Recent questions and answers in Bioprocess Engineering and Process Biotechnology

0 0 votes
1 1 answer
Fed batch cultivation is suitable for which of the following?Processes with substrate inhibitionProcesses with product inhibitionHigh cell density cultivationP and Q only...
0 0 votes
1 1 answer
It is desired to scale-up a fermentation from $1L$ to $1000L$ vessel by maintaining a constant power-to-volume ratio. The small fermenter is operated at an agitator speed...
0 0 votes
1 1 answer
Which one of the following represents non-growth associated product formation kinetics in a bioprocess system? $X$ and $P$ denote viable cell and product concentrations, ...
0 0 votes
0 0 answers
The transfer function of a Proportional-Integral $\text{(PI)}$ controller $G_{C}(s)$ is given by\[G_{C}(s)=K_{C}\left(1+\frac{1}{\tau_{I} s}\right)\]where $K_{C}$ is the ...
0 0 votes
0 0 answers
The correct sequence of the four steps involved in anaerobic production of biogas from complex organics is:Hydrolysis → Acidogenesis → Acetogenesis → MethanogenesisMethan...
0 0 votes
0 0 answers
In the open-loop process shown in the figure, the input $U(s)$, the transfer function $G_{p}(s)$ and the output $Y(s)$ are given in the Laplace domain in terms of the Lap...
0 0 votes
0 0 answers
A microbial culture is being grown in a bioreactor with continuous aeration. The dissolved oxygen probe provided with the system shows a reading of zero. In this context,...
0 0 votes
0 0 answers
In an aerobic fermentation with air sparging, which of the following options can be used to increase the volumetric mass transfer coefficient for oxygen transfer?Using pu...
0 0 votes
0 0 answers
For an ideal plug flow reactor, which of the following statements is/are true?It can be approximated by a large number of ideal continuous stirred tank reactors connected...
0 0 votes
0 0 answers
A microbial culture (following Monod model for growth) has a maximum specific growth rate of $0.1 \mathrm{~h}^{-1}$, Monod constant of $1 \mathrm{mg} \mathrm{L}^{-1}$ and...
0 0 votes
0 0 answers
A $\text{CSTR}$ with a volume of $100 \mathrm{~m}^{3}$ is operated in cell recycle mode. At a volumetric flow rate of $10 \mathrm{~m}^{3}$ day ${ }^{-1}$ and effluent bio...
0 0 votes
0 0 answers
A batch sterilizer is being operated at $121^{\circ} \mathrm{C}$ for sterilizing a medium containing microbial cells. Assume that the thermal deactivation of cells is a f...
0 0 votes
0 0 answers
A substrate is consumed in a zero order reaction such that its concentration falls from $42 \mathrm{~g} \mathrm{~L}^{-1}$ to $14 \mathrm{~g} \mathrm{~L}^{-1}$ in $4$ hour...
0 0 votes
0 0 answers
A microbe that follows Monod growth kinetics on a limiting substrate (maximum specific growth rate of $0.5 \mathrm{~h}^{-1}$ and Monod constant of $0.1 ~\mathrm{mg} \math...
0 0 votes
0 0 answers
It is desired to cultivate $150$ mg (dry weight) microbial cells with an empirical formula of $\mathrm{C}_{5} \mathrm{H}_{7} \mathrm{O}_{2} \mathrm{~N}$. If the phosphoru...
0 0 votes
0 0 answers
A packed bed bioreactor with length $1 \text{~m}$ and inside diameter $10 \text{~cm}$ has liquid flowing at an interstitial velocity of $1 \mathrm{~cm} \mathrm{~s}^{-1}$....
–2 –2 votes
1 1 answer
​​​​Correctly match the following Product classes with their representative Products.Product classProductP. Biofuel1. CellulaseQ. Bioplastic2. CephalosporinR. Industrial ...
0 0 votes
1 1 answer
​​​​Which of the following fluids exhibit(s) non-Newtonian behaviour at $25^{\circ} \mathrm{C}$ ?ToothpasteMercuryBrineBlood plasma
0 0 votes
1 1 answer
A binary mixture of benzene and toluene under vapour-liquid equilibrium at $80^{\circ} \mathrm{C}$ follows ideal Raoult's law. At this condition, the saturation pressures...
0 0 votes
1 1 answer
An industrial fermentor containing $10,000\:L$ of medium needs to be sterilized. The initial spore concentration in the medium is $10^{6}$ spores $mL^{-1}$. The desired ...
