This thesis summarizes the microbial transformation of two compounds, Estrone, a steroid and Cedryl Acetate, a terpene. The steroid, estrone (1) was transformed by two microbes, Cunninghamella elegans and Rhizopous stolonifer. When transformed by Cunninghamella elegans, two transformed products were produced including metabolites (2) and (3), one showed hydroxyl addition while other showed addition of hydroxyl group along with conversion of carbonyl group to hydroxyl group. Estrone also gave transformed products by Rhizopous stolonifer which are similar to that obtained by Cunninghamella...