f215 module 2 chapter 2

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F215 module 2 Chapter 2-Biotechnology

a. State that biotechnology is the industrial use of living organisms (or parts of living organisms) to produce food, drugs or other products

  • Biotechnology:

Technology based on biology.

Involves the exploitation of living organisms or biological processes.

Improves agriculture, animal husbandry, food science, medicine and industry.

b. Explain why microorganisms are often used in biotechnological processes

  • Production of foods:

Cheese and yogurt making:

Lactobacillus in milk changes the flavour and texture.

Bacteria prevent the growth of other bacteria that would cause spoilage.


Quorn/meat alternatives.

Fusarium is grown in culture.

Fungal mycelium is produced and separated which is to be processed as a food.

Naturally brewed soya sauce:

Roasted soya beans are fermented with yeast or fungi like Aspergillus.

  • Production of drugs/pharmaceutical chemicals:

Penicillum is grown in culture to produce the antibiotic as a by-product of the metabolism.


E.coli is genetically modified to carry the human insulin gene.

Insulin protein is then secreted as they grow.

  • Production of enzymes/chemical for commercial use:


Fruit juice extraction.

A.niger grown in certain conditions secretes pectinase enzymes.

Calcium citrate:

Used in detergents.

A.niger produces citric acid as a by-product of their metabolism.

Biogas fuel production:

Methanogenic bacteria grown on concentrated sewage.

They respire anaerobically and produce gases that can be used as fuel.

Biomedication of waste:

Waste water treatment:

Bacteria and fungi use organic waste in the water as nutrients making the water harmless.

E.g. Fusarium is grown on corn steep liquor which is a waste product of the corn milling industry.

Why use microorganisms?

They grow rapidly in favourable conditions, with them being able to double in as little as 30 minutes (generation time).

Can produce proteins and chemicals which are released into the surrounding medium where they can be harvested.

Can be genetically engineered to produce specific products e.g. Insulin.

Can grow well in relatively low temperatures.

Can be grown anywhere in the world regardless of climate.

Products tend to be more pure than those generated in chemical processes.

Can be grown in nutrient materials that would be useless or toxic to humans.

c. Describe with the aid of diagrams and explain the standard growth curve of a microorganism in a closed culture

  • Lag phase:

The organisms may be taking in water, undergoing cell expansion, activating specific genes and synthesising specific enzymes.

  • Log phase:

Sometimes known as the exponential phase.

Population size increases each generation.

There is enough space and nutrients to reproduce.

Low amount of limiting factors.

death rate is greater than birth rate.

  • Stationary phase:

Nutrient levels decrease.

Waste products build up.

Birth rate equals death rate.

  • Decline/death phase:

Nutrient exhaustion.

Increased level of toxic products.



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