Category: Fermentation Technology Objective Questions

Fermentation Technology Interview Questions and Answers for freshers on “Instrumentation and Control – Agitation and Foam Sensing and Valves”.

1. Which of the following is used in agitation measurement?
A. Torsion dynamometer
B. Bourdon tube
C. Diaphragm gauge
D. Strain gaugeid5fdbe71901bc0″

Answer: A
Clarification: Torsion dynamometer is used in the agitation measurement. It is used on a small scale and is placed outside the vessel. It is less accurate due to friction. The Bourdon tube, Diaphragm gauge, and strain gauge are used in the measurement of pressure.

2. Which of the following is used to control the agitation speed?
A. Dynamometer
B. Tachometer
C. Strain gauge
D. Bourdon tubeid5fdbe71901be0″

Answer: A
Clarification: The Tachometer is used to control the agitation speed. The rate of rotation is monitored either by electromagnetic voltage or induction generation or light sensing or magnetic force.

3. Who gave the treatment of strain gauge measurements?
A. Brodgesell
B. Aiba
C. Bourdon
D. Hallid5fdbe71901bee”

Answer: B
Clarification: The theoretical treatment of the strain gauge measurements was covered by Aiba et al. in 1973. They mounted four identical strain gauge at 45° to the axis of the hollow shaft.

4. In which of the following valve a sliding disc is moved in or out of flow path?
A. Gate valve
B. Globe valve
C. Needle valve
D. Piston valveid5fdbe71901bfa”

Answer: A
Clarification: The gate valve consists of a sliding disc that moved in or out of the flow path. It is used for purpose steam or a water line. It is not used for regulating flow.

5. Which of the following valve consists of a tapered plug?
A. Piston valve
B. Globe valve
C. Needle valve
D. Plug valveid5fdbe71901c04″

Answer: C
Clarification: The needle valve consists of a tapered plug. It is similar to the globe valve but the disc is replaced by a tapered valve or needle fitted into the tapered valve seat.

6. Which of the following valve consists of a disc which rotates about a shaft in a housing?
A. Butterfly valves
B. Piston valve
C. Ball valves
D. Pinch valvesid5fdbe71901c0e”

Answer: A
Clarification: Butterfly valve consists of a disc which rotates about a shaft in a housing. It is usually used in large diameter pipes operating under low pressure. It is not suitable for aseptic operation.

7. Which of the following valve is used for pressure control?
A. Gate valves
B. Globe valves
C. Needle valves
D. Safety valvesid5fdbe71901c17″

Answer: D
Clarification: The safety valves are used for controlling pressure. It must be incorporated into every vessel which is subjected to pressure to ensure pressure does not exceed over safe limit recommended by the manufacturer.

8. What is the function of check valves?
A. To prevent the reversal of flow of liquid
B. To reduce the pressure
C. To reduce the flow rate
D. To increase the flow rateid5fdbe71901c21″

Answer: A
Clarification: The function of check valves is to prevent the accidental reversal of the flow of liquid. It consists of three basic types of valves: swing check, lift check, and combined stop and check.

9. Which of the following valves is the most suitable for aseptic operation?
A. Butterfly valves
B. Ball valves
C. Needle valves
D. Globe valvesid5fdbe71901c2b”

Answer: B
Clarification: Ball valve is the most suitable valve for aseptic operation. It is made up of stainless steel ball through which orifice is machined. The butterfly valve is not suitable for aseptic operation. The needle valve has very limited application in aseptic operation.

10. Which of the following valve is the most widely used in the design of the fermenter?
A. Diaphragm valve
B. Needle valve
C. Butterfly valve
D. Plug valveid5fdbe71901c35″

Answer: A
Clarification: The diaphragm valve is most widely used in designing of the fermenter. Ball valves are also used, but they are more robust and contain crevices which make the sterilization more difficult.

11. Which of the following valve consists of a horizontal plug or disc is raised or lowered to control flow rate?
A. Plug valves
B. Globe valves
C. Butterfly valve
D. Needle valvesid5fdbe71901c3e”

Answer: B
Clarification: The globe valve consists of a horizontal plug or disc. This disc is lowered or raised to control the rate of flow. It is most commonly useful in regulating the flow of water or steam. It is not suitable for aseptic operation.

