HORTICULTURE

Detailed explanation-1: -The ground corn and water slurry is liquefied using -amylase enzymes at high temperatures to convert starch into dextrins. The dextrins are further converted to glucose using glucoamylase (GA) enzymes during saccharification process, which is fermented to ethanol by yeast.

Detailed explanation-2: -Yeast (Saccharomyces cerevisiae) alcohol dehydrogenase I (ADH1) is the constitutive enzyme that reduces acetaldehyde to ethanol during the fermentation of glucose.

Detailed explanation-3: -The correct answer is Saccharomyces cerevisiae. In the commercial production of ethanol, Saccharomyces cerevisiae is used as yeast because it can tolerate a wide range of pH thus reducing the risk of infections during the process.

Detailed explanation-4: -The last enzyme of glycolysis, lactate dehydrogenase, is replaced by two enzymes in alcoholic fermentation. These two enzymes, pyruvate decarboxylase and alcoholic dehydrogenase, convert pyruvic acid into carbon dioxide and ethanol in alcoholic fermentation.