Category: Fermentation Technology Objective Questions

Fermentation Technology Multiple Choice Questions on “Microbial Growth Kinetics – Batch Culture”.

1. The Batch culture is a/an ______ culture system.
A. Open
B. Closed
C. Isolated
D. Semi-closed

Answer: B
Clarification: The Batch culture is a closed culture system that contains an initial, limited amount of nutrients. The Continuous culture is an open system where nutrients are added continuously whereas the Fed-Batch culture is a semi-closed system.

2. A period during which the growth rate of cells gradually increases is known as _____
A. Lag phase
B. Log phase
C. Stationary phase
D. Deceleration phase

Answer: B
Clarification: A period during which the growth rate of cells gradually increases is known as a log or exponential phase. This is the period of maximum growth rate. This is usually the longest phase of the microbial growth period.

3. During batch culture/fermentation, nutrients in the fermenter are utilized at a fast rate.
A. True
B. False

Answer: B
Clarification: In batch culture, the nutrients in the fermenter are added only once and are utilized by microbes at a slow rate whereas, in continuous culture, the nutrients in the fermenter are utilized at a very fast rate.

4. The exponential phase may be described by the equation _______
A. dx/dt = µx
B. dt/dx = µ
C. dx/dt = µt
D. dx²/dt² = µ

Answer: A
Clarification: The exponential phase is described by equation,
dx/dt = µx
Where, x is concentration of microbial biomass, t is time in hours and µ is the specific growth rate, in hours^-1.

5. During batch fermentation, in which phase the microbes in the fermenter are adapting to the new environment?
A. Lag phase
B. Log or exponential phase
C. Stationary phase
D. Death phase

Answer: A
Clarification: Microbes in the fermenter show lag phase when they are introduced in the fermenter where they adapt themselves for a particular environment. This is the phase where microorganisms prepare themselves and produce necessary enzymes or the metabolites necessary for their growth.

6. The following figure shows the growth of typical microbial culture in batch conditions. What is A, B, C and D?

A. A-lag phase, B-log phase, C-stationary phase, D-deceleration
B. A-log phase, B-lag phase, C-stationary phase, D-deceleration
C. A-deceleration, B-log phase, C-lag phase, D-stationary
D. A-lag phase, B-log phase, C-deceleration, D-stationaryid5fddbb9e1aed9″

Answer: D
Clarification: The growth of microbial culture initiates with lag phase followed by a log phase followed by deceleration phase and finally stationary phase. The microorganism has to pass through all these phases for normal metabolism.

7. Who first suggested that filamentous fungi have a ‘growth unit’ which is replicated at a constant rate?
A. Trinci
B. Petersen
C. Plomley
D. Griffiths

Answer: C
Clarification: Plomley (1959) was the first to suggest that filamentous fungi have a ‘growth unit’ which is replicated at a constant rate and is composed of the apex of hypha and a short length of supporting hypha.

8. Which of the following organisms represent the highest specific growth rate, µ_max?
A. Vibrio natriegens
B. Methylomonas methanolytica
C. Aspergillus nidulans
D. Penicillium chrysogenum

Answer: A
Clarification: Vibrio natriegens represents the highest specific growth rate with µ_max=4.24h^-1 whereas, other organisms have a value between 0 to 1.

9. The size of fermenters is usually large in batch fermentation.
A. True
B. False

Answer: A
Clarification: The size of fermenters is larger as batch culture is mostly utilized of large-scale production and has therefore huge application in industrial production. The larger the size of the fermenter greater number of active microorganism can be added.

10. The Yield factor (Y) is the measure of the efficiency of _______
A. Conversion of anyone substrate into biomass
B. Conversion of all the substrates into biomass
C. The Affinity of an enzyme to the substrate
D. Number of microbes which produced the biomass

Answer: A
Clarification: The Yield factor (Y) is the measure of the efficiency of conversion of anyone substrate into biomass and it can be used to predict substrate concentration required to produce certain biomass.

11. The Yield Factor (Y) does not vary upon which of the following?
A. pH
B. Growth rate
C. Temperature
D. Amount of enzyme

Answer: D
Clarification: Yield factor varies on the growth rate, pH, temperature, the limiting substrate and the concentration of the substrate in excess. It does not depend on the amount of enzyme which is added for catalyzing the reaction.

