Category: Fermentation Technology Objective Questions

Fermentation Technology Multiple Choice Questions on “Fermenter Design – Body Construction”.

1. What is the basic function of the fermenter?
A. To sterilize the medium
B. To recover the product
C. To provide optimum growth conditions to organisms and obtain the desired product
D. To purify the productid5fd0988933fb4″

Answer: C
Clarification: The main function of the fermenter is to provide the optimum growth conditions for the growth of microorganisms and obtain the desired product. The recovery and purification of the product are the parts of downstream processing.

2. While constructing the fermenter, which of the following is not required?
A. High-speed Agitation and Aeration system
B. Temperature control system
C. pH control system
D. Sample facilitiesid5fd0988933fe8″

Answer: A
Clarification: In designing and constructing the fermenter, the fermenter must be provided with adequate aeration and agitation system. The agitation speed should not be higher and must not cause damage to the microorganisms.

3. Which of the following material is preferable for the construction of small-scale fermenter?
A. Quartz
B. Glass
C. Iron steel
D. Woodid5fd0988933ff5″

Answer: B
Clarification: The glass is the most preferred material for the construction of fermenters. It is transparent so that it is easy to visualize the interior of the glass vessel. Moreover, the glass is non-toxic and corrosion proof.

4. The largest diameter for glass fermenter is _____________
A. 50 cm
B. 70 cm
C. 60 cm
D. 80 cmid5fd0988933fff”

Answer: C
Clarification: The largest practical diameter for the glass fermenter is 60 cm. This was discovered by Cowan and Thomas in 1988. The glass containers were made up of borosilicate battery jars. The glass vessels must be sterilized before using them.

5. Which of the following institute grades the steel?
A. TATA
B. AISI
C. JSW
D. SAILid5fd0988934008″

Answer: B
Clarification: The American Iron and Steel Institute grades the steel. It is one of the oldest associations in North America. TATA, JSW Steel, SAIL are the associations for the manufacturing and the production of steel.

6. Which of the metal is used to make stainless steel?
A. Cr
B. Pb
C. Mn
D. Feid5fd0988934011″

Answer: A
Clarification: Chromium is used to make stainless steel. The American Iron and Steel Institute (AISI) states that steels containing less than 4% chromium are classified as steel alloys and those containing more than 4% are classified as stainless steels.

7. Which of the following is not the property of Chromium film?
A. Non-porous
B. Soluble
C. Self-healing
D. Continuousid5fd0988934019″

Answer: B
Clarification: The Chromium film is non-porous, insoluble, self-healing, and continuous. If the film gets damaged then it gets healed by itself when exposed to air or an oxidizing agent.

8. Which of the following element does not enhances the property of stainless steel?
A. Nickel
B. Molybdenum
C. Silicone
D. Manganeseid5fd0988934021″

Answer: D
Clarification: Nickel, Molybdenum, Silicone, Tungsten are the elements used to enhance the property of stainless steel. Nickel enhances resistance and improves engineering properties. Molybdenum improves the resistance against halogen salts. Corrosion resistance is improved by tungsten and silicone and a few other elements.

9. The AISI grade 316 contains _______ amount of chromium.
A. 15 %
B. 18 %
C. 20 %
D. 18.5 %id5fd098893402a”

Answer: B
Clarification: The AISI grade 316 steel contains 18 % chromium. In addition to chromium, 10% nickel and about 2 – 2.5 % of molybdenum is also used in the fermenter construction.

10. The AISI grade 317 contains ________ amount of molybdenum.
A. 5 – 10 %
B. 3 – 5 %
C. 1 – 2 %
D. 11 – 14 %id5fd0988934032″

Answer: B
Clarification: The AISI grade 317 contains 3 – 4 % of molybdenum. It was used in citric acid fermentation to prevent the leaching of heavy metals with steel which interferes in the process of fermentation.

