Biotransformation of Steroids and Sterols

Biotransformation of Steroids and Sterols

1. Biotransformation of Steroids and Sterols Biotransformation is process an organisms or Enzymes bring out chemical changes on compounds that are not part of their metabolism and they result in the formation of novel or useful products that are often difficult or impossible to obtain by conventional chemical methods. Microorganisms have the ability to Chemically modify a wide variety of organic compounds such changes are called “ Biological or Microbial Transformation ” KKR1116 1

2. Steroids Steroids are biological active organic compounds Found- plant, Animal Bacteria and Fungi Manufactured from Sterols Lanosterol (Plant) and Cyclosterol (Animal).  Fused Four Membered Rings (A,B,C,D) and composed of 17 carbon atoms and 28 hydrogen atoms KKR1116 2

3. Structure of steroid KKR1116 3

4. Steroids Naturally occurring steroids have hormonal properties very important to human beings. Cell membrane As a signaling Molecules Example : Adrenal hormones- Cortisone, Cortisol and Corticosterone . Progestational Hormone-progesterone’s Testerosterons , Dihydrosteron Estradiol , Estrone . The These steroids are widely used medically as KKR1116 4

5. Steroids Anti-inflammatory agents (Cortisone) Anesthetics, Antifertility agents Contraceptives Sedatives Rreduce mineral corticoid activity by Triamcinolone and Medrol Recent applications of steroid compounds include the treatment. KKR1116 5

6. TYPES OF STEROIDAL TRANSFORMATION Oxidation – Hydroxylation – Dehydrogenation. – Epoxidations – Oxidation to ketone through hydroxylation – Ring A Aromatization – Degradation of steroid nucleus   – KKR1116 6

7. TYPES OF STEROIDAL TRANSFORMATION Oxidation of alcohols to ketone : 3 β- OH to 3-keto – Side chain cleavage of steroids – Decarboxylation of acids Reduction – Double bond – aldehyde and ketone to alcohol Hydrolysis Isomerization Resolution of racemic mixture Other reactions – Aminations – Enolization of carbonyl compounds – Esterification . KKR1116 7

8. Hydroxylation KKR1116 8

9. Rhizopus arrhizus and R. nigricans KKR1116 9

10. Dehydrogenation KKR1116 10

11. Dehydrogenation KKR1116 11

12. Dehydrogenation KKR1116 12

13. Aromatization by Pseudomonas testosteroni   KKR1116 13

14. Degradation of steroid nucleus KKR1116 14

15. Epoxidation Curvularia lunata , Cunninghamella blakesleeana Helicostylum piriforme Mucor griseocyanus Mucor parasiticus Rhizopus nigricans KKR1116 15

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17. Esterification KKR1116 17

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21. ADVANTAGES Microorganisms have great potential for inducing new or novel enzyme systems capable of converting foreign substrates. • Microorganisms are capable of producing unique enzymes which are stable toward heat, alkali and acid. • A combination of microbial transformation and chemical transformations (chemo-enzymatic synthesis) can be exploited for partial, as well as the total synthesis of the organic compounds KKR1116 21

22. DISADVANTAGES If the substrate is toxic, it can kill the microorganisms. Hence no transformation will be observed. • Alternatively, if the micro-organisms use the substrate as an energy source (carbon source food), no transformed or untransformed material will be recovered. • Very low chemical yields are obtained due to the involvement of a complex biological system KKR1116 22

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