12. Which of the following is not an antifoam device?
A. Discs
B. Propellers
C. Brushes
D. Load cellid5fdbe71901c47″

Answer: D
Clarification: The mechanical antifoam devices are devices, Propellers, Brushes or Hollow cones. They are used for the mechanical breaking of foam. Load cells are used for determining the weight of the fermenter vessel.

13. Which of the following is used for measuring gas flow?
A. Rotameter
B. Spectrophotometer
C. UV transilluminator
D. Chromatographyid5fdbe71901c51″

Answer: A
Clarification: The Rotameter is useful in the measurement of gas flow. It consists of a vertically mounted glass tube. Rotameters are also used to measure the flow rate of liquid if abrasive or fibrous materials are not present.

14. The pinch valve consists of a sleeve closed by pinch bar.
A. True
B. Falseid5fdbe71901c5a”

Answer: A
Clarification: The pinch valves consists of a flexible sleeve closed by a pair of pinch bars that can be operated by compressed air remotely or automatically. It is suitable for aseptic operations.

15. Load cells are used for the measurement of pressure.
A. True
B. Falseid5fdbe71901c63″

Answer: B
Clarification: Load cells are used for the measurement of weight of the fermenter vessel. It is essentially an elastic body. It is assembled in a suitable housing with an electrical cable connecting points.

To practice all areas of Fermentation Technology for Interviews, .

Fermentation Technology Multiple Choice Questions on “Beer Types”.

1. Pilsener beer originated in ______________
A. Westphalia
B. Bohemia
C. Munich
D. USAid5fe3082a93193″

Answer: B
Clarification: Pilsener beer originated in Bohemia, the Czech Republic in 1842 by Josef Groll from local ingredients. It was obtained from the bottom-fermented system. Pilsener beer has highly hopped lager brewed with very soft water (5% abv). Example: Pilsener Urquell.

2. Which of the following beer is obtained from the bottom-fermented system?
A. Dortmunder
B. Bockbier
C. Bitter Ale
D. Doppelbockid5fe3082a931b6″

Answer: A
Clarification: Dortmunder is obtained from the bottom-fermented system. It was originated in Westphalia, Germany. It has golden coloured lager with less hop than Pilsener. An example of this type of beer is Dortmunder Aktien Brauerei.

3. Which of the following beer has dark, malty and lightly hopped lager?
A. Munchener Dunkel
B. Munchener Helles
C. Bitter Ale
D. Doppelbockid5fe3082a931c5″

Answer: A
Clarification: Munchener Dunkel is a dark and malty beer with lightly hopped lager. It was originated in Munich, Bavaria, Germany. It is obtained from the bottom-fermented system. One of the examples is Paulaner.

4. Bock beer originated in ______________
A. Germany
B. UK
C. USA
D. Belgiumid5fe3082a931d0″

Answer: C
Clarification: Bock beer originated in the United States of America and Canada. It was obtained from the bottom-fermented system. The beer was dark in colour and lightly hopped. It is very stronger than a typical lager and stronger can be made by freezing the beer.

5. Which of the following beer is obtained from the top-fermented system?
A. Brown Ale
B. Bock beer
C. Eisbock
D. Doppelbockid5fe3082a931db”

Answer: A
Clarification: Brown Ale is obtained from the top-fermenting system. It was originated in the United Kingdom. It is a sweet beer and lightly hopped. It is brown in colour and is brewed from 100 % brown malt with alcohol by volume per cent of 3.5 – 5.5 %.

6. Indian Pale Ale was originated in ________
A. India
B. UK
C. USA
D. Germanyid5fe3082a931e4″

Answer: B
Clarification: Indian Pale Ale was originated in the United Kingdom. It is a highly bittered strong bottled pale ale originally brewed for export to British troops in India. It was obtained from the top-fermenting system with alcohol by volume percent of 4.5 – 12.1 %.

7. Which of the following is also called an ice beer?
A. Doppelbock
B. Indian Pale Ale
C. Bock beer
D. Eisbockid5fe3082a931ee”

Answer: D
Clarification: Eisbock is also called as an ice beer. It was originated in Bavaria, Germany. It was obtained from the bottom-fermenting system with very-low temperature lagering to increase alcohol content by removal of ice. It is a very strong beer.

