Microbial Biotechnology Overview

Microbial Biotechnology Overview

• Microbial biotechnology utilizes microorganisms for industrial and medical applications.
• Dr. Eman Owis is a lecturer in Microbial Biotechnology at Mansoura University and has a PhD from Göttingen University.
• Key processes in microbial biotechnology include fermentation, genetic engineering, and nanotechnology.

Fermentation

• Fermentation is used to produce various products, including pharmaceuticals, enzymes, and industrial chemicals.
• Fermenters provide a contained, controlled, and homogeneous environment for optimized fermentation processes.
• Important factors for fermenter design include cost, reliability, and safety.
• The specific design parameters depend on the purpose of the fermenter.

Penicillin Production

• Penicillin is a group of antibiotics produced by the Penicillium fungi.
• It is not a single compound, but a group of closely related compounds (e.g. Amoxicillin, Ampicillin, Phenoxymethylpenicillin).
• Alexander Fleming discovered penicillin in 1928.
• Later, Howard Florey and Ernst Chain purified and produced penicillin on a large scale in 1941 and 1943, respectively.
• This was instrumental in treating WWII casualties.

Penicillin Production Process

• Medium: The medium for Penicillin production commonly contains Corn Steep Liquor, Glucose, MgSO₄, K₃PO₄, and sodium nitrates to provide essential ions for the fungus's metabolic activity.
• Heat Sterilization: The medium is sterilized at high heat and pressure (121°C at 30 psi, or twice atmospheric pressure). This is usually done in a holding tube or together with the fermenter.
• Fermentation: Fermentation is typically carried out in a fed-batch manner, slowly adding nutrients over time. This process is conducted at temperatures in the range of 20-24°C and pH of 6.5. The pressure in the bioreactor is significantly higher than atmospheric pressure (1.02 atm) to minimize contamination. Stirring is crucial for homogeneous distribution of the culture medium and is typically maintained at 200 rpm.
• Seed Culture: Penicillium chrysogenum spores are first grown in a liquid medium until sufficient for inoculation into the fermenter. During this stage, the medium is constantly aerated and agitated. Parameters such as pH, temperature, stirring speed, and dissolved oxygen are regularly monitored. Penicillin secretion begins typically after 40 hours of seed culture. The growth process typically concludes after 7 days, with consequent rise in pH to 8.0 or above. At this time, penicillin production stops.
• Biomass Removal: The biomass is separated from the penicillin-containing medium using a rotary vacuum filter.
• Solvent Addition: Organic solvents (e.g., amyl acetate or butyl acetate) are added to dissolve the penicillin from the filtrate.
• Centrifugation: The penicillin, now in solution, is separated from the other solids by centrifugation.
• Extraction: The penicillin solution undergoes further extraction stages including mixing with phosphate buffers and chloroform solution, and finally, with an ether solution to obtain high penicillin concentration and purity. The final product (Penicillin G) is obtained in a stable powder form as Sodium salt, after being combined with sodium bicarbonate.
• Drying: The penicillin is dried, removing the remaining moisture, in a fluidized bed dryer.
• Storage: Penicillin is stored in containers in a dry environment.

Media Formulation

• Media should provide all necessary elements for cell synthesis, and desired product formation
• Should be cost-effective, and foster a favorable culture environment
• The composition for penicillin fermentation includes various nutrients and chemicals like glucose, various salts, and other components.

Primary and Secondary Metabolism

• Primary metabolism involves essential metabolic processes like energy production and cell biosynthesis.
• Secondary metabolism is the production of special metabolites (like penicillin) not directly involved in energy production but often in defense mechanisms or acting as signaling molecules to compete with other microorganisms. Penicillin production in Penicillium chrysogenum is an example.