Questions and answers for exam Preparation

MCQs

Total Questions : 146 | Page 4 of 15 pages

Question 31. The bubble column fermenter is usually limited to

aerobic fermentations
anaerobic fermentations
Both (a) and (b)
facultative fermentation

Discuss Question

Answer: Option A. -> aerobic fermentations
Answer: (a).aerobic fermentations

Question 32. A culture in a closed vessel to which no additional medium is added and from which no waste products are removed is called a __________ culture.

continuous
batch
fed-batch
semi continuous

Discuss Question

Answer: Option B. -> batch
Answer: (b).batch

Question 33. The diameter of the baffles in a standard stirred tank bioreactor ranges from

1/10th - 1/12th of the tank diameter
1/3rd - 1/4th of the tank diameter
1/15th - 1/20th of the tank diameter
1/20th - 1/25th of the tank diameter

Discuss Question

Answer: Option A. -> 1/10th - 1/12th of the tank diameter
Answer: (a).1/10th - 1/12th of the tank diameter

Question 34. If the specific growth rate, μ. is constant with time during the exponential growth period, the equation correlating bacterial number density Cn), cell number concentration with respect to time can be expressed as

Cn= Cn0 exp[μ (t - t0)]
Cn0 = Cn exp[μ (t - t0)]
Cn/Cn0 =(1/μ)exp(t-t0)
Cn0 / Cn = (1/μ)exp(t-t0)

Discuss Question

Answer: Option A. -> Cn= Cn0 exp[μ (t - t0)]
Answer: (a).Cn= Cn0 exp[μ (t - t0)]

Question 35. During the log phase cell numbers increase exponentially

because cells produce enzymes
because cells do not have cell membranes
because cells are autocatalysts
because the rate of cell division increases exponentially

Discuss Question

Answer: Option C. -> because cells are autocatalysts
Answer: (c).because cells are autocatalysts

Question 36. The contents in bubble column and air lift reactor are mixed through

compressed air
a mechanical internal moving part
external pumping
any of these

Discuss Question

Answer: Option A. -> compressed air
Answer: (a).compressed air

Question 37. The main function(s) of a draft tube in an air lift fermenter is/are to

increase the solubility of oxygen
distribute shear forces throughout the reactor and minimise bubble coalescence
concentrate shear forces around the sparger
concentrate shear forces near the disengagement zone

Discuss Question

Answer: Option B. -> distribute shear forces throughout the reactor and minimise bubble coalescence
Answer: (b).distribute shear forces throughout the reactor and minimise bubble coalescence

Question 38. Which of the following is incorrect?