Fermentation to produce alcohol by Yeast (Saccharomyces) is due to

(A) Amylase

(B) Invertase

(C) Zymase

(D) Lactase

Correct! Wrong!

Fermentation to produce alcohol by Yeast (Saccharomyces) is due to Zymase.

Amylase: Amylase catalyzes the hydrolysis of starch (polymer of glucose) into sugars. The enzyme is present in the saliva of humans as well as secreted by the pancreas. The enzyme is classified into α-amylase (EC 3.2.1.1), β-amylase (EC 3.2.1.2), and γ-amylase (EC 3.2.1.3). Amylase hydrolases the α-1,4-glycosidic bonds and produce disaccharides and trisaccharides. Animals, plants, and microbes synthesize the Amylase enzymes.

Invertase: Invertase (EC 3.2.1.26) catalyzes the breakdown of sucrose (table sugar) into fructose and glucose. Sucrose (C₁₂H₂₂O₁₁) is a disaccharide made up of glucose (C₆H₁₂O₆) and fructose (C₆H₁₂O₆). Invertase is also known as beta-fructosidase or sucrase. Invertase breaks the O-C(fructose) bond between glucose and fructose. For industrial use, the invertase enzyme is extracted from yeast (Saccharomyces cerevisiae).

Zymase: Zymase is an enzyme complex isolated from yeast (Saccharomyces cerevisiae) by  German chemist Eduard Buchner in 1897. For his discovery, Eduard Buchner was awarded Nobel Prize in Chemistry (1907). The enzyme is responsible for the fermentation of sugar into ethanol (C₂H₅OH) and carbon dioxide (CO₂).

Lactase: Lactase (3.2.1.108) enzyme catalyzes the breakdown of milk protein lactose. Lactose is made up of glucose (C₆H₁₂O₆) and galactose (C₆H₁₂O₆). The lactase enzyme breaks the  β-1→4 glycosidic bond between glucose and galactose.