8. Which of the following is also called smoked beer?
A. Porter
B. Gueze
C. Rauchbier
D. Saisonid5fe3082a931f8″

Answer: C
Clarification: Rauchbier is also called a smoked beer. It was originated in Bamberg, Bavaria, Germany. It is a dark beer with smoked taste due to drying malts over beechwood fires. That is why it is also called as smoked beer. It is obtained from the bottom-fermenting system.

9. Scotch Ale originated in ___________
A. India
B. Germany
C. USA
D. Scotlandid5fe3082a93201″

Answer: D
Clarification: Scotch Ale originated in Scotland, UK. It is dark copper brown in colour obtained from the bottom-fermenting system. It is a strong sweet Ale with creamy taste and alcohol by volume percent of 7 – 10 %. The fermentation is usually carried out at a low temperature.

10. Which of the following is a maize beer?
A. Aca
B. Basi
C. Chi
D. Doloid5fe3082a9320a”

Answer: A
Clarification: Aca is a maize beer which was originated in Peru. It is a cheap beer and is available everywhere in Peru. Whereas, the other three beers were obtained from barley, millet, wheat, etc.

11. Which of the following beer is made of London water?
A. Porter
B. Provisie
C. Lambic
D. Rauchbierid5fe3082a93213″

Answer: A
Clarification: Porter is a type of beer obtained from London water which is high in bicarbonate. It is obtained from the top-fermenting system and originated in London, UK. It is of deep ruby colour.

12. The Gueze beer is obtained from ____________ fermenting system.
A. Top
B. Bottom
C. Side
D. Bottledid5fe3082a9321c”

Answer: D
Clarification: The Gueze beer is obtained from the bottled fermented system. It was originated in the Brussels area, Belgium. It is dry, fruity and highly carbonated beer. It is the blend of old and young lambic beer.

13. Which of the following is not a type of beer?
A. Appy
B. Weizenbier
C. Stout
D. Saisonid5fe3082a93225″

Answer: A
Clarification: Appy is not a type of beer. It is a fruit juice obtained from apple and it tastes similar to beer. Weizenbier, Stout, Saison are the types of beer that are obtained from the top-fermenting system.

14. Bitter Ale is an originally top-fermented beer.
A. True
B. Falseid5fe3082a9322e”

Answer: A
Clarification: Bitter Ale is an original top-fermented beer which was originated in the United Kingdom. It is very bitter in taste and is sold for draught dispense, originally cask conditioned with alcohol by volume percent of 2.5 – 5.5 %.

15. Pombe is a Sorghum beer.
A. True
B. Falseid5fe3082a93237″

Answer: A
Clarification: Pombe is a Sorghum beer which was originated in Africa. It is flavoured with banana juice and various herbs. Sorghum is used in the production of a variety of beverages and is considered a very important ingredient. Alcohol content varies from 1 % to 8 %.

Fermentation Technology Multiple Choice Questions on “Laboratory Fermentation System”.

1. Which of the following is not a type of laboratory scale fermenter?
A. Mini fermenter
B. Tower fermenter
C. Stirred fermenter
D. Tall tubesid5fdb457c95b00″

Answer: B
Clarification: Tower fermenter is not a type of laboratory scale fermenter. It is a large-scale fermenter. Mini fermenter, Stirred laboratory fermenters, and tall tubes are the types of laboratory scale fermenters.

2. The capacity of hypovials in mini fermenters is ____________
A. 120 ml
B. 260 ml
C. 150 ml
D. 200 mlid5fdb457c95b48″

Answer: A
Clarification: The mini fermenters consists of 120 ml hypovials (up to 100 ml operating volume). The vials are sterilized by the process of autoclaving while already filled with the medium.

3. The hypovials in the mini fermenter are fitted with ___________
A. Ethyl septa
B. Propyl septa
C. Pentyl septa
D. Butyl septaid5fdb457c95b66″

Answer: D
Clarification: The hypovials in the mini fermenter are fitted with gas-tight butyl septa held in place by metal crimped caps. The gaseous exchange in mini fermenters is achieved via inlet and outlet tubes.

4. The sterile filters in mini fermenters are made from _______________
A. Pasteur pipettes
B. Graduated pipette
C. Volumetric pipette
D. Micropipetteid5fdb457c95b89″

Answer: A
Clarification: The sterile filters in mini fermenters are made from cut down Pasteur pipettes which are attached by silicone tubing to needles. The tubes (inlet and outlet) in the mini fermenters are shaped with sterile filters which have hypodermic needles and the tip of needles pass through septa.

