Microbial transformation of ursolic acid by Syncephalastrum racemosum (Cohn) Schroter AS 3.264

► Biotransformation of ursolic acid by S. racemosum yielded five triterpenoids. ► The catalytic reactions included hydroxylation, carbonylation, and condensation. ► The condensation to form a lactone or epoxy ring is unusual for biotransformation. ► One compound showed moderate PTP1B inhibitory activity.