12. Which scientist(s) pointed out that the stationary phase is a misnomer in terms of the physiology of organism?
A. Burrow et al.
B. Bu’Lock et al.
C. Bull
D. Monod

Answer: C
Clarification: Bull in 1974 pointed out that the stationary phase is a misnomer in terms of the physiology of organism as the population is still metabolically active during this phase.

13. What is Idiophase?
A. Production of secondary metabolites
B. Production of primary metabolites
C. Production of tertiary metabolites
D. Production of quaternary metabolites

Answer: A
Clarification: Idiophase refers to the period subsequent to the exponential phase where secondary metabolites are synthesized.

14. Borrow et al. investigated the biosynthesis of Gibberellic acid by Gibberella fujikuroi and divided growth of organisms into balanced, storage and maintenance phase. What do you mean by storage phase?
A. The phase equivalent to the early to middle exponential phase
B. The phase equivalent to the late exponential phase
C. The phase equivalent to the stationary phase
D. The phase equivalent to the lag phase

Answer: B
Clarification: Storage phase means the phase equivalent to the late exponential phase where the increase in mass is due to the accumulation of lipid and carbohydrate.

15. The batch culture or fermentation can be used to produce ________
A. Organic acids
B. Amino acids
C. Single Cell Protein
D. Antibiotics

Answer: D
Clarification: The batch culture or fermentation can be used to produce primary metabolites such as antibiotics which help in retarding the growth of bacteria. Organic acids, amino acids, SCP can be prepared by Continuous fermentation.

Fermentation Technology Multiple Choice Questions on “Fermenter Design – Aeration and Agitation”.

1. The purpose of aeration is to provide ___________
A. The medium to organisms
B. The carbon dioxide to organisms
C. The oxygen to organisms
D. The water to organismsid5fe1d9b8008de”

Answer: C
Clarification: The main function or purpose of aeration is to provide oxygen to the microorganisms for metabolic requirements. It is the major process of the fermentation process.

2. The Aeration is mainly provided to organisms present in _______
A. Submerged culture
B. Solid State culture
C. Surface culture
D. Batch cultureid5fe1d9b80090b”

Answer: A
Clarification: The aeration is mainly provided to the microorganisms present in submerged culture. The microorganisms in the submerged culture grow beneath the fermentation media and thus are in less contact with oxygen. Therefore, aeration system is required.

3. The non-agitated fermentations are carried out in vessels of a height/diameter ratio of ________
A. 1:2
B. 5:1
C. 3:2
D. 4:1id5fe1d9b800928″

Answer: B
Clarification: The non-agitated fermentations are carried out in vessels of a height/diameter ratio of 5:1. In such vessels, aeration is sufficient enough to produce high disruption but a tall column of liquid requires greater input energy in compressed air production.

4. The agitator is required to _________
A. Provide air
B. Mixing objectives
C. Purify the product
D. Sterilize the mediaid5fe1d9b800935″

Answer: B
Clarification: The agitator is required to achieve a number of mixing objectives, e.g. oxygen transfer, heat transfer, fluid and gas-mixing, and maintaining a uniform environment throughout the vessel contents.

5. Which of the following is not the component of aeration and agitation system?
A. Impeller
B. Baffles
C. Stirrer gland and bearing
D. Thermometerid5fe1d9b800940″

Answer: D
Clarification: The structural components of the fermenter involved in aeration and agitation are Impeller or agitator, Baffles, Stirrer glands and bearing, and the sparger or the aeration system.

6. Which of the following agitator consists of vanes in a vertical plane around the circumference?
A. vaned discs
B. disc turbines
C. variable pitch turbines
D. marine propellerid5fe1d9b800967″

Answer: B
Clarification: The disc turbines are the type of agitators that consists of a series of rectangular vanes arranged in a vertical plane or fashion around the circumference of the discs. The disc turbines rotate at a very high speed.

