The main objective of the project is the development of new industrial biotransformation processes of natural sterols (e.g., phytosterols) or steroidic compounds of pharmaceutical interest (e.g., androstenedione (AD), androstadiendione (ADD), dehydroepiandrosterone (DHEA) and testosterone) using recombinant strains of bacteria or fungi that are competitive with existing chemical processes. This project is funded by the Programme Retos Colaboración of the Ministerio de Economía y Competitividad (RTC-2014-2249-1).