200 Best MCQs on Fermentation Reactors- biochemical engineering
Q41). 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
Correct Answer:
be zero
Explaination:
Q42). A fed-batch reactor containing 2 litre of medium and 0.1 g.l^-1 of biomass is fed with a medium containing 1 g.l^-1 of substrate at 1 litre per hour. If after 10 hours, the concentration of biomass in the reactor was 0.2 g.l, then the biomass produced during the 10 hour period is
a).1.5 g
b).2.2 g
c).3.0 g
d).6.0 g
Correct Answer:
2.2 g
Explaination:
Q43). Which of the following organisms will continue their metabolism at high substrate concentrations?
a).Pseudomonas aeruginosa
b).Saccharomyces cerevisiae
c).Bacillus subtilis
d).Escherichia coli
Correct Answer:
Pseudomonas aeruginosa
Explaination:
Q44). Yeast is typically produced in fed batch reactors because
a).yeast cells produce ethanol at low glucose concentrations
b).yeast cells ferment at low glucose concentrations
c).yeast cells respire at low glucose concentrations
d).all of the above
Correct Answer:
yeast cells respire at low glucose concentrations
Explaination:
Q45). 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
Correct Answer:
the concentration of glucose in reactor 1 would be equal to reactor 2
Explaination:
Q46). 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)
Correct Answer:
both (a) and (b)
Explaination:
Q47). The production of an amylase from starch by Aspergillus niger is often performed in a fed batch fermenter. This is due to the reason that
a).fed-batch reactor can be used to minimize starch concentrations and prevent a. nigre from fermenting
b).fed-batch reactor can be used to minimize starch concentrations and thus reduce the viscosity of the medium
c).continuous reactor can be used to minimize starch concentrations and their inhibitory effects
d).all of the above
Correct Answer:
fed-batch reactor can be used to minimize starch concentrations and thus reduce the viscosity of the medium
Explaination:
Q48). The fastest route of NADH reoxidation is
a).aerobic respiration
b).anaerobic respiration
c).fermentation
d).decomposition
Correct Answer:
fermentation
Explaination: