Gene Therapy Risks & Food Production with Microorganisms

Risks of Gene Therapy

The risks associated with gene therapy include:

  • Undesirable health effects (e.g. cancers, death)
  • If gene insertion occurs in the wrong location, it may affect the functioning of pre-existing genes that are vital within the genome.
  • Viral vectors may infect healthy cells or tissues.
  • Virus may revert to original form (mutate) and become pathogenic.
  • Virus entry may trigger an immune response, leading to inflammation, toxicity, and organ failure.
  • Treatment must be repeated at regular intervals, increasing the likelihood of adverse treatment response over time.

Saccharomyces Use in Beer, Wine, and Bread Production

  • Saccharomyces cerevisiae (yeast) undergoes anaerobic respiration in the absence of oxygen to produce ethanol and carbon dioxide.
  • Anaerobic respiration in yeast: Glucose → Pyruvate → Ethanol + CO2
  • This reaction forms the basis for the production of a range of food sources, including beer, wine, and bread.

Beer

  • Barley grains are wetted to cause germination, which triggers the breakdown of starch to maltose – making a liquid called malt.
  • More water is added to make a sweeter-tasting liquid called wort, and then hops are added to give the liquid a bitter taste.
  • The mixture is boiled and cooled before yeast is added, which breaks down the maltose into glucose.
  • Fermentation by yeast produces ethanol and carbon dioxide, and the beer is finally pasteurized (heated) to kill any remaining yeast cells.

Wine

  • In wine production, yeast is added to crushed grapes and put into a tank. When the oxygen is consumed aerobically, fermentation occurs.
  • Carbon dioxide escapes from the tank while the ethanol stays behind.
  • The yeast cells are not killed by heat as this would affect the taste (may be killed later by the concentration of ethanol).
  • Different strains of yeast produce different flavors, and the strains used are capable of withstanding higher concentrations of alcohol (>10 – 15%).

Bread

  • The primary function of Saccharomyces in bread-making is the production of carbon dioxide to make the dough rise.
  • Yeast acts on sugars in the dough, breaking them down by fermentation to make carbon dioxide and ethanol.
  • When the bread has risen to a desired height, the bread is baked in an oven to kill the yeast and evaporate the ethanol.

Soy Sauce Production Using Aspergillus oryzae

  • Soya beans are soaked, boiled, and drained before being mixed together with toasted, crushed wheat.
  • A culture of Aspergillus oryzae is added, and the mash is incubated for 3 days at 30ºC.
  • Salt and water are then included before the mixture is allowed to ferment for 3 – 6 months.
  • At the end of this process, the mix is filtered and pasteurized, with sediments and oils removed, to make soy sauce.

Food Preservation: Acids and High Salt/Sugar

  • Food preservation allows food to be successfully stored for longer periods of time by preventing the growth of microorganisms that may feed on it.
  • Foods can be preserved by submerging in acid solutions – microbes cannot survive in low pH environments unless they are acidophiles.
  • Foods can also be preserved in high salt or sugar solutions – these are hypertonic and draw water out of the microbe by osmosis, desiccating them.
  • An example of food preservation using acids is pickling foods in vinegar (acetic acid), while the use of hypertonic mixtures includes the making of jam.