ABSTRACT
Steroids are a group of natural compounds derived from the cyclopentane-perhydro-phenantrene nucleus that have a great interest for the pharmaceutical industries as a consequence of their physiological effects. Among their functions are anti-inflammatory, immunosuppressive, or contraceptive activities. Nowadays, microbial transformation of steroid precursors is winning relevance opposite to the chemical synthesis, since it allows for decreasing time, expenses, and environmental pollution. Pharmaceutical industry tends to use cholesterol and phytosterols as starting materials due to their low cost. Aspergillus ochraceus and Aspergillus nidulans, a fungus whose biochemistry and genetics are well known, have been chosen because of their capacity of 11-α-hydroxylation over some steroids which confers on them their anti-inflammatory properties. We have cloned the genes encoding the 11-α-hydroxylase enzymatic activities with the aim to introduce them in other microorganisms, such as Mycobacterium smegmatis, used in the industry to split the side chain of phytosterols, and thus creating recombinant microorganisms able to generate useful steroids from cheap precursors in just one-step fermentation.
