Biochemical Engineering Test 8 - Online Biochemical Engineering Test

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Total number of questions: 20.
Time allotted: 30 minutes.
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In competitive inhibition a factor is obtained from the measurement of

V_max

K_M

Y-intercept in Lineweaver-Burk Plot

None of these

[#]

Which of the following is taken as an assumption in the distributed model?

The reaction occurs at every position and the kinetics of the reaction are of the same form as observed for free enzyme.

Mass transfer through the immobilized enzyme occurs via molecular diffusion

There is no mass transfer limitation at the outside surface of the spherical immobilized enzyme

All of the above

[#]

A fed-batch reactor initially contains 2 litre of medium. If it was fed at 1 litre per hour, then after 10 hours, the volume of the reactor will be

1 litre

2 litre

3 litre

13 litre

[#]

In a fluidized bed reactor mixing is achieved by

gravity flow of fluid

upward movement of the incoming feed

diffusion

both (a) and (b)

[#]

Saccharomyces cerevisiae when grown in high glucose concentration medium, the cells activity depends on which of the following?

High concentration of dissolved oxygen

Low concentration of dissolved oxygen

No effect of dissolved oxygen

High concentration of dissolved oxygen and sodium salts

[#]

Which of the following is not correct for the Monod model and the Michaelis Menten Model?

The Michaelis Menten Model was derived from a curve fitting exercise

The Michaelis Menten model was derived from an analysis of the mechanism of microbial growth

The Monod model was derived from an analysis of the mechanism of microbial growth

All of the above

[#]

The dilution rate, D is defined as(where F = volumetric flow rate, V_R = total volume of culture in the reactor and μ specific growth rate)

F/V_R

V_R/F

μ/F

F/μ

[#]

If the specific growth rate, μ. is constant with time during the exponential growth period, the equation correlating bacterial number density C_n), cell number concentration with respect to time can be expressed as

C_n= C_n₀ exp[μ (t - t₀)]

C_n₀ = C_n exp[μ (t - t₀)]

C_n/C_n₀ =(1/μ)exp(t-t₀)

C_n₀ / C_n = (1/μ)exp(t-t₀)

[#]

Swirling and vortex formation can be prevented by

using baffles

using diffusion ring with turbines

both (a) and (b)

none of these

[#]

10.

Which of the following type(s) of stirrer can be used for microbiological processes?

Mig

Intermig

Turbine

All of these

[#]

11.

The average concentration of oxygen in the boundary layers surrounding the bubbles (C_o^*) in a reactor is normally determined by

ultra-small dissolved oxygen probes

laser based photographic systems

measuring the steady state concentration of oxygen in the bulk liquid prior to inoculation of the reactor

measuring the steady state concentration of oxygen in the bulk liquid after inoculation of the reactor

[#]

12.

The oxygen uptake requirements of a microbial population is characterized by the following parameters: μ_m= 0.2 h^-1, K₀ = 0.2 mg O₂.l^-1, Y₀ = 0.5 mg dry weight/mg O₂ and C_0,crit=0.8 mg.l^-1 The required concentration of cells is 1000 mg.l^-1 and the saturation oxygen concentration of the medium is 5.8 mg.l^-1. The required K_La must be greater than

64 h^-1

32 h^-1

16 h^-1

8h^-1

[#]

13.

Which of the following would be best described as a radial flow impeller?

An impeller with blades pitched at 45° to the vertical

A Rushton turbine

Both (a) and (b)

An impeller which directs liquid flow towards the base of the reactor

[#]

14.

The advantage of axial flow impellers over radial flow impellers is that axial flow impellers

provide better lift of solids

provide high shear conditions

provide low shear conditions

are cheaper to build

[#]

15.

Which of the following describes the importance of the Kolmogorov eddy size in the biotechnology?

The Kolmogorov eddy size is a measure of the smallest eddy size in a liquid

When the Kolmogorov eddy size become equivalent or smaller than the cell or particle diameter, then the cell or particle will become susceptible to shear damage

At the Kolmogorov eddy size, much of the energy of the originating eddy will be released

All of the above

[#]

16.

The viscosity of a fluid changes with either stirrer speed or mixing time. But when mixing ceases, the viscosity returns to its original state. This fluid is best described as

newtonian

rheopectic

viscoelastic

thixotropic

[#]

17.

The collection efficiency by diffusion increases with

decreasing particle size

decreasing air velocity

both (a) and (b)

increasing particle size

[#]

18.

The X₉₀ value for a filtration system is

the time required to reduce microbial population by 90%

the time required to traverse survivor curve by one log cycle.

the depth required to reduce population by 90%

the depth of the filter required to reduce population by 99%

[#]

19.

The activated sludge process consists of returning a portion of the clarifier

effluent water entering the reactor

influent water coming out of the reactor

influent water entering the reactor

effluent water coming out of the reactor

[#]

20.

Coliform bacteria in water is an indication of the presence of

radioactive wastes

excess fertilizer

decaying animals and plants

human feces

[#]

Online Biochemical Engineering Test - Biochemical Engineering Test 8

Marks : 2/20

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