Transcript Biotechnology - Sir Joseph Williamson

Biotechnology
Introduction
• Biotechnology can be defined as any process
that “makes use of living organisms (or parts
of them) to produce useful products or
services”
• Biotechnology has a very long history:
– Use of microbes in the food industry, for example:
• Beer and bread making
• Cheese and yoghurt production
• Mycoprotein production
• Microbes were used extensively in the First World War.
• British used the bacterium Clostridium acetobutylicum
to make acetone and butanol.
– Acetone was needed for the explosives industry
– Butanol was needed for making artificial rubber
• The Germans used yeast to
make glycerol needed for the
manufacture of explosives like
nitroglycerine.
The normal fermentation
process is blocked by hydrogen
sulphite and causes production
of glycerol instead of ethanol.
• Today, people tend to think that biotechnology is
concerned with:
– Production of pharmaceuticals and drugs, e.g.
antibiotics
– Micropropagation and tissue culture
– Production of enzymes used in food production and
the detergents industry
– Genetic engineering and the production of
genetically modified organisms (GMOs), for example:
• Herbicide/pesticide resistant crops
• Crops with better nutrient levels like Golden Rice™ with
high levels of β-carotene (the precursor of vitamin A)
• Pharming, i.e. modifying farm animals so they produce
pharmaceuticals, which can then be obtained from milk
Use of Microbes in Biotechnology
• The following slides provide a few examples of
the use of microbes in:
– Food industry
– Pharmaceutical industry
– Enzyme production
– Bioremediation and metal extraction
TASK: Complete a mind map to summarise these
details
Cheese and Yoghurt
Brie and Shropshire Blue cheese.
The cheese is ripened by fungi on
the surface (brie) or within it
(Shropshire Blue).
• Cheese and yoghurt are
fermented milk products.
• Lactic acid bacteria ferment
lactose which changes the
consistency of the milk
protein casein.
– With cheese, the protein
coagulates and separates into
curds, which are then turned
into cheese
– With yoghurt, the milk thickens
and sets
Q. What are the basic differences in cheese and yoghurt production?
– Lactic acid bacteria used
– Temperature
– Use of rennet
Mycoprotein (Quorn™)
• The filamentous fungus,
Fusarium is grown in
continuous culture on corn
steep liquor.
• The fungus is:
– Extracted and
– The mycelium (fungal threads)
is textured and flavoured
• The mycoprotein produced is
a low-cholesterol, low-fat
meat substitute.
Q. Suggest why mycoprotein might be preferred by some people to meats like
chicken, lamb, pork and beef.
– Ethics (it is not animal)
– Health (it is low cholesterol, low fat and high fibre)
Soy Sauce and Tofu
• Soya bean can be
fermented to produce soy
sauce. The fungi Aspergillus
oryzae and A. soyae are
used in the fermentation.
• Although bean curd (tofu)
is usually made by
precipitating soya protein
from soya milk, it can be
made using the enzyme
papain.
Q. What are the health benefits of soya?
– High protein, low fat and cholesterol
– Meat substitute with full complement of essential amino acids
– Source of phyto-oestrogen
Yeast Extract
• The brewing industry
makes large amounts of
waste yeast
(Saccharomyces cerevisiae)
• It is hydrolysed:
– Used to make yeast extracts
such as Marmite™
• It is rich in a range of B
vitamins.
Q. Assess the health benefits of yeast extracts like Marmite™.
– Good: Rich in B vitamins – niacin, thiamin, riboflavin, folic acid
and vitamin. May be an important source for some people.
– Bad: Salt content. Individuals with high blood pressure need to
control salt intake.
Beer and Wine
• Sugar is fermented to
ethanol by the yeast
Saccharomyces cerevisiae.
– Beers
• Sugar is from malted barley (or
other cereal)
– Ciders
• Sugar is from apple
– Wine
• Sugar is from grapes (or other
fruits in country wines)
Q. Briefly describe what happens during the malting process.
– Cereal grain is wetted and germination starts.
• Enzymes are produced which convert stored starch into maltose.
– Boiled to stop enzyme action and extract the maltose for
fermentation.
Antibiotics, e.g. penicillin
Penicillin sensitivity of Bacillus subtilis
• Antibiotics are chemicals
made by living organisms that
either kill or inhibit the
growth of microbes.
• The first antibiotic to be
extracted and produced
commercially was penicillin.
– Discovered by Alexander
Fleming, but production and
extraction was developed by
Howard Florey and Ernst Chain.
Q. Penicillin was initially thought of as a ‘magic bullet’ that could treat most
infections. Suggest why it has not lived up to this image.
