Transcript Communication

F215 control, genomes and environment
Module 2 – Biotechnology and gene
technologies
Learning Outcomes
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State that biotechnology is the
industrial use of living organisms (or
parts of living organisms) to produce
food, drugs or other products.
Explain why micro organisms are often
used in biotechnological processes.
Biotechnology
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Biotechnology is the industrial use of
living organisms to produce food,
drugs and other products.
Biotechnology has four major
applications that affect our lives
 Healthcare and medical processes
 Agriculture
 Industry
 Food science
Using Micro organisms
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Features of micro organisms that make
them suitable for large-scale industrial
processes
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Rapid life cycles
Reproduce asexually
Very specific and simple requirements for growth
Can be grown on waste materials from industry
Does not raise ethical questions
Bacteria have a single copy of each gene
Simple control of gene expressions
Wide range of metabolic pathways
Some evolved to survive at high temperatures
Learning Outcomes
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Describe, with the aid of diagrams,
and explain the standard growth
curve of a microorganism in a closed
culture.
Standard Growth curve
Growth curve
in a closed
culture
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Lag phase
 Bacteria adjusting to
new conditions
 Takes a while for
enzyme production
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Log phase
 Number of bacteria
increase rapidly
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Stationary Phase
 Rate of growth is
equal to rate of
death
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Decline Phase
 Death rate is greater
than “birth rate”
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The first three stages
represent a sigmoid
growth curve
Learning Outcomes
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Explain the importance of
manipulating the growing conditions
in a fermentation vessel in order to
maximise the yield of product
required.
Large-Scale production
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Microorganisms are cultured in large
containers called fermenters
The growing conditions within the
fermenter are manipulated and
controlled
 Precise growing conditions
▪ Temperature
▪ Type and time of the addition of the nutrient
▪ Oxygen concentration
▪ pH
A batch fermenter
Large scale production
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Three examples are
 The production of penicillin
 The production of protease enzymes
 The production of mycoprotein
Learning Outcomes
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Compare and contrast the processes
of continuous culture and batch
culture.
Describe the differences between
primary and secondary metabolites.
Metabolism and metabolites
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Metabolism (process)
 Sum total of all the chemical reactions
 Processes produce
▪ New cell and cell components
▪ Chemicals
▪ Waste products
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Metabolites (products)
 A substance produced during cell
processes
Primary and secondary
metabolites
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Primary metabolite
 Substance produced
by organism as part
of it’s normal growth
 E.g. amino acids,
proteins, enzymes
 Production of
primary metabolites
matches the growth
in population
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Secondary metabolite
 A substance only
produced at a
particular growth phase
 No direct involvement
in fundamental
metabolite processes
 Production usually
begins after the main
growth phase of the
micro organisms
Batch culture
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Starter population is mixed with a
specific quantity of nutrient solution
Allowed to grow for a fixed period
Products removed
Fermentation tank emptied
Examples
▪ Penicillin production
▪ Enzyme production
Continuous Culture
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Nutrients are added and products are
removed from the fermentation tank
at regular intervals
Examples
▪ Insulin production from genetically modified
E.Coli
▪ Production of mycoprotein
Learning outcomes
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Explain the importance of asepsis in
the manipulation of microorganisms
Asepsis
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Asepsis
 absence of unwanted microorganisms
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Aseptic techniques
 Any measure taken during a
biotechnological process to prevent
contamination by unwanted
microorganisms
The importance of asepsis
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Unwanted microorganisms
 Compete with the culture microorganisms
 Reduce the yield of useful products
 Cause spoilage of the product
 Produce toxic chemicals
 Destroy the culture microorganism or its
products.
Methods to maintain asepsis
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Ensure all fermenters and attachments are sterile
 Cleaning with pasteurised steam
 Chemical sterilisation
Sterilise all liquids, solids and gases that enter the
reaction vessel
 Maintain a pressure difference between the air in
the room where fermentation is taking place and
outside
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 Maintains a steady airflow out of the room
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Ensure culture of microorganisms is pure
Ensure the workers do not introduce unwanted
microorganisms from their skin.
Learning Outcomes
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Describe how enzymes can be
immobilised.
Explain why immobilised enzymes are
used in large-scale production.
Immobilising enzymes
Enzymes act as catalysts in metabolic
reactions
 Enzymes are useful in industrial processes
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 Specificity
 Temperature of enzyme action
Enzymes in solution need to be separated
from the products.
 Immobilised enzymes can be re-used many
times and leaves the product enzyme free.
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Methods for immobilising
enzymes
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Gel entrapment
 Example – immobilising lactase in alginate
 Stages
▪ Enzyme solution is mixed with sodium alginate
solution
▪ Droplets of this solution are added to a solution
of calcium chloride
▪ The droplet turns into a bead which contains
the enzyme
Immobilising lactase in alginate
Immobilising lactase in alginate
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The beads can be tightly
packed into a column
The liquid substrate can
be trickled over the
beads
The product trickles out
of the bottom of the
column
The product is collected
and purified.
Methods of immobilising
enzymes
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Adsorption / carrier
bound
 Enzyme molecules
are mixed with
immobilising support
e.g. glass beads or
clay
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Covalent Bonding /
cross-linked
 Enzyme molecules
covalently bonded
to a support
Methods of immobilising
enzymes
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Entrapment / inclusion
 Enzymes trapped in their
natural state in a gel bead
 Reaction rate can be
reduced as substrate needs
to get through the trapping
barrier
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Membrane separation
 Substrate separated from
the mixture by a partially
permeable membrane.
Advantages of immobilised
enzymes
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The advantages of using immobilised
enzymes over enzymes in solution are
 Immobilised enzymes can be reused
 Product is enzyme free
 Immobilised enzymes are more tolerant to
pH and temperature changes