Downstream Processing

Q1: The disk centrifuge is the type of centrifuge used most often for bio separations due to its

A continuous operation

B lesser cost

C higher speed

D ease in operation

ANS:B - lesser cost

No answer description is available.

Q2: Which of the following is not the physical method for the cells rupturing?

A Milling

B Homogenization

C Ultrasonication

D Enzymatic digestion

ANS:D - Enzymatic digestion

No answer description is available.

Q3: The optimum wet solid content for the cell suspension for a bead mill is typically somewhere between

A 5-15% by volume

B 15-30% by volume

C 30-60% by volume

D 60-90% by volume

ANS:C - 30-60% by volume

No answer description is available.

Q4: Conventional adsorption is a

A reversible process

B irreversible process

C either reversible or irreversible

D none of these

ANS:A - reversible process

No answer description is available.

Q5: Micro filtration refers to the separation of suspended material such as bacteria by using a membrane with spore sizes of

A 0.02 to 10μm

B 1-10A°

C 20-30μm

D 10-200A°

ANS:A - 0.02 to 10μm

When general size range for bacteria is less than 10 micrometer.

How <10 micrometer pore size solves the purpose of filtration?

Q6: If the solute passes through membrane freely, the the rejection coefficient (s) is

A 1

B 0

C >1

D <1

ANS:B - 0

No answer description is available.

Q7: The conventional filtration involves the separation of large particles generally

A dp>5μm

B dp>10μm

C dp>15μm

D dp>20μm

ANS:B - dp>10μm

No answer description is available.

Q8: The purity of a solute collected between two times t1 and t2 during chromatographic separation can be calculated as

A amount of solute eluted - amount of impurity eluted

B amount of solute eluted / amount of impurity eluted

C amount of solvent eluted + amount of impurity eluted

D amount of solvent eluted / amount of impurity eluted

ANS:B - amount of solute eluted / amount of impurity eluted

No answer description is available.

Q9: 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

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

ANS:A - 15,000 to 50,000 rpm

No answer description is available.

Q10: Maintenance cost varies from

A 0-4% of the capital cost

B 12-16% of the capital cost

C 4-8% of the capital cost

D 8-12% of the capital cost

ANS:C - 4-8% of the capital cost

No answer description is available.

Q11: Start up expenses in a fermentation industry varies from

A 0-5% of the capital cost

B 10-15% of the capital cost

C 5-10% of the capital cost

D 15-20% of the capital cost

ANS:C - 5-10% of the capital cost

No answer description is available.

Q12: Selectivity can be expressed as

A ratio of the distribution coefficients in different solute

B mass fraction of the solute in the extract phase at equilibrium

C mass fraction of the solute in the raffinate phase

D ratio of the mass fraction of the solute in the extract phase to the raffinate phase

ANS:A - ratio of the distribution coefficients in different solute

No answer description is available.

Q13: In antibiotic manufacturing processes, the fermentation time ranges from

A 2-3 weeks

B 1-2 weeks

C 4-5 weeks

D 2-4 weeks

ANS:C - 4-5 weeks

No answer description is available.

Q14: Concentration polarization can be reduced further by

A pre filtering the solution

B reducing the flow rate per unit membrane surface area

C back washing periodically

D all of the above

ANS:D - all of the above

No answer description is available.

Q15: 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?

A 1.54 ft2

B 3.08 ft2

C 65 ft2

D 65 lbs/ ft2.hr

ANS:A - 1.54 ft2

No answer description is available.

Q16: 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)

A Y = YmaxX/(KL+X)

B YYmax/(KL+X)

C YYmaxX/KL

D Y = YmaxX/ (KL+X)

ANS:A - Y = YmaxX/(KL+X)

Very helpful question.

Q17: A common filter medium is the cloth filter generally made of

A canvas

B synthetic fabrics

C metal or glass fiber

D all of these

ANS:D - all of these

No answer description is available.

Q18: Which of the following is considered as a pretreatment to the biological feeds?

A Heating to denature the proteins

B Addition of filter aids to increase the porosity

C Addition of electrolytes

D All of the above

ANS:D - All of the above

No answer description is available.

Q19: For the extractions operation, the selectivity should be

A > 1

B < 1

C 1

D zero

ANS:A - > 1

No answer description is available.

Q20: Chromatography is based on the

A different rate of movement of the solute in the column

B separation of one solute from other constituents by being captured on the adsorbent

C different rate of movement of the solvent in the column

D any of the above

ANS:A - different rate of movement of the solute in the column

B should be the right answer.

Q21: 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)

A J = Lpp - σΔπ)

B J/A = Lpp - σΔπ)

C JLp/σΔπ

D J/A = Lpp

ANS:A - J = Lpp - σΔπ)

No answer description is available.

Q22: If the membrane rejects all solute, the rejection coefficient (s) is

A 1

B 0

C >1

D <1

ANS:A - 1

No answer description is available.

Q23: 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 Lis the thickness of the filter cake)

A (1/AdVf/dt = Δp/μ(L/K)

B dVf/dt = (1/A)Δp/μ(L/K)

C (1/AdVf/dt = Δp/μ LK

D dVf/dt = (1/A)Δp/μ LK

ANS:A - (1/AdVf/dt = Δp/μ(L/K)

No answer description is available.

Q24: An ion exchange resin is composed of

A polymeric network

B ionic functional groups

C counter ions

D all of these

ANS:D - all of these

No answer description is available.

Q25: The efficiency of cell disruption in a bead mill depends on the

A concentration of the cells

B amount and size of beads

C type and rotational speed of agitation

D all of these

ANS:D - all of these

No answer description is available.

Q26: A system which require less solvent and produces a more concentrated extract phase, is desired with a

A large distribution coefficients

B small distribution coefficients

C very small distribution coefficients

D constant distribution coefficients

ANS:A - large distribution coefficients

No answer description is available.

Q27: For cost analysis in a fermentor system, the depreciation cost varies from

A 5-6% of the capital cost

B 6-7% of the capital cost

C 6-10% of the capital cost

D 8-10% of the capital cost

ANS:C - 6-10% of the capital cost

How is it 6-10%?

Q28: Which of the operation does not come under upstream processing?

A Media preparation

B Inoculum development

C Effluent treatment

D Storage of raw material

ANS:C - Effluent treatment

No answer description is available.

Q29: The stage wise operation of adsorption is called

A contact filtration

B conventional adsorption

C affinity adsorption

D ion exchange

ANS:A - contact filtration

No answer description is available.

Q30: The effectiveness of a solvent can be measured by the

A distribution coefficients

B selectivity

C both (a) and (b)

D diffusivity

ANS:C - both (a) and (b)

No answer description is available.



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