Back to: MICROBIOLOGY 400 LEVEL
Welcome to class!
Hello bright mind! I’m really happy to see your consistency. You’re doing an amazing job staying committed to your learning. Today’s topic is Filtration, Centrifugation, Chromatography, and Drying—four powerful techniques used in industrial microbiology, especially in the separation and purification of products. You’ve already touched on these in our last lesson, but now let’s look at each one more closely. Think of them as the tools in your scientific toolbox for making sure your final microbial product is clean, pure, and ready to use.
Filtration, Centrifugation, Chromatography, Drying
Filtration
Filtration is used to separate solid particles (like microbial cells or debris) from a liquid. It works just like using a sieve to separate sand from water or using a fine cloth to strain pap (akamu).
Types of filtration:
Gravity filtration: Liquid passes through a filter using natural gravity.
Vacuum filtration: A vacuum is used to speed up the process by pulling the liquid through.
Membrane filtration: Very fine filters separate even tiny particles like bacteria.
Filtration is commonly used when the microbial product is found in the liquid part of the fermentation broth.
Centrifugation
This technique involves spinning a mixture very fast so that heavier particles settle at the bottom while lighter ones stay on top. It works just like how clothes spin in a washing machine to remove water.
In microbiology, centrifugation helps separate cells from the broth or to collect products that are heavier than the liquid.
Low-speed centrifuges: Used for separating cells from liquid.
High-speed centrifuges (ultracentrifuges): Used for separating smaller components like proteins or DNA.
Chromatography
Chromatography is a method used to separate mixtures of substances based on how they move through a material. Imagine pouring different coloured inks on paper and watching how they separate into different colours.
Types of chromatography:
Paper chromatography: Often used for small samples like plant pigments.
Column chromatography: Used in labs and industries to separate proteins, enzymes, or antibiotics.
Gas chromatography: Used for volatile compounds.
High-performance liquid chromatography (HPLC): A very accurate and sensitive method used in modern laboratories and industries.
Chromatography is excellent for both identifying and purifying products to a high standard.
Drying
Drying removes moisture from a microbial product to preserve it and make it easier to store or transport. Just like drying cassava to make garri or drying pepper for long-term use.
Methods of drying:
Air drying: Simple and natural but slow.
Spray drying: Liquid product is sprayed into hot air, drying it instantly into powder—used for milk, enzymes, or yeast.
Freeze drying (lyophilisation): Product is frozen and then dried under vacuum. This method preserves sensitive products like vaccines or microbial cultures.
Imagine you’re producing amylase enzyme in a fermentation tank in Kaduna. After fermentation:
You filter out the fungal cells,
Centrifuge to remove fine particles,
Use chromatography to purify the enzyme,
Then dry it into powder form for packaging and use in food industries.
Summary
- Filtration separates solids from liquids using sieves or membranes.
- Centrifugation uses high-speed spinning to separate components by weight.
- Chromatography separates and purifies components based on movement through a medium.
- Drying removes moisture to preserve and stabilise microbial products.
Evaluation
- Which technique would you use to separate bacteria from a liquid broth?
- Why is drying important after product purification?
- List two types of chromatography used in microbiology.
These are real-world techniques you’ll likely use in labs or industries across Africa. Keep going strong—you’re building practical knowledge that changes lives. Afrilearn is proud to walk with you on this journey. Keep shining, and see you in the next class!