Two new mulinane-type derivatives: 16-hydroxy mulin-11,13-dien-20-oic (2) acid and 7α, 16-dihydroxy mulin-11,13-dien-20-oic (3) acid were obtained by microbial transformation of mulin-11,13-dien-20-oic acid (1), along with tyrosol (4) using liquid cultures of Mucor plumbeus. The latter compound has not been previously identified in the genus Mucor. Structural elucidation of these metabolites was achieved using 1D- and 2D-NMR spectroscopy. Copyright © 2008 John Wiley & Sons, Ltd.