Biocatalysis of artemisinin by different strains of Mucor ramannianus* illustrates a simple approach to bioengineering for attaining useful biotransformation strains for preparative or downstream development. Three different strains of M. ramannianus on the malt/sucrose medium were compared for their native ability to metabolize the antimalarial artemisinin and produce significant yields of hydroxylated artemisinin derivatives. The M. ramannianus strains transformed the antimalarial into hydroxylated metabolites, in particular 7β-hydroxyartemisinin at 88% yield and 6β-hydroxy artemisinin at 51% yield. M. ramannianus strains: M. ramannianus 1839, University of Wisconsin, M. ramannianus ATCC 9624, American Typical Cultures Collection, M. ramannianus ATCC MYA-883 (R-56), Jefferson County, Arkansas (American Typical Cultures Collection). © 2005 Taylor & Francis Ltd.