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Downstream Processing problems


  • 1. A typical tubular centrifuge has a bowl of 2 to 5 inch in diameter and 9 to 30 inch in height with a maximum rotating speed of

  • Options
  • A. 15,000 to 50,000 rpm
  • B. 50,000 to 100,000 rpm
  • C. 100,000 to 150,000 rpm
  • D. 150,000 to 200,000 rpm
  • Discuss
  • 2. The disk centrifuge is the type of centrifuge used most often for bio separations due to its

  • Options
  • A. continuous operation
  • B. lesser cost
  • C. higher speed
  • D. ease in operation
  • Discuss
  • 3. Which of the following is not the physical method for the cells rupturing?

  • Options
  • A. Milling
  • B. Homogenization
  • C. Ultrasonication
  • D. Enzymatic digestion
  • Discuss
  • 4. The optimum wet solid content for the cell suspension for a bead mill is typically somewhere between

  • Options
  • A. 5-15% by volume
  • B. 15-30% by volume
  • C. 30-60% by volume
  • D. 60-90% by volume
  • Discuss
  • 5. The effectiveness of a solvent can be measured by the

  • Options
  • A. distribution coefficients
  • B. selectivity
  • C. both (a) and (b)
  • D. diffusivity
  • Discuss
  • 6. A system which require less solvent and produces a more concentrated extract phase, is desired with a

  • Options
  • A. large distribution coefficients
  • B. small distribution coefficients
  • C. very small distribution coefficients
  • D. constant distribution coefficients
  • Discuss
  • 7. If the membrane rejects all solute, the rejection coefficient (s) is

  • Options
  • A. 1
  • B. 0
  • C. >1
  • D. <1
  • Discuss
  • 8. Assuming the laminar flow across the filter, the rate of filtration (dVf/dt) can be expressed as a function of pressure drop Dp by the modified D'Arcy's equation as (where A is the area of filtering surface, K is the D'Arcy's filter cake permeability and L is the thickness of the filter cake)

  • Options
  • A. (1/A) dVf/dt = ?p/?(L/K)
  • B. dVf/dt = (1/A)?p/?(L/K)
  • C. (1/A) dVf/dt = ?p/? LK
  • D. dVf/dt = (1/A)?p/? LK
  • Discuss
  • 9. Filtration leaf test results indicate that the filtration rate of a protein product is 100 dry lbs/(ft2 hr). What size production filter would be required to obtain 100 dry lbs of filter cake/hr?

  • Options
  • A. 1.54 ft2
  • B. 3.08 ft2
  • C. 65 ft2
  • D. 65 lbs/ ft2.hr
  • Discuss
  • 10. Which of the operation does not come under upstream processing?

  • Options
  • A. Media preparation
  • B. Inoculum development
  • C. Effluent treatment
  • D. Storage of raw material
  • Discuss

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