This set of Fermentation Technology Multiple Choice Questions & Answers (MCQs) focuses on “Batch Culture”.
1. The Batch culture is a/an ______ culture system.
Explanation: The Batch culture is a closed culture system which 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
Explanation: 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.
Explanation: 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
Explanation: 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
Explanation: 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-stationary
Explanation: 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?
Explanation: 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, µmax?
a) Vibrio natriegens
b) Methylomonas methanolytica
c) Aspergillus nidulans
d) Penicillium chrysogenum
Explanation: Vibrio natriegens represents the highest specific growth rate with µmax=4.24h-1 whereas, other organisms have a value between 0 to 1.
9. The size of fermenters is usually large in batch fermentation.
Explanation: 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
Explanation: 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?
b) Growth rate
d) Amount of enzyme
Explanation: 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.
Explanation: 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
Explanation: 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
Explanation: 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
Explanation: 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.
Sanfoundry Global Education & Learning Series – Fermentation Technology.
To practice all areas of Fermentation Technology, here is complete set of 1000+ Multiple Choice Questions and Answers.