biotechnology used to make food

• biotechnology

  the broad area of biology, involving systems and organisms to develop or make products
• cheese

  • milk is treated with lactobacilius producing lactic acid from the lactose, then mixed with rennet
  • rennet contains an enzyme rennin obtained from stomachs of mammals which coagulates milk protein casein. casein broken down, turning soluble casein into insoluble. calcium ions bind casein together and precipitate it to form curd
  • whey is removed from curd and then its moulded
• yogurt

  • bifidobacterium added as a probiotic to aid gastrointestinal function
  • milk that has been fermented
  • the lactose in milk is converted to lactic acid which gives it the typical flavour and the acidity also denatures the milk protein making it coagulate together.
  • partial digestion of the milk by bacteria make the product easy for digestion
• baking

  • bread is made by mixing flour, water, salt and yeast together to produce a dough
  • the dough is left to prove in a warm place while the yeast respire anaerobically to produce carbon dioxide causing the dough to rise
• alcohol

  • yeast used
  • wine is produced using the natural yeast present on the skin of grapes
  • yeast uses the fructose and glucose from the crushed grapes to respire and release carbon dioxide and alcohol.
  • beer is produced by germinating barely grains in malting. as grain germinates it converts stored starch to maltose which is respired by yeast to produce carbon dioxide and alcohol
  • hops added to give a bitter taste
• advantages

  • contains no animal fat or cholesterol
  • provide a good source of protein
  • production of protein can be made many times faster than that of animal or plant protein
  • production is independent of seasonal variations
  • no animal welfare issues
  • microorganisms can be easily genetically modified
• disadvantages

  • isolation of the protein
  • microbia biomass can have high proportion of nucleic acids - need to be removed
  • protein does not have the same taste or textures as protein sources
  • people dont want to eat fungal protein or food grown on waste
  • can be deficient in methlonine
• quorn

  • fungal protein or mycoprotein also called SCP (single celled protein) is produced from fungus
  • contains no animal fat or cholesterol
• bioremediation

  • use of microorganisms to clean soil/ underground water on polluted sites
  • the organisms convert the toxic pollutants to non toxic substances
  • pseudomonas bacterium used to break down crude oil and can be used in treating oil spills
  • solvents and pesticides can also be treated using bioremediation
  • requires the right growth conditions for the organisms that are using contaminants as a source of food
• primary metabolites

  • substances produced by an organism as part of its normal growth. concentrations match population size
• secondary metabolites

  • substances produced by an organism not part of its normal growth
  • rarer than primary metabolites
  • only produced when microbe is well established in growth medium
• batch culture

  • microorganisms inoculated into fixed volume of medium
  • nutrients get used up, new biomass in waste builds up
  • stationary phase. overall growth stops, biochemical change
  • only single batch lost if contaminated
  • useful for production of secondary metabolites
• continuous culture

  • microorganisms inoculated into sterile medium
  • sterile nutrient medium added continually once it reaches exponential growth
  • product made during normal growth
  • product, cells and waste removed regularly
  • useful for production of primary metabolites
• parts of a fermenter

  • sterilising steam inlet
  • nutrient inlet
  • inoculation inlet
  • thermocouple
  • cooling water inlet
  • motor
  • pH control resevoir
  • sterilising stream inlet
  • gas exhaust outlet
  • cooling water outlet
  • baffle
  • paddle
  • filtered air inlet
  • harvesting line
• sterilising steam inlet

  before penicillin added
• nutrient inlet


  contains nutrients
• inoculation inlet

  penicillium added to begin fermentation
• thermocouple

  measure temp
• cooling water inlet

  cooling water runs through outer jacket to regulate temp
• motor

  rotates the blades to mix culture evenly
• pH control reservoir

  prevent it from getting too alkaline
• gas exhaust outlet

  prevent pressure building up
• baffle

  creates turbulence to mix contents
• paddle

  mixes contents, creates smaller air bubbles
• filtered air inlet

  penecillium respires aerobically so needs oxygen