5. Which of the following stirrer is used to mix the contents of hypovials?
A. Electrical stirrer
B. Magnetic stirrer
C. Mechanical stirrer
D. Automatic stirrerid5fdb457c95b9f”

Answer: B
Clarification: The contents of the hypovials are mixed using magnetic stirrers. The magnetic follower or stirrer employs a rotating magnetic field to mix the contents uniformly. Before using, the vials are sterilized properly using an autoclave.

6. Mini-fermenters are used to study _____________
A. The amount of oxygen evolved
B. The effect of oxygen concentration on yeast fermentation
C. The effect of carbon dioxide concentration on yeast
D. The amount of carbon dioxide consumedid5fdb457c95bb5″

Answer: B
Clarification: The mini-fermenters are used to study the effect of varying the initial oxygen concentration on the fermentation performance of individual yeast strains. This was reported by Boulton and Quain in 1987.

7. The air from hypovial is displaced by using _____________
A. Sterile water
B. Sterile oxygen
C. Sterile nitrogen
D. Sterile hydrogen gasid5fdb457c95bcb”

Answer: C
Clarification: The air from each hypovials is displaced by sparging with sterile nitrogen and then the yeast is inoculated. The hypovials are calibrated with a volume scale. It allows the establishment of a graduation initial dissolved oxygen concentrations.

8. What is the capacity of stirred laboratory fermenter vessel?
A. 4.0 L
B. 1.0 L
C. 2.5 L
D. 3.0 Lid5fdb457c95be4″

Answer: C
Clarification: The capacity of stirred laboratory fermenter vessel is 2.5 liters with 2.0 liters of working volume. The vessel body and the lid are joined by the ground glass.

9. Which of the following is used to maintain the gas-tight seal in stirred fermenters?
A. Silicone rubber
B. Neoprene rubber
C. EPDM rubber
D. Buna-N rubberid5fdb457c95bfa”

Answer: A
Clarification: The Silicone rubber gasket is used to maintain the gas-tight seal in stirred laboratory fermenters. The vessel body and the lid are joined by the ground glass and have a silicone rubber gasket and the joint is held together with a screw and wire clip arrangement.

10. The number of ports in the lid of stirred vessel are _____________
A. One
B. Three
C. Five
D. Sevenid5fdb457c95c11″

Answer: C
Clarification: The number of ports in the lid of the stirred fermenter vessel is five. They are of Quickfit type and are used to attach probes or sensors like pH sensor, temperature sensor, antifoam sensor, dissolved oxygen measurement, pressure measurement, etc.

11. The tall tubes are sterilized for minimum ____________
A. 20 min
B. 30 min
C. 10 min
D. 40 minid5fdb457c95c3d”

Answer: B
Clarification: The tall tubes are sterilized with steam for a minimum of 30 minutes. It may also be sterilized by emptying the tubes and treating it with disinfectants like phenol compounds.

12. Who developed the ‘Multiferm’?
A. Sigsgaard and Rasmussen
B. Jacob and Monod
C. Briggs et al.
D. Skandsid5fdb457c95c6d”

Answer: A
Clarification: Sigsgaard and Rasmussen in 1985 working at Carlsberg Research Centre in Copenhagen, Denmark, described the system of 60 x 2 liter tall tubes. This was termed as the ‘Multiferm’. It was used to evaluate the fermentation performance of genetically modified yeast strains.

13. The automated E.B.C. tube was developed in 1985.
A. True
B. Falseid5fdb457c95c85″

Answer: B
Clarification: The automated E.B.C. tube was developed in 1997 by Skands. It was developed at Carlsberg Research Centre in Copenhagen and it comprises eight pairs of 2 liter stainless steel tubes with automatic sampling and logging facilities.

14. The tall tubes are commonly used in the set of 15.
A. True
B. Falseid5fdb457c95c9c”

Answer: B
Clarification: The tall tubes are commonly used in the set of 12, each holding 2 liters of wort, and fitted to racks on a trolley. Water is used as a coolant which is pumped from an attemperated bath through the jackets of each tall tube in a closed loop.

