Previous studies in our laboratory have shown that the synthetic abietane diterpene, triprophenolide is metabolized by the filamentous fungus, Cunninghamella elegans to three products : triptoquinone, 5 alpha,14-dihydroxybutenolide, and 14 beta-glucosyltriptophenolide in yields of 35, 12, and 5%, respectively. The purpose of this study was to increase the yield of the triptoquinone while simultaneously decreasing the production of the other metabolites. The effects of four factors (glucose concentration, nutrient broth concentration, malt extract concentration, and biotransformation lime) on the yield of triptoquinone were assessed using a sequential factorial design. Biotransformation time was critical for the production of triptoquinone whereas the concentration of the medium components affected the yield of triptoquinone to a lesser extent The optimal factor levels for its formation (41% yield) did not correspond to the settings for maximal biomass production. Similarly, the pH of the growth medium was nor correlated to the yield to triptoquinone. A second optimization experiment was performed using factor levels within a narrower range of the settings determined from the first experiment. The yield of triptoquinone predicted by the mathematical model increased to 70% and this value was confirmed experimentally.