Modification of organic compounds and synthetic drugs by simple chemically defined reaction catalyzed by isolated enzymes, whole cells is termed as biotransformation. These reactions are performed by plant cells, animal cells, and microbial cells, but microbial process is most efficient and economical because of rapid microbial growth and its high metabolic rate. Biotransformations are employed in enhancing the activity of drugs and organic molecules, in predicting mammalian drug metabolism, and in discovering novel compounds with enhanced biological activity.

This review highlights the methodology, applications, and factors influencing biotransformation of drugs in relation to enhanced bioactivity and production of biotransformed products with special reference to fungal systems.