Fermentation Technology Multiple Choice Questions on “Practical Benefits – Citric Acid Production”.

1. Who first isolated citric acid?
A. Thomas Edison
B. Carl Wilhelm
C. Charles Darwin
D. Francis Crickid5fdb3dec179cc”

Answer: B
Clarification: Carl Wilhelm Scheele in 1784 first isolated citric acid from lemon juice. He crystallized citric acid from lemon juice and this method became the primary method for the production of citric acid.

2. Citric acid is a ____________ acid.
A. Monobasic
B. Tribasic
C. Monoprotic
D. Tribasicid5fdb3dec17a07″

Answer: D
Clarification: Citric acid (2-Hydroxy-1,2,3-propane tricarboxylic aciD. is a tribasic acid which can yield three hydrogen ions (free) upon ionization of each molecule of acid. It is also called as triprotic acid. Phosphoric acid is another example of tribasic or troprotic acid.

3. Who observed citric acid as a by-product of calcium oxalate produced by Penicillium glaucum?
A. Thomas Edison
B. Carl Wilhelm
C. Wehmer
D. Adamid5fdb3dec17a6c”

Answer: C
Clarification: Wehmer in 1893 observed citric acid as a by-product of calcium oxalate produced by Penicillium glaucum. This resulted in the encouragement of the production of citric acid.

4. Which of the following is used in the manufacturing of cheese?
A. Sulphuric acid
B. Amylase
C. Kinase
D. Sodium citrateid5fdb3dec17a7a”

Answer: D
Clarification: Sodium citrate has been used in the manufacturing of cheese. It is also used in the transfusion of blood and bacteriology for the prevention of bacteriology. It can also serve as a source of energy.

5. Which of the following is the most common method for citric acid production?
A. Solid-state fermentation
B. Submerged fermentation
C. Surface fermentation
D. Surface adhesion fermentationid5fdb3dec17a86″

Answer: B
Clarification: Submerged fermentation is the most common method for the production of citric acid. It is the most commonly employed technique and it is estimated that about 80 % of the world production of citric acid is obtained by submerged fermentation.

6. Which of the following organisms is not used for the production of citric acid?
A. Aspergillus wentii
B. Bacillus licheniformis
C. Candida oleophila
D. Saccharomyces cerevisiaeid5fdb3dec17a91″

Answer: D
Clarification: Saccharomyces cerevisiae is not used for the production of citric acid. It is mainly used in the production of beer as it is a brewers’ yeast. Aspergillus niger, Aspergillus wentii, Bacillus licheniformis, Candida oleophila, etc. are used in the production of citric acid.

7. The first product of TCA cycle is ___________
A. Fumaric acid
B. Oxalic acid
C. Malic acid
D. Citric acidid5fdb3dec17a9b”

Answer: D
Clarification: The first product of TriCarboxylic Acid cycle is citric acid. Therefore, it is also called a citric acid cycle or Krebs cycle. The cycle is primarily regulated by the concentration of ATP, NADH and is controlled by the key enzymes like isocitrate dehydrogenase, α-ketoglutarate dehydrogenase, etc.

8. Which of the following fruit contain more amount of citric acid?
A. Mango
B. Tomato
C. Orange
D. Coconutid5fdb3dec17aa5″

Answer: C
Clarification: Oranges contain more amount of citric acid including lemon, lime, grapefruit, etc. are high in citrus whereas tomatoes contain a low amount of citric acid and coconut and mango do not contain citric acid at all.

9. Citrate is the feedback inhibitor of ____________
A. Hexokinase
B. Phosphofructokinase
C. Pyruvate dehydrogenase
D. Malate dehydrogenaseid5fdb3dec17aaf”

Answer: B
Clarification: Citrate is the feedback inhibitor of phosphofructokinase (PFK). The reduction or inhibition of Phosphofructokinase is required for the good accumulation of citric acid.

10. Magnesium hydroxide is used to precipitate calcium citrate.
A. True
B. Falseid5fdb3dec17ab9″

Answer: B
Clarification: Magnesium hydroxide cannot be used for the precipitation of calcium citrate as some of the acids may get lost in the solution as magnesium citrate if magnesium is added. The addition of magnesium-free calcium hydroxide is used for the precipitation of calcium citrate.

