57. The main function(s) of a draft tube in an air lift fermenter is/are to
A.increase the solubility of oxygen
B.distribute shear forces throughout the reactor and minimise bubble coalescence
C.concentrate shear forces around the sparger
D.concentrate shear forces near the disengagement zone
58. Which of the following is incorrect?
A.The mechanical agitation and aeration are effective for suspension of cells
B.The mechanical agitation and aeration are effective for mixing the medium
C.STF can't be used for high viscosity medium
D.The mechanical agitation and aeration are effective for oxygenation
59. The contents in bubble column and air lift reactor are mixed through
A.compressed air
B.a mechanical internal moving part
C.external pumping
D.any of these
60. Which of the following statements would be appropriate while comparing bubble column and air lift fermenter of the same size?
A.The average bubble size is smaller in an airlift bioreactor
B.Oxygen transfer rate is higher in an airlift bioreactor
C.The surface area for gas exchange is higher in an airlift bioreactor
D.All of the above
61. During the lag phase
A.cells just start growing
B.cells synthesize new proteins and membrane components
C.cells produce antibiotics to kill competing organisms
D.cells simply grow slowly
62. Concentration of the growth limiting substrate means
A.trace elements concentration
B.the concentration of the substrate that controls the growth rate of the cells
C.sugar concentration in the fermentation medium
D.dissolved oxygen concentration
63. Tower fermentors are used for
A.continuous penicillin production
B.continuous beer production
C.production of enzymes
D.batch production of beer
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