Case scenario A waste productfor cheese making is whey. You have been tasked wit
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Question
Case scenario A waste productfor cheese making is whey. You have been tasked with findinga use for the whey from Swiss cheese (aside from a dietary supplementfor 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. Table 1. Composition of milk, cheese whey and casein whey 6CH2OH % 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 93.4 100.00 CH,OH 5 2 Glucose Galactose Figure I. LactoseExplanation / Answer
If the microorganism respires, NADH/FADH2 is the electron donor and O2 is the final electron acceptor. In aerobic respiration of bacteria it performs citric acid cycle and produces NADH and FADH2, which enter into electron transport chain and where O2 accepts the electrons.
The organic waste product produced in the fermentation of bacteria is lactic acid. The pH of lactic acid is around 2.4. In the absence of oxygen, the pyruvate produced in the glycolysis will undergoes fermentation and anaerobic respiration. In this process the pyruvate gets converted into organic compounds like lactate, ethanol etc…