11. Citric acid is used in the manufacture of jams and jellies.
A. True
B. Falseid5fdb3dec17ac2″

Answer: A
Clarification: Citric acid is used in the manufacture of jams and jellies. It is also used in the manufacture of sweets and soft drinks. It can also be used for artificial flavoring of various foods and is also used in the manufacture of processed cheese.

12. Who discovered the citric acid cycle?
A. Hans Krebs
B. Carl Wilhelm
C. Wehmer
D. Adamid5fdb3dec17acc”

Answer: A
Clarification: Citric acid cycle was discovered by Sir Hans Adolf Krebs and these studies were performed in the breast muscle of pigeon as the breast muscle was a powerful muscle for flight and the oxidative capacity of the breast muscle was maintained even after its disruption and suspension in aqueous media. It is also called a Krebs’ cycle.

13. Citric acid cycle occurs in _____________
A. Vacuoles
B. Golgi apparatus
C. Mitochondria
D. Nucleusid5fdb3dec17ad6″

Answer: C
Clarification: The citric acid cycle or TriCarboxylic acid cycle occurs in the innermost compartment of mitochondria where the chemical energy is generated from the end product of the glycolysis pathway. It occurs in mitochondria of eukaryotes whereas, in prokaryotes, it occurs in the cytoplasm.

Fermentation Technology Assessment Questions and Answers on “Preservation of Industrial Microorganisms”.

1. Which scientists gave the details of the techniques of preservation?
A. Jacob and Monod
B. Kirsop and Doyle
C. William and Wilkins
D. Boliver and Rodriguezid5fd05d2ded5c5″

Answer: B
Clarification: Kirsop and Doyle in 1991 gave the full details of the preservation techniques. The preservation techniques were used to store the microbial culture for a longer period of time.

2. Which of the following is NOT the technique of preservation?
A. storage on agar slants
B. storage under liquid nitrogen
C. dried cultures
D. storage in waterid5fd05d2ded5e6″

Answer: D
Clarification: The techniques of preservation include – storage on agar slants, storage under liquid nitrogen, dried cultures, lyophilization. Storage in water is not a technique for the preservation of microbes.

3. The preservation of agar slopes has an expiration of 6 months and the agar needs to be changed every 6 months. Which of the following can be used to extent sub-culturing to 1 year?
A. Paraffin oil
B. DMSO
C. Glycerol
D. Loamy Soilid5fd05d2ded5f3″

Answer: A
Clarification: The agar slants can be covered by paraffin oil and the extension time can be increased from 6 months to 1 year. DMSO, Glycerol, Loamy soil are used in the preservation techniques for the preservation of microbes more than decades.

4. What is the temperature of liquid nitrogen (°C.?
A. -150°C
B. -122°C
C. -194°C
D. -196°Cid5fd05d2ded5fd”

Answer: D
Clarification: The temperature of liquid nitrogen is -196°C. It is used to store and preserve the microbial culture for a decade or even more. The cryoprotectants are added to the culture suspension before adding to liquid nitrogen.

5. Which of the following is NOT a cryoprotective agent?
A. DMSO
B. Glycerol
C. Ethylene Glycol
D. Paraffin waxid5fd05d2ded606″

Answer: D
Clarification: The cryoprotective agents like DMSO, 10% Glycerol, Glycol are the agents that are added to microbial cell culture to protect the cells at a lower temperature or in liquid nitrogen at -196°C.

6. The preservation by liquid Nitrogen is called as ___________
A. Cryopreservation
B. Lyophilization
C. Freeze-drying
D. Desiccationid5fd05d2ded60e”

Answer: A
Clarification: The preservation by liquid Nitrogen is called as Cryopreservation. The cryoprotective agents are added to the culture before preservation, hence the name, Cryopreservation.

7. Which of the following method involves sublimation of cell water?
A. Cryopreservation
B. Lyophilization
C. Dried Culture
D. Desiccationid5fd05d2ded617″

Answer: A
Clarification: Lyophilization is the method that is based on freezing of culture followed by drying under vacuum. This is known as sublimation. It is useful for the storage or preservation of culture for more about 25 years.

