Discussion
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- Question
To increase the oxygen transfer rate in a shake flask culture system, which of the following (s) is/are followed?
Options- A. Liquid volume in the flask is reduced
- B. Stirrer speed is increased
- C. Baffled flasks are used
- D. All of the above
- Correct Answer
- All of the above
- 1. The Intermig impeller is
Options- A. an axial flow impeller which can be used for the culture of aerobic organisms
- B. directed upwards rather than towards the base of the reactor
- C. a fork shaped extensions to the impeller facilitate bubble break up
- D. All of the above Discuss
- 2. Which of the following is not classified as an axial flow impeller?
Options- A. A propeller
- B. A marine impeller
- C. A Rushton turbine
- D. A hydrofoil impeller Discuss
- 3. The oxygen absorption rate can be determined by
Options- A. sodium sulfite oxidation method
- B. dynamic gassing out technique
- C. direct measurement
- D. all of these Discuss
- 4. The power required by an impeller in a gas sparged system compare to the power required by impeller operating at same speed in a gas free liquid is usually
Options- A. lesser
- B. higher
- C. same
- D. may be lesser or higher depending upon the geometry Discuss
- 5. The maximum solubility of the alkane in the medium is 5 ppm. If the actual dissolved concentration of the alkane in the medium is 1 ppm. what conclusion may be drawn?
Options- A. The growth rate is limited by the rate of mass transfer of the alkane into the fermentation medium
- B. The growth rate is limited by the intrinsic kinetic properties of the cells and not by mass transfer
- C. The growth rate is neither mass transfer nor kinetically limited
- D. No conclusion on the growth rate can be withdrawn Discuss
- 6. Industrial paddle agitators turn at the speed of
Options- A. 20 and 150 rpm
- B. 150 and 300 rpm
- C. 400 and 800 rpm
- D. 1150 rpm Discuss
- 7. Detergent like substances produced by microorganisms during a fermentation will lead to
Options- A. decrease the surface tension of the liquid
- B. accumulate at the gas liquid interface
- C. decrease the rate of bubble coalescence
- D. all of the above Discuss
- 8. Which of the following stirrer requires least amount of energy for same yield?
Options- A. Mig
- B. Intermig
- C. Turbine
- D. Disc Discuss
- 9. Pure oxygen, if used instead of air will increase oxygen transfer rates because
Options- A. the saturation concentration of oxygen is higher
- B. the bubble size is smaller
- C. the oxygen transfer coefficient is larger
- D. the partial pressure of oxygen in the gas phase is lower Discuss
- 10. A cylindrical reactor fitted with Rushton Turbine has a liquid volume of 100,000 litres. It has an aspect ratio (the ratio of the channel height to the width) of 2:1. The diameter of the impeller should be approximately:
Options- A. 1.3 m
- B. 3.3 m
- C. 5.3 m
- D. 7.3 m Discuss
Agitation and Aeration problems
Search Results
Correct Answer: All of the above
Correct Answer: A Rushton turbine
Correct Answer: all of these
Correct Answer: lesser
Correct Answer: No conclusion on the growth rate can be withdrawn
Correct Answer: 20 and 150 rpm
Correct Answer: all of the above
Correct Answer: Intermig
Correct Answer: the saturation concentration of oxygen is higher
Correct Answer: 1.3 m
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