Biotransformation of testosterone and testosterone heptanoate by four filamentous fungi.

•Biotransformation of testosterone and testosterone heptanoate was investigated.•Four filamentous fungi were used for the biotransformation.•6β and 14α-hydroxytestosterone were obtained in biotransformation of testosterone heptanoate.•Androst-4-ene-3,17-dione was the major product in the biotransformation of testosterone.•Time course study was also carried out with four fungal species.