Fermentation Reactors problems
- 1. A Bacillus sp. produces an antibiotic only during the stationary phase when grown in a batch culture. If grown in a 5 litre continuous culture, the steady state productivity of the antibiotic
Options- A. will increase until the culture washes out
- B. will decrease after washout
- C. will be zero
- D. will be infinite Discuss
Correct Answer: will be zero
- 2. Mixing per unit volume is observed to be poorest in
Options- A. continuous packed bed reactor
- B. continuous fluidized bed bioreactor
- C. continuous airlift bioreactor
- D. none of the above Discuss
Correct Answer: continuous packed bed reactor
- 3. A continuous reactor has a dilution rate of 0.5 h-1. Its residence time would be
Options- A. ln(2)/0.5
- B. ln(2) x 0.5
- C. 0.5 h
- D. 2 h Discuss
Correct Answer: 2 h
- 4. Formation of end product by Lactococcus lactis will become non-growth associated as lactic acid accumulates because
Options- A. cells will redirect ATP to anabolism
- B. cells will redirect NAD+ to anabolism
- C. cells will redirect ATP to facilitate the diffusion of lactic acid and H+ out of the cells
- D. cells will redirect ATP to the active transport of lactic acid and H+ out of the cells Discuss
Correct Answer: cells will redirect ATP to the active transport of lactic acid and H+ out of the cells
- 5. Yield coefficient represents
Options- A. total biomass or product produced
- B. conversion efficiency of a substrate into product
- C. conversion rate of a substrate into biomass or product
- D. production time of biomass or product Discuss
Correct Answer: conversion efficiency of a substrate into product
- 6. A continuous bioreactor in which only the flow rate is used to control the rate of cell or product productivity is called
Options- A. turbidostat
- B. chemostat
- C. level stat
- D. pH Discuss
Correct Answer: chemostat
- 7. If biomass yields are constant, then the biomass productivity of a culture grown in continuous reactor will
Options- A. always decrease with dilution rate
- B. increase with dilution rate until washout
- C. remain constant irrespective of the dilution rate
- D. decrease with dilution rate until washout Discuss
Correct Answer: increase with dilution rate until washout
- 8. A fed-batch reactor initially contains 2 litre of medium. If it was fed at 1 litre per hour, then after 10 hours, the volume of the reactor will be
Options- A. 1 litre
- B. 2 litre
- C. 3 litre
- D. 13 litre Discuss
Correct Answer: 2 litre
- 9. When two populations compete for a single growth limiting substrate in a continuous fermenter, which organism would not be washed out?
Options- A. Organism maintaining the highest substrate concentration
- B. Organism maintaining the lowest substrate concentration
- C. Both (a) and (b)
- D. Organism maintaining the moderate substrate concentration Discuss
Correct Answer: Organism maintaining the lowest substrate concentration
- 10. In fed-batch fermentation, mass of substrate utilized is calculated using the relationship
Options- A. initial mass of substrate in the reactor + final mass of substrate in the reactor + flow rate x [substrate in the feed]
- B. initial mass of substrate in the reactor - final mass of substrate in the reactor + flow rate x [substrate in the feed]
- C. initial mass of substrate in the reactor + final mass of substrate in the reactor - flow rate x [substrate in the feed]
- D. initial mass of substrate in the reactor + final mass of substrate in the reactor - flow rate Discuss
Correct Answer: initial mass of substrate in the reactor - final mass of substrate in the reactor + flow rate x [substrate in the feed]
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