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.