Bioprocess Engineering Multiple Choice Questions on “Medium Formulation”.
1. The equation of aerobic fermentation is a qualitative term –
Carbon and energy source + Nitrogen source + O2 + other requirements → Biomass + products + CO2 + H2O + heat.
A. True
B. False
Answer: B
Explanation: This equation should be expressed in quantitative terms, which is important in the economical design of media if component wastage is to be minimal. Thus, it should be possible to calculate the minimal quantities of nutrients which will be needed to produce a specific amount of biomass.
2. Biomass and product formation are related.
A. True
B. False
Answer: A
Explanation: Knowing that a certain amount of biomass is necessary to produce a defined amount of product, it should be possible to calculate substrate concentrations necessary to produce required product yields. There may be medium components which are needed for product formation which are not required for biomass production.
3. For bacteria with a Y for glucose of 0.5, which is 0.5 g cells g-1 glucose, the concentration of glucose needed to obtain 30 g dm-3 cells will be ____________
A. 20 g dm-3 glucose
B. 40 g dm-3 glucose
C. 50 g dm-3 glucose
D. 60 g dm-3glucose
4. For bacteria with a Y for glucose of 0.5, which is 0.5 g cells g-1 glucose, the concentration of glucose needed to obtain 60 g dm-3 cells will be ______________
A. 50 g dm-3 glucose
B. 60 g dm-3 glucose
C. 100 g dm-3 glucose
D. 120 g dm-3 glucose
5. For bacteria with a Y for glucose of 0.2, which is 0.2 g cells g-1 glucose, the concentration of glucose needed to obtain 60 g dm-3 cells will be __________________
A. 60 g dm-3 glucose
B. 30 g dm-3 glucose
C. 300 g dm-3 glucose
D. 600 g dm-3 glucose
6. The culture medium should not ________________
A. Be sterilized
B. Be cheap and readily available
C. Contain desired products
D. Allow high yield of undesired products
Answer: D
Explanation: There should not be any undesirable changes in the consistency of the medium during preparation of media and after sterilization. There should be minimum production of unwanted products.
7. Medium containing pure compounds is suitable for large scale.
A. True
B. False
Answer: B
Explanation: It is easy to devise a medium containing pure compounds on a small scale but this medium may be unsuitable for use in a large scale fermentation processes.
8. Which of the following is not an antifoaming agent?
A. Sodium lauryl sulfate
B. Silicones
C. Glycols
D. Alkyl polyacrylates
Answer: A
Explanation: Sodium laureth sulfate, or sodium lauryl ether sulfate (SLES), is a detergent and surfactant found in many personal care products (soaps, shampoos, toothpastes, etc.). It is an inexpensive and effective foamer. Sodium lauryl sulfate (also known as sodium dodecyl sulfate or SDS) and ammonium lauryl sulfate (ALS) are commonly used alternatives to SLES in consumer products.
9. Chelating agents prevent formation of insoluble of _________________________
A. Calcium precipitates
B. Enzyme precipitates
C. Metal precipitates
D. Product precipitates
Answer: C
Explanation: A chelate is a chemical compound composed of a metal ion and a chelating agent. A chelating agent is a substance whose molecules can form several bonds to a single metal ion. In other words, a chelating agent is a multidentate ligand. An example of a simple chelating agent is ethylenediamine.
10. Which of the following is an upstream process?
A. Product recovery
B. Product purification
C. Media formulation
D. Cell lysis
Answer: C
Explanation: Upstream processing includes formulation of the fermentation medium, sterilisation of air, fermentation medium and the fermenter, inoculum preparation and inoculation of the medium.
11. Suppression of regulatory mechanism is necessary in mutation for strain improvement.
A. True
B. False
Answer: A
Explanation: Microorganisms usually have regulatory mechanisms that control the amount of metabolites synthesized, therefore suppression of regulatory mechanisms is necessary to develop the strains for higher yields.