Fermentation Reactors

Question: Which of the following would be correct concerning the concentration of biomass (X). growth limiting substrate (S) and product (P) in a chemostat when the cells have been washed out?
[A].

X,S and P will be zero

[B].

X,S and P can not be predicted for the above condition

[C].

X and P will be zero while S is equal to the substrate concentration in feed

[D].

None of the above

Answer: Option C

Explanation:

No answer description available for this question.

Question: A strain of Escherichia coli has a maximum specific growth rate of 0.8 h-1 on a glucose based medium. If this organism is being grown in a chemostat with a dilution rate of 1.2 h-1, then at steady state the concentration of E. coli in the same medium will
[A].

increase

[B].

be zero

[C].

change randomly

[D].

decrease

Answer: Option B

Explanation:

No answer description available for this question.

Question: For organisms growing in a chemostat, the specific growth rate
[A].

cannot be determined

[B].

can be determined from the dilution rate

[C].

equals to the maximum specific growth rate of the culture

[D].

none of the above

Answer: Option B

Explanation:

No answer description available for this question.

Question: Saccharomyces cerevisiae is being grown in a chemostat converts glucose to biomass, ethanol, glycerol and carbon dioxide. At steady state, the concentration of glucose, biomass, ethanol and glycerol will
[A].

decrease with time

[B].

increase with time

[C].

be constant

[D].

change randomly with time

Answer: Option C

Explanation:

No answer description available for this question.

Question: Two continuous bioreactors containing the same organisms, fed with the same feed at the same dilution rate were compared. Reactor 1 started with an initial concentration of glucose of 10 g.l-1, while reactor 2 contained 0.1 g.l-1 of glucose at the start of the process then at steady state
[A].

the concentration of glucose in reactor 1 would be greater than that in reactor 2

[B].

the concentration of glucose in reactor 1 would be equal to reactor 2

[C].

the concentration of glucose in reactor 1 would always be zero.

[D].

the concentration of glucose in reactor 1 would be less than that in reactor 2

Answer: Option B

Explanation:

No answer description available for this question.

Question: The ideal tubular-flow fermenter without radial variations is called a
[A].

plug flow fermenter

[B].

continuous stirred tank fermenter (CSTF)

[C].

column fermenter

[D].

any intensity of dilution rate near the wash out points

Answer: Option A

Explanation:

No answer description available for this question.

Question: In plug flow tubular reactor the axial velocity profile on cross-section will be
[A].

constant

[B].

varying with time

[C].

non-linear

[D].

power function of time

Answer: Option A

Explanation:

No answer description available for this question.

Question: Mixing profiles closest to plug flow are observed in
[A].

continuous packed bed reactor

[B].

stirred tank reactor with biomass recycles

[C].

continuous fluidized bed bioreactor

[D].

all of these

Answer: Option A

Explanation:

No answer description available for this question.

Question: In a plug flow reactor, the highest concentration of substrates is exposed to the cells that
[A].

are near the effluent or exit of the reactor

[B].

are in the mid way along the reactor

[C].

are located near entrance of feed

[D].

are near the wall of the reactor

Answer: Option C

Explanation:

No answer description available for this question.

Question: The concentration of biomass in a continuous stirred tank reactor is 20 g dry weight per litre. What would be the concentration of biomass in the effluent?
[A].

Greater than 20 g dry weight per litre

[B].

Approximately 20 g dry weight per litre

[C].

Lesser than 20 g dry weight per litre

[D].

More than 30 g dry weight per litre

Answer: Option B

Explanation:

No answer description available for this question.