Penicillin: History, Structure, Production & Recovery

Content

1st antibiotic to be produced and still one of the best antibiotic available.
Penicillin is a group of antibiotics, isolated from common molds known as Penicillium Molds.
It is active against many gram-positive bacteria, Nocardia, Actinomycetes.
It generally, interferes with cell wall synthesis of organisms which is sensitive and it is active only against vegetative cell.

Sir, Alexander Fleming in 1929, first observed the antibiotic properties and possible therapeutics value of penicillin.

He observed that an airborne contaminant, later shown to be Penicillium notatum inhibited the growth of a culture of Staphylococcus aureus on agar medium in the area surrounding the fungal activity.
Fleming further showed that this inhibitory effect Caused by a soluble, diffusible mold product.
Penicillin observed by Fleming was Penicillin-G.

Various compounds resembling the side chain can be added as precursor to fermentation medium & through microbial strain are directly incorporated into Penicillin molecule.
Fungi: Aspergillus & Penicillium.
Various penicillin differs as nature of their “R’’ side chain.

Whereas, in present day commercial terms penicillin is regarded as the Penicillin-G.
The Penicillin nucleus consists of two amino acids, L-cysteine and D-valine.

Penicillinase is an extracellular enzyme adaptively produced by members of the coliform group of bacteria, by most Bacillus sp.
Major factor for penicillin resistance during infection.
This enzyme hydrolyses penicillin to penicilloic acid.

Sensitive to Penicillinase enzyme.
Can be recovered from fermentation broth.
Chemically converted to penicillin by chemical addition of various R side chains. Yield of this material is low.
Penicillin acylase enzyme cleaves side chains of penicillin so resulted in commercial production 6-Amino penicillanic acid.

Commercially, penicillin was first produced in stationary mat culture.
Production of penicillin is previously achieved by surface process i.e. solid-state fermentations and surface liquid fermentation.

Penicillin production mainly consists of three steps:

1. Inoculum preparation
2. Production fermentation
3. Product recovery

Inoculum: Penicillium chrysogenum.
For inoculum production, spores from heavily sporulated working stocks (special agar sporulation) are suspended in water or in a dilute solution of a nontoxic wetting agent, such as 1:10,000 sodium lauryl sulfonate.
These spores are then poured in the flask which contains wheat bran and nutrient solution for heavy sporulation.
Incubate for at 24°C for 5-7 days to provide heavy sporulation.
Resulting spores are directly inoculated into inoculation tanks.
Incubated at 25 to 26°C for 3 to 5 days exact duration of fermentation depends on various factors.

Method: fed batch or batch.
Media: (Jackson 1958)
1. Corn steep liquor solids-3.5%
2. Lactose: 3.5%
3. Cellulose: 1%
4. CaCO3: 1%
5. K2HPO4: 0.4%
Edible oil: 0.25%
Fermenter: stirred tank or air lift tank.
Temperature: 25-27°C.
Aeration: 0.5 – 27 1 VVM.
Anti-foam: edible oil
pH: set at 5.5 to 6.0 which increased up to 7-7.5.
Inoculum media is same as production media.
Lactose precursor is not added, at start of fermentation.
PH remain constant, glucose, corn steep liquor, Carbon compounds and ammonia are utilised.
Carbon compounds depleted, pH rise to 7-7.5.
At the end of fermentation pH rises to 8 higher because depletion of lactose brings an autolysis in mycelium.
Penicillium is harvested before this.

Discard aqueous fraction
Add potassium acetate to the solvent extract in a crystallization tank to crystallize as potassium salt.
Recover crystal from centrifuge.
Further processing.
Packaging.

1% – https://www.slideshare.net/guest08f61f/project-antibioticsbyharkiran-presentation
1% – https://quizlet.com/182638247/microbiology-iclicker-smartwork5-quiz-1-flash-cards/
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edium_for_the_production_of_Penicillin_G_acylase_from_Bacillus_sp
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