200 Best MCQs on Fermentation Reactors- biochemical engineering
Q17). If biomass yields are constant, then the biomass productivity of a culture grown in continuous reactor will
a).always decrease with dilution rate
b).increase with dilution rate until washout
c).remain constant irrespective of the dilution rate
d).decrease with dilution rate until washout
Correct Answer:
increase with dilution rate until washout
Explaination:
Q18). Low dissolved oxygen concentrations leads to
a).low biomass yields
b).high biomass yields
c).no effect on biomass yields
d).none of the above
Correct Answer:
low biomass yields
Explaination:
Q19). In a continuous reactor, the medium contains 40 g.l^-1 of maltose and the medium flow rate is 10 litres per hour and the effluent contains 20 g.l^-1 of lactate. What is the productivity of lactate production from this reactor?
a).50 g maltose.l^-1
b).50 g lactate.l^-1
c).200 g maltose.l^-1
d).200 g lactate.l^-1
Correct Answer:
200 g lactate.l^-1
Explaination:
Q20). A fed-batch reactor containing 1 g.l^-1 of substrate in 2 litre of medium. It is fed with 1 g.l^-1 of substrate at the rate of 1 litre per hour. After 10 hours, the concentration of substrate in the reactor was 0.5 g.l . The mass of substrate that was used by the culture in the reactor was
a).2g
b).6g
c).8g
d).12g
Correct Answer:
6g
Explaination:
Q21). Toxins accumulated in a reactor can lead to low biomass yields probably due to which of the following?
a).NAD+ is diverted away from homeostasis to anabolism
b).ATP is diverted away from homeostasis to anabolism
c).NAD+ is diverted away from anabolism to homeostasis
d).ATP is diverted away from anabolism to homeostasis
Correct Answer:
ATP is diverted away from anabolism to homeostasis
Explaination:
Q22). The cellular productivity in a continuous stirred tank fermenter (CSTF) increases with an increase in the dilution rate and reaches a maximum value. If the dilution rate is increased beyond the maximum point, the productivity will
a).decrease abruptly
b).increase
c).increase drastically
d).be zero
Correct Answer:
decrease abruptly
Explaination:
Q23). Fluidized bed bioreactors provide higher mass transfer rates than packed bed bioreactors because
a).mixing is higher in fluidized bed bioreactors
b).particles move with the fluid in a fluidized bed bioreactor
c).immobilized particles are smaller in the fluidized bed bioreactors
d).all of the above
Correct Answer:
particles move with the fluid in a fluidized bed bioreactor
Explaination:
Q24). In fed-batch fermentation, mass of substrate utilized is calculated using the relationship
a).initial mass of substrate in the reactor + final mass of substrate in the reactor + flow rate x [substrate in the feed]
b).initial mass of substrate in the reactor – final mass of substrate in the reactor + flow rate x [substrate in the feed]
c).initial mass of substrate in the reactor + final mass of substrate in the reactor – flow rate x [substrate in the feed]
d).initial mass of substrate in the reactor + final mass of substrate in the reactor – flow rate
Correct Answer:
initial mass of substrate in the reactor – final mass of substrate in the reactor + flow rate x [substrate in the feed]
Explaination: