How Antibiotics are Made: Steps Techniques

How Antibiotics Are Made? The production of antibiotics begins with the discovery and isolation of microorganisms, like certain bacteria and fungi, that naturally produce antibiotic compounds. Once identified, these organisms undergo cultivation in controlled environments where they multiply and produce antibiotics in significant quantities through a process called fermentation. In large bioreactors, optimal conditions—such as temperature, pH, and nutrient supply—are maintained to maximize antibiotic yield. Afterward, complex purification methods are used to separate the antibiotic from other by-products, ensuring safety and efficacy. Advanced techniques, including genetic engineering, further enhance production efficiency, allowing for antibiotics that meet stringent medical standards and global demands.

In this article, we will explore the antibiotic production techniques, covering everything from the initial discovery of antibiotic-producing organisms to large-scale manufacturing, purification, and quality control. We will also examine modern techniques that have enhanced antibiotic production, including genetic engineering and fermentation technologies.

Key Takeaways

• Discovery of Antibiotic-Producing Organisms: The production of antibiotics begins with finding microorganisms that naturally produce antimicrobial compounds, often isolated from soil, fungi, or bacteria.
• Fermentation Process: Antibiotics are typically produced through fermentation, where microorganisms are cultured in controlled environments to maximize antibiotic yield.
• Recovery and Purification: After fermentation, antibiotics are purified through processes like filtration, extraction, and crystallization to ensure they meet medical standards.
• Modern Techniques: Genetic engineering and synthetic biology are advancing antibiotic production by increasing yields and discovering new antibiotics to fight resistance.
• Formulation and Packaging: Antibiotics are then formulated into various forms (e.g., tablets, injections) and packaged under sterile conditions for patient use.

The Discovery and Isolation of Antibiotic-Producing Microorganisms

Before antibiotics can be mass-produced, scientists first need to identify microorganisms that produce antibiotic compounds. These microorganisms are often found in nature, particularly in soil, where bacteria and fungi compete for resources and produce chemicals to inhibit the growth of competitors. The discovery of such organisms marks the first step in antibiotic production.

Screening for Antibiotic-Producing Organisms

The search for new antibiotics begins with a process known as microbial screening, where samples from the environment (such as soil, water, or plant surfaces) are collected and tested for their ability to inhibit bacterial growth. This process was pioneered by Alexander Fleming when he discovered penicillin in 1928, observing that a mold (Penicillium notatum) produced a substance that killed surrounding bacteria.

• Soil samples are a common source of antibiotic-producing microorganisms, as soil bacteria and fungi often secrete antimicrobial compounds to protect themselves from other microbes.
• Agar diffusion tests are used in the laboratory to screen for antibiotic activity. In this method, samples are placed on agar plates inoculated with bacteria, and any zones of inhibition (clear areas around the sample where bacteria do not grow) indicate the presence of antibiotic-producing microorganisms.

Isolation of Antibiotic-Producing Strains

Once a potential antibiotic-producing microorganism is identified, the next step is to isolate the strain responsible for producing the antibiotic compound. This involves culturing the microorganism under controlled laboratory conditions to ensure it consistently produces the desired antibiotic.

• Pure culture techniques are used to isolate single colonies of the microorganism. These colonies can be grown on specific media that promote the production of antibiotics.
• The antibiotic compound produced by the microorganism is then extracted and tested for its effectiveness against various bacterial pathogens.

After the discovery and isolation of an antibiotic-producing strain, researchers work to understand the structure and properties of the antibiotic compound, which will guide the production process.

Fermentation: The Core of Antibiotic Production

The large-scale production of antibiotics typically relies on fermentation, a biological process where microorganisms are cultivated in controlled environments to produce antibiotics in significant quantities. Fermentation is the key technique used in the mass production of antibiotics like penicillin, streptomycin, and erythromycin.

Submerged Fermentation

The most widely used technique for antibiotic production is submerged fermentation, where the antibiotic-producing microorganism is grown in a liquid nutrient medium. The medium contains essential nutrients like sugars, amino acids, and vitamins that support the growth of the microorganism and promote the production of the antibiotic.

• Fermenters or bioreactors are large vessels where fermentation takes place. These fermenters are designed to maintain optimal conditions, including temperature, pH, oxygen levels, and agitation, which ensure the efficient growth of the microorganism and maximum antibiotic yield.
• During the fermentation process, microorganisms secrete the antibiotic compound into the liquid medium. The process can last anywhere from several days to weeks, depending on the type of antibiotic being produced.

Solid-State Fermentation

In addition to submerged fermentation, solid-state fermentation is another method used in antibiotic production, particularly for certain fungi. In this technique, the microorganisms are grown on solid materials (such as grains or bran) instead of in a liquid medium. This method is often used for antibiotics like cephalosporins and tetracyclines.

• Solid-state fermentation can offer certain advantages, such as reduced water usage and lower energy costs. However, it is generally less common than submerged fermentation for large-scale antibiotic production.

Recovery and Purification of Antibiotics

After fermentation, the antibiotic compound is present in the growth medium, but it is mixed with other metabolic by-products and cellular debris from the microorganisms. The next step in antibiotic production is the recovery and purification of the antibiotic to ensure it is safe and effective for use in medical treatments.

Separation of Biomass

The first stage of recovery involves separating the microbial biomass (cells and debris) from the liquid medium that contains the antibiotic. This can be achieved through processes such as filtration or centrifugation.

• Filtration involves passing the fermentation broth through filters to remove large particles and microbial cells, leaving behind the antibiotic in solution.
• Centrifugation uses high-speed rotation to separate the heavier microbial cells from the lighter liquid containing the antibiotic.

Extraction and Concentration

Once the antibiotic is separated from the biomass, it needs to be extracted from the liquid medium. Depending on the chemical properties of the antibiotic, different extraction techniques are used:

• Solvent extraction: This process uses organic solvents to dissolve and extract the antibiotic from the aqueous medium. The antibiotic is then recovered by evaporating the solvent, leaving behind a concentrated form of the antibiotic.
• Precipitation: In some cases, the antibiotic can be precipitated out of the solution by adjusting the pH or temperature. The solid antibiotic is then collected and purified further.

Purification and Crystallization

To ensure the antibiotic is free from impurities and meets the required standards for medical use, additional purification steps are employed. These steps include chromatography, which separates the antibiotic based on its size, charge, or affinity for certain materials, and crystallization, which purifies the antibiotic by encouraging the formation of pure crystals.

• Crystallization is often the final step in purification, where the antibiotic is converted into a solid crystalline form. This ensures that the antibiotic is stable, highly pure, and ready for further formulation into medicines.
• After purification, the antibiotic is tested for potency, purity, and safety to meet regulatory standards set by agencies like the Food and Drug Administration (FDA) or the European Medicines Agency (EMA).

Antibiotic Formulation and Packaging

Once purified, antibiotics must be formulated into a form suitable for administration to patients. Antibiotics are available in various forms, including tablets, capsules, liquids, ointments, and injectables. The process of formulation involves combining the active antibiotic with other ingredients to create a final product that is stable, effective, and easy to administer.

Tablet and Capsule Production

For oral antibiotics, the purified antibiotic is mixed with excipients, which are inactive ingredients that help form the tablet or capsule. Excipients can include fillers, binders, and disintegrants that aid in the stability and absorption of the drug.

• Tableting machines compress the antibiotic mixture into solid tablets, which are then coated if necessary to protect the drug from stomach acid or improve taste.
• For capsules, the antibiotic is placed inside a gelatin shell that dissolves once it reaches the stomach.

Injectable Antibiotics

For antibiotics that need to be administered intravenously or intramuscularly, the antibiotic is dissolved in a sterile solution and packaged in vials or ampoules. These products are prepared under strict sterile conditions to prevent contamination.

• Injectable antibiotics must be formulated with stabilizers and buffers to maintain the potency of the drug during storage and transport.

