GATE BT topic:bioreaction-engineering PYQs & Answers

Questions 1–8 of 8. Imported answers require independent review unless marked reviewed.

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, which of the following inferences is/are correct?

Your answerSelect all correct options. You can choose more than one.

The culture has died due to absence of oxygen

The culture has run out of carbon source

The culture growth becomes oxygen limited

The culture growth is independent of dissolved oxygen

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For an ideal plug flow reactor, which of the following statements is/are true?

Your answerSelect all correct options. You can choose more than one.

It can be approximated by a large number of ideal continuous stirred tank reactors connected in series

It has significant back mixing

It has significant axial mixing

It has a uniform velocity profile across any cross section

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A microbial culture (follow Monod model for growth) has a maximum specific growth rate of 0.1 h

, Monod constant of 1 mg L

and endogenous decay rate of 0.1 day

. At limiting substrate concentration of 23 g L

, the net specific growth rate will be ________ day

. (rounded off to one decimal place)

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A CSTR with a volume of 100 m

is operated in cell recycle mode. At a volumetric flow rate of 10 m

day

and effluent biomass of 20 mg L

, the steady state biomass concentration is 200 mg L

. The mean cell retention time in the reactor is ____ days. (answer in integer)

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A substrate is consumed in a zero order reaction such that its concentration falls from 42 g L

to 14 g L

in 4 hours. The total time taken for complete utilization of substrate will be ________ hours. (answer in integer)

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A microbe that follows Monod growth kinetics on a limiting substrate (maximum specific growth rate of 0.5 h

and Monod constant of 0.1 mg L

) is cultivated in a continuous reactor for microbial growth (chemostat with sterile feed). Given that the chemostat volume is 5 L and inlet concentration of limiting substrate is 10 g L

, the minimum inlet feed flow rate for chemostat washout is ______ L h

. (rounded off to one decimal place)

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An enzyme immobilised in a porous spherical pellet, catalyses a strong mass-transfer limited first-order reaction. The effectiveness factor for the immobilised enzyme reaction increases with the

Your answerSelect all correct options. You can choose more than one.

decrease in the size of the pellet

increase in the pore diffusivity within the pellet

decrease in the enzyme turnover number

increase in the enzyme concentration within the pellet

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A 2 L bioreactor is being operated as a chemostat, at a flow rate of 0.8 L/h and sterile feed of 10 g/L substrate. The bacterial growth follows Monod kinetics at a maximum specific growth rate of 0.6 h

with a Monod constant of 0.5 g/L and a biomass yield coefficient of 0.4 g/g.

The exit biomass concentration is ______ g/L.

(Round off to one decimal place)

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GATE BT topic:bioreaction-engineering PYQs

How to practice topic:bioreaction-engineering

Question 44

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Question 56

Question 60

Question 61

Question 54

Question 62