Case scenario A waste product for cheese making is whey. You have been tasked wi
ID: 95632 • Letter: C
Question
Case scenario
A waste product for cheese making is whey. You have been tasked with finding a use for the whey from Swiss cheese (aside from a dietary supplement for humans). You isolate a microbe that is genetically related to Lactobacillus. This microbe is able to grow exceptionally well on the whey when you allow for aeration of the culture – it grows weakly without aeration and the pH drops dramatically over time due to an acidic waste product. See Figure 1 and Table 1 for the structure of lactose and the composition of whey. When you sequence the genome you identify genes for Embden Meyerhoff Parnas as well as oxidoreductases and quinones. You also notice it produces an interesting antibiotic when grown in a closed batch system.
5. If the microorganism respires, name an electron acceptor and the electron donor. If it ferments, predict what the organic waste product would be based on the microbe’s relation to Lactobacillus?
Table 1. Composition of milk, cheese whev and casein whev % by weight Fat Lactose (milk sugar) Casein protein Whey protein Minerals Minor components Water TOTAL Milk 4.7 4.5 2.7 0.55 0.85 0.20 86.5 100.00 Cheese whey 0.05 5.0 0.10 0.65 0.50 0.30 93.4 100.00Explanation / Answer
NADH is the electron donor and pyruvate is the electron acceptor.
The end product would be lactate.