Fermentation Reactors problems
- 1. 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
Options- A. decrease with time
- B. increase with time
- C. be constant
- D. change randomly with time Discuss
Correct Answer: be constant
- 2. Which of the statement is true for continuous reactor at steady state?
Options- A. The rates of biomass, substrate and product concentrations are zero
- B. Biomass, substrate and product concentrations are zero
- C. Biomass, substrate and product concentrations do not change with time
- D. Biomass, substrate and product concentrations change with time Discuss
Correct Answer: Biomass, substrate and product concentrations do not change with time
- 3. Which of the following is used to calculate mass of substrate in the reactor?
Options- A. Flow rate x substrate concentration in the reactor
- B. Volume of reactor x substrate concentration in reactor
- C. Flow rate x mass of reactor
- D. Volume of reactor x Flow rate Discuss
Correct Answer: Volume of reactor x substrate concentration in reactor
- 4. Mixing in an anaerobic sludge blanket reactor is due to
Options- A. rapid change in water temperatures throughout the reactor
- B. release of gases by the microbial populations
- C. swimming of microbes
- D. none of the above Discuss
Correct Answer: release of gases by the microbial populations
- 5. Fluidized bed bioreactors provide higher mass transfer rates than packed bed bioreactors because
Options- 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 Discuss
Correct Answer: particles move with the fluid in a fluidized bed bioreactor
- 6. Low dissolved oxygen concentrations leads to
Options- A. low biomass yields
- B. high biomass yields
- C. no effect on biomass yields
- D. none of the above Discuss
Correct Answer: low biomass yields
- 7. In aerobic yeast fermentation for production of citric acid from alkanes using a fed-batch culture, why alkanes are slowly fed to the yeast?
Options- A. Citric acid is toxic to the cells
- B. Alkanes cause foaming
- C. Fast addition of alkanes will inhibit the cells and reduce oxygen transfer rates
- D. Fast addition of alkanes will cause the cells to grow too quickly Discuss
Correct Answer: Fast addition of alkanes will inhibit the cells and reduce oxygen transfer rates
- 8. Immobilized cell reactors for wastewater treatment have the advantage of having/being
Options- A. higher cell concentration
- B. more stable and prevent washout
- C. higher dilution rate before the cells washout
- D. all of the above Discuss
Correct Answer: all of the above
- 9. The growth of an organism on glucose is described by the following Monod model parameters: ?m = 0.5 h-1 and Ks =0.1 g.l-1, if the concentration of glucose in the feed is 10 g.l-1 and the dilution rate is set to 0.4 h-1, then the steady state concentration of glucose in the effluent will be
Options- A. 0 g.l-1
- B. 0.5 g.l-1
- C. 1.0 g.l-1
- D. 10 g.l-1 Discuss
Correct Answer: 0.5 g.l-1
- 10. The lowest yield of ATP /is in
Options- A. fermentation
- B. aerobic respiration
- C. anaerobic respiration
- D. same in (a), (b) and (c) Discuss
Correct Answer: fermentation
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