Fermentation Reactors

Question: 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:

No answer description available for this question.

Question: 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
[A].

1 litre

[B].

2 litre

[C].

3 litre

[D].

13 litre

Answer: Option B

Explanation:

No answer description available for this question.

Question: Immobilized cell reactors for wastewater treatment have the advantage of having/being
[A].

higher cell concentration

[B].

more stable and prevent washout

[C].

higher dilution rate before the cells washout

[D].

all of the above

Answer: Option D

Explanation:

No answer description available for this question.

Question: In aerobic yeast fermentation for production of citric acid from alkanes using a fed-batch culture, why alkanes are slowly fed to the yeast?
[A].

Citric acid is toxic to the cells

[B].

Alkanes cause foaming

[C].

Fast addition of alkanes will inhibit the cells and reduce oxygen transfer rates

[D].

Fast addition of alkanes will cause the cells to grow too quickly

Answer: Option C

Explanation:

No answer description available for this question.

Question: In an activated sludge process, the biomass is recycled to
[A].

increase the efficiency of the process

[B].

reduce sludge volumes

[C].

increase the concentration of cells

[D].

all of the above

Answer: Option D

Explanation:

No answer description available for this question.

Question: In a fluidized bed reactor, the function of the disengagement zone is to
[A].

reduce loss of particles from the reactor

[B].

reduce the velocity of the particles near the surface of the reactor

[C].

reduce foaming problems

[D].

all of the above

Answer: Option D

Explanation:

No answer description available for this question.

Question: In a fluidized bed reactor mixing is achieved by
[A].

gravity flow of fluid

[B].

upward movement of the incoming feed

[C].

diffusion

[D].

both (a) and (b)

Answer: Option D

Explanation:

No answer description available for this question.

Question: Which of the following is used to calculate mass of substrate in the reactor?
[A].

Flow rate x substrate concentration in the reactor

[B].

Volume of reactor x substrate concentration in reactor

[C].

Flow rate x mass of reactor

[D].

Volume of reactor x Flow rate

Answer: Option B

Explanation:

No answer description available for this question.

Question: 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.

Question: In fed batch bioreactor modelling, the rate of change in the bioreactor volume is assumed to be equal to
[A].

flow rate

[B].

initial volume

[C].

volume of solids in the reactor

[D].

none of these

Answer: Option A

Explanation:

No answer description available for this question.