How Antibiotics are Made?: Modern Production Techniques

With the rise of antibiotic resistance and the demand for more efficient production methods, modern techniques such as genetic engineering and synthetic biology have become integral to the antibiotic production process. These advanced methods are designed to enhance the yield of antibiotics and enable the discovery of novel antibiotic compounds.

Genetic Engineering

In some cases, natural antibiotic-producing microorganisms can be genetically modified to increase their productivity or produce new variants of antibiotics. By altering the genetic pathways involved in antibiotic biosynthesis, scientists can create strains that produce higher yields or more potent antibiotics.

• Recombinant DNA technology allows researchers to insert genes from one microorganism into another, creating new strains that can produce antibiotics that the original microorganism could not.

Synthetic Biology

Synthetic biology is an emerging field that involves designing and constructing new biological systems or modifying existing ones for specific purposes. In antibiotic production, synthetic biology can be used to engineer microorganisms with optimized metabolic pathways that produce antibiotics more efficiently.

• This technique can also help in the discovery of novel antibiotics, especially as researchers can design new compounds that target resistant bacteria.

Conclusion

The production of antibiotics is a complex and multi-step process that involves the discovery of antibiotic-producing microorganisms, large-scale fermentation, recovery and purification of the antibiotic, and final formulation into medicines. Advances in technology, including genetic engineering and synthetic biology, have enhanced the efficiency and yield of antibiotic production, helping to meet the global demand for these life-saving drugs.

By understanding the techniques used in antibiotic production, we can appreciate the intricate processes involved in bringing antibiotics from discovery to the bedside, where they continue to be essential tools in fighting bacterial infections.

References

• Santi M Mandal, Anupam Roy, Ananta K Ghosh, Tapas K Hazra, Amit Basak, Octavio L Franco, Challenges and future prospects of antibiotic therapy: from peptides to phages utilization, Front Pharmacol, 2014 May 13;5:105. doi: 10.3389/fphar.2014.00105.
• Bruno Diez, Encarnación Mellado, Marta Rodriguez, Roberto Fouces, José-Luis Barredo, Recombinant microorganisms for industrial production of antibiotics,  Biotechnology and bioengineering, 2000, https://doi.org/10.1002/(SICI)1097-0290(19970705)55:1<216::AID-BIT22>3.0.CO;2-I. 
• Alexander A. Zhgun, Industrial Production of Antibiotics in Fungi: Current State, Deciphering the Molecular Basis of Classical Strain Improvement and Increasing the Production of High-Yielding Strains by the Addition of Low-Molecular Weight Inducers,Fermentation 2023, 9(12),1027; https://doi.org/10.3390/fermentation9121027.

Frequently Asked Questions

• How are antibiotics made? Antibiotics are made through a multi-step process, starting with the discovery of antibiotic-producing microorganisms. These organisms are cultivated in fermentation tanks, where they produce antibiotics. The compounds are then extracted, purified, and formulated into various forms for patient use.
• What is the role of fermentation in antibiotic production? Fermentation is a key process in antibiotic production, where microorganisms such as bacteria and fungi are cultured in nutrient-rich environments. During this process, they produce large quantities of antibiotics, which are then harvested and purified.
• What is the importance of genetic engineering in antibiotic production? Genetic engineering helps increase the yield and efficiency of antibiotic production by modifying microorganisms to enhance their ability to produce antibiotics. This includes altering their genetic makeup to produce more potent or novel antibiotic compounds.
• How are antibiotics purified after production? After fermentation, antibiotics are purified using processes like filtration, centrifugation, solvent extraction, and crystallization. These steps remove impurities and ensure the antibiotic is safe and effective for use in medical treatments.
• What are the steps involved in the production of antibiotics? The steps include discovering antibiotic-producing microorganisms, fermentation, recovery and purification, and final formulation into doses like tablets or injectables. Advances in genetic engineering and synthetic biology have enhanced these processes.
• Why is antibiotic resistance a concern in production? Overuse and misuse of antibiotics can lead to antibiotic resistance, where bacteria evolve to resist the effects of drugs. This is a significant concern in production, as it can limit the effectiveness of antibiotics and make infections harder to treat.