8. “Each batch of newly preserved cultures should be routinely checked to ensure their quality”. Who outlined the statement?
A. Lincoln
B. Snell
C. Malik
D. Pridhamid5fd05d2ded620″

Answer: A
Clarification: Lincoln in 1960 outlined the statement “Each batch of newly preserved cultures should be routinely checked to ensure their quality” for quality control of preserved stock cultures.

9. Which of the following is/are used in dried culture preservation?
A. Sand
B. Soil
C. Sand and Soil
D. Slitsid5fd05d2ded628″

Answer: C
Clarification: The use of sand and soil in dried culture preservation is that it reduces the metabolic activity of the culture and also doesn’t allow oxygen to diffuse.

10. The cultures grown on agar slopes may be stored in the refrigerator or freezer at 5°C to -20°C.
A. True
B. Falseid5fd05d2ded630″

Answer: A
Clarification: The cultures grown on agar slopes may be stored in the refrigerator or freezer at 5°C to -20°C and sub-cultured at approximately 6-monthly intervals.

11. Which of the following is NOT the advantage of lyophilization?
A. Dissolution of product
B. Processed in aseptic conditions
C. Handling and processing time increases
D. Do not use heatid5fd05d2ded637″

Answer: C
Clarification: The processing and the handling time in lyophilization are more as there are many incubation periods, thus a time-consuming process. Handling and processing time is a major disadvantage of lyophilization.

12. The cryoprotective agents are used to prevent cell damage.
A. True
B. Falseid5fd05d2ded63f”

Answer: A
Clarification: The main function of cryoprotective agents is to prevent cell damage for the preservation of microbial cell culture in liquid nitrogen at -196°C.

13. During the preservation of microbial cell culture ______
A. metabolism stops
B. metabolism continues
C. metabolism changes
D. physiology changesid5fd05d2ded65f”

Answer: B
Clarification: The preservation of microbial cell culture does not alter the metabolism of microbes. Metabolism continues. The microbial culture is active viably and dividing during the preservation.

14. Which of the following method of preservation is more suitable and used widely?
A. Dried Cultures
B. Lyophilization
C. Salt Storage
D. Storage in liquid Nitrogenid5fd05d2ded669″

Answer: B
Clarification: Lyophilization is the process of freeze-drying which involves sublimation of cell water and can be used to store culture for about 25 years.

15. Which of the following is not the composition of N-agar plates/ slants?
A. Yeast/Beef extract
B. Peptone
C. NaCl
D. Dextroseid5fd05d2ded672″

Answer: D
Clarification: The nutrient agar plates contain yeast/beef extract, peptone, NaCl and Agar-Agar Powder. Dextrose is constituent of Potato Dextrose Agar.

To practice all areas of Fermentation Technology Assessment Questions, .

Fermentation Technology Multiple Choice Questions on “Instrumentation and Control – Dissolved Oxygen Monitoring”.

1. The details of steam-sterilized electrodes was given by ________
A. Lee and Tsao
B. Kell et al.
C. Schwan
D. Buhler and Ingoldid5fdbe7215bf86″

Answer: A
Clarification: Lee and Tsao in 1979 gave the details of steam sterilized oxygen electrodes. Those electrodes were useful for the measurement of oxygen concentration. It measures the partial pressure of dissolved oxygen.

2. The probe signal of O₂ is determined by the equation ____________
A. P(O₂) = C(O₂) * T_P
B. P(O₂) = C(O₂) * P_T
C. P(O₂) = C(O₂) / P_T
D. P(O₂) = C(O₂) + P_Tid5fdbe7215bfa5″

Answer: B
Clarification: The probe signal of O₂ is determined by the equation: P(O₂) = C(O₂) * P_T where P(O₂) is the partial pressure of dissolved oxygen sensed by the probe, C(O₂) is the volume or mole fraction of oxygen in the gas phase, and P_T is the total pressure.

3. Which of the following acts as the anode in the galvanic electrode?
A. Silver
B. Magnesium
C. Lead
D. Platinumid5fdbe7215bfb3″

Answer: C
Clarification: Lead acts as the anode in the galvanic electrode whereas silver acts as the cathode. The galvanic electrode is used in the measurement of the partial pressure of the dissolved oxygen (DO) concentration.

4. Which of the following is used as an electrolyte in the galvanic electrode?
A. NaCl
B. KCl
C. SnCl₂
D. MgCl₂id5fdbe7215bfbe”

Answer: B
Clarification: Potassium Chloride is used as an electrode in a galvanic electrode. However, Potassium hydroxide or bicarbonate or acetate is an alternative to Potassium chloride.