11. The fermenter vessel should be reliable for the long-term.
A. True
B. Falseid5fd098893403a”

Answer: A
Clarification: The fermenter vessel should be reliable for long-term operations. It should be capable of being operated aseptically, must withstand fermentation temperatures and pressure and must meet the requirements of containment regulations.

12. The fermenter vessel must be provided with all the facilities for temperature, pH.
A. True
B. Falseid5fd0988934041″

Answer: A
Clarification: The fermenter must be provided with facilities like temperature control system, pH control system, Agitation and Aeration control system, etc. All these facilities are essential in the production of the desired product.

13. The hazard group criteria were given by ___________
A. Collins
B. Winkler
C. Park
D. Frommerid5fd0988934049″

Answer: A
Clarification: Collins in 1992 gave the criteria for placing non-genetically engineered organisms into a hazard group (1 to 4) to access risks. A detailed assessment of risk and ways to reduce it was given by Winkler and Park.

14. The Genetically engineered organisms are classified as ___________ and _____________
A. Harmless (Group II) and Potentially Harmful (Group I)
B. Harmless (Group I) and Potentially Harmful (Group II)
C. Potentially Harmless (Group I) and Harmful (Group II)
D. Harmless (Group II) and Harmful (Group I)id5fd0988934051″

Answer: B
Clarification: The Genetically engineered organisms are classified as Harmless (Group I) and Potentially Harmful (Group II). This was further classified into either small scale or Large scale according to the Health and Safety Executive document.

15. Collins hazard group criteria did not include _______________
A. The ease of prophylaxis and treatment
B. The routes of infection
C. The pathogenicity of a microorganism
D. The reproductive cycle of a microorganismid5fd098893406d”

Answer: D
Clarification: Collins hazard group criteria did not mention about the reproductive cycle of microorganism. It included the routes of infection, the pathogenicity of the organism, ease of treatment, number of organisms required to initiate an infection, amount of organism used in the fermentation process, etc.

Fermentation Technology Multiple Choice Questions on “Fermentation Laboratory – Harvesting and Disrupting Cells “.

1. What is the flow rate of Autoclude V8/55/24HR?
A. 350 mL/min
B. 8 L/min
C. 8 mL/min
D. 350 L/minid5fdc65bfd7f76″

Answer: B
Clarification: The flow rate of Autoclude V8/55/24HR is 8 L/min. It is a variable speed peristaltic pump used for the large scale centrifugation. The range of pumps can be extinguished between panel mounted and free-standing.

2. The flow rate of Watson Marlow 501 was _______________
A. 350 mL/min
B. 350 dL/min
C. 350 µL/min
D. 350 L/minid5fdc65bfd7fc8″

Answer: A
Clarification: The flow rate of Watson Marlow 501 peristaltic pump was approximately up to 350 mL/min. It was used for the lower volume of cell harvesting. They are accurate pumps with low maintenance and are simple to install and easy to use.

3. The flow rate of Haraeus continuous centrifuge is ______________
A. 10 mL/h
B. 8 L/h
C. 8 mL/h
D. 10 L/hid5fdc65bfd7fdd”

Answer: D
Clarification: The flow rate of Haraeus continuous flow centrifuge is 10 L/h. It has a smaller capacity but gives excellent clarity of supernatant. This machine cannot be used for cultures above 10 L volume because of low flow rates.

4. The capacity of rotor of Cepa Z41 centrifuge is _____________
A. 850 g of wet cells
B. 750 g of wet cells
C. 750 g of dry cells
D. 850 g of dry cellsid5fdc65bfd7fed”

Answer: B
Clarification: The capacity of the rotor of Cepa Z41 tubular bowl centrifuge is 750 g of wet cells. It is a high-speed peristaltic pump which gives high clarity and high throughput. About 30 L of cell is harvested within 20 minutes of time and 100 L in an hour.

