Transcript biotech start (becsmith v1)

Biotechnology basics
• State that biotechnology is the industrial
use of living organisms (or parts of them)
to produce food, drugs or other products.
What sort of organisms are involved?
See page 159
Biotechnology basics
Explain why microorganisms are often
used in biotechnological processes.
•
•
•
•
•
Fast growth
Often secrete products into growth medium
Can be genetically engineered easily
Grow well at low temp, lower that chemical processes
Not climate dependent, can be grown in culture
anywhere
• Produce purer product than chemical processes
• Can utilise waste products as growth medium
Biotechnology basics
•
•
•
•
What is a culture?
What is a mixed culture?
What is nutrient broth?
How is nutrient broth different from nutrient
agar?
• What is a fermentation tank?
•
•
Describe and explain, with the aid of diagrams, the standard
growth curve of a population of microorganisms in a closed
culture.
What are the 4 phases on the graph and why do they occur?
© Pearson Education Ltd 2009
This document may have been altered from the original
Describe the differences between
primary and secondary metabolites.
• What is metabolism?
• What are primary metabolites?
• What are secondary metabolites?
Primary metabolite and Secondary metabolite
Growth and product curves
showing the production of (a)
a primary metabolite and (b) a
secondary metabolite
Primary metabolites are made
during normal growth, eg
proteins, enzymes, nucleic acids,
ethanol, lactate etc. Their
production rate follows the
growth curve
Secondary metabolites are not
produced during normal growth.
Their production usually starts
after the normal growth phase
Not all microbes produce
secondary metabolites
Immobilised Enzymes
• Describe how enzymes can be immobilised
•
Adsorption onto clay, resin, glass beads and porous carbon.
Enzymes are held on the surface by hydrophobic interactions and ionic links.
Good exposure of active sites.
Enzyme not tightly bound so may leach off surface and be lost. Bonding may
affect active site.
•
Covalent bonding to other enzyme molecules and to a support.
Enzyme tightly bound so little leakage from support but cannot bind large
amounts of enzyme. Bonding may affect active site.
•
Entrapment within a gel bead or cellulose fibres.
Reaction rates can be slowed because substrate molecules have to get
through the gel or fibres to get to the active sites.
•
Membrane separation
Partially permeable membrane separates enzyme and substrate. Substrate
passes through, reaction takes place, products pass back through
membrane to be collected.
a) Adsorption on clay etc
b) Covalent linking
c) Trapped in fibres
© Pearson Education Ltd 2009
This document may have been altered from the original
Immobilised Enzymes
• Explain why immobilised enzymes are used in largescale production.
ADVANTAGES
• Enzymes are kept separate from the products so
purification costs are low
• Enzymes immediately available for re-use, no need for
complicated extraction process
• Immobilised enzymes are more stable because the
immobilising matrix protects the molecules (eg from
temperature changes or pH changes)
© Pearson Education Ltd 2009
This document may have been altered from the original
Immobilised Enzymes
• Explain the problems with immobilised enzymes in largescale production.
DISADVANTAGES
• Immobilising enzymes is more expensive
• Immobilised enzymes may give slower reaction rates as
molecules do not mix freely with substrate molecules
• Substrate has to diffuse into bead structures or through
mesh
• Contamination is more difficult to deal with
© Pearson Education Ltd 2009
This document may have been altered from the original
Immobilised organisms
• Sometimes microorganisms are immobilised
instead of individual enzymes.
Advantages
• Enzymes unlikely to leach out into product
• Microorganisms make the enzymes necessary
Disadvantages
• Reaction rates may be slower as substrate has
to enter through cell membrane
• Other unwanted products may be made in
addition to the required one, these then need
separating out.
The production of penicillanic acid using an
immobilised enzyme reactor
As microbes become resistant to penicillin
biochemists try to produce new antibiotics.
They put penicillin through immobilised
penicillin acyclase.
This produces 6 amino penicillanic acid
which can be used as a base molecule to
produce a range of penicillin- like
antibiotics
Currently microbes are not resistant to
these new molecules
© Pearson Education Ltd 2009
This document may have been altered from the original
Compare and contrast the processes of
continuous and batch culture.
Batch
• Growth slower as nutrients
decline
• Easy to set up and
maintain
• Only one batch lost if
contamination occurs
• Less efficient, fermenter
not always in use
• Useful for producing
secondary metabolites
Continuous
• Growth faster as always
nutrients there
• Difficult to set up and
maintain
• Huge volumes lost if
contamination occurs
• More efficient fermenter
in use constantly
• Useful for producing
primary metabolites
© Pearson Education Ltd 2009
This document may have been altered from the original
Manipulating the growing conditions in a fermentation vessel
in order to maximise the yield of product required.
© Pearson Education Ltd 2009
This document may have been altered from the original
Explain the importance of asepsis in the manipulation of
microorganisms.
Asepsis is ensuring there is no entry of any possible
contaminating microorganism that could:
•Compete for the nutrients in the growth medium
•Compete for space in the fermenter
•Reduce the yield of product from cultured microbes
•Cause spoilage of the product
•Produce toxic chemicals which could be harmful to users
of the product
•Destroy the culture organisms and/or their products
Aseptic Technique
Lab measures
• Sterilise all equipment before
and after transfers. Dry heat,
eg transfer loops; steam/
autoclave, eg liquid or agar
medium UV treat, eg plastic
petri dishes; ethanol flamed,
eg forceps etc
• Air currents from Bunsen
burners or lamina flow
cabinets carry airborne
contaminants away
• Cultures kept closed at all
times when not in use
Industrial measures
• Wash, disinfect and steam
clean fermenter and pipes
• Surfaces made of easy clean
stainless steel
• High temperature and pressure
(autoclave) sterilisation of all
culture media before adding to
fermenter
• Micro filters on inlets and
outlets prevent unwanted
microbes entering or leaving
accidentally