biotech

• Biotechnology

  Industrial use of living organisms to produce food, drugs and other products
• Using microorganisms


  • ideal conditions can be provided
  • pH, moisture levels, availability of gases
  • short life cycle - grow rapidly, products made quickly
  • inexpensive materials
  • can be grown any time of year
• Enzymes

  extracellular enzymes that are naturally secreted are easier to obtain, and are cheaper too
• Uses:

  • brewing - anaerobic respiration of yeast to produce alcohol
  • baking - anaerobic respiration of yeast for CO2, so goods rise
  • cheese - bacteria and fungi, to clot, solidify and sour cheese
  • yoghurt - lactic acid bacteria, thickening
  • penicillin - fungus (penicillium) produces antibiotics
  • insulin - GM bacteria can produce human insulin
  • bioremediation - using organisms to remove pollutants
• Advantages of biotech:


  • waste products of processes as feed
  • grow quickly, easily and cheaply
  • can be cultured anywhere
  • considered to be healthier than animal protein
  • low fat, high complete protein
  • can be GM, taste can also be modified
• Disadvantages of biotech:

  • risk of contamination of other microorganisms (aseptic techniques required)
  • not the same texture / flavour of real meat
  • general concerns of GM, growth from waste products
• Fusarium venenatum


  • a single cell protein (SCP)
  • a fungus
  • mixed with egg white to form quorn
• Cyanobacteria


  • a bacteria
  • makes a complete protein in a tablet or powder forms
  • a dietary supplement
  • single cell protein (SCP)
• Fermentation vessel

  A) water jacket

  B) water in

  C) water out

  
• Fermentation vessel

  • air flow - allows for aerobic fermentation
  • water jacket - regulate temperature
  • steam in, nutrients in
  • outlet for product
  • stirring paddles - mix culture evenly
  • a probe
  • filters - prevent contamination
• Fermentation vessel - probe


  • monitors
  • pH
  • temperature
  • oxygen levels
  • allows optimum conditions for enzymes
• Batch fermentation


  • reduced contamination
  • closed culture - everything added at once or removed at once
  • easy to maintain optimum and sterile conditions
  • product is harvested during stationary phase to collect secondary metabolites
• Continuous fermentation:


  • open culture - nutrients are continuously added, waste and products are continuously removed
  • aseptic conditions and optimum conditions are difficult to maintain
  • high contamination risk
  • efficient process
  • product is harvested during exponential phase to collect primary metabolites
• Standard growth curve

  A) lag

  B) log

  C) stationary

  D) decline

  
• Standard growth curves in biotech

  • death/decline phase present if a closed system
  • waste products are in great concentrations - toxic
  • food is scarce
• Calculating population size


  initial number of cells x 2^ number of divisions
• Primary metabolites


  • produced as part of normal growth
  • includes enzymes and nucleic acids
  • follows pattern of normal population growth
  • in industry - continuous fermentation
  • harvested during exponential phase

  
• Secondary metabolites

  • not produced as part of normal growth
  • things produced to reduce number of competitors, to protect nutrient supply
  • often stress responses - e.g. anitbiotics
  • production rate does not follow pattern of normal growth
  • in industry - batch fermentation
  • harvested during stationary phase

  
• Downstream processing - extraction and purification of products

  • intracellular products - cells must be broken open
  • cells or cell debris is removed through CENTRIFUGATION or FILTRATION
  • EVAPORATION to remove water, concentrating the product
  • purification through CHROMATOGRAPHY or PRECIPITATION
• Culturing microorganisms


  • agar pate - sterile Petri dish, containing agar jelly
  • nutrients can be added to agar to improve growing conditions
  • inoculation loop or sterile pipette and spreader
  • incubation - 25°C, plates stored upside down and taped shut
• Aseptic techniques

  • to prevent contamination by unwanted microorganisms
  • they can effect growth of the microorganism being cultured
  • imprecise results may result in hazards to health
  • industrial scale - contamination results in lots of waste
• Aseptic techniques

  • regularly disinfect work surfaces
  • work near a bunsen flame so hot air rises to remove contaminants
  • sterilise instruments, bottle necks and glass wear before and after use
  • work in an inoculating cabinet
  • wear a lab coat, wear gloves, tie hair back
• Advantages of enzymes in biotech

  • catalysts
  • specific
  • biodegradable
  • work under 'normal conditions'
• Disadvantages of enzymes


  • sensitivity to pH and temperature
  • expensive production
• Immobilised enzymes

  • isolated enzymes are immobilised so they are prevented from dispersing in a solution
  • they are bound together, attached or entrapped
• Advantages of isolated enzymes

  • less waste of substrate
  • single product formed
  • easier to maintain optimum conditions
• Advantages of immobilised enzymes

  • enzyme is reusable
  • simpler downstream processing
  • increased enzyme stability
  • greater control over reaction
• Disadvantages of immobilised enzymes

  • expensive to buy
  • require expensive equipment
  • can lead to a reduction in enzyme activity
• Methods to immobilise enzymes

  • adsorption
  • covalently bonded
  • lattice entrapment
  • membrane encapsulation
• Adsorption - immobilised enzymes

  • ionic bonds
  • low cost
  • active site is usually available
• Covalent bonds - immobilised enzymes

  • high costs
  • active site is always available
• Lattice entrapment - immobilised enzymes

  • silica lattice or cellulose lattice
  • enzyme is trapped, not bound
  • difficult to reach enzyme within mesh
  • moderate cost
• Membrane encapsulation - immobilised enzymes

  • high cost
  • partially permeable membrane
  • substrate has to diffuse in and out of the membrane
• immobilised enzymes in industry

  • a column is used
  • substrate solution runs DOWN the column so immobilised enzymes can act
  • product comes out the bottom