List of top Bioprocess Engineering and Process Biotechnology Questions asked in GATE BT

The transfer function of a process is $ G(s) = \frac{K_p}{T_p s + 1} $, where $ K_p $ is the gain and $ T_p $ is the time constant. This is a _____ process.

In adsorption chromatography, the adsorption of uncharged solute molecules onto a silica-based stationary phase is by

The degree of reduction of lactic acid (C₃H₆O₃) is _________.

The specific growth rate of a yeast having a doubling time of 0.693 h (rounded off to nearest integer) is _________ h^-1.

A fermentation broth of density 1000 kg m^-3 and viscosity 10^-3 kg m^-1 s^-1 is mixed in a 100 L fermenter using a 0.1 m diameter impeller, rotating at a speed of 2 s^-1. The impeller Reynolds number is _________.

Figure below depicts simplified metabolic and transport reactions taking place in the production of B from A in a cell. The subscript ‘i’ refers to intracellular metabolites. $r_j$ is the $j^{\text{th}}$ reaction flux in $\frac{g}{(g\;dry\;mass)\;h}$. Under pseudo–steady–state condition, the following reaction fluxes are available: $r_1 = 4,\; r_3 = 1,\; r_6 = 1$. The transport flux of B, $r_4$, is _________ $\frac{g}{(g\;dry\;mass)\;h}$.

Liquid-phase mass transfer coefficient ($k_L$) is measured in a stirred tank vessel using $\textit{steady-state method}$ by sparging air. Oxygen uptake by the microorganism is measured. The bulk concentration of O$_2$ is $10^{-4}$ mol L$^{-1}$. Solubility of O$_2$ in water at 25$^\circ$C is $10^{-3}$ mol L$^{-1}$. If the oxygen consumption rate is $9\times10^{-4}$ mol L$^{-1}$ s$^{-1}$, and interfacial area is 100 m$^2$/m$^3$, the value of $k_L$ is _________ cm s$^{-1}$.

Consider the growth of S. cerevisiae under aerobic condition in a bioreactor and the specific growth rate of yeast is 0.5 h$^{-1}$. The overall reaction of the process is \[ 2C_6H_{12}O_6 + 0.2 NH_3 + 10.35 O_2 \to CH_{1.8} O_{0.5} N_{0.2} + 0.2 C_2 H_6 O + 10.6 CO_2 + 10.8 H_2 O \] The heat of combustion values for different compounds are tabulated below with reference to CO$_2$, H$_2$O, O$_2$, and N$_2$ at standard conditions. Heat of Combustion

Compound	Heat of combustion (kJ mol^-1)
C₆H₁₂O₆	2802
NH₃	383
CH_1.8O_0.5N_0.2	560
C₂H₆O	1366

The specific rate of heat production (rounded off to the nearest integer) is _________ kJ mol$^{-1}$ h$^{-1}$.

A pilot sterilization was carried out in a vessel containing 100 m³ medium with an initial spore concentration of 10⁸ spores/ml. The accepted level of contamination after sterilization is 1 spore in the entire vessel. The specific death rate constant for the spore is 2 min^-1 at 121°C. Assuming no death takes place during the heating and cooling cycles, the holding time at 121°C (rounded off to nearest integer) is _________ min.

An enzyme catalyzes the conversion of substrate A into product B. The rate equation for this reaction is \[ -r_A = \frac{C_A}{5 + C_A} \;\; \text{mol L}^{-1}\text{min}^{-1} \] Substrate A at an initial concentration of 10 mol L$^{-1$ enters an ideal mixed flow reactor (MFR) at a flow rate of 10 L min$^{-1}$. The volume of the MFR required for 50% conversion of substrate to product is _________ L.}

A fed-batch operation is initiated by feeding substrate solution at 1 L h\textsuperscript{-1 containing 50 g L\textsuperscript{-1} substrate. The reactor initially contains 50 g biomass. The biomass yield $Y_{X/S}^{M}$ is 0.4 $\frac{g\;biomass}{g\;substrate}$. Assuming quasi-steady state, the maximum biomass after 5 h of feeding is _________ g.}

Which of the following statements are CORRECT for an enzyme entrapped in a spherical particle?

Which of the following statements are CORRECT for a controller?

A microorganism is grown in a batch culture using glucose as a carbon source. The apparent growth yield is 0.5 g biomass / g substrate. The initial concentrations of biomass and substrate are 2 g L$^{-1}$ and 200 g L$^{-1}$, respectively. Assuming that there is no endogenous metabolism, the maximum biomass concentration that can be achieved is _________ g L$^{-1}$.

The overall stoichiometry for an aerobic cell growth is $ 3C_6H_{12}O_6 + 2.5 NH_3 + O_2 \rightarrow 1.5 C_a H_b O_c N_d + 3 CO_2 + 5 H_2O $.
What is the elemental composition formula of the biomass?

Match the media component (Column I) with its role (Column II).