Case scenario A waste product for cheese making is whey. You have been tasked wi
ID: 95638 • 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.
10. If you were able to genetically alter your microbe to overproduce your antibiotic, how would you grow your microbe so that it would be able to produce the most antibiotic possible? Would you choose a batch system or chemostat? Explain why you chose your answer and how this method would enable you to maximize the efficiency of antibiotic production.
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
A chemostat is a bioreactor to which fresh medium is continuously added, while culture liquid is continuously removed to keep the culture volume constant.By changing the rate at which medium is added to the bioreactor the growth rate of the microorganism can be easily controlled.
In batch culture, the culture environment continuously changes
• Growth, product formation, and substrate utilization all terminate after a certain time interval.
Thus it would be preferable to use the chemostat for the continuous production of the desired antibiotic.