Biocatalysts are complex organic compounds. In living organisms, they can act as catalysts for various biochemical reactions. Enzymes are one of the most important biocatalysts which are used for the manufacture of Ethanol.The following method is used to produce ethanol from sugar solution( molasses).

Molasses is a non-crystalline form of sugar which is obtained from mother liquor of sugar solution. Mother liquor can be prepared by crystallization of sugar from the sugar solution. This mother liquor contains about 50% sugar. It is then diluted to almost 10%.In this diluted solution, yeast is added and it is kept for 2 to 3 days. Yeast is a microorganism which produces the enzymes zