List of top Biotechnology Questions on Bioprocessing

Temperature of a reaction with an activation energy value of 15 kcal mol\(^{-1}\) is increased from 300 K to 310 K. If the value of the ideal gas constant (R) is 1.9872 cal mol\(^{-1}\) K\(^{-1}\), the ratio of the reaction rate constants \(\left(\frac{k_{310}}{k_{300}}\right)\) (rounded off to two decimal places) is ____________.

E. coli cultivated at 298 K uptakes an uncharged compound (A) by passive diffusion. The intracellular and extracellular concentrations of A are 0.001 M and 0.1 M, respectively. If \(R=1.9872\ \mathrm{cal\ mol^{-1}\ K^{-1}}\), the free-energy change (in \(\mathrm{kcal\ mol^{-1}}\)) for this passive diffusion of A (rounded off to two decimal places) is ________________.

E. coli is cultivated in a chemostat operated at a dilution rate of 0.2 h\(^{-1}\). The values of biomass yield due to oxygen consumption and the steady state biomass concentration are 0.2 g g\(^{-1}\) and 10 g L\(^{-1}\), respectively. The oxygen transfer rate (in g L\(^{-1}\) h\(^{-1}\)) is ____________.

The values of the consistency index ‘\(K\)’ and the flow behavior index ‘\(n\)’ of a dilatant fluid are 0.415 (in CGS units) and 1.23, respectively. The value of the apparent viscosity (in \( g \cdot cm^{-1} \cdot s^{-1} \)) of this fluid at a shear rate of 60 \( s^{-1} \) (rounded off to the nearest integer) is __________________.

An evaporator is insulated using glass wool material of \(0.15\ \text{m}\) thickness. The inner most surface and the outer surface of the insulation are at \(700^{\circ}\text{C}\) and \(80^{\circ}\text{C}\), respectively. The mean thermal conductivity of the glass wool under these conditions is \(0.29\ \text{W}\,\text{m}^{-1}\,\text{K}^{-1}\). The rate of heat loss (in W) through \(1.2\ \text{m}^2\) of the evaporator wall surface (rounded off to the nearest integer) is ________________.

A proportional controller is used to control the temperature of an autoclave from \(60^{\circ}C\) to \(130^{\circ}C\). If the proportional band setting of the controller is 25%, the proportional gain value is ______________.

The following schematic diagram shows a chemostat with cell recycle (feed flow rate \(F_0\) and recycle flow rate \(F_r\) in \(\mathrm{L\,h^{-1}}\)). The cell concentrations in the reactor, recycle stream, and product stream are \(X_1\), \(X_0\), and \(X\) (in \(\mathrm{g\,L^{-1}}\)), respectively. If \(\dfrac{X_0}{X_1}=1.5\), \(\dfrac{F_r}{F_0}=0.7\), and \(X_1=7.3~\mathrm{g\,L^{-1}}\), the value of \(X\) (in \(\mathrm{g\,L^{-1}}\), rounded off to one decimal place) is ________________.

If \(1000\) bp of a double-helical DNA weighs \(1\times10^{-18}\) g and the distance between two bp is \(0.34~\text{nm}\), the total amount of DNA (in mg, rounded to one decimal) required to stretch from Earth to Moon (distance \(=3.74\times10^{5}\) km) is ________________.

A protein has three identical sites arranged at the vertices of an equilateral triangle. With one site filled with donor dye, the quantum yield \(\phi_D\) is \(0.5\). Filling one site with donor and a second with acceptor gives \(\phi_D=0.25\). Find \(\phi_D\) when one site has donor and the other two have acceptor dyes (rounded to three decimals).

The following reaction represents biomass synthesis from hexadecane:
\(\,C_{16}H_{34} + 12.5 O_2 + 2.13 NH_3 \rightarrow 10.6 CH_{1.66}O_{0.27}N_{0.27} + 5.37 CO_2 + 11.4 H_2O \)
where \( CH_{1.66}O_{0.27}N_{0.27} \) represents the biomass. The value of respiratory quotient (rounded off to two decimal places) is ________________.

Aqueous two-phase extraction is used to recover \(\alpha\)-amylase from a solution. A polypropylene glycol–dextran mixture is added and the solution separates into upper and lower phases. The partition coefficient is 4.0 and the ratio of upper to lower phase volume is 5.0. The enzyme recovery or yield (in percentage, rounded off to the nearest integer) is ____________________.

Which one of the following methods CANNOT be used to determine the secondary structure content of a protein?