7. Which of the following agitator consists of vanes attached vertically inside?
A. vaned discs
B. disc turbines
C. variable pitch turbines
D. marine propellerid5fe1d9b800975″

Answer: A
Clarification: The vaned discs are the type of agitators that consists of rectangular vanes attached vertically to the underside. Whereas the disc turbines include a series of rectangular vanes attached around the circumference of the discs.

8. Which of the following agitator consists of blades directly attached to a boss on agitator shaft?
A. vaned discs
B. disc turbines
C. rectangular turbines
D. marine propellerid5fe1d9b80097f”

Answer: B
Clarification: The blades in the marine propeller are attached directly to a boss on the agitator shaft. In this type of agitator, air bubbles do not initially hit any surface before dispersion by blades.

9. Which of the following is not the type of modern agitator?
A. SCABA
B. Prochem Maxflo
C. Lightning A315
D. New Brunswick Scientificid5fe1d9b80098a”

Answer: D
Clarification: The modern agitators include SCABA 6SRGT, Prochem Maxflo T, Lightning A315, Ekato Intermig. A Rushton disc turbine is also a type of disc turbine. New Brunswick Scientific is a type of glass fermenter.

10. Which of the following seal assembly has not been used in stirrer glands and bearings?
A. Stuffing box
B. Bush seal
C. Electric drive
D. Mechanical sealid5fe1d9b800993″

Answer: C
Clarification: The four basic types of seal assembly used in stirrer glands and bearings are the stuffing box or packed-gland seal, the simple bush seal, the mechanical seal, and the magnetic drive. The stirrer shaft can enter from the top, bottom, side of the fermenter vessel.

11. Which of the following is not the use of baffles?
A. Increase the effect of agitation
B. Improve aeration efficiency
C. Improve cooling capacity
D. Improve the fermenter capacityid5fe1d9b80099d”

Answer: D
Clarification: The Baffles are metal strips about one-tenth of vessel diameter attached to the wall. They prevent vortex and improve aeration efficiency. Agitation effect is also increased using wider baffles. The cooling coils are attached to the baffles to increase the cooling capacity.

12. Which of the following sparger is made of ceramic or metals?
A. Porous sparger
B. Orifice sparger
C. Nozzle sparger
D. Combined sparger-agitatorid5fe1d9b8009a7″

Answer: A
Clarification: The porous spargers are made up of sintered glass, ceramics, or metals. The size of the bubble produced by it is usually larger than the pore size. It is used in non-agitated vessels.

13. Who developed the combined-agitator sparger?
A. Herbert
B. Rivett
C. Johnson
D. Petersonid5fe1d9b8009b1″

Answer: A
Clarification: The combined sparger-agitator was developed by Herbert et al. in 1965. The air is introduced via agitator shaft and is emitted through holes drilled in discs between the blades.

14. The nozzle sparger does not get blocked.
A. True
B. Falseid5fe1d9b8009bb”

Answer: A
Clarification: The nozzle sparger is a partially closed pipe used to provide a stream of air bubbles. It normally causes low-pressure loss and does not get blocked.

15. The use of flat disc in the turbine is to ensure the bulk of energy consumption occurs at blades.
A. True
B. Falseid5fe1d9b8009c4″

Answer: A
Clarification: The Rushton turbine has a flat disc which is useful in the consumption of energy. The size, number of blades, the speed of agitator, and power input in a turbine plays an important role in energy consumption.

Fermentation Technology Multiple Choice Questions on “Media Design for Bioprocesses – Media Types”.

1. Which of the following is not a microbiological culture media?
A. Natural media
B. Synthetic media
C. Complex media
D. Semi-synthetic mediaid5fdc69f985688″

Answer: A
Clarification: The microbiological media consist of synthetic media, synthetic media, and complex media. Natural media is not the type of microbiological media. It can be solid, semi-solid or liquid in the state. It must be sterilized before any use.

2. Magnesium is required in the medium for _____________
A. Membrane stabilization
B. Production of ATP
C. Membrane structure and function
D. Amino acid synthesisid5fdc69f9856b7″

Answer: C
Clarification: Magnesium is required significantly for the role in membrane structure and function. It also acts as a cofactor for the activity of enzymes. It keeps the heartbeat steady and regulates blood glucose levels.

