Transcript Using Microbes

Recap - just write the numbers
Task 1 – put these in order
1) tRNA enters the ribosome bringing amino acids
2) mRNA is transcribed from the DNA template
3) Ribosomes attach to the mRNA strand
4) The DNA double helix untwists
5) RNA polymerase at aches to the DNA
6) As translation occurs a polypeptide is produced
7) mRNA migrates out of the nucleus
8) The polypeptide folds into a protein & is
released
Answers - not on a post card
• 4–5–2–7–3–1–6–8
• The DNA double helix untwists, RNA polymerase
at aches to the DNA, mRNA is transcribed from
the DNA template, mRNA migrates out of the
nucleus, Ribosomes attach to the mRNA strand,
tRNA enters the ribosome bringing amino acids,
As translation occurs a polypeptide is produced,
The polypeptide folds into a protein & is
released.
Using Microbes
C Know some microbes used in food production
C Fermenters are used to cultivate microbes
B DNA can be transferred into microbes
B Explain how insulin is mass produced
A Evaluate the use of microbes for food
A Explain the reasons why specific factors are
controlled in a fermenter
What can micro-organisms
possibly be useful for?
Microbes
Making GM Insulin
What’s insulin? Where’s it made? What’s its job?
• Locate and remove the human insulin gene
• Transfer the gene into Escherichia coli
• Cultivate the bacteria in a fermenter
• Harvest and purify the insulin produced
Other uses of
microbes
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Spirulina
Quorn from mycoprotein
Bio ethanol
Yoghurt
Cheese
Antibiotics
Microbes
in
food
Quorn
Quorn is Mycoprotein produced by growing fungus in a fermenter. It is very
healthy because it is very low in fat so helps those with heart problems and
those on calorie controlled diets.
Mycoprotein produced by the fungal microbe is protein. Mycoprotein is made
from the mycelium (sorts of roots) of the fungus. The fungus is grown in huge
fermenters about 40 meters tall.
The fermenter is sterilised between batches using steam to ensure all
contamination is removed and no other microbes are able to grow and spoil the
mycoprotein that is harvested.
The nutrient supply that is added glucose of energy and minerals which are
also needed for the mycelium to be grown and the air supply is sent through a
filter to stop any other microbes entering the fermenter. The air and ammonia
gas pumped into the fermenter also acts to stir the mixture, as the bubbles float
to the surface the liquid is drawn upwards. The ammonia provides nitrogen for
growth. The waste gas is carbon dioxide, produced from the fungus as they
use the glucose for energy. The carbon dioxide is removed at the top of the
fermenter.
The fermentation process takes six weeks.
The temperature is kept between 35 and 38°C, the pH and oxygen supply are
also closely controlled. The mycoprotein is harvested and put through a heat
treatment process at 65 Celsius. The solid is then dried and pressed, cut,
coloured and sometimes flavoured.
The fungus requires 5 main nutrients and substances for growth, what are
they?
Growing microbes in fermenters
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Types of fermenter
Variables to control
What might be the impact if they were not?
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Growing microbes in fermenters
• Types of fermenter – gas or mechanical stirring
• Variables to control
– pH, temp, sterility, nutrients, waste gasses and
chemicals, product level, oxygen, movement,
• What might be the impact if they were’nt
controlled?
What are the advantages of
microbes as food?
What are the advantages of
microbes as food?
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Small amounts of land use
Can be produced anywhere – control
Simple management
Almost continuous production
Can use waste from other processes as food
What are the disadvantages of
microbes as food?
•They do not taste very nice!
Apart from Quorn none have been
successful for humans, many used as
animal feed.
Home work
• Complete the Quorn sheet and find out
how to make cheese.
• The main point in this and the part I’m
really interested in is the microbes that are
used and how they are used. Several
types of cheese might need to be
researched. Please present as a brief
table or series of bullet points.