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Bioprocess Engineering PYQs

27 previous year questions across 14 subtopics · answers and explanations included

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Showing 27 questions · page 1 of 2

1

The temperature of media post sterilization drops from 100°C to 60°C in 40 min by simply keeping it on the lab bench and allowing slow atmospheric cooling to take place at an ambient temperature of 20°C. In the next 40 min, the approximate temperature (°C)…

HardView answer

2

A fermentation medium is being cooled from 70 °C to 32 °C in a double pipe heat exchanger. Fluid flowing counter currently with this stream is heated from 20 °C to 46 °C. The log mean temperature difference (in °C) for the two streams is

HardView answer

3

Which of the combination of gases is finally produced during anaerobic digestion?

EasyView answer

4

In an exponentially growing batch culture of Saccharomyces cerevisiae, the cell density is 30 gL^{-1} (DCW), the specific growth rate ( \mu ) is 0.4 h^{-1} and substrate uptake rate (q) is 18 gL^{-1}h^{-1} . The cell yield coefficient Y_{X/S} will be

HardView answer

5

Immobilization of enzymes to water insoluble, anionic porous carriers often results in an apparent shift in the pH optima of the enzyme. The physico-chemical interaction likely to cause such a behaviour is

HardView answer

6

In the design of a fermenter, which one of the following is NOT the intended use of baffles?

MediumView answer

7

If an enzyme is NOT damaged during the process of entrapment in a bead, then internal pore diffusion will:

MediumEnzyme Immobilization & DiffusionView answer

8

Two film theory of mass transfer considers

HardView answer

9

In an external recycle reactor (CSTR with external recycle), the outlet stream is concentrated 20 fold with respect to biomass and half of this concentrated cells is fed back into the reactor. In such a situation, washout will take place when dilution rate…

MediumBioreactor Design - CSTR with RecycleView answer

10

A concentrated feed of substrate is added at a constant rate in a fed-batch reactor. If all the substrate is utilized, the specific growth rate (μ) pattern will be:

MediumFed-Batch Reactor & Growth KineticsView answer

11

For Bingham Plastics and pseudo plastic liquids, the apparent viscosity:

MediumFluid Rheology & ViscosityView answer

12

You wish to reduce the maximum shear rate in your reactor (given by impeller tip speed), without changing the power consumption (agitator power). For this, you will:

MediumBioreactor Agitation & Shear RateView answer

13

An exponentially increasing feed of concentrated substrate is fed into a fed batch reactor to maintain a constant specific growth rate 0.35 h^{-1} . If the feed is 5 ml/hr at time, t = 0, then feed after 4 hrs will be approximately:

MediumFed-Batch Reactor - Exponential FeedView answer

14

Yeast cells are immobilized in a column and glucose is fed through the inlet at a concentration of 90 g/l. If all the glucose is consumed and we can treat this as an anaerobic fermentation with negligible cell growth, then the ethanol concentration at the…

MediumImmobilized Cell Bioreactor - Ethanol ProductionView answer

15

In an ideal Continuous Stirred Tank Reactor (CSTR) at steady state:

EasyCSTR Steady State CharacteristicsView answer

16

Aqueous two phase partitioning (ATPS) is used for the recovery of an enzyme from the cell free culture filtrate. On addition of PEG-2000 and dextran, the mixture separates into two phases with a partition coefficient for the enzyme as 4.2. The maximum…

HardView answer

17

A continuous reactor has a productivity of 0.5 g/l/h. The volume of reactor required to produce 1.2 ton/day of the product is:

MediumBioreactor Productivity & VolumeView answer

18

If the respiratory quotient (R.Q.) for growing cells is 1.1 and the exit gas analyzer of a bioreactor shows 3% CO_2 in the outlet gases; then given normal air as input to the reactor, you expect the outlet O_2 concentration to read approximately:

MediumRespiratory Quotient & Gas AnalysisView answer

19

If in a bioreactor, the gas hold up (ε) is 0.1 and the average diameter of the air bubbles is 1 mm; then the interfacial area (of the air bubble - liquid interface), per unit reactor volume is:

MediumGas-Liquid Mass Transfer - Interfacial AreaView answer

20

A Continuous Stirred Tank Reactor (CSTR) is running at a dilution (D) of 0.3 h^{-1} and the product formed is growth associated with Y_{P/X} = 0.2 g/g. In order to obtain productivity = 1.2 gl^{-1}h^{-1} we need to have at steady state a biomass…

MediumCSTR Biomass & Product ConcentrationView answer