3. Which of the following provides the fewest problems while downstream processing?
A. Natural media
B. Synthetic media
C. Complex media
D. Semi-synthetic mediaid5fdc69f9856c7″

Answer: B
Clarification: The synthetic media provides the fewest problems while downstream processing as it is fully soluble. But it is generally used only at the small-scale level as it is very expensive and in pure form. It is used to determine the effect of a particular component on the growth of organisms.

4. Which of the following media consists of a few components which are poorly specified?
A. Natural media
B. Synthetic media
C. Complex media
D. Semi-synthetic mediaid5fdc69f9856d3″

Answer: D
Clarification: Semi-synthetic media consists of a few components whose composition is poorly specified. But a large amount of its components are of known concentration. It is required when an organism requires a substrate which is very expensive in its pure form.

5. Which of the following is responsible for the formation of foam?
A. Natural media
B. Synthetic media
C. Complex media
D. Defined mediaid5fdc69f9856de”

Answer: C
Clarification: The complex media and the semi-synthetic media is responsible for the formation of foam. This is due to the presence of amino acids, and proteinaceous material in complex media. There is a greater need of antifoams in these media types.

6. Which of the following is required for the synthesis of amino acids?
A. Phosphorus
B. Calcium
C. Magnesium
D. Sulfurid5fdc69f9856e9″

Answer: D
Clarification: Sulfur is used for the synthesis of amino acids and also for the production of vitamins e.g. biotin. It also acts as a coenzyme. The deficiency of sulfur leads to a reduction in protein synthesis. It also acts as an antibacterial agent against a few bacteria.

7. What is the composition of carbohydrates in yeast?
A. 55 %
B. 38 %
C. 32 %
D. 45 %id5fdc69f9856f3″

Answer: B
Clarification: The composition of carbohydrates in yeast is about 38%. The carbon components of yeast, bacteria, and fungi are almost similar but their nitrogen concentration varies largely. This is the way in which different organisms grow.

8. What is the use of calcium in media?
A. Production of phospholipids
B. Production of vitamins
C. Stabilization of cell walls
D. Production of nucleic acidsid5fdc69f9856fe”

Answer: C
Clarification: Calcium is required for the stabilization of cell walls and is important particularly for the formation of endospore as it contains a high concentration of calcium dipicolinate.

9. Which of the following is used for the production of nucleic acids?
A. Phosphorus
B. Calcium
C. Magnesium
D. Sulfurid5fdc69f985708″

Answer: A
Clarification: Phosphorus is used for the production of nucleic acids. It is also used in the production of phospholipids, and generation of energy in the form of ATP and ADP. It is also required for growth and repair of body cells and tissues.

10. There is a high amount of nutrients in growth media.
A. True
B. Falseid5fdc69f985712″

Answer: B
Clarification: There is a high amount of nutrients in the fermentation media and is used in creating final products. Whereas, low amount of nutrients are present in the growth media. As for example, yeast requires 1 % carbon for normal growth and about 13 % of carbon during fermentation.

11. Which of the following media is used in determining the colony characteristics of the isolate?
A. Solid media
B. Semi-solid media
C. Liquid media
D. Complex mediaid5fdc69f98571c”

Answer: A
Clarification: Solid media is useful in determining the colony characteristics of the isolate. It is also used in the isolation of bacteria. It usually contains an agar medium at a concentration of about 2%, which is a solidifying agent.

12. Which of the following is not an example of selective media?
A. Mannitol Salt Agar
B. MacConkey’s agar
C. Crystal Violet Blood Agar
D. Tryptic Soyid5fdc69f985726″

Answer: D
Clarification: Tryptic Soy is an example of broth which is used in broth formula. Mannitol agar, MacConkey’s agar, crystal violet blood agar, Thayer Martin agar, etc. are examples of selective media.

13. Which of the following primary metabolite is produced by Streptomyces erythreus?
A. Penicillin
B. Cephalosporin
C. Gibberellin
D. Erythromycinid5fdc69f985731″

Answer: D
Clarification: The primary metabolite is produced by Streptomyces erythreus is Erythromycin. It is used in the production of antibiotic which is useful in the treatment of a variety of bacterial infections and many respiratory tract infections like bronchitis, pneumonia, etc.

