Question

Fermentation of starch solution to ethyl alcohol does not require:
A.Invertase
B.Diastase
C.Zymase
D.Maltase

Answer 1

Hint:
Fermentation is a metabolic process that generally includes conversion of any carbohydrate, such as starch or a sugar, into alcohol and carbon dioxide. Starch is a carbohydrate which is primarily composed of glucose.

Complete step by step answer:
Starch is a polysaccharide which is made up of monomers of D-glucose. The general formula of starch solution is - ${{({{C}_{6}}{{H}_{10}}{{O}_{5}})}_{n}}$.
The fermentation of starch solution to ethyl alcohol occurs in three steps –
Step 1
Conversion of starch to maltose by the enzyme – Diastase
This reaction is a hydrolysis reaction.
The substrate for this reaction in germinated barley or barley malt.
The reaction for this is as given below –
$2{{({{C}_{6}}{{H}_{10}}{{O}_{5}})}_{n}}+n{{H}_{2}}O\xrightarrow{Diastase}n({{C}_{12}}{{H}_{22}}{{O}_{11}})$
Step 2
Conversion of maltose to glucose by the enzyme - Maltase
This reaction is carried out with the help of yeast.
The reaction for this is as given below –
${{C}_{12}}{{H}_{22}}{{O}_{11}}+{{H}_{2}}O\xrightarrow{Maltase}2{{C}_{6}}{{H}_{12}}{{O}_{6}}$
Step 3
Conversion of glucose to ethyl alcohol by the enzyme - Zymase
This reaction is carried out with the help of yeast.
The reaction for this is as given below –
${{C}_{6}}{{H}_{12}}{{O}_{6}}\xrightarrow{Zymase}2{{C}_{2}}{{H}_{5}}OH+2C{{O}_{2}}$
Therefore, the answer is – option (a) – Fermentation of starch solution to ethyl alcohol does not require invertase.

Additional Information: The word ‘ferment’ is derived from the Latin word ‘fervere’, meaning "to boil."

Note:
Starch is the main storage polysaccharide in plants. It is composed of amylose and amylopectin. Amylose is a straight-chain polymer made by C1-C4 glycosidic linkage of glucose, whereas amylopectin is a branched polymer made up of C1-C4 and C1-C6 glycosidic linkage of glucose.