5. Which of the following is not used in DO measurement?
A. Polarographic electrode
B. Tubing method
C. Tachometers
D. Galvanic electrodeid5fdbe7215bfc7″

Answer: C
Clarification: The tachometer is used in the measurement of pressure. The tubing method, polarographic electrode, galvanic electrode, etc are used in the measurement of dissolved oxygen concentration.

6. Which of the following method is uses fluorescence for oxygen measurement?
A. Tubing method
B. Fluorometric method
C. Polarographic method
D. Galvanic methodid5fdbe7215bfd1″

Answer: B
Clarification: The fluorometric method uses fluorescence phenomena for the measurement of dissolved oxygen. It has a fast response and is based on the fact that change in the partial pressure of oxygen quenches the fluorescence lifetime of a chromophore.

7. Which of the following is not the type of paramagnetic gas analyzers?
A. Magnetodynamic
B. Thermomagnetic
C. Magnetopneumatic
D. Load cellsid5fdbe7215bfda”

Answer: D
Clarification: The load cells are the cells used for determining the weight of the fermenter vessel. The paramagnetic gas analyzers are of three types: magnetodynamic, thermomagnetic, and magnetopneumatic.

8. Which of the following has a dumbbell shape?
A. Magnetodynamic
B. Thermomagnetic
C. Magnetopneumatic
D. Load cellsid5fdbe7215bfe2″

Answer: A
Clarification: The magnetodynamic type is of the shape of a dumbbell. It is a type of gas analyzer which is used for the measurement of dissolved oxygen.

9. Which of the following is not used for monitoring the pH?
A. Glass electrode
B. Galvanic electrode
C. Silver electrode
D. Combined electrodeid5fdbe7215bfec”

Answer: B
Clarification: The galvanic electrode is used in the measurement of dissolved oxygen. Whereas, glass electrodes, silver electrodes, combined electrodes are used in the measurement of pH of a solution.

10. Which of the following makes contact with a solution whose pH is to be measured?
A. Ceramic plug
B. Electrolyte
C. Silver wire
D. Reference solutionid5fdbe7215bff5″

Answer: A
Clarification: The ceramic plug or bulb is the part of an electrode which makes the contact with the solution whose pH is to be measured. Electrolyte, Silver wire, Reference solution are the part of pH electrodes.

11. What is the value of Faraday’s constant?
A. 96500 J/mol
B. 96400 J/mol
C. 36300 J/mol
D. 36500 J/molid5fdbe7215bffe”

Answer: A
Clarification: The value of Faraday’s constant is 96500 J/mol. It was a constant named after famous scientist Michael Faraday. The Faraday constant equals 1 Faraday of charge per mole.

12. pH is the measurement of _________
A. concentration of H⁺
B. concentration of H^–
C. concentration of OH⁺
D. concentration of OH^–id5fdbe7215c006″

Answer: A
Clarification: The pH is the measurement of H⁺ ions in the solution. The pH scale was given by Sorenson. pH scale consists of numbers 1 to 14 with a pH of 1 being most acidic and 14 being most basic. pH 7 is a neutral solution.

13. Thermomagnetic is a ‘wind type’ analyzer.
A. True
B. Falseid5fdbe7215c00f”

Answer: A
Clarification: Thermomagnetic is a wind type gas analyzer used for the measurement of dissolved oxygen concentration. It is the measure of magnetic susceptibility of the substance that is magnetized.

14. Nitric oxide exhibits the paramagnetic property.
A. True
B. Falseid5fdbe7215c018″

Answer: A
Clarification: Nitric oxide exhibits the paramagnetic property and has the ability to get attracted to the magnetic field. The electrons get weakly magnetized in presence of the magnetic field.

15. Which of the following is a ferromagnetic substance?
A. Cobalt
B. Nitrogen
C. Nitric oxide
D. Heliumid5fdbe7215c020″

Answer: A
Clarification: Cobalt, Iron are examples of a ferromagnetic substance. The electrons aligned themselves in the direction of the magnetic field and are strongly magnetized. Here, Nitrogen is a diamagnetic material and Nitric oxide is a paramagnetic material.