Back to: MICROBIOLOGY 400 LEVEL
Welcome to class!
Hello, brilliant one! I’m truly glad to see you back in class today. Your curiosity and dedication to learning are what set you apart. In today’s lesson, we’re going to talk about something very important in industrial microbiology—Selection Criteria. Think of this topic like choosing the best players for a football team. In the world of microbes, not every organism qualifies to be part of industrial processes. So, let’s learn how scientists pick the best microbes for the job.
Selection Criteria
Selection criteria are the factors or qualities scientists use to choose microorganisms that are most suitable for industrial applications. This is important because using the wrong microbe can waste time, money, and resources.
Just like a farmer selects the best seeds to plant for a good harvest, industries must select the best microbial strains that can produce high-quality, stable, and safe products.
Key Selection Criteria in Industrial Microbiology
1. High Yield of Product
Microorganisms selected must produce a large quantity of the desired product (e.g., antibiotic, enzyme, alcohol). The higher the yield, the more efficient and profitable the process becomes. For example, if you’re making bread, you’d want a yeast that produces enough carbon dioxide to make the dough rise properly.
2. Fast Growth Rate
The selected microbe should grow quickly and reach the production stage within a short time. Fast-growing microbes save time and make the production process more efficient.
3. Genetic Stability
The organism must be genetically stable. This means it should not easily lose its ability to produce the desired product over time. If a strain becomes weak or changes too often, it cannot be relied on for continuous production.
4. Non-pathogenic and Safe
The microorganism should be safe for humans, animals, and the environment. Pathogenic (disease-causing) microbes are avoided to prevent contamination and health risks.
5. Ability to Grow on Cheap Substrates
Microbes that can grow on inexpensive materials like agricultural waste, molasses, or cassava peel are preferred. This reduces production cost and makes the process more sustainable.
6. Ease of Harvesting Product
The product (e.g., enzyme or antibiotic) should be easy to extract and purify from the culture. This makes processing easier and cheaper.
Think of selecting gari sellers at the market. You’ll likely choose one who sells in bulk (high yield), always has stock (stable), sells fresh gari (safe), sells at a good price (cheap input), and is consistent. The same logic applies to microbes in industry.
For example, Aspergillus niger is selected for citric acid production because it grows well, produces high yield, and is genetically stable. Saccharomyces cerevisiae is commonly used for ethanol because it’s safe, fast-growing, and feeds on cheap sugars.
Summary
- Selection criteria help identify the best microorganisms for industrial use.
- Important criteria include high product yield, fast growth, and genetic stability.
- Microbes must be non-pathogenic and safe for handling.
- The ability to grow on cheap substrates lowers production cost.
- Ease of product recovery makes the process efficient and economical.
Evaluation
- What are selection criteria in industrial microbiology?
- List four important factors used in selecting microorganisms for industrial use.
- Why is it important that a microbe is genetically stable?
You’re learning the science behind the scenes of many things we use every day—from food to medicine. Stay confident, stay curious, and keep growing with Afrilearn. You’re on the path to becoming a true microbiology expert. See you in the next class!