14. Xanthum gum is ____________
A. A rheology modifier
B. A vitamin
C. A flavor enhancer
D. An alcoholic beverageid5fdc69f98574b”

Answer: A
Clarification: Xanthum gum is used as a rheology modifier and food additive. It is produced by Xanthonomonas campestris as a primary metabolite. It is a polysaccharide which is also used as a stabilizer.

15. Crude media contains inorganic salts with a carbon source.
A. True
B. Falseid5fdc69f985756″

Answer: A
Clarification: Crude media contains inorganic salts containing cations and anion along with a carbon source. Some of the ions such as magnesium ions, phosphates or sulfates are required by microorganisms which are fulfilled by the addition of these ions to balance the crude media.

Fermentation Technology Questions and Answers for Entrance exams on “Properties of Fermentation Vessels”.

1. Which of the following is a fabricated material used for the construction of a fermentation vessel?
A. Wood
B. Ceramics
C. Stone
D. Gourdsid5fdba55f8be92″

Answer: B
Clarification: Ceramic is a fabricated material used for the construction of fermentation vessels. It is inert, non-porous, inexpensive and suitable for small scale domestic brewing. Wood, stone, gourds are natural materials used for constructing fermentation vessel.

2. Which of the following has a very high thermal conductivity?
A. Concrete
B. Glass
C. Wood
D. Copperid5fdba55f8bec3″

Answer: D
Clarification: Copper has a very high thermal conductivity which is used as a fabricated material in the construction of fermentation vessel. It is strong, durable, expensive, easily worked, and cleaned. Glass, concrete, and wood have very low conductivity.

3. Which of the following is not used in the construction of a fermentation vessel?
A. Iron
B. Steel
C. Potassium
D. Stainless steelid5fdba55f8bede”

Answer: C
Clarification: Potassium cannot be used in the construction of a fermentation vessel. Iron, steel and stainless steel can be used for constructing a fermentation vessel. They are porous, durable, strong, and has a high thermal conductivity.

4. Which of the following is a natural material used in the fermentation vessel construction?
A. Aluminium
B. Glass
C. Plastic
D. Slateid5fdba55f8bef4″

Answer: D
Clarification: Slate is a natural material used in the construction of the fermentation vessel. It is durable, non-porous, inert, very heavy and has low thermal conductivity. It is suitable for small vessel and rectangular vessels.

5. The composition of chromium in ferritinic alloy is _____________
A. 13 – 20 %
B. 10 – 12 %
C. 18 – 20 %
D. 25 – 30 %id5fdba55f8bf09″

Answer: A
Clarification: The composition of chromium in Ferritinic alloy is 13 – 20 % with less than 0.1% carbon content. They are usually less expensive. They also have good resistance to stress-corrosion cracking.

6. Which of the following alloy has up to 2% nickel content?
A. Ferritinic
B. Austenitic Type 304
C. Martensitic
D. Austenitic Type 316id5fdba55f8bf1f”

Answer: C
Clarification: Martensitic alloy has nickel content of up to 2% with 10 – 12 % of chromium and 0.2 – 0.4% carbon content. Austenitic alloys have more than 10% of carbon content and ferritinic alloys have little or no nickel content.

7. The 4 x 400 hl vessels is better than 1 x 1600 hl vessel in terms of _____________
A. Flexibility
B. Vessel space utilization
C. Capital costs
D. Revenue costsid5fdba55f8bf33″

Answer: A
Clarification: The 4 x 400 hl vessel is better than 1 x 1600 hl vessel in terms of flexibility. It is good that the system has the ability to ferment four simultaneous product lines whereas in 1 x 1600 hl vessel only one product line can be fermented at a time.

8. Which of the following is not important for the maintenance of the hygiene of vessel?
A. The vessels must be capable of being cleaned
B. Before using, it must be acted upon by antibiotics
C. The vessel should be disinfected prior to filling wort
D. The vessel must present a barrier to the external environmentid5fdba55f8bf48″

Answer: B
Clarification: The hygiene requirements are: The vessels must be capable of being cleaned between fermentations, It must be necessary to disinfect the vessel prior to filling the wort, and during fermentation, the vessel must be present as a barrier to the external environment. Using antibiotics is not required.