5. Which of the following uses the membrane to concentrate cell suspension?
A. Cepa Z41
B. Watson Marlow 501
C. Filtration
D. Autoclude V8id5fdc65bfd7ffb”

Answer: C
Clarification: Filtration uses the membrane to concentrate the cell suspension. It is also known as tangential flow filtration. Cell washing can also be done through cross-flow filtration before centrifugation, although the process is time-consuming.

6. Which of the following is not the function of buffer?
A. Prevent cell lysis
B. Chelating the metals
C. Prevent protease action
D. Prevent lipase actionid5fdc65bfd800a”

Answer: D
Clarification: The buffer is used to prevent the lysis of cells, and chelate the metals and prevent the action of protease enzymes. The buffer is added to the pellet prior to processing and defrosting.

7. The number of bacteria can be determined by ___________
A. Streaking
B. Four flame method
C. Pour plate
D. Pour plate and spread plateid5fdc65bfd801a”

Answer: D
Clarification: The number of bacteria can be determined quantitatively by pour plate and spread plate technique due to a higher degree of dilution. The number of colonies can be counted which helps us to determine the number of bacteria present in a liquid specimen.

8. Which of the following is the method of cell disruption?
A. Sonication
B. Homogenization
C. Streaking
D. Chemical Treatmentid5fdc65bfd8029″

Answer: C
Clarification: Streaking is not the method of cell disruption. It is used in isolation of species of microorganisms like bacteria. Sonication, homogenization, chemical treatment is used in the disruption of cells in order to get intracellular fluid.

9. Which of the following technique uses sound waves for cell disruption?
A. Homogenization
B. Sonication
C. Blender
D. Mortar and Pestleid5fdc65bfd8037″

Answer: B
Clarification: Sonication uses the sound waves of high frequency and vibrations for the disruption of cells. It is mostly used for fungal and plant cells but its disadvantage is it creates a lot of noise and needs a separate room for it.

10. Which of the following method uses a solvent (mostly water) for cell disruption?
A. Homogenization
B. Sonication
C. Blender
D. Osmotic shockid5fdc65bfd8045″

Answer: D
Clarification: Osmotic shock uses a solvent (mostly water) for the disruption of cells. The water can be moved inside the cells using osmosis causing the cell to increase in the volume and finally bursting of cells occur.

11. Chitinase is used for the disruption of __________ cell wall.
A. Bacterial
B. Plant
C. Fungal
D. Animalid5fdc65bfd8053″

Answer: C
Clarification: Chitinase is used for the disruption of the cell wall of fungi. The cell wall of fungi is made up of chitin and it gives the structural strength to the cell. It is also present in the exoskeleton of a few insects and protects the cell wall from desiccation. Thus, the use of chitinase can break the cell wall of fungi.

12. Which of the following is not the product of cell disruption?
A. DNA
B. RNA
C. Protein
D. Waterid5fdc65bfd8061″

Answer: D
Clarification: Water is not the product of cell disruption as water is freely available outside whereas, DNA, RNA, Proteins, Toxins, Insulin, Growth Hormone, etc. are the products of cell disruption.

13. Which of the following is a physical method of cell disruption?
A. Using detergents
B. Using solvents
C. Using French press
D. Using osmotic shockid5fdc65bfd806e”

Answer: C
Clarification: The physical method of cell disruption is using a French press. Other physical methods include bead mill, colloid mill, ultrasonic vibrations, etc. Using detergents, solvents, enzymes, the osmotic shock is an example of chemical cell disruption.

14. The Haraeus centrifuge is not used for volume above 10 L.
A. True
B. Falseid5fdc65bfd807c”

Answer: A
Clarification: The Haraeus continuous flow centrifuge is used only for volume below 10 L as the capacity of the centrifuge is smaller and it also has a very low flow rate of 10 L/h. That is why it is not suitable to use it with more than 10 L of volume.

