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Indian Institute of Technology Kharagpur (IIT-K) 2007 B.Tech Biotechnology Biochemical reaction engineering & bioenergetics - Question Paper

Wednesday, 23 January 2013 01:10Web


Time: 3 Hrs.

Date of Examination...................

End-Autumn Semester 2007-2008 .FN/AN    Full Marks : 50

2nd yr.B.Tech.

Subject No. BT21105 Subject: Biochemical Reaction Engineering & Bioenergetics No. of Students : 30 of the Department of Biotechnology

Instruction : Answer all questions from Group-A and any two questions from group-B. Answer to the point. Assume suitable data with necessary justification, if required.


2. a) In PS II which molecule is electron donor which molecules are electron acceptor. What is function of

Peso molecule on PS II?


The release of one dioxygen molecule requires the transfer of 4 electrons from 2 molecules of water to 2 molecules of NADP+. Given the Emj of 2H2O 2H+ + O2 couple as +0.82 V and Em,7 of NADP++ 2e +2H+ NADPH couple as -0.32 V. Calculate the net thermodynamic efficiency of the electron transfer

steps of photosynthesis.


3. i) Enumerate the equations related to enthalpy, entropy and Gibbs free energy with heat capacity and temperature, ii) Define Tm of protein unfolding and how will you calculate fraction unfolded from a typical thermograph of protein unfolding due to increase of temperature. Iii) What is the significance of

the measurement of ACP of protein unfolding.

2 + 2+1

4. a)Binding constant ( K) of ligand( X) with macromolecule( M) is accurately determined by titration calorimeter. Enumerate the equation related to heat change ( dQ) with change in [MX} concentration, molar enthalpy and cell volume.    1

b)    How the dimensionless parameter C is related with macromolecular concentraion and binding constant (K). What is the range of C by which binding constant ( K) could be determined by using titration calorimeter.    2

c)Describe    in brief the thermodynamic signature optimization process for the selection of HIV protease inhibitor drug.    2


5. a) An enzyme is immobilized on the surface of a non-porous solid matrix. Assuming that external

mass-transfer resistance for substrate is not negligible and that the Michaelis-Menten equation describes the intrinsic kinetics. Derive an expression which indicates the explicit form of the coefficients in a Lineweaver-Burk plot. Find out the values of vmax, Km and km(mass-transfer coefficient)?


b) Glucose is converted to fructose by using immobilized glucose isomerase. Find out the height of the immobilized enzyme column? Following data are given:

1.    Diameter of the column = 5 cm.

2.    Particle size 30/40 mesh (about 0.71 mm average diameter, dp),

3.    Glucose concentration in feed at 60C = 500 g/1,

4.    Glucose conversion efficiency = 60% w/w,

5.    Feed viscosity = 3.6 c.p. at 60C,

6.    Feed density = 1.23 g/ml at 60C,

7.    Substrate diffusivity = 0.21 x 10'5 cm2/sec at 60C,

8.    Void fraction = 0.35.    7

(a) What do you mean by DamkOhler number and effectiveness factor of an immobilized enzyme process? Find out the mathematical correlation between them. Explain the diffusion-limited regime of the immobilization process.    2+2+1.5

b) Write the Monod chemostat models. Derive the equation for finding out the cell mass and substrate concentration in a chemostat under steady state conditions. Write the mathematical expressions for the Dmax and DwaSh0ut. Explain the importance ofDwaShout for the operation of a CSTR system.


y, i) Candida utilis utilizes xylose at any concentration constitutively with a maximum growth rate of

0.31 h'1 and has a saturation constant (Ks) of 2.6 g/I and a cell yield on substrate (IVs) of 0.5 g/g. C. utilis can also metabolize galactose (with Ks = 0.8 g/1 and Yx/S = 0.5 g/g), but can only metabolize galactose at xylose concentrations at or below 0.5 g/1. If we have a feed stream that contains 10 g/1 of xylose and 30 g/1 of galactose entering a chemostat containing C. utilis. Find the following:

a. D (h'1) at which galactose begins to be metabolized.

a.    Dilution rate for maximum cell productivity (Dopt)

b.    Maximum ceil productivity


ii) D-(-)-4-hydroxyphenylglycin is the optically active intermediate in the synthesis of the broad-spectrum antibiotics amoxicilline. This intermediate is among others produced from a hydantoin derivative by means of the enzyme hydantoinase. The hydantoin derivative is poorly soluble in water, about I kg m'3. The price of the substrate is cost determining and degree of conversion should therefore be very high, at least 99%.

Calculate the volume needed to produce 100 kg of product per day by immobilized hydantoinase in a

-    batch reactor    2.5

-    CSTR    2

-    Plug-flow reactor.    2


Michaelis-Menten reaction kinetics with vmax = 1.5 x 10-4 kg s'3 m'3 biocatalyst and Km = 5 x 10'

3 kg m3

Yp/s = 1 kg kg1 Degree of conversion 99%

Down-time for batch reactor 12 h

The activity of the biocatalyst can be assume to be constant in time

The reactor contain 0.1 m3 immobilized biocatalyst per m3, except the plug-flow reactor, which is packed with 0.5 m3 immobilized biocatalyst per m3 reactor.


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