Fermentation and Bioreactors: Principles and Applications in Biotechnology

Question 1

Which substance is not typically produced through fermentation?

Accepted Answer

Oxygen

Answer

Ethanol

Answer

Citric acid

Answer

Penicillin

Question 2

Which of the following is crucial for maintaining sterile conditions within a bioreactor?

Accepted Answer

Aseptic operation protocols

Answer

Temperature monitoring

Answer

pH monitoring

Answer

Substrate availability

Question 3

Which type of fermentation occurs in the absence of oxygen?

Accepted Answer

Anaerobic fermentation

Answer

Aerobic fermentation

Answer

Semi-aerobic fermentation

Answer

Microaerobic fermentation

Question 4

Which of the following is not a parameter that can be monitored and controlled in a bioreactor?

Accepted Answer

Gravity

Answer

Temperature

Answer

pH

Answer

Oxygen concentration

Question 5

What is the primary purpose of a fermenter in a bioreactor system?

Accepted Answer

To provide a controlled environment for cell growth

Answer

To regulate environmental conditions

Answer

To eliminate waste products

Answer

To produce the final product

Question 6

Which is LEAST important for directly controlling the environment inside a bioreactor?

Accepted Answer

Reactor volume

Answer

Temperature

Answer

pH

Answer

Agitation rate

Question 7

In downstream processing, which techniques are commonly used to separate and purify products from fermentation processes?

Accepted Answer

Centrifugation and filtration

Accepted Answer

Chromatography and ultrafiltration

Answer

Sterilization and pasteurization

Answer

Fermentation and bioreactor operation

Question 8

Which of the following is NOT a common product of fermentation?

Accepted Answer

Carbon dioxide

Answer

Ethanol

Answer

Lactic acid

Answer

Citric acid

Question 9

The exponential growth phase of microbial cultures is characterized by:

Accepted Answer

Constant growth rate and unlimited nutrient availability

Answer

Slow growth rate and limited nutrient availability

Answer

Spore formation and nutrient depletion

Answer

Stationary phase and constant biomass

Question 10

Which type of bioreactor is commonly used for large-scale production of antibiotics due to its efficient oxygen transfer capability?

Accepted Answer

Stirred-tank bioreactor

Answer

Airlift bioreactor

Answer

Column bioreactor

Answer

Fluidized-bed bioreactor

Question 11

Shear stress in bioreactors primarily refers to:

Accepted Answer

Damaging mechanical forces acting on cells due to impeller agitation

Answer

Rate of oxygen transfer into the culture

Answer

Limitation of essential nutrients for microbial growth

Answer

Gradient of temperature within the bioreactor

Question 12

The 'lag phase' observed in microbial growth is primarily caused by:

Accepted Answer

Adaptation of cells to the new growth environment

Answer

Depletion of essential nutrients

Answer

Formation of spores by the cells

Answer

Rapid cell death due to unfavorable conditions

Question 13

Which type of bioreactor is particularly suitable for cultivating high-density microbial cultures?

Accepted Answer

Fluidized-bed bioreactor

Answer

Stirred-tank bioreactor

Answer

Airlift bioreactor

Answer

Packed-bed bioreactor

Question 14

The 'Krebs cycle,' also known as the citric acid cycle, is primarily involved in:

Accepted Answer

Generating energy through the breakdown of carbohydrates

Answer

Synthesizing amino acids for protein production

Answer

Breaking down lipids into fatty acids

Answer

Fixing nitrogen from the atmosphere

Question 15

For most industrial fermentation processes, the optimal pH range to ensure optimal microbial activity is:

Accepted Answer

6-8

Answer

2-4

Answer

4-6

Answer

8-10

Question 16

What is the primary function of a sparger in a bioreactor?

Accepted Answer

To provide oxygen to the culture

Answer

To control pH

Answer

To agitate the culture

Answer

To remove waste products

Question 17

Which type of culture medium is most commonly used for the production of recombinant proteins in bioreactors?

Accepted Answer

Defined medium

Answer

Complex medium

Answer

Minimal medium

Answer

Enriched medium

Question 18

What is the purpose of a foam breaker in a bioreactor?

Accepted Answer

To prevent excessive foaming

Answer

To increase oxygen transfer

Answer

To control pH

Answer

To sterilize the reactor

Question 19

Which of the following is NOT a crucial operating parameter directly influencing microbial growth and metabolism in a bioreactor?

Accepted Answer

Harvest time

Answer

Temperature

Answer

pH

Answer

Agitation

Question 20

Which of the following is NOT a characteristic of aerobic fermentation?

Accepted Answer

Anaerobic conditions

Answer

Production of organic acids

Answer

High energy yield

Answer

Use of oxygen

Question 21

What is the primary function of a sparger in a bioreactor?

Accepted Answer

To introduce air or gas into the culture

Answer

To control pH

Answer

To measure oxygen consumption

Answer

To separate cells from the medium

Question 22

What is the primary advantage of a continuous bioreactor over a batch bioreactor?

Accepted Answer

Higher productivity and efficiency

Answer

Easier to scale up

Answer

Requires less operator attention

Answer

Lower contamination risk

Question 23

Which of the following components is essential for a stirred-tank bioreactor?

Accepted Answer

Impeller

Answer

Heat exchanger

Answer

Packed bed

Answer

Condenser

Question 24

What is the critical role of aseptic conditions in bioreactor operation?

Accepted Answer

To prevent contamination and ensure product integrity

Answer

To reduce energy consumption

Answer

To improve product yield

Answer

To increase oxygen transfer

Question 25

Which of the following is a widely recognized application of bioreactors in the food industry?

Accepted Answer

Production of beer and other fermented beverages

Answer

Synthesis of pharmaceuticals

Answer

Biodiesel production

Answer

Wastewater treatment

Question 26

What is the primary benefit of utilizing genetically modified microorganisms in fermentation processes?

Accepted Answer

Enhanced product yield, improved quality, or specific product modifications

Answer

Lower operating costs

Answer

Reduced contamination risk

Answer

Faster fermentation rates