15. Lysozyme is used for bacterial cell disruption.
A. True
B. Falseid5fdc65bfd808a”

Answer: A
Clarification: Lysozyme is used for the disruption of the cell wall of bacteria. It targets the peptidoglycan layer which is mainly present in the Gram-negative bacterial cell wall. Lysozyme also has its applications in the preservation of food items like fruits, vegetables, cheese, sauce, etc.

Fermentation Technology Multiple Choice Questions on “Brewing Yeast – Cell Wall and Flocculation”.

1. What is the percentage of glucans found in the cell wall of yeast?
A. 25 – 30 %
B. 30 – 60 %
C. 50 – 70 %
D. 40 – 50 %id5fdc0f66e3ffd”

Answer: B
Clarification: Glucans account for 30 – 60 % in the cell wall of yeast. It is the major polymers found in the cell wall of yeast. They cover the entire cell in the form of the microfibrillar net and are restricted to the inner layer of the wall.

2. Who described glucans into three classes?
A. Cabib
B. Kollar
C. Fleet
D. Ballouid5fdc0f66e401f”

Answer: C
Clarification: Fleet in 1991 described glucans into three classes: alkaline insoluble- acetic acid insoluble β-(1,3), alkali-soluble β-(1,3), and highly branched β-(1,6). Alkali-soluble accounts for 20% of the cell wall, alkaline insoluble- acetic acid insoluble accounts for 30% of the cell wall and highly branched accounts for only 5% of the cell wall.

3. The outer layer of the cell wall is composed of ___________
A. Mannoprotein
B. Lysosome
C. Glucans
D. Chitinid5fdc0f66e402f”

Answer: A
Clarification: The outer layer of the cell wall is composed of mannoprotein. It is a glycoprotein that accounts for 25 – 50 % of the cell wall. Mannoproteins are essential in the cell wall for the survival of the cell. They play an important role as antigenic determinants.

4. Chitin is present in the cell wall of ___________
A. Bacteria
B. Protozoa
C. Fungi
D. Virusesid5fdc0f66e403a”

Answer: C
Clarification: Chitin is found in the cell wall of fungi. It is also found in the exoskeleton of crustaceans and insects. It is a linear polymer of β-(1,4) linked with N-acetylglucosamine. It is an important polysaccharide present in the cell wall of yeasts.

5. Which of the following is used to break the cell wall of fungi?
A. Lysozyme
B. Chitinase
C. Protease
D. Mannoseid5fdc0f66e4045″

Answer: B
Clarification: Chitinase is used to break the cell wall of fungi as chitin is a polysaccharide present in the cell wall of fungi and yeasts. They break the glycosidic bond in chitin resulting in the breakdown of the cell wall.

6. Which of the following separates the suspended particles from liquids?
A. Acid washing
B. Flocculation
C. Fining
D. Fermentingid5fdc0f66e404f”

Answer: C
Clarification: Fining is a process that separates suspended particles from liquids. The fining agents are added to the wine or beer to create an adsorbent with the suspended particles, leading to the precipitation of particles out of the wine or beer.

7. What do you mean by trub?
A. Carbohydrates
B. Lipids
C. Hop
D. The complex of carbohydrates, lipids, hop, polyphenolsid5fdc0f66e4059″

Answer: D
Clarification: Trub is the complex of carbohydrates, insoluble proteins, lipids, polyphenols, and hop substances. It is a miscellany of substances. The complexity of trub depends on the composition of wort. The more turbid the wort, the more trub it contains.

8. Who proposed the adhesins?
A. Miki
B. Stratford
C. Eddy
D. Rudinid5fdc0f66e4063″

Answer: A
Clarification: Miki et al. in 1982 proposed the involvement of lectin-like proteins or ‘adhesins’ in flocculation. The interaction of lectin-like proteins with the mannose receptors is accepted as being at the heart of flocculation. Adhesins are present on the flocculent cell surfaces.

