Sterol is a polycyclic alcohol such as a cholesterol or ergosterol. Cortisone steroid can be synthesized chemically from deoxycholic acid. This process requires 37 steps many of which must be carried out under extreme condition of temperature and pressure with the resulting product costing over $200 per gram.
Deoxycholic acid → Cortisone
So cortisone synthesis is an example of steroid biotransformation. The major difficulty in chemically synthesized cortisone is need to introduce an oxygen atom at number 11 position of the steroid ring which can be accompanied by using microorganism. The fungus Cunningham Ella blakesleeana can hydroxylate the steroid cortexolone to form hydrocortisone with the introduction of oxygen at the number 11 position.
The fungus Rhizopus arrhizus for example hydroxylates progesterone forming another steroid with the introduction of oxygen at the number 11 position. Steroids are very important in pharmaceutical industry. Steroid hormone regulates various aspect of metabolism.
One such hormone cortisone has been known to relieve the pain of rheumatoid arthritis. It regulates human sexuality and reproduction cycles. Some of steroids are used as oral contraceptives also. Some cortisone derivatives are also useful in alleviating the symptoms associated with allergic and other undesired inflammatory responses of the human body.
A good example of steroid transformation processes involving microorganisms like Rhizopus Nigerians which can be by growing the mould in a fermentor using an appropriate growth medium and incubation conditions to obtain high biomass, of course, aeration and agitation are employed to achieve rapid growth. After the growth of microorganism the steroid to be transformed is added.
When progesterone is added to a fermentor having Rhizopus Nigerians which has been growing for about one day, the steroid is hydroxylated at the number 11 position to form 11 – a – hydroxyprogesterone. The product is recovered by extraction with methylene chloride or various other solvents followed by purification chromatographically and recovered by crystallization (Fig. 22.5).
