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Fermentation Reactors problems


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

  • Options
  • A. 2g
  • B. 6g
  • C. 8g
  • D. 12g
  • Discuss
  • 2. A continuous reactor at steady state contains 0.04 g.l-1 of biomass and 0.02 g.l-1 of phenol. The feed contained 0.1 g.l-1 of phenol. The biomass yield would be

  • Options
  • A. 0.4 g.g-1
  • B. 0.5 g.g-1
  • C. 1.0 g.g-1
  • D. 5.0 g.g-1
  • Discuss
  • 3. 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-l of lactate. What is the productivity of lactate production from this reactor?

  • Options
  • A. 50 g maltose.l-1
  • B. 50 g lactate.l-1
  • C. 200 g maltose.l-1
  • D. 200 g lactate.l-1
  • Discuss
  • 4. On a glucose medium, the growth of an organism is characterized by the following Monod model and stoichiometric parameters ?m = 0.3 h-1, Ks =0.05 g.l-1 and Yxs = 0.3 g.g-1 When this organism is grown in a 2 litre continuous on a medium containing 10 g.l-1 of glucose added at 1 l.h-1, the steady state concentration of biomass in the reactor will be

  • Options
  • A. 0 g.l-1
  • B. 0.4 g.l-1
  • C. 0.5 g.l-1
  • D. 10 g.l-1
  • Discuss
  • 5. Which of the following would not be subjected to the "glucose effect"?

  • Options
  • A. Aspergillus fumigatus
  • B. Saccharomyces cerevisiae
  • C. Escherichia coli
  • D. Aspergillus niger
  • Discuss
  • 6. A culture system with constant environmental conditions maintained through continual provision of nutrient and removal of wastes is called __________ culture system.

  • Options
  • A. continuous
  • B. batch
  • C. fed-batch
  • D. semi continuous
  • Discuss
  • 7. Fed batch reactors is used to produce vinegar because

  • Options
  • A. it can maintain low ethanol concentrations
  • B. it can maintain low acetic acid concentrations
  • C. acetic acid bacteria tend to ferment at high ethanol concentrations
  • D. all of the above
  • Discuss
  • 8. In a fluidized bed reactor, the function of the disengagement zone is to

  • Options
  • A. reduce loss of particles from the reactor
  • B. reduce the velocity of the particles near the surface of the reactor
  • C. reduce foaming problems
  • D. all of the above
  • Discuss
  • 9. A chemostat has a liquid volume of 2 litres and is being fed at a rate of 4 litres per hour. Dilution rate for this reactor will be

  • Options
  • A. 2 litres
  • B. 2 litres per hour
  • C. 2 h-1
  • D. 4 litres per hour
  • Discuss
  • 10. 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

  • Options
  • A. decrease abruptly
  • B. increase
  • C. increase drastically
  • D. be zero
  • Discuss

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