions with two different substrates indicated that their substrate specificity, as well as the corresponding E value and, to a lesser extent, their regioselectivity, were different. Also, we could observe that the absolute configuration of the residual epoxide was opposite. This indicates that these two epoxide hydrolase activities are substantially different and are, therefore, interestingly complementary biocatalysts for the preparation of the corresponding epoxides and/or vicinal diols in nearly enantiopure form.