F215 control, genomes and environment

Module 2 – Biotechnology and gene technologies

Learning Outcomes

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

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

Features of micro organisms that make them suitable for large-scale industrial processes 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

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

Lag phase Bacteria adjusting to

new conditions Takes a while for

enzyme production Log phase

Number of bacteria increase rapidly

Stationary Phase Rate of growth is

equal to rate of death

Decline Phase Death rate is greater

than “birth rate” The first three

stages represent a sigmoid growth curve

Learning Outcomes

Explain the importance of manipulating the growing conditions in a fermentation vessel in order to maximise the yield of product required.

Large-Scale production

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

Three examples are The production of penicillin The production of protease enzymes The production of mycoprotein

Learning Outcomes

Compare and contrast the processes of continuous culture and batch culture.

Describe the differences between primary and secondary metabolites.

Metabolism and metabolites

Metabolism (process) Sum total of all the chemical reactions Processes produce▪ New cell and cell components▪ Chemicals▪ Waste products

Metabolites (products) A substance produced during cell

processes

Primary and secondary metabolites

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

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

Starter population is mixed with a specific quantity of nutrient solution

Allowed to grow for a fixed periodProducts removedFermentation tank emptiedExamples

▪ Penicillin production▪ Enzyme production

Continuous Culture

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

Explain the importance of asepsis in the manipulation of microorganisms

Asepsis

Asepsis absence of unwanted microorganisms

Aseptic techniques Any measure taken during a

biotechnological process to prevent contamination by unwanted microorganisms

The importance of asepsis

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 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 Maintains a steady airflow out of the room

Ensure culture of microorganisms is pure Ensure the workers do not introduce unwanted

microorganisms from their skin.

Learning Outcomes

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 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.

Methods for immobilising enzymes

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

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

Adsorption / carrier bound Enzyme molecules

are mixed with immobilising support e.g. glass beads or clay

Covalent Bonding / cross-linked Enzyme molecules

covalently bonded to a support

Methods of immobilising enzymes

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

Membrane separation Substrate separated from

the mixture by a partially permeable membrane.

Advantages of immobilised enzymes

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