This set of Fermentation Technology Multiple Choice Questions & Answers (MCQs) focuses on “Media Design and Preparation for Bioprocesses – Filtration”.
1. What is the pore size of the filtration membrane to remove bacteria?
a) 0.25 µm
b) 0.22 µm
c) 0.27 µm
d) 0.26 µm
View Answer
Explanation: The pore size of the filtration membrane to remove the bacteria is 0.22 µm. Filtration is very useful in removal for unnecessary components of the medium. The sterility of the filtration is also an important aspect.
2. The pore size for the removal of viruses is _______________
a) 20 nm
b) 30 nm
c) 25 nm
d) 35 nm
View Answer
Explanation: The pore size of the filtration membrane for the removal of the virus is 20 nm. The viruses are smaller than bacteria and therefore the pore size for the removal of the virus is less than that of bacteria. Viruses also reproduce inside the bacteria and can infect them which are commonly referred to as bacteriophage.
3. Which of the following is not the application of filtration?
a) Sterilization of media
b) Removal of debris
c) Plasma clarification
d) Off-gas analysis
View Answer
Explanation: Off-gas analysis is done with the help of mass spectroscopy and not by the filtration process. The applications of filtration are to sterilize the media, removal of debris, plasma clarification, serum clarification, endotoxin removal, cell culture clarification, additive, and buffer sterilization.
4. Which of the following filters are ideal for vitamin sterilization?
a) Bottle top filters
b) Cellulose Nitrate filters
c) Cellulose Acetate filters
d) PES membrane filters
View Answer
Explanation: The bottle top filters are ideal for the sterilization of vitamins, growth factors, trace elements, buffers, etc. It is useful for sterilizing small volumes. It has a range of membranes and pore sizes which are used for suitable purposes.
5. Which of the following filter is used in the filtration of bacteria?
a) Bottle top filters
b) Oxalate filters
c) Cellulose Acetate filters
d) PES membrane filters
View Answer
Explanation: Cellulose Acetate filters are used in the filtration of bacteria with a pore size of 0.22 µm. Cellulose Nitrate filters are also used for the filtration of bacteria and for sterilization of buffers and solutions.
6. The advantage of cellulose acetate filters is ________________
a) Recovery of microorganisms
b) Low throughput
c) High protein binding
d) Low flow rates
View Answer
Explanation: The analytical filters along with cellulose acetate membranes are used for the recovery of microorganisms at the laboratory or industrial scale. The drawbacks of cellulose acetate filters are low throughput, high protein binding, and low flow rates.
7. Which of the following is not an advantage of PES membrane filters?
a) Low extractables
b) Fast flow
c) High protein binding
d) High throughput
View Answer
Explanation: The advantages of PES membrane filter have low extractables, fast flow, low protein binding, fast flow, high throughput. They are used for the sterilization of small or large volumes according to laboratory use.
8. In which of the following the size of particles retained is much smaller than the pore size of the medium?
a) Batch filtration
b) Surface filtration
c) Submerged filtration
d) Depth filtration
View Answer
Explanation: In depth filtration, the size of particles retained is much smaller than the pore size of the medium. It has high capacity and the strength of filter is also higher. Examples are ceramic and sintered filters.
9. Which of the following does not influence filtration?
a) Temperature
b) Density
c) Viscosity
d) pH
View Answer
Explanation: The pH of the solution does not influence the filtration of the solution. The factors that affect the filtration are temperature, density, pressure, viscosity, particle size, particle shape, charge, and corrosiveness.
10. Filtration is a steady state.
a) True
b) False
View Answer
Explanation: The flow of liquid through a filter follows the basic rules that govern the flow of any liquid through medium offering resistance. Rate of flow is the ratio of driving force to resistance. The resistance is not constant, it increases with an increase in deposition of solids on the filter medium. Therefore, filtration is not a steady state.
11. In surface filtration, the size of particles retained is higher than the mean pore size of the medium.
a) True
b) False
View Answer
Explanation: The size of particles is higher than the mean pore size of the medium. It has low capacity and the particles size retained is more predictable. Examples are cellulose Acetate and Cellulose Nitrate filters.
12. The slurry is ______________
a) A suspension to be filtered
b) A porous membrane used to retain the solids
c) The solids which are present on the filter
d) A clear liquid passing through the filter
View Answer
Explanation: The slurry is a suspension that is to be filtered. It is a semi-liquid mixture which consists typically of fine particles of cement, manure, or coal suspended in water.
13. What do you mean by filter cake?
a) The cake which is to be filtered
b) A porous membrane used to retain the solids
c) The solids which are present on the filter
d) A suspension to be filtered
View Answer
Explanation: The filter cake consists of the solids which are present on the filter. It is usually the insoluble matter which is left on the filter. As the cake grows, the particulate matter is retained, resulting in the thickening of cake.
14. Which of the following process is used to separate insoluble particles from liquids?
a) Filtration
b) Extraction
c) Drying
d) Sieving
View Answer
Explanation: The filtration is the process of separation of insoluble particles from liquids. It can be physical, mechanical, biological methods are used for separation of solids from fluids. The filtrate is obtained which is collected in a glass and the residue remains on the filter.
Sanfoundry Global Education & Learning Series – Fermentation Technology.
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