D A I R Y P R O D U C T S
Rennin/Chymosin Rennin(also called chymosin or rennet) is the enzyme that aids in the production of cheese. Adding rennin to milk curdles the milk. Eventually, they whey(liquid) is separable from the curds(solid). The seperated and dried curds is what we refer to as cheese. (citation 25) Traditionally, cheese-makers obtained this enzyme from cows because rennin was found exclusively in the stomach of calves. However in the 1980s the Food and Agriculture Organisation of the United Nations predicted a shortage of calf rennet, and as a response several substitutes for this enzyme have been formed. One method of substitution uses the GM route; microorganisms have been genetically modified to produce chymosin identical to the enzyme found in the stomach of calves. | (image 17) The making of chymosin using genetically modified yeast |
Lactase
Lactase is the enzyme that breaks down lactose, a compound sugar. Lactase is found in the intestine of mammals, plants, fungi, yeast, and bacteria. Each organism produces lactase that functions best under different conditions of temperature and acidity.
Humans typically produce the enzyme lactase to break down the ingested lactose. Lactose intolerant people do not produce enough lactase to break up lactose into sugar. This results in discomfort in the digestive system; lactose intolerant people experience cramps, gas, and diarrhea when ingest diary products. Modern technology has made it possible for lactase to be dervived from different organisms and tailored to be useful to humans.
The fungus Aspergillis oryzae produces lactase that works best under high acidity, making it an ideal candidate for humans because of the acidity of human stomachs. Manufacturers produce pills containing the enzyme lactase formed from the fungus
Aspergillis oryzae and sell it commercially to lactose intolerant people who are unable to produce sufficient amount of lactase.Kluyveromyces lactis,a yeast, produces lactase and stands as another candidate to act as a substitute for humans. However, this does not bode well in an acidic environment; stomach acid would destroy the lactace. Lactase produced from
Kluyveromyces lactis cannot be taken directly as pills; instead it is added to milk and other dairy products to create lactose-free products.