9. Which of the following is not an element in controlling and monitoring brewery fermentations?
A. Set of final conditions
B. Set of initial conditions
C. Controlling fermentation rate
D. Monitoring the progress of fermentationid5fdba55f8bf5c”

Answer: A
Clarification: There are mainly the elements of controlling and monitoring brewery fermentations. They are Setting of the desired initial conditions, Monitoring the progress of fermentation and Controlling the rate, and identifications of completion of key stages during fermentation.

10. The carbon dioxide concentration can be monitored by ____________
A. Manual monitor
B. Automatic monitor
C. Alarm
D. Automatic monitor with an audible alarmid5fdba55f8bf6e”

Answer: D
Clarification: The carbon dioxide concentration in the fermenting room can be monitored at all times using an automatic monitor fitted with an audible alarm. It is necessary to provide ventilation in the fermentation room so that gases are dissipated safely.

11. Which of the following is referred to as machinery mould?
A. Geotrichum candidum
B. Geotrichum capitatum
C. Geotrichum pneumonia
D. Geotrichum klebahniiid5fdba55f8bf81″

Answer: A
Clarification: Geotrichum candidum is also referred to as machinery mould. It is because it is capable of producing slimy growth on the surface of the metals. It is also called as the black mould.

12. Who reported that height-aspect-ratio is linked with perturbations in beer flavour?
A. Hoggan
B. Shardlow
C. Vrieling
D. Ulenbergid5fdba55f8bfab”

Answer: C
Clarification: Vrieling in 1978 reported that height-aspect-ratio is linked with perturbations in beer flavour. The concentrations of the important flavour compounds, ethyl acetate and isoamyl acetate, formed during fermentation is inversely related to the height of the vessel.

13. The wood used in the vessel is relatively light.
A. True
B. Falseid5fdba55f8bfc3″

Answer: A
Clarification: The wood used in the fermentation vessel is relatively lighter. It should be durable, easily worked and shaped and requires inert lining. It should be of low thermal conductivity and must be well-seasoned.

14. Stainless steel is expensive.
A. True
B. Falseid5fdba55f8bfd6″

Answer: A
Clarification: Stainless steels are very expensive than carbon steel because it contains a variety of alloying elements like nickel, chromium, manganese, etc. There are different grades of stainless steel available according to the price range.

To practice all areas of Fermentation Technology for Entrance exams, .

Fermentation Technology Multiple Choice Questions on “Microbial Growth Kinetics – Continuous Culture”.

1. The Continuous culture is a/an ______ culture system.
A. Open
B. Closed
C. Isolated
D. Semi-closedid5fdbc659c84f8″

Answer: A
Clarification: The Continuous culture is an open culture system where the nutrients are added in a continuous fashion. The batch culture is a closed system with limiting the number of nutrients and fed-batch culture is a semi-closed system.

2. During continuous culture/fermentation, nutrients in the fermenter are utilized at a fast rate.
A. True
B. Falseid5fdbc659c8526″

Answer: A
Clarification: In Continuous Fermentation, the nutrients in the fermenter are added continuously and are utilized by microbes at a fast rate whereas, in batch culture, the nutrients are utilized at a slow rate.

3. Which Growth phase is usually longer in continuous culture?
A. Log
B. Exponential
C. Stationary
D. Deathid5fdbc659c8534″

Answer: B
Clarification: Exponential phase is usually longer as the nutrients are added continuously and therefore the microbes show exponential growth. This is the phase of the maximum growth rate where the growth of cells usually increases.

4. What is the dilution rate (D.?
A. D = F/V
B. D = V/F
C. D = µF
D. D = µDid5fdbc659c853f”

Answer: A
Clarification: The flow of medium into the vessel is called dilution rate, and is defined as,
D = F/V
where V is volume and F is the flow rate.

