The solvent extraction process of penicillin is an important part of antibiotic production, which is used to extract and purify penicillin from fermentation broth. This process mainly relies on the distribution characteristics of penicillin between the aqueous phase and the organic phase. The following are the general steps and characteristics of penicillin extraction by solvent extraction:
Solvent selection

• Commonly used solvents include butyl acetate, isoamyl alcohol, etc. These solvents have good solubility for penicillin and are immiscible with water, which facilitates the separation of the two phases.
•  When selecting a solvent, factors such as its toxicity, volatility, cost, and whether it is easy to recycle should also be considered.

 
Pre-extraction treatment

• Filtration: First, remove solid particles (such as bacteria) in the fermentation broth by filtration or centrifugation.
• PH adjustment: Adjust the pH value of the fermentation broth to about 2.0, because penicillin is more likely to enter the organic phase under this pH condition.

 
Extraction operation

• Mixing: The pretreated fermentation broth and the selected organic solvent are input into the centrifugal extractor in a certain proportion, and fully mixed and contacted under the stirring of the impeller, so that penicillin can be effectively transferred from the aqueous phase to the organic phase.
• Centrifugal separation: The mixed liquid enters the clarification chamber of the centrifugal extractor, so that the organic phase and the aqueous phase are quickly separated under the centrifugal force far exceeding gravity. The two phases are respectively output from the centrifugal extractor through the collection chamber to obtain an organic phase solution containing penicillin.

Concentration and purification

• Reverse extraction: Sometimes a reverse extraction operation is performed, that is, the organic phase containing penicillin is contacted with a new buffer solution again, so that penicillin returns to the aqueous phase, and the residual impurities are further removed.
• Concentration: The amount of solvent is reduced by evaporation or other methods to concentrate the penicillin solution.
• Crystallization: Finally, penicillin is precipitated in the form of crystals by controlling conditions (such as temperature changes, adding precipitants), and then washed and dried to obtain the finished product.

Process advantages

• Efficient extraction: Penicillin can be extracted quickly and in large quantities from the fermentation broth.
• Easy to scale: The technology is mature and reliable, suitable for large-scale industrial production.
• High flexibility: The extraction efficiency can be optimized by adjusting parameters such as pH value and solvent type.
• Environmentally friendly: A reasonably designed process can effectively recycle solvents and reduce environmental pollution.