Biotechnology

• Biotechnology


  Making microorganisms work for us

  
• Even though biotechnology as branch of applied life sciences is relatively new, it is also one of the oldest branches of science
• Early biotechnology


  • Ancient Egyptians brewed beer 6000 B.C.
  • Archaeologists in China discovered Neolithic pottery containing the chemical signatures of honey, rice and compounds associated with the process of fermentation 7000 B.C.
• Microbial biotechnology (industrial microbiology)


  Using microorganisms to produce valuable commercial products and carry out important processes

  
• Requirements for an industrial microorganism

  • Produce the product of interest in high yield
  • Grow rapidly on inexpensive culture media
  • Be amenable to genetic manipulation
  • If possible, be nonpathogenic

  
• Primary metabolites


  Directly related to normal cellular growth, include amino acids, nucleotides, fermentation end products, enzymes
• Secondary metabolites


  Usually accumulate in the period of nutrient limitation or waste product accumulation that follows active growth
• Fermentation


  The mass culture of cells in industrial settings
• Fermenter (bioreactor)


  • Enclosed and sterilised vessel that maintains optimal conditions for the growth of a microorganism
  • Probes and sensors monitor conditions
  • Acid/base inlets allow pH regulation
  • External water jacket absorbs excess heat
  • Aerator introduces compressed air
  • Motorised stirring paddles distribute heat and nutrients
  • Nutrient inlets and waste outlets
  • Harvest line for product removal
• Batch culture


  Fermentation is carried out in a closed fermenter, with nothing added or removed during the process except venting of gas
• Continuous culture


  Fermentation is carried out in an open fermenter, with nutrients added and product removed at a steady rate throughout
• Advantages of batch culture

  • Low risk of contamination or mutation
  • Less expensive than continuous culture
  • More flexible with varying products/biological systems
• Disadvantages of batch culture

  • Lower productivity due to idle time
  • Need to prepare cultures to inoculate the fermenter each time
  • Higher labour costs
• Advantages of continuous culture

  • Higher degree of control possible
  • Growth rates can be regulated and maintained for extended periods
  • Higher productivity
  • Automation makes it more cost effective and less sensitive to human error
• Disadvantages of continuous culture

  • Cell aggregation or growth on walls can prevent accurate monitoring and maintenance
  • Long growth periods increase risk of contamination or mutation
  • Continuous fermentation is feasible only when the inoculated cells are genetically stable
• Wild-type


  Not always very efficient due to slow growth rates, complex nutritional requirements, and risk of mutation
• Genetically modified organism (GMO)


  Can be a faster-growing organism with less complex requirements, and can be 'forced' to overproduce the protein of interest
• White biotechnology (industrial biotechnology) involves the employment of microorganisms in chemical production
• Areas within white biotechnology

  • Chemical production
  • Designing processes and products that consume fewer resources
  • Production of biodegradable polymers
  • Production of industrially relevant enzymes
  • Production of fuel from renewable sources or from waste
• Biocatalysts


  Enzymes used in the industrial production of chemicals and pharmaceuticals, conduct processes more efficiently than chemical synthesis
• Biocatalytic modification of a steroid (progesterone)


  • Water-insoluble steroid added to reactor containing the fungus Rhizopus nigricans, steroid is hydroxylated and purified
• Advantages of biocatalysis over chemical synthesis

  • Natural enzymes have stereospecificity
  • Products are biologically active
  • Can occur under mild conditions, less energy/resources required, fewer toxic chemicals
• Biofuels are fuels made from living organisms or the waste they produce
• Bioethanol


  The most common biofuel, produced by yeasts fermenting the sugars in plants like sugar cane, sugar beet, or corn
• Advantages of using bioethanol as fuel

  • Low in toxicity and causes little environmental pollution
  • Ethanol burns to produce carbon dioxide and water
  • Lower greenhouse gas emissions
  • Renewable resource
• Blending ethanol with petrol helps to oxygenate the fuel mixture so it burns more completely and reduces polluting emissions
• Issues with bioethanol production

  • Ethanol is not particularly energy dense
  • Ethanol is easily hydrated and cannot be easily transported via pipelines
  • Requires distillation to keep it pure and free from water
  • Ethanol is made from food crops, need to find other sources
• Lignocellulose


  The woody, inedible parts of plants, a source of glucose for secondary biofuel production
• Creating secondary biofuels from lignocellulose

  1. Fermentation with microorganisms with cellulase enzymes breaks down cellulose into glucose

  2. Glucose is then fermented by yeast into bioethanol
• Microorganisms used for lignocellulose breakdown

  • Trichoderma reesei
  • Sulfolobus sulfataricus
• Red biotechnology involves the use of microorganisms for medical/healthcare applications

  
• Biopharmaceuticals


  Any drug product manufactured by or extracted from a biological source
• Over 65% of all antibiotics are produced by microorganisms, mostly from the soil bacteria Streptomyces and filamentous fungi
• Antibiotics


  • Penicillin
  • Ampicillin
  • Amoxicillin
• Recombinant DNA technology allowed the gene for human insulin to be isolated and cloned into a bacterial expression system
• Green biotechnology involves technologies that have a positive impact on agriculture
• Agrobacterium tumefaciens


  Soil bacterium that can introduce genetic material into plant cells, altering their genetic makeup
• Pharmaceutical products produced using biotechnology

  • Hormones
  • Antibodies
  • Blood clotting factors
  • Vaccines
• Green biotechnology


  Technologies that have a positive impact on agriculture
• Green biotechnology involves


  1. Creation of new crops using traditional/GM approaches

  2. Creation of new fertilisers

  3. Creation of new biopesticides