This set of Fermentation Technology Multiple Choice Questions & Answers (MCQs) focuses 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 tubes
View Answer
Explanation: 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 ml
View Answer
Explanation: 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 septa
View Answer
Explanation: 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) Micropipette
View Answer
Explanation: 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 stirrer
View Answer
Explanation: 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 consumed
View Answer
Explanation: 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 gas
View Answer
Explanation: 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 L
View Answer
Explanation: 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 rubber
View Answer
Explanation: 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) Seven
View Answer
Explanation: 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 min
View Answer
Explanation: 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) Skands
View Answer
Explanation: 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) False
View Answer
Explanation: 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) False
View Answer
Explanation: 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.
Sanfoundry Global Education & Learning Series – Fermentation Technology.
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