1. The unit of Ks is the same as the unit of
a. Growth rate
b. Specific growth rate
c. Substrate concentration
b. None of the above

2. How is the value of Ks related to to the affinity of a microorganism for a particular nutrient
a. Inversely proportional
b. Directly proportional

3. Calculate the specific growth rate of a microorganism whose maximum specific growth rate is 20 per minute available substrate concentration is 10 grams per liter and substrate concentration required to reach half of the maximum specific growth rate is 7 grams per litre.

4. Maximum specific growth rate of a microorganism can be increased by
a. Providing complex chemical compounds as substrate
b. Increasing the substrate concentration to excess
c. Providing simpler and favourable substrates
d. Both B and C.

5. The unit of specific growth rate and growth rate are same
a. True
b. False

Answers -
1- c
2- a
3- 11.8 per min.
4- c
5- b

Notes - Monods equation is derived from Michaelis menten equation and it provides us with a relationship between specific growth rate and the substrate concentration as following

u= umax S /(Ks + S)

u= specific growth rate
umax = maximum specific growth rate
Ks = substrate concentration at which half of the maximum specific growth rate is achieved.
S = present substrate concentration

The unit of Ks is the same as the substrate concentration.
Ks value for different types of substrate is different and a higher Ks Value shows that a higher amount of substrate is required to achieve half of the maximum specific growth rate which means that the microorganism has a lower affinity for the substrate whereas lower Ks Value shows that even a low amount of substrate concentration is able to achieve half of the maximum specific growth rate hence, that microorganism has a higher affinity for this particular type of the substrate.

It has been found that, if the favourable substrate is not provided or the substrate provided is complex for the breakdown by microorganisms then, the maximum specific growth rate may decrease.

Monods equation can be used as it is for the calculations regarding batch culture.


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