0 0 votes
1 1 answer
Which one of the following statements is correct about Reynolds Number $\left(N_{R e}\right)$ in a stirred tank bioreactor?$N_{R e}$ is independent of the viscosity of th...
0 0 votes
1 1 answer
Fermentation medium is cooled from $121^{\circ} \mathrm{C}$ to $30{ }^{\circ} \mathrm{C}$ in a double pipe heat exchanger. If cold water is flowing in the counter-current...
0 0 votes
1 1 answer
For a double-pipe heat exchanger, the inside and outside heat transfer coefficients are $100$ and $200 \; \text{W m}^{-2} \text{K}^{-1},$ respectively. The thickness and ...
0 0 votes
1 1 answer
A $2 \: \mathrm{L}$ bioreactor is being operated as a chemostat, at a flow rate of $0.8 \: \mathrm{~L} / \mathrm{h}$ and sterile feed of $10 \: \mathrm{~g} / \mathrm{L}$ ...
0 0 votes
1 1 answer
A hot, freshly-sterilised fermentation medium is cooled in a double-pipe heat-exchanger. The medium enters the inner pipe of the exchanger at $95^{\circ} \mathrm{C}$ and ...
0 0 votes
1 1 answer
​​​​An enzyme immobilised in a porous spherical pellet, catalyses a strongly mass-transfer limited first-order reaction. The effectiveness factor for the immobilised enzy...
0 0 votes
1 1 answer
​​​​For a specific bioreactor configuration, the power requirement for a Rushton-turbine impeller agitating an unaerated Newtonian fluid in the turbulent regime will bepr...
0 0 votes
0 0 answers
​​​​A recombinant protein is secreted extracellularly in soluble form by an $E. coli$ culture. Which of the following downstream processes is/are involved in the purifica...
0 0 votes
0 0 answers
​​​​A thermometer measuring body temperature follows a first-order response with a time constant of $40$ seconds. The instrument will reach $95 \%$ of its steady-state ou...
0 0 votes
0 0 answers
​​​​​The output $y(t)$ of a first-order process is governed by the following differential equation\[\tau_{p} \frac{d y}{d t}+y=K_{p} f(t)\]where $\tau_{p}$ is a non-zero ...
0 0 votes
0 0 answers
In a fermentation process, each mole of glucose is converted to biomass $\left(\mathrm{CH}_{1.8} \mathrm{O}_{0.5} \mathrm{~N}_{0.2}\right)$, with a biomass yield coeffici...
0 0 votes
0 0 answers
Aqueous two-phase extraction is used to recover α-amylase from a solution. A polypropylene glycol-dextran mixture is added and the solution separates into upper and lower...
1 1 vote
1 1 answer
The following reaction represents biomass synthesis from hexadecane$\mathrm{C}_{16} \mathrm{H}_{34}+12.5 \mathrm{O}_2+2.13 \mathrm{NH}_3 \rightarrow 10.6 \mathrm{CH}_{1.6...
0 0 votes
0 0 answers
The transfer function of a process is $G(s)=\frac{K_{p}}{\tau_{p} s+1}$, where $K_{p}$ is the gain and $\tau_{p}$ is the time constant. This is a $\_\_\_\_\_\_$ process.f...
0 0 votes
0 0 answers
Under complete cell washout condition in a chemostat with sterile feed, which of the following statements is/are correct?Biomass concentration in the reactor is maximumS...
0 0 votes
0 0 answers
Aspergillus niger is grown in a $10,000$ L stirred batch bioreactor under aerated conditions to produce citric acid. At steady state oxygen transfer conditions, the speci...
0 0 votes
0 0 answers
Ethanol is produced in a $10,000$ L stirred bioreactor using an impeller of diameter $1 \mathrm{~m}$. The density and viscosity of fermentation broth are $1000 \mathrm{~k...
0 0 votes
0 0 answers
A fermentor is filled with medium at a rate of $1 \mathrm{~L} \mathrm{~min}^{-1}$. A leak develops at the bottom of the fermentor when the medium in the fermentor reaches...
0 0 votes
0 0 answers
A fed batch process is running at quasi-steady state with respect to substrate and biomass concentration. At $2 \mathrm{~h}$, the culture volume is $500 \mathrm{~L}$ with...
0 0 votes
0 0 answers
Consider scale-up of fungal fermentation from a $20 \mathrm{~L}$ model-type to $20,000 \mathrm{~L}$ prototype stirred tank reactor. The model-type and prototype have the ...
To see more, click for all the questions in this category.