Biochemical Engineering

Question: At 25°C, the saturation concentration of oxygen in water is 1.26 mmol/l and the partial pressure of oxygen is 1 atm. The Henry’s law constant will be
[A].

0.793atml/mmol

[B].

0.207atml/mmol

[C].

1.26 atml/mmol

[D].

8.74 atml/mmol

Answer: Option A

Explanation:

No answer description available for this question.

Question: Henry’s law relates
[A].

the partial pressure of oxygen and the saturation concentration of oxygen in the liquid

[B].

the oxygen transfer rate and the bubble size

[C].

the oxygen transfer rate and the temperature

[D].

the oxygen transfer rate to the partial pressure of oxygen in the liquid

Answer: Option A

Explanation:

No answer description available for this question.

Question: Pure oxygen, if used instead of air will increase oxygen transfer rates because
[A].

the saturation concentration of oxygen is higher

[B].

the bubble size is smaller

[C].

the oxygen transfer coefficient is larger

[D].

the partial pressure of oxygen in the gas phase is lower

Answer: Option A

Explanation:

No answer description available for this question.

Question: The oxygen uptake requirements of a microbial population is characterized by the following parameters: μm = 0.2 h-1, K0 = 0.2 mg O2.l-1, Y0 = 0.5 mg dry weight/mg O2 and C0,crit=0.8 mg.l-1 The required concentration of cells is 1000 mg.l-1 and the saturation oxygen concentration of the medium is 5.8 mg.l-1. The required KLa must be greater than
[A].

64 h-1

[B].

32 h-1

[C].

16 h-1

[D].

8h-1

Answer: Option A

Explanation:

No answer description available for this question.

Question: In a bioreactor, if at a particular time the oxygen transfer rate is 23 kg.h-1, then the oxygen uptake will be
[A].

23 kg.h-1

[B].

less than 23 kg.h-1

[C].

greater than 23 kg.h-1

[D].

2.3 kg.h-1

Answer: Option A

Explanation:

No answer description available for this question.

Question: In a tall reactor, oxygen transfer rates will be
[A].

highest at the surface of the reactor

[B].

highest at the base of the reactor

[C].

highest in the middle of the reactor

[D].

the same throughout the reactor

Answer: Option B

Explanation:

No answer description available for this question.

Question: When the height of an aerated bioreactor is increased, it will increase the oxygen transfer rate by
[A].

increasing the partial pressure of oxygen at the base of the reactor

[B].

decreasing the saturation concentration of oxygen in the reactor

[C].

decreasing the gas-holdup

[D].

all of the above

Answer: Option A

Explanation:

No answer description available for this question.

Question: Which of the following will have the highest surface area available for oxygen transfer?
[A].

A shake flask

[B].

A standing test tube

[C].

A non-sparged stirred tank reactor agitated at 400 rpm

[D].

A sparged stirred tank reactor agitated at 400 rpm

Answer: Option D

Explanation:

No answer description available for this question.

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.