KJB - The use of microorganisms in biotechnology

Question 1

What is biotechnology?

Answer 1

Using biological entities to manufacture a product

Question 2

What are the four reasons why microorganisms are so useful for biotechnology?

Answer 2

• high metabolic rate
• wide range of enzyme capability
• reactions carried out under mild conditions
• can grow on plentiful supplies of cheap nutrients

Question 3

Why do microorgansims have a a high metabolic rate?

Answer 3

Microorganisms are SMALL and therefore have a LARGE SURFACE AREA: VOLUME RATIO. This allows a RAPID transport of nutrients into the cell.

Question 4

What effect does surface area of a microorganism have on metabolic rate?

Answer 4

The larger the surface area, the higher the metabolic rate.

Question 5

Expand on the wide range of enzymatic capability of microorganisms. Give an example of saprophytes.

Answer 5

Fungi.
They can produce many different enzymes.
They can thus produce an extensive range of metabolic end products (which can break down almost anything).

Question 6

Give an example of a saprophyte.

Answer 6

Fungi

Question 7

Define saprophyte.

Answer 7

A plant, fungus, or microorganism that lives on dead or decaying organic matter/ plant waste.

Question 8

Microorganisms can undergo reactions under mild conditions. Why is this better than many chemical reactions?

Answer 8

Chemical reactions require
- high temp
- high pressures
- the use of organic solvents
This can be EXPENSIVE

Question 9

Microbial systems are better than chemical systems because:

Answer 9

The reactions require:
- low temp
- low pressures
- use AQUEOUS solvents
Therefore, there are LOWER energy costs

Question 10

What are examples of the cheap nutrients that microorganisms grow on? What is another benefit of using these?

Answer 10

• Cornsteep liqour
• Waste paper pulp
• Petrleum products
• Molasses

THEY ARE READILY AVAILABLE

Question 11

What sort of materials can be produced from biotechnology?

Answer 11

• The cells themselves
• Large molecules such as enzymes, polysaccharides and proteins (both natural and bioengineered)
• Microbial transformations
• Primary metabolic products (vitamins, organic acids, alcohol)
• Secondary metabolic products (antibiotics)

Question 12

What sort of materials can be produced from biotechnology? The cells themselves. e.g.

Answer 12

• Baker’s Yeast
• Probiotic yogurts/ supplements
• Mushrooms
• Marmite (yeast extract)
• Quorn
• Single cell protein for animal feed

Question 13

Small organisms not only have a high metabolic rate but also a high _____ content. List the following in protein content from highest to lowest: soya bean, meat, yeast

Answer 13

protein
yeast (40-50%)
soya bean (35%)
meat (20%)

Question 14

How are single cell proteins made? Name what other materials are made from this process

Answer 14

Bioengineering process takes in grease and bio-sludge from waste treatment and converts it to SCP, fertiliser, recycled water and biogas.

Question 15

Name a microbial enzyme and its use for industrial applications

Answer 15

Pectinase. Derived from Aspergillus spp. Clarification of fruit juices and wines

Question 16

Name a microbial polysaccharide/ polymer and its use for industrial applications

Answer 16

Alginate. Derived from Pseudomonas sp. Used in a wide range of pharmaceutical formulations,

Question 17

Name a microbial protein and its use for industrial applications/ therapeutic use.

Answer 17

Insulin. Therapeutic use is treatment of diabetes

Question 18

Primary metabolic products are synthesised by an

Answer 18

organism in the course of active growth and metabolism. Primary metabolite accumulates as number of cells producing it accumulates

Question 19

Primary metabolites..

Answer 19

High cell concentrations give rise to high yields of primary metabolites. Therefore, microorganisms are often mutated to greatly overproduce the product of interest e.g.
Alcohol
Vitamins
Amino acids
Nucleotides
Organic acids (including vinegar)

Question 20

What do mutated cells do? (in relation to primary metabolites)

Answer 20

They vastly overproduce the product of interest. UNFORTUNATELY normally, enzymes are unstable and can back mutate therefore, in order to ensure only the desired product is produced, we either mutate or block any other enzymes that may act on the desired product and convert it to an undesired product so that they are no longer able to do this.

Question 21

There are __ essential amino acids that have some kind of use either industrially, food production or therapeutically

Answer 21

20

Question 22

When are secondary metabolites produced?

What condition is needed to achieve high amounts of secondary metabolites?

Answer 22

When the organism/ cells stop growing/ have finished actively dividing and are in STATIONARY phase.
Need slow cell growth rate but high cell yields in order to produce large secondary metabolite yields

Question 23

Examples of secondary metabolites include

Answer 23

Antibiotics
Toxins
Alkaloids

Question 24

Class growth curve includes

Answer 24

Lag, Log, Stationary phase, Death/ Decline phase (NOT always observed)

Question 25

Expand on the classic growth curve and state whether you can relate it to natural environments?

Answer 25

NO
It is a laboratory artefact
It arises as a result of growing a pure culture of cells in a fixed volume of nutritious medium (Batch culture)
Cells don't grow like this in nature.
In the natural environment, growth is much slower because:
- nutrients are in short supply
- competition with other MOs
- predators/ immune system
- Temperature is not optimal for growth

Question 26

Cell growth can be manipulated by varying the concentration of

Answer 26

growth limiting substrate.

Question 27

The more you decrease the growth limiting substrate,

Answer 27

the more you decrease growth rate of culture

Question 28

Growth rate is proportional to

Answer 28

concentration of the limiting substrate

Question 29

How can you achieve slow growth rate and high cell yields?

Answer 29

Nutritious mediums give high growth rate and high cell yields.
Poor mediums give slow growth rate and low cell yields.
Need a medium rich in nutrients but essential components only slowly fed in.
Cells therefore grow slowly as nutrients are in limited supply

Question 30

What type of culture allows for slow growth rate and high cell yields?

Answer 30

Fed batch culture.
Rich medium but supplied to growing culture slowly.
Result - slow growth rate and high cell concentration

Question 31

Fed-batch culture with limiting substrate e.g. GLUCOSE. Explain how this would happen

Answer 31

Cells are inoculated in incomplete rich medium (contains all components necessary for growth except for one - glucose).
Glucose is then added slowly to the culture and as the concentration in broth is slow, growth is slow
By the end of the process, the same amount of glucose would have been added as would have been in a complete rich medium but just over a longer period of time

Question 32

Chemostat cultures are

Answer 32

There is a constant rate of medium input. At the same time you are feeding out waste, thus culture volume remains constant. Steady state growth can be maintained indefinitely but not used often in pharmaceutical production due to risk of contamination