Continuous production of the pharmaceutical 7,8-dihydroxy N-di-n-propyl 2-aminotetralin using a phenoloxidase from cell cultures of Mucuna pruriens

Abstract

Alginate-entrapped cells of Mucuna pruriens as well as the phenoloxidase isolated from the cell cultures, are able to ortho-hydroxylate several mono-, bi- and tri-cyclic monophenols. In this study, 7,8-dihydroxy N-di-n-propyl 2-aminotetralin, a catechol of pharmaceutical interest and difficult to prepare chemically, could be produced in considerable quantities by bioconversion of the precursor 7-hydroxy N-di-n-propyl 2-aminotetralin. A continuous flow system on a laboratory scale was used, which consisted of a phenoloxidase suspension in dialysis tubing as the biocatalysator in an airlift fermentor coupled with an aluminium oxide column for selective product isolation. Product formation continued for at least 50 h, resulting in ca. 130 mg product per liter, this being a bioconversion percentage of 25%. When the enzyme preparation was reused, 85% of the original activity was measured.