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G192306 Pages:2

With the help of a neat sketch, outline the steps involved in the transport of
substrate and product molecules between a well-mixed liquid phase and the
interior of a heterogeneous solid enzyme pellet. Also identify the major mass
transfer resistances associated with this process.
Explain the chemical techniques used for immobilization of enzymes.
Explain the surface renewal theory of mass transfer.
Describe any three applications of immobilized enzyme systems.
PART ^

Answer any two full questions, each carries 20 marks.

Discuss the benefits of “recycling” in a continuous enzyme reactor.

Consider a series of equivolume continuous stirred tank bioreactors, n in
number. The rate of medium flow through the series of vessels is F litres/h
and the volume of each vessel is V litres. Using steady state and unsteady
state mass balances, develop a general model for the limiting substrate
concentration in the 17 vessel. Assume that the medium flowing from the (n-
1)" vessel into the n™ vessel is mixed instantaneously and completely with
the contents of the 0% vessel. The yields based on the cell mass may be
assumed as constant regardless of the number of vessels under consideration.
Define all notations used and show clearly all the steps involved in the model
development.

With the aid of a neat sketch, describe the main components of a biosensor

with their functions.

Outline the applications of biosensors in the food industry.

Explain the principle and working of potentiometric biosensors. Append a
neat sketch.

With a neat sketch, explain the operation of a fluidized bed reactor for
immobilized enzymes.

Outline any five applications of biosensors in medical diagnostics.

Compare the operation of a stirred tank enzyme reactor in batch, continuous
and recycle modes. Write the relevant rate equations in each case, assuming
the applicability of Michaelis-Menten kinetics for enzyme catalysis.

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