Penicillin Fermentation - Introduction

 Antibiotic - defined by Selman Waksman as

“an organic compound produced by one microorganism that, at great dilutions, inhibits the growth of or kills another or even group of other harmful microorganisms”

Antibiotics are available in various forms- ointment, powders, capsules, etc. For example, to treat bacterial infection on the surface, an antibiotic should be there in an ointment or cream form.  But to treat internal infection it can be directly injected into the bloodstream which finally distributed throughout the body.

Antibiotics are produced primarily by bacteria, Streptomyces, Nocardia and fungi. Antibiotics produced by Streptomyces spp. (Streptomycin, Neomycin etc..) have the most commercial applications.

On the basis of mode of action antibiotics are divided into

i) Antibiotics affecting cell wall 

ii) Antibiotics damaging cell membrane 

iii) Antibiotics interfering with protein synthesis

iv) Antibiotics inhibiting nucleic acid synthesis

v) Antibiotics blocking cell metabolism

The first discovered natural antibiotic was Penicillin by Alexander Fleming. Penicillin was obtained from “Penicillium notatum”.

                

History 

In 1928, Sir Alexander Fleming made one of the most important contributions to the field of antibiotics. 

 He first observed the antibiotic properties & therapeutic value of penicillin.

In an experiment, he observed that air born contaminant, later shown to be Penicillium notatum, inhibited the growth of a culture of S. aureus on an agar plate.  He called this material Penicillin after the mold that had produced it. In 1932, he published paper, which proposed a method for use of penicillin in treatment of infected wounds.

 But early samples of penicillin were not purified, and further refinements were needed. 

Howard Florey, Ernst Chain and associates purified Penicillin in the 1940s. 

Later on, different scientists worked in on different aspects of Penicillin and their production on large scale which helped launch the modern antibiotics industry. 

                                       

The World War II had brought a demand for penicillin on a large scale for the treatment of burns and wounds.

By the end of the war (late 1943), many drug manufacturing companies started mass production of  Penicillin.

In 1945 Fleming, Florey and Chain were awarded the Nobel Prize in Physiology and Medicine.

 

               

Mode of action: Penicillin is active against many Gram positive bacteria, Nocardia, and Actinomycetes, but not against most Gram negative bacteria except at higher dosage level. It interferes with cell wall synthesis of actively growing sensitive organisms. It mainly inhibit the cross linking steps of peptidoglycan synthesis in the cell wall.

Penicillin

Penicillin is a group of compounds having common basic nucleus, 6-amino penicillanic acid (6-APA).  6-APA contains ring like structure termed as a β-lactam ring.

                                         

Penicillin

Penicillins are of two different types- Natural Penicillin & Synthetic Penicillin

Natural penicillin is directly harvested from the Penicillium mold. Synthetic penicillin has the basic Penicillin nucleus (6-APA), but with new side chains that provide altered properties of to the natural compound. Eg., Ampicillin, Methicillin, Penicillin

(contd..)

References

• Principles of Fermentation Technology: (2nd edition, by Peter F. Stanbury, Allan Whitaker and Stephen J. Hall, Butterworth-Heinemann, An imprint of Elsevier Science.)
• Industrial Microbiology: (By Casida L. E.New Age international (P) ltd publications)
• A Text Book of Industrial Microbiology: (2nd edition By Wulf Crueger & Anneliese Crueger)