– Only effective against certain (Gram-positive) bacteria with a thick
murein/ peptidoglycan cell wall.
– Resistance now widespread due to its overuse.
Human Insulin
• Type I diabetics do not
produce insulin and blood
sugar increases.
• Insulin can be extracted from
the pancreas of dead animals
– Cattle – bovine insulin
– Pigs – porcine insulin
Glucose can be detected in the
urine using reagent strips like these.
Better control is achieved using
electronic blood monitors.
• The bacterium Escherichia
coli has been genetically
modified so that it expresses
the human insulin gene.
Q. Suggest reasons why human insulin has become widely accepted in preference
to porcine and bovine insulin.
– It is human insulin and so fewer problems experienced.
– Ethical and religious reasons.
Pectinase
• Pectinase is widely used in
fruit juice extraction.
– It softens the cell walls
– Makes it easier for juice to
be extracted
– Significantly more juice is
extracted if the pulp is
treated with pectinase
• The fungus Aspergillus
niger produces pectinase.
Q. Suggest an economic reason for the use of pectinase in juice extraction.
– More juice from the same amount of fruit
• More profit
• Less waste (cheaper disposal)
Proteases and Lipases
• Enzymes are used in
biological detergents.
– Proteases digest protein
based stains (e.g. blood)
– Lipases digest fats and oils
One brand of biological detergent
• Cellulases may also be
present to remove the
outer layers from cellulose
fibres and help restore
saleroom colours to older,
faded garments.
Q. Suggest why biological detergents are considered by some to be
environmentally friendly.
– Effective stain removal at lower temperatures
• Less energy used to heat water
• Reduced carbon footprint
Meat Tenderisers
• Meat tenderisers do what
they say:
– They digest tough protein
fibres in meat.
• Traditionally, tenderisers
include:
– Papain
• From papaya
Papaya and pineapple.
– Bromelain
• From pineapple
• Fruit pulp can be used
Q. Pineapple is sometimes used as a marinade to soften meat before
cooking. Why should fresh, rather than tinned pineapple be used?
– During the tinning process, the pineapple is heated and so
enzymes, including the bromelain, are denatured.
Oil Spill Clean-Up
Exxon Valdez after it ran aground on Bligh Reef.
Public Domain image: US National Oceanic and
Atmospheric Administration.
• Torrey Canyon (1967); Exxon
Valdez in Prince William Sound,
Alaska (1989); Sea Empress in
Milford Haven, Pembrokeshire
(1996); Deepwater Horizon drilling
platform, Gulf of Mexico (2010).
• Strains of Pseudomonas can digest
individual hydrocarbon
components of oil. GM has
produced strains that can digest a
range of hydrocarbons, rather than
just single ones.
Q. What is the benefit of using bacteria to digest the oil from a spill rather
than using detergents and labour intensive manual cleaning?
– Detergents do not remove oil, simply emulsify it; can be toxic
to marine life; labour is expensive.
Sewage Treatment
Waste water is sprayed on the percolating filter –
microbes in the filter remove the majority of
soluble organic matter.
• Waste water contains organic
waste which, if it was
released untreated into rivers
could cause oxygen
depletion.
• It is treated before release:
–
–
–
–
Percolating/trickling filters
Oxidation ponds
Activated sludge
Anaerobic digestion
• All of these use microbes.
Q. Suggest why release of untreated waste water might result in oxygen depletion
in the receiving water.
– Untreated sewage contains organic waste and is food for microbes.
Microbes use the waste, grow rapidly and consume O2 in their
respiration.
Larger bits of waste sink to the bottom of the sedimentation tank. The sediment goes
Waste water is sprayed on the percolating filter. Microbes form a biofilm and consume
to anaerobic digesters. The water containing soluble organic waste goes to the
most of the organic waste, so that the effluent has a low biochemical oxygen demand
percolating filter, oxidation pond or activated sludge process.
(BOD) and can be safely discharged.
Copper Extraction
• The bacterium Thiobacillus
ferrooxidans has been used
to improve copper recovery
from mine tailings and low
grade chalcopyrite ore.
– Oxidises sulphur in the
chalcopyrite
CuFeS2+2Fe2(SO4)3+2H20+3O2 
CuSO4+2H2SO4+energy
Copper can be extracted from ore
(chalcopyrite) using ‘microbial miners’.
– Copper then extracted by
reacting with iron
CuSO4+Fe  Cu+FeSO4
Q. Suggest advantages of using ‘microbial miners’ to extract copper, rather than
using traditional techniques.
– Traditional techniques costly (energy requirements) and not efficient
(hence relatively large quantities in the mine tailings). Microbes
much more cost effective – lower grades profitable.