5. What is the unit of flow rate (F)?
A. dm³ h^-1
B. km³ h^-1
C. ml³ h^-2
D. dm² h^-2id5fdbc659c8548″

Answer: A
Clarification: Flow rate is the product of dilution rate and volume of the vessel. The unit of dilution rate is h^-1 and that of the volume of the vessel is dm³. Therefore, the unit of flow rate is dm³ h^-1.

6. The chemostat and turbidostat are the types of bioreactors that are used in which of the following culture?
A. Batch culture
B. Continuous culture
C. Fed-Batch culture
D. Solid State cultureid5fdbc659c8551″

Answer: B
Clarification: Turbidostat is a microbiological culture device, similar to a chemostat, which has feedback between the turbidity of the culture vessel and the dilution rate. Continuous fermentation is useful in the production of potentially more important products than batch fermentation.

7. Which scientist(s) gave a full kinetic description of external and internal feedback system?
A. Monod
B. Pirt
C. Bull
D. Harte and Webbid5fdbc659c855a”

Answer: B
Clarification: Pirt in 1975 gave a full description of these feedback systems and he also discussed the kinetics of product of microbial culture.

8. A multistage system is shown below. Label the stages 1 and 2.

A. 1-Medium inlet and 2-culture effluent
B. 1-Mixing chamber and 2-culture effluent
C. 1-Medium inlet and 2-Liquid reservoir
D. 1-Culture effluent and 1-Medium Inletid5fdbc659c8563″

Answer: A
Clarification: Multistage system is a chemostat that is separated in different stages where the medium inlet is followed by culture effluent which is followed by effluent collection or subsequent stages.

9. What are the disadvantages of continuous culture?
A. It can rarely be used for other productions
B. The growth rate is higher
C. If contamination occurs, huge volumes of the product may be lost
D. It is very useful for processes involving the production of primary metabolitesid5fdbc659c856c”

Answer: C
Clarification: Continuous culture is an open culture system and therefore, there are very high chances of microbial contamination. Thus, a huge amount of product may be lost. The other three options include the advantages of continuous culture.

10. In continuous culture, the turnover rate is high.
A. True
B. Falseid5fdbc659c8574″

Answer: A
Clarification: The turnover rate in continuous culture is higher because the nutrients are added constantly and continuously and thus the products are produced in a high amount.

11. Which of the following is not the type of continuous brewing?
A. Cascade system
B. Multistage system
C. Tower system
D. Extract brewingid5fdbc659c8588″

Answer: D
Clarification: The main types of continuous brewing are cascade, multisystem and the tower system. The extract brewing is a type of home brewing. The continuous brewing is useful in converting the wort into beer.

12. All the constituents of medium are excess in _______
A. Chemostat
B. Turbidostat
C. Batch culture
D. Fed-Batch cultureid5fdbc659c8591″

Answer: A
Clarification: In the continuous culture all the constituents of the medium are in excess in the chemostat. The batch and the fed-batch culture contains a limited amount of nutrients in the medium.

13. Which carbon source has great application for SCP production?
A. Cellulose
B. Starch
C. Methanol
D. Methaneid5fdbc659c859a”

Answer: A
Clarification: Cellulose has been investigated as a potential carbon source for SCP production and was reviewed by Callihan et al and Woodward. Cellulose is a compound present in the cell wall of plants. Humans do not have an enzyme that can digest cellulose, therefore cellulose directly gets excreted in the form of roughage.

14. The continuous culture or fermentation can be used to produce _______
A. Biomass
B. Primary metabolites
C. Secondary metabolites
D. Antibodiesid5fdbc659c85af”

Answer: B
Clarification: The continuous culture or fermentation can be used to produce primary metabolites such as amino acids, SCP, organic acids, etc. Biomass, Secondary metabolites, and a few primary metabolites are produced by batch fermentation.

15. Which of the following is NOT correct for Continuous fermentation?
A. Setup is not changed from outside once the fermentation has started
B. Nutrients are added many times
C. Closer to the natural environment
D. The small size of fermenters are requiredid5fdbc659c85b8″

Answer: A
Clarification: In Continuous Fermentation the system is open and therefore the setup can be changed from outside during the fermentation process. The other three options are possible for batch fermentation.