9. Which of the following is a major candidate of flocculation receptor?
A. Chitin
B. Mannose
C. Lysosome
D. Glucansid5fdc0f66e406d”

Answer: B
Clarification: Mannose is the major candidate of the flocculation receptor as it is the major component of the yeast cell wall. Miki et al. in 1982 showed the inhibition of the flocculation process by a plant lectin (Concanavilin A. which selectively binds to α-mannan.

10. The product of FLO 1 gene is involved in ___________
A. Fining
B. Sedimentation
C. Flocculation
D. Agglutinationid5fdc0f66e4077″

Answer: C
Clarification: The product of FLO 1 gene is a cell wall protein that is involved in flocculation. The flocculation is strongly correlated with the amount of FLO 1 protein that is expressed.

11. Which of the following is a key determinant of cell hydrophobicity?
A. Sulfur
B. Potassium
C. Sodium
D. Phosphateid5fdc0f66e4081″

Answer: D
Clarification: Phosphate is the key determinant of cell hydrophobicity which appears in the outer layer of the cell wall. Hydrophobicity is associated with low phosphate and vice and versa. It is also related to the age of the cell, and the number of bud scars.

12. Zeta potential is the measure of __________
A. Flocculation
B. Surface charge
C. Agglutination
D. Fermentation productid5fdc0f66e408b”

Answer: B
Clarification: Zeta potential is the measure of surface charge which is primarily determined by phosphate found in the cell wall mannoproteins and the pH of the surrounding medium. A curvilinear relationship is observed between increasing phosphate concentration and negative zeta potential.

13. Proteins account for 50% of the cell wall.
A. True
B. Falseid5fdc0f66e4095″

Answer: B
Clarification: Proteins account for 5 – 10 % of the cell wall. The cell wall proteins are represented by structural proteins, enzymes, and surface receptor proteins. Structural proteins involve mannoproteins. Enzymes are also divided into two groups. Lectin-like proteins represent the surface receptor proteins.

14. Mannoproteins implicated the cell wall porosity.
A. True
B. Falseid5fdc0f66e40aa”

Answer: A
Clarification: Mannoproteins also implicate the cell wall porosity. The mannoproteins in the cell wall obstruct or block the diffusion through ionic interactions and the web of mannan side chains.

Fermentation Technology Multiple Choice Questions on “Commercial Applications – Flavoured Spirits, Sake and Vinegar”.

1. Which of the following is a non-alcoholic spirit?
A. Vodka
B. Ceder
C. Gin
D. Liqueurid5fdb737510a50″

Answer: B
Clarification: Ceder is a non-alcoholic spirit which is found only in the Cederberg Mountains of the Western Cape. Vodka, Gin, Anise, Liqueur, etc. are the alcoholic spirit. All these products have a base of high purity alcohol or neutral alcohol which has been distilled.

2. Which of the following is added in vodka to enhance the mouthfeel?
A. Ethyl alcohol
B. Propylene glycol
C. Ethidium bromide
D. Magnesium oxideid5fdb737510a70″

Answer: B
Clarification: Propylene glycol is added in vodka to enhance the mouthfeel. Sometimes, glycerol is also used to enhance mouthfeel. It is commonly found in all the foods which are packaged, such as dried soups, popcorn, bread, etc.

3. Which of the following concentrate alcohol?
A. Wash column
B. Rectifier
C. Purifier
D. Distillation columnid5fdb737510a7e”

Answer: B
Clarification: The rectifier is used to concentrate the alcohol. It is the second major column for purification and concentration of alcohol. Wash column separates the alcohol from the wash and purifier is between the wash column and the final rectifier.

4. Which of the following is not a flavourant in Gin?
A. Juniper berry
B. Coriander seed
C. Angelica
D. Fennelid5fdb737510a93″

Answer: D
Clarification: Fennel is a flavourant added in Ouzo. Some of the flavorants added in Gin are Juniper berry (Juniperus communis), coriander seed (Coriandrum sativum), and Angelica (Archangelicum officianalis). It also contains the peel of orange and lemon.

