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Substrate consumption in lag phase of microbial growth is primarily used for<br>P. Turnover of the cell material.<br>Q. Maintenance of intracellular pH.<br>R. Motility.<br>S. Increase in cell number.

Correct Answer: P, Q and R only

Consider the growth of a microorganism in batch culture. When the substrate concentration is high, the cell density doubles every 0.75 h, the observed substrate yield coefficient is 0.3 g DCW/g, and substrate consumption is allocated towards biosynthesis (60%), maintenance (10%), as well as product formation (30%). The product formation is strictly growth-associated. The batch reactor is inoculated with 0.01 g DCW/L and 10 g/L substrate. Estimate the maximum cell density (after lag phase).

In balanced growth phase of a cell,
P. All components of a cell grow at the same rate.
Q. Specific growth determined by cell number or cell mass would be the same.
R. The growth rate is independent of substrate concentration.
S. The growth rate decreases with decreasing substrate concentration.

Structured William's model
P. Can describe the changes in intracellular components of the cell during growth.
Q. Cannot describe the death phase of the cells.
R. Can describe the variation of size of cells in the different phases of growth.
S. Cannot describe the lag period of growth.
Which one of the following is correct?

In a bioprocess, assume that only cell mass is formed. Due to a variation in process condition, if the microbial cell yield has halved, what would be the rate of substrate consumption to maintain the same rate of cell mass production?

Diauxic pattern of biomass growth is associated with
P. Multiple lag phases.
Q. Sequential utilization of multiple substrates.
R. Simultaneous utilization of multiple substrates.
S. Absence of lag phase.

Zymomonas mobilis is used to convert glucose to ethanol in a batch fermenter under anaerobic conditions. The yield of biomass from substrate is 0.06 g g-1; YPX is 7.7 g g-1. The maintenance coefficient is 2.2 g g-1 h-1; the specific rate of product formation due to maintenance is 1.1 h-1. The maximum specific growth rate of Z. mobilis is approximately 0.3 h-1.5 g bacteria are inoculated into 50 litres of medium containing 12 g l-1 glucose. Determine batch culture times required to produce 10 g biomass.

After the increase of price of oil by 40%, a family decided to reduce its oil consumption so that the expenditure for oil goes up by 26% only. If the total consumption of oil before the price rise was 10 kg per month, then what is the current consumption of oil per month (in kg)?

A single phase motor is connected to 400V, 50Hz supply. The motor draws a current of 31.7A at a power factor 0.7 lag. The capacitance required in parallel with motor to raise the power factor of 0.9 lag (in micro farads) is __________

A single phase motor is connected to 400V, 50Hz supply. The motor draws a current of 31.7A at a power factor 0.7 lag. The capacitance required in parallel with motor to raise the power factor of 0.9 lag (in micro farads) is ___________

Which of the following factors can influence the lag phase of a microbial culture in a batch fermenter?
P. Inoculum size
Q. Inoculum age
R. Medium composition