50. During the log phase cell numbers increase exponentially
A.because cells produce enzymes
B.because cells do not have cell membranes
C.because cells are autocatalysts
D.because the rate of cell division increases exponentially
51. Lag phase occurs mainly due to
A.acclimatization with new environment and substrate
B.higher growth temperature
C.substrate disliking
D.variation in substrate concentration
52. In a batch reactor specific growth rate
A.remains constant throughout the process
B.increases exponentially
C.changes during the fermentation
D.is highest during the stationary phase
53. Turbidostat is recommended when continuous fermentation needs to be carried out at
A.high dilution rates near the washout point
B.low dilution rates near the washout point
C.moderate dilution rates near the washout point
D.any intensity of dilution rates near the washout point
54. The advantage of airlift bioreactors over stirred tank bioreactors of a similar size is
A.higher oxygen transfer rates
B.more uniform shear conditions
C.both (a) and (b)
D.less foaming
55. Stirred tank fermenter (STF) can be employed for
A.aerobic fermentation of a wide range of cells including microbial, animal and plant cells
B.anaerobic fermentation of a wide range of cells including microbial, animal and plant cells
C.Both (a) and (b)
D.anaerobic fermentation of plant cells only
56. The specific growth rate is affected by
A.sabstrate concentration
B.product concentration
C.oxygen supply
D.all of these
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