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Question: To increase the oxygen transfer rate in a shake flask culture system, which of the following (s) is/are followed?
[A].

Liquid volume in the flask is reduced

[B].

Stirrer speed is increased

[C].

Baffled flasks are used

[D].

All of the above

Answer: Option D

Explanation:

No answer description available for this question.

Question: Oxygen transfer rate is increased with an increase in the stirrer speed in aerated bioreactor because
[A].

it decrease the bubble size

[B].

it decreases the size of the boundary layer surrounding a bubble

[C].

it increases the rate of movement of oxygen molecules through the bulk liquid

[D].

all of the above

Answer: Option D

Explanation:

No answer description available for this question.

Question: Higher temperatures affect oxygen transfer rates by
[A].

increasing KLa but lowering C*o

[B].

lowering KLa but increasing C*o

[C].

increasing KLa and increasing Co

[D].

lowering KLa and lowering Co

Answer: Option A

Explanation:

No answer description available for this question.

Question: An aerated bioreactor will increase oxygen transfer rates with the addition of detergents because it
[A].

enhances bubble coalescence

[B].

causes bubbles to expand

[C].

discourages bubble coalescence

[D].

increases the surface tension of the liquid

Answer: Option C

Explanation:

No answer description available for this question.

Question: A microbial population in a suspension culture will only be limited by oxygen availability if the dissolved oxygen
[A].

concentration is less than the critical concentration

[B].

concentration is greater than the critical concentration

[C].

levels are greater than the saturation concentration of oxygen

[D].

levels are equal to saturation oxygen level

Answer: Option A

Explanation:

No answer description available for this question.

Question: The addition of antifoams to an aerated bioreactor will decrease oxygen transfer rates because antifoams
[A].

increase the tendency of bubbles to coalesce

[B].

tend to accumulate in the gas liquid interface

[C].

reduce the surface tension of the liquid

[D].

All of the above answers

Answer: Option D

Explanation:

No answer description available for this question.

Question: Which of the following will have the largest interfacial area per unit volume?
[A].

A bubble with a diameter of 1 mm

[B].

A bubble with a diameter of 5 mm

[C].

A bubble with a diameter of 15 mm

[D].

A bubble with a diameter of 50 mm

Answer: Option A

Explanation:

No answer description available for this question.

Question: The main function of the dimples provided in the cooling jacket is to
[A].

increase the level of turbulence of the cooling water in the jacket

[B].

increase the residence time of the cooling water in the jacket

[C].

increase the cooling water-jacket wall boundary layer size

[D].

all of the above

Answer: Option A

Explanation:

No answer description available for this question.

Question: Which have the maximum resistance while transferring carbon dioxide from the bulk liquid to an air bubble?
[A].

Moving through the gas liquid interface

[B].

Moving through the bubble boundary layer

[C].

Moving across the cell membrane

[D].

Moving through the bulk liquid

Answer: Option B

Explanation:

No answer description available for this question.

Question: During fermentation, the saturation concentration of oxygen was reduced from 7 ppm. to 1 ppm. Which one of the following conclusions can be drawn?
[A].

Microbial growth is oxygen limited since the oxygen concentration is lesser than the saturation concentration

[B].

Microbial growth is not oxygen limited since the oxygen concentration is lesser than the saturation concentration

[C].

Experimental error leads to the reduction

[D].

No conclusion can be drawn

Answer: Option D

Explanation:

No answer description available for this question.