Case scenario A waste productfor cheese making is whey. You have been tasked wit
ID: 95534 • Letter: C
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
6. Stationary phase
Log phase cannot be favour in batch culture because due to limited availabilty of nutrients and accumulation of inhibitory chemicals etc.
Stationary phase involved in production of secondary metabolites due to lot of stress happen in batch culture after some period of duration. Due to stress it produce the secondary metabolites like antibiotics.