Multiple Choice Questions (MCQ) and Answers on Downstream Processing
Question 1: For the extractions operation, the selectivity should be
- >1
- <1
- zero
Answers: 1
Question 2: The purity of a solute collected between two times t1 and t2 during chromatographic separation can be calculated as
- amount of solute eluted – amount of impurity eluted
- amount of solute eluted / amount of impurity eluted
- amount of solvent eluted + amount of impurity eluted
- amount of solvent eluted / amount of impurity eluted
Answers: 2
Question 3: Chromatography is based on the
- different rate of movement of the solute in the column
- separation of one solute from other constituents by being captured on the adsorbent
- different rate of movement of the solvent in the column
- any of the above
Answers: 1
Question 4: The correlation often employed to correlate adsorption data for protein is (where Ymax is the maximum amount of solute adsorbed per mass of adsorbent, X is the mass fraction of solute in the diluent phase in solute-free basis, KL is a constant and Y is the equilibrium value of the mass of solute adsorbed per mass of adsorbent)
- Y = YmaxX/(KL+X)
- Y = Ymax/(KL+X)
- Y = YmaxX/KL
- Y = Ymax– X/ (KL+X)
Answers: 1
Question 5: 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
- 15,000 to 50,000 rpm
- 50,000 to 100,000 rpm
- 100,000 to 150,000 rpm
- 150,000 to 200,000 rpm
Answers: 1
Question 6: For cost analysis in a fermentor system, the depreciation cost varies from
- 5-6% of the capital cost
- 6-7% of the capital cost
- 6-10% of the capital cost
- 8-10% of the capital cost
Answers: 3
Question 7: Micro filtration refers to the separation of suspended material such as bacteria by using a membrane with spore sizes of
- 0.02 to 10μm
- 1-10A°
- 20-30μm
- 10-200A°
Answers: 1
Question 8: Start up expenses in a fermentation industry varies from
- 0-5% of the capital cost
- 10-15% of the capital cost
- 5-10% of the capital cost
- 15-20% of the capital cost
Answers: 3
Question 9: The solvent flux across the membrane can be expressed as (where A is the area, Lp is the membrane permeability, σ is the reflection point, Δp is applied pressure and Δπ is the osmotic pressure)
- J = Lp(Δp – σΔπ)
- J/A = Lp(Δp – σΔπ)
- J = Lp/σΔπ
- J/A = Lp/Δp
Answers: 1
Question 10: Which of the following is considered as a pretreatment to the biological feeds?
- Heating to denature the proteins
- Addition of filter aids to increase the porosity
- Addition of electrolytes
- All of the above
Answers: 4
Question 11: If the solute passes through membrane freely, the the rejection coefficient (s) is
- 1
- 0
- >1
- <1
Answers: 2
Question 12: If the membrane rejects all solute, the rejection coefficient (s) is
- 1
- 0
- >1
- <1
Answers: 1
Question 13: In antibiotic manufacturing processes, the fermentation time ranges from
- 2-3 weeks
- 1-2 weeks
- 4-5 weeks
- 2-4 weeks
Answers: 3
Question 14: The conventional filtration involves the separation of large particles generally
- dp>5μm
- dp>10μm
- dp>15μm
- dp>20μm
Answers: 2
Question 15: Which of the operation does not come under upstream processing?
- Media preparation
- Inoculum development
- Effluent treatment
- Storage of raw material
Answers: 3
Question 16: The disk centrifuge is the type of centrifuge used most often for bio separations due to its
- continuous operation
- lesser cost
- higher speed
- ease in operation
Answers: 2
Question 17: The effectiveness of a solvent can be measured by the
- distribution coefficients
- selectivity
- both (a) and (b)
- diffusivity
Answers: 3
Question 18: The stage wise operation of adsorption is called
- contact filtration
- conventional adsorption
- affinity adsorption
- ion exchange
Answers: 1
Question 19: Which of the following is not the physical method for the cells rupturing?
- Milling
- Homogenization
- Ultrasonication
- Enzymatic digestion
Answers: 4
Question 20: Conventional adsorption is a
- reversible process
- irreversible process
- either reversible or irreversible
- none of these
Answers: 1
Question 21: Maintenance cost varies from
- 0-4% of the capital cost
- 12-16% of the capital cost
- 4-8% of the capital cost
- 8-12% of the capital cost
Answers: 3
Question 22: The optimum wet solid content for the cell suspension for a bead mill is typically somewhere between
- 5-15% by volume
- 15-30% by volume
- 30-60% by volume
- 60-90% by volume
Answers: 3
Question 23: 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)
- (1/A) dVf/dt = Δp/μ(L/K)
- dVf/dt = (1/A)Δp/μ(L/K)
- (1/A) dVf/dt = Δp/μ LK
- dVf/dt = (1/A)Δp/μ LK
Answers: 1
Question 24: Filtration leaf test results indicate that the filtration rate of a protein product is 100 dry lbs/(ft2hr). What size production filter would be required to obtain 100 dry lbs of filter cake/hr?
- 1.54 ft2
- 3.08 ft2
- 65 ft2
- 65 lbs/ ft2.hr
Answers: 1
Question 25: Selectivity can be expressed as
- ratio of the distribution coefficients in different solute
- mass fraction of the solute in the extract phase at equilibrium
- mass fraction of the solute in the raffinate phase
- ratio of the mass fraction of the solute in the extract phase to the raffinate phase
Answers: 1
Question 26: Concentration polarization can be reduced further by
- pre filtering the solution
- reducing the flow rate per unit membrane surface area
- back washing periodically
- all of the above
Answers: 4
Question 27: A system which require less solvent and produces a more concentrated extract phase, is desired with a
- large distribution coefficients
- small distribution coefficients
- very small distribution coefficients
- constant distribution coefficients
Answers: 1
Question 28: The efficiency of cell disruption in a bead mill depends on the
- concentration of the cells
- amount and size of beads
- type and rotational speed of agitation
- all of these
Answers: 4
Question 29: A common filter medium is the cloth filter generally made of
- canvas
- synthetic fabrics
- metal or glass fiber
- all of these
Answers: 4
Question 30: An ion exchange resin is composed of
- polymeric network
- ionic functional groups
- counter ions
- all of these
Answers: 4