Biotechnology and genetic

• Biotechnology


  The application of biological organisms, systems or processes to manufacturing and service industries
• Genetic modification


  The transfer of genes from one organism to (usually) an unrelated species
• Bacteria


  • They can make complex molecules (proteins, for example)
  • They have a rapid reproduction rate
• Bacteria are useful in biotechnology and genetic modification because they can be grown and manipulated without raising ethical concerns
• Bacterial DNA is in the form of a circular strand and also small circular pieces called plasmids
• Genetic modification using bacteria

  1. Cut open plasmids

  2. Insert sections of DNA from other organisms

  3. Bacterium divides, modified plasmid DNA is copied
• Anaerobic respiration


  The fermentation of glucose to alcohol
• Biotechnology applications


  • Bread-making
  • Biofuel production
  • Fruit juice production
  • Biological washing powders
  • Lactose-free milk production
  • Antibiotic production
  • Insulin production
  • Mycoprotein production
• Pectinase


  Enzyme that breaks down pectin, the jelly-like substance that sticks plant cell walls together
• Biological washing powders


  Contain protein-digesting enzymes (proteases) and fat-digesting enzymes (lipases) to remove stains
• Lactase


  Enzyme that breaks down lactose sugar into glucose and galactose
• Lactose-free milk production


  1. Add lactase enzyme to milk

  2. Immobilise lactase on beads to remove lactose from milk
• Antibiotic production


  1. Grow microorganism in fermenter

  2. Extract and purify antibiotic compound
• Mycoprotein


  Protein-rich meat substitute extracted from the filamentous fungus Fusarium venenatum
• Conditions that need to be controlled in a fermenter include nutrient levels, temperature, pH, moisture, and air supply
• Antibiotic production


  1. Nutrient fluid containing antibiotic is filtered off

  2. Antibiotic is extracted by crystallisation or other methods
• Mycoprotein


  Protein-rich meat substitute extracted from fungi
• Mycoprotein


  • Contains no cholesterol
  • Lower in saturated fats than protein in meat products
  • Suitable as part of a vegan diet
• Mycoprotein is becoming more popular partly because of its high protein content
• Mycoprotein manufacture


  Fermented in a similar way to antibiotics and enzymes, using glucose and salts as the feedstock
• Mycoprotein product


  • Quorn
• Conditions that need to be controlled in a fermenter

  • Temperature
  • pH
  • Oxygen
  • Nutrient supply
  • Waste products
• Temperature


  Maintained at around 28°C. Heat is generated during fermentation, so the mixture needs to be cooled
• pH


  Slightly acidic - 5 to 5
• Oxygen


  Sterilised air is blown into the mixture through air pipes and the mixture is stirred to aerate it
• Nutrient supply


  Depends on what is being manufactured, but for penicillin the feedstock is molasses or corn-steep liquor
• Waste products


  Depends on what is being manufactured, but for penicillin they are the waste nutrient fluid with bacterial residue. These are quite hazardous because of the presence of traces of antibiotic. Gases given off may include carbon dioxide.
• Bacteria are microscopic single-celled organisms with cytoplasm, cell membranes and cell walls, but without a proper nucleus
• Genetic control in a bacterium is carried out by a double strand of deoxyribonucleic acid (DNA) in the form of a circle, but not enclosed in a nuclear membrane
• Bacteria also have a number of small, circular pieces of DNA called plasmids present in the cytoplasm
• Plasmids


  Often carry genes that give the bacterium resistance to particular antibiotics like tetracycline and amnicillin
• Restriction enzymes


  Produced by bacteria, they cut DNA molecules at specific sites
• Genetic modification using restriction enzymes


  1. DNA from human cells is removed and restriction enzymes used to cut out a sequence of DNA that includes a gene

  2. Plasmids are removed from bacteria and cut open with the same restriction enzyme

  3. Human DNA attaches to the plasmids by their sticky ends

  4. Plasmids containing the human DNA are returned to the bacteria

  5. Bacteria reproduce rapidly to make millions of cells containing the recombinant DNA

  6. The human DNA in the plasmids continues to produce the same protein as it did in the human cells
• Expression


  When bacteria are modified so they can produce a human protein like insulin
• Insulin production in genetically modified bacteria

  1. Bacteria are cultured in fermenters

  2. Insulin produced by the bacteria is extracted from the culture medium and purified
• Variations in genetic modification include using viruses as vectors, inserting DNA directly without a vector, synthesising donor DNA from nucleotides, and using yeast instead of bacteria
• Applications of genetic modification

  • Production of human proteins like insulin
  • Hepatitis B vaccine production in genetically modified yeast
  • Transgenic plants producing vaccines like rabies and cholera
• Strict control measures must be applied to ensure plants modified to produce drugs and vaccines cannot find their way into the human food chain
• GM crops


  • Herbicide resistance
  • Pest resistance
• Herbicide resistance in GM crops

  Allows use of effective herbicides like glyphosate that kill any green plant but become harmless in the soil