5. Liqueurs contain ______________
A. 30 – 40 % ABV
B. 35 – 45 % ABV
C. 60 – 70 % ABV
D. 50 – 60 % ABVid5fdb737510aa7″

Answer: B
Clarification: Liqueurs contain 35 – 45 % alcohol by volume (ABV). However, some of the liqueurs are less strong and contain less alcohol and are produced by dissolving and blending of several components.

6. Which of the following are the key components of sake?
A. Wheat and barley
B. Wheat and rice
C. Water and rice
D. Rice and barleyid5fdb737510ab0″

Answer: C
Clarification: The key components of sake are water and rice. About 25 kL of water is used for each ton of rice. The water should contain traces of minerals and organic components and should be colorless, tasteless and odorless.

7. Which of the following is the traditional center for sake production?
A. Fushimi
B. France
C. USA
D. UKid5fdb737510ab8″

Answer: A
Clarification: Fushimi is the traditional center for the production of sake. Nada is also a traditional center and the great brands emerge from here. Jizaki sakes are produced by local brewers.

8. Koji comprises of _____________
A. Aspergillus niger
B. Aspergillus flavus
C. Aspergillus oryzae
D. Aspergillus fumigatusid5fdb737510ac0″

Answer: C
Clarification: Koji comprises of Aspergillus oryzae. It furnishes the hydrolytic enzymes like glucoamylase, transglucosidase, acid protease, carboxypeptidase, etc. for the digestion of starch and proteins. The process is such that the organisms other than the sake yeast will also develop.

9. Which of the following is an undiluted sake?
A. Jummai-shu
B. Koshu
C. Karakuchi
D. Genshuid5fdb737510ac9″

Answer: D
Clarification: Genshu is an undiluted sake which is served on ice. Genshu has an alcohol content of 18 – 21 %. However, sake which contains water added within a range that reduces the alcohol content by less than 1% is also considered genshu.

10. Which of the following process is employed to manufacture high-quality vinegar?
A. Orleans process
B. Haber’s process
C. Contact process
D. Ostwald’s processid5fdb737510ad1″

Answer: A
Clarification: Orleans process is employed for the production of high-quality vinegar and it is a slow process. The starting liquor is held in large casks where the microbes thrive. After that acetification commences and then vats are clarified using clarifying agents. Haber’s process is used in the production of ammonia and the contact process is used for sulphuric acid production. Ostwald’s process is used for the production of nitric acid.

11. Which of the following is also called as white distilled vinegar?
A. Rice vinegar
B. Spirit vinegar
C. Cider vinegar
D. Wine vinegarid5fdb737510ad9″

Answer: B
Clarification: Spirit vinegar is also called as a white distilled vinegar. It is derived from alcohol which is obtained by the distillations of fermented sugar solutions. It is the cheapest vinegar to produce and is the most widespread vinegar for general use.

12. Which of the following vinegar has a base material Trebbiano?
A. Rice vinegar
B. Cider vinegar
C. Balsamic vinegar
D. Malt vinegarid5fdb737510ae1″

Answer: C
Clarification: Balsamic vinegar has the base material as Trebbiano which is a wine grape. It is a very dark, concentrated, and intensely flavored vinegar which was originated in Italy. It is healthy as it contributes to weight loss and lowering the cholesterol level.

13. Rice vinegar is produced from cider.
A. True
B. Falseid5fdb737510ae9″

Answer: B
Clarification: Rice vinegar is derived from the acetification of sake or its co-products. It has very low acidity and has a light and delicate flavor which is highly favored for oriental cooking. Cider vinegar is produced from hard cider or apple wine.

14. The key organism for the production of vinegar is Mycoderma.
A. True
B. Falseid5fdb737510af1″

Answer: A
Clarification: The key organism for the production of vinegar is Mycoderma which is now called as Acetobacter with the most appropriate strains being Acetobacter aceti, Acetobacter pastorianas, and Acetobacter hansenii.

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.