Questions and answers for exam Preparation

MCQs

Total Questions : 114 | Page 6 of 12 pages

Question 51. Which of the following organisms will continue their metabolism at high substrate concentrations?

Pseudomonas aeruginosa
Saccharomyces cerevisiae
Bacillus subtilis
Escherichia coli

Discuss Question

Answer: Option A. -> Pseudomonas aeruginosa
Answer: (a).Pseudomonas aeruginosa

Question 52. In a fluidized bed reactor mixing is achieved by

gravity flow of fluid
upward movement of the incoming feed
diffusion
both (a) and (b)

Discuss Question

Answer: Option D. -> both (a) and (b)
Answer: (d).both (a) and (b)

Question 53. 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.l¹, while reactor 2 contained 0.1 g.l¹ of glucose at the start of the process then at steady state

the concentration of glucose in reactor 1 would be greater than that in reactor 2
the concentration of glucose in reactor 1 would be equal to reactor 2
the concentration of glucose in reactor 1 would always be zero.
the concentration of glucose in reactor 1 would be less than that in reactor 2

Discuss Question

Answer: Option B. -> the concentration of glucose in reactor 1 would be equal to reactor 2
Answer: (b).the concentration of glucose in reactor 1 would be equal to reactor 2

Question 54. Yeast is typically produced in fed batch reactors because

yeast cells produce ethanol at low glucose concentrations
yeast cells ferment at low glucose concentrations
yeast cells respire at low glucose concentrations
all of the above

Discuss Question

Answer: Option C. -> yeast cells respire at low glucose concentrations
Answer: (c).yeast cells respire at low glucose concentrations

Question 55. If biomass yields are constant, then the biomass productivity of a culture grown in continuous reactor will

always decrease with dilution rate
increase with dilution rate until washout
remain constant irrespective of the dilution rate
decrease with dilution rate until washout

Discuss Question

Answer: Option B. -> increase with dilution rate until washout
Answer: (b).increase with dilution rate until washout

Question 56. Which of the following is used to calculate mass of substrate in the reactor?

Flow rate x substrate concentration in the reactor
Volume of reactor x substrate concentration in reactor
Flow rate x mass of reactor
Volume of reactor x Flow rate

Discuss Question

Answer: Option B. -> Volume of reactor x substrate concentration in reactor
Answer: (b).Volume of reactor x substrate concentration in reactor

Question 57. Low dissolved oxygen concentrations leads to

low biomass yields
high biomass yields
no effect on biomass yields
none of the above

Discuss Question

Answer: Option A. -> low biomass yields
Answer: (a).low biomass yields

Question 58. A continuous reactor has a dilution rate of 0.5 h¹. Its residence time would be

ln(2)/0.5
ln(2) x 0.5
0.5 h
2 h

Discuss Question

Answer: Option D. -> 2 h
Answer: (d).2 h

Question 59. In a continuous reactor, the medium contains 40 g.l¹ of maltose and the medium flow rate is 10 litres per hour and the effluent contains 20 g.l¹ of lactate. What is the productivity of lactate production from this reactor?

50 g maltose.l¹
50 g lactate.l¹
200 g maltose.l¹
200 g lactate.l¹

Discuss Question

Answer: Option D. -> 200 g lactate.l¹
Answer: (d).200 g lactate.l¹

Question 60. A fed-batch reactor containing 1 g.l¹ 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.l¹ . The mass of substrate that was used by the culture in the reactor was

Discuss Question

Answer: Option B. -> 6g
Answer: (b).6g