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BIO1004:
Microbial biotechnology
Dr Alison Graham
19 November 2015
Ridley Building 2
Room 5.68
[email protected]
What is biotechnology?
•Use of organisms to make useful products.
•Application of organisms or their cellular
components to specific processes.
•Can include organisms manipulated by
genetic engineering.
•Also called industrial microbiology.
Microbial biotechnology: some examples
Medical
• insulin
• antibiotics
• anti-venom
• Botox
• vaccines
Food and beverages
• bread
• cheese
• citric acid
• alcohol
• QuornTM
• probiotics
• marmite
• yoghurt
Enzyme production
• washing powder enzymes
• amylases – hydrolyse
starch to other sugars
• DNA polymerases
Environmental applications
• bioremediation
• biosensors
• agriculture e.g. Rhizobium
• sewage treatment
Microbial biotechnology: some examples
Medical
• insulin
• antibiotics
• anti-venom
• Botox
• vaccines
Food and beverages
• bread
• cheese
• citric acid
• alcohol
• QuornTM
• probiotics
• marmite
• yoghurt
Enzyme production
• washing powder enzymes
• amylases – hydrolyse
starch to other sugars
• DNA polymerases
Environmental applications
• bioremediation
• biosensors
• agriculture e.g. Rhizobium
• sewage treatment
Not new
Wine, cheese, bread produced with aid of microbes.
How have things changed?
Ability to manipulate cells to control what they
produce and how they produce it.
Now, many many more substances are produced by microbes
(e.g. food, medicines, chemicals).
In 2012…
Europe
USA
Private
Revenue
companies
1799
$20 billion
1859
$64 billion
Source: Biotechnology in Europe, 2014, EY and EuropaBio
By the end of the lecture, you will be able to…
• Describe the characteristics that are required of a
microbial process for it to be industrially useful.
• Explain the difference between primary and
secondary metabolites.
• Describe the key steps in the industrial
production of:
• Penicillin
• Insulin
Characteristics required for industrial use
It is economically advantageous to do so (e.g. more economical than
chemical processes).
•
Must produce large quantities of the required product (high yield)
•
Must grow rapidly in liquid culture
•
Must be suitable for growth in large batch or continuous
fermentation systems
•
Must use nutrients which can be obtained readily and cheaply
•
Product must be easily separated from other compounds
produced by the organism
•
Must be able to be scaled up
•
Must not be pathogenic
•
Beneficial if easily genetically engineered
Primary metabolites and secondary
metabolites
Primary metabolites
• Products produced
up to end of
exponential phase of
growth.
• Often associated
with essential
energy metabolism,
e.g. lactic acid,
ethanol.
Production of product
mimics cell growth
Primary metabolites and secondary
metabolites
Secondary metabolites
• Produced at end of
exponential and during
stationary phase of
growth.
•
Characteristic of specific
organisms.
•
Not essential for growth.
•
Production varies
depending on
environmental conditions.
Production of product starts at
or near beginning of stationary
phase
Antibiotic production
Penicillin – famously discovered by Alexander Fleming.
The Nobel Prize in Physiology or Medicine 1945 “for the
discovery of penicillin and its curative effect in various
infectious diseases” with Ernst Chain and Howard Florey.
b-lactam antibiotics – prevent peptidoglycan cross-links
forming.
Antibiotic production
Penicillin – famously discovered by Alexander Fleming.
The Nobel Prize in Physiology or Medicine 1945 “for the
discovery of penicillin and its curative effect in various
infectious diseases” with Ernst Chain and Howard Florey.
b-lactam antibiotics – prevent peptidoglycan cross-links
forming.
Penicillin production
• Produced by Penicillium
chrysogenum.
• Originally (1 mg/L), now
(~50 g/L).
• Grown in a fed-batch
culture.
Photos from:
http://www.abdn.ac.uk/ims/research/microbiology/profiles/l.a.glover
http://www.flickr.com/photos/ajc1/2902232380/
Penicillin production
First stage – focused on growth.
Second stage – when the target biomass is
achieved, “starve” the culture to induce
stress.
This triggers the production of the
antibiotic.
About 40 h before penicillin produced but
production can last for a further 100+ hours.
•
•
Aerobic, ~26 °C,
Nutrients:
•
corn steep liquor (by-product of the
production of corn starch - rich in
nitrogen and growth factors),
•
whey (by-product of cheese
production – lactose)
•
glucose and lactose are common
sugars used
Harvesting penicillin
excreted
into medium
by cells.
Figure by MIT OpenCourseWare
Production of insulin
• Insulin regulates uptake of glucose from the blood into cells.
• Type I diabetes is caused by lack of insulin  high blood sugar.
• Originally purified from pancreas of slaughtered pigs and cows.
• Not identical to human insulin so not as effective and could potentially
cause allergic reaction.
• Genetic engineering enabled human insulin to be produced by
microorganisms.
• Insulin made of an A and B chain linked by disulphide bonds
• Proinsulin produced then C-peptide removed to produce insulin
• Two options industrially (bacteria or yeast as host):
• Both chains produced separately then joined
• Proinsulin produced then cleaved
Photo from:
http://www.bbc.co.uk/news/health-16657425
Leonard Thompson
– first human to
receive an injection
of insulin in 1922
Johnson (2003)
Penicillin is a secondary metabolite
produced by
1. Penicillium
expansum
2. Penicillium
chrysogenum
3. Penicillium
notatum
86%
9%
1.
5%
2.
3.
Which production method is used to make
penicillin?
1. Batch culture
2. Continuous
culture
3. Fed-batch
culture
85%
11%
1.
5%
2.
3.
Suggested further reading on industrial microbiology:
• Staley et al. Microbial Life, 2nd ed. Relevant parts of
Chapter 31.
• Slonczewski and Foster, Microbiology: An evolving
science. Relevant parts of Chapter 16.
• Demain AL (2000) Microbial biotechnology. Trends in
biotechnology 18:26-31.
Suggested further reading on insulin production:
• Johnson IS (2003) The trials and tribulations of
producing the first genetically engineered drug.
Nature reviews: Drug discovery 2:747-751.
• https://www.youtube.com/watch?v=iMosKBs-v0E