Biochemical Engineering - Fermentation Reactors

Exercise :: Fermentation Reactors - Section 1

21. 

A fed-batch reactor containing 1 g.l-1 of substrate in 2 litre of medium. It is fed with 1 g.l-l of substrate at the rate of 1 litre per hour. After 10 hours, the concentration of substrate in the reactor was 0.5 g.l-1 . The mass of substrate that was used by the culture in the reactor was

A. 2g
B. 6g
C. 8g
D. 12g

Answer: Option B

Explanation:

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22. 

Toxins accumulated in a reactor can lead to low biomass yields probably due to which of the following?

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

Answer: Option D

Explanation:

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23. 

The cellular productivity in a continuous stirred tank fermenter (CSTF) increases with an increase in the dilution rate and reaches a maximum value. If the dilution rate is increased beyond the maximum point, the productivity will

A. decrease abruptly
B. increase
C. increase drastically
D. be zero

Answer: Option A

Explanation:

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24. 

Fluidized bed bioreactors provide higher mass transfer rates than packed bed bioreactors because

A. mixing is higher in fluidized bed bioreactors
B. particles move with the fluid in a fluidized bed bioreactor
C. immobilized particles are smaller in the fluidized bed bioreactors
D. all of the above

Answer: Option B

Explanation:

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25. 

In fed-batch fermentation, mass of substrate utilized is calculated using the relationship

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

Answer: Option B

Explanation:

No answer description available for this question. Let us discuss.