Thermal death of microorganisms in the liquid medium follows first order kinetics. If the initial cell concentration in the fermentation medium is 10⁸ cells mL^-1 and the final acceptable contamination level is 10^-3 cells, for how long should 1 m³ medium be treated at temperature of 120°C (thermal deactivation rate constant = 0.23 min^-1) to achieve acceptable load?

Which of the following techniques is best suited for immobilizing an affinity ligand?

Which one of the following can not be a limiting substrate if Monod's growth kinetics is applicable?

During cultivation of microorganisms in a fermenter, various parameters are controlled by appropriate sensor (probe). Match each probe in Group I with the appropriate response mechanism in Group II.

Group I (Probe)	Group II (Response)
P. Thermistor	1. Activation of acid/alkali pump
Q. Oxygen electrode	2. Activation of vegetable oil pump
R. Metal rod	3. Activation of hot/cold water pump
S. pH electrode	4. Increase/decrease in stirrer motor speed

The kinetics of the disintegration of baker's yeast cells in a bead mill is described as $$\frac{{dp}}{{dt}} = K\left( {{P_m} - P} \right)$$   , where P is the concentration of protein released, m is the maximum protein concentration achievable, K is the first order rate constant and is 0.5 h⁻¹ for the system studied. The time required for the release of 90% of the intracellular proteins will be: