Which of following is not component of downstream processing ____________.

$\text{Correct answer: A}$ 

$\text{Option (A):}$ 

$?$ The expression of a specific character in the microorganism depends on the condition in which it is present. 

$?$ It includes the expression of genes if the proper conditions are provided to the microorganism. A suitable environment is all that the microorganism needs. 

$\text{Option (B):}$ 

$?$ The process of separation of the end product from the cellular residues and the growth medium from the outlet is essential. 

$?$ The residues are left out so that the end product in crude form can be isolated.

$\text{Option (C):}$ 

$?$ It is important to have the purified form of the end product after the process is completed.

$?$ There are specific chemical and physical methods in which the contaminants can be removed and only purified products can be separated. 

$\text{Option (D):}$ 

$?$ Preservation is the process of keeping the end product of the process preserved for use. 

$?$ This is done to prevent contamination after the product is produced so that it can be used for its specific function.

Hence, the correct answer is option (A).