Fermentation Reactors problems
- 1. Unsteady state mass balance for dynamic model of continuous stirred tank reactor (CSTR) is
Options- A. time rate of total amount in rector = rate of addition to reactor -rate of removal + rate of formation
- B. total amount in rector = rate of addition to reactor - rate of removal + rate of formation
- C. rate of total amount in rector = rate of addition to reactor - rate of removal + rate of formation
- D. none of the above Discuss
Correct Answer: time rate of total amount in rector = rate of addition to reactor -rate of removal + rate of formation
- 2. In batch culture, protogon is produced from peptone during the stationary phase with a yield of 0.4 protogon mg per g of peptone. If it is to be produced in a chemostat at a dilution rate of 0.5 h-1 from a medium containing 10 g.l-1 of peptone, then the rate of protogon synthesis would be
Options- A. 0 g.l-1h-1
- B. 0.5 g.l-1h-1
- C. 1 g.l-1h-1
- D. 2 g.l-1h-1 Discuss
Correct Answer: 0 g.l-1h-1
- 3. The lowest biomass yield in a culture of Escherichia coli will be in
Options- A. an aerated batch culture containing a initial high concentration of glucose
- B. an aerated batch reactor containing an initial low concentration of glucose
- C. an aerated fed-batch reactor having a low glucose concentration
- D. an aerated continuous reactor having a low glucose concentration Discuss
Correct Answer: an aerated batch culture containing a initial high concentration of glucose
- 4. The main reason for production of antibiotics in fed batch reactors is
Options- A. the presence of precursors is often toxic to the cells
- B. higher yields when cells enter the stationary phase
- C. higher yields when cell growth slows
- D. all of the above Discuss
Correct Answer: all of the above
- 5. When a culture of fermenting yeast becomes metabolically uncoupled, ethanol
Options- A. becomes a secondary metabolite
- B. production becomes growth associated
- C. production becomes non-growth associated
- D. becomes a growth nutrient Discuss
Correct Answer: production becomes non-growth associated
- 6. For organisms growing in a chemostat, the specific growth rate
Options- A. cannot be determined
- B. can be determined from the dilution rate
- C. equals to the maximum specific growth rate of the culture
- D. none of the above Discuss
Correct Answer: can be determined from the dilution rate
- 7. Mixing profiles closest to plug flow are observed in
Options- A. continuous packed bed reactor
- B. stirred tank reactor with biomass recycles
- C. continuous fluidized bed bioreactor
- D. all of these Discuss
Correct Answer: continuous packed bed reactor
- 8. Toxins accumulated in a reactor can lead to low biomass yields probably due to which of the following?
Options- A. NAD+ is diverted away from homeostasis to anabolism
- B. ATP is diverted away from homeostasis to anabolism
- C. NAD+ is diverted away from anabolism to homeostasis
- D. ATP is diverted away from anabolism to homeostasis Discuss
Correct Answer: ATP is diverted away from anabolism to homeostasis
- 9. The continuous cultures are not widely used in industry because
Options- A. they are not suited for the production of secondary metabolites
- B. contamination or mutation can have a disastrous effect on the operation
- C. the government will not approve the licensing of pharmaceuticals produced in continuous cultures
- D. all of the above Discuss
Correct Answer: all of the above
- 10. Saccharomyces cerevisiae produces high biomass yields at low glucose concentrations and high dissolved oxygen concentrations. Which of the following should be followed for maximizing its biomass productivity?
Options- A. Batch fermenter with a high initial glucose concentration
- B. Continuous fermenter with a low initial glucose concentration
- C. Fed batch fermenter
- D. All of the above Discuss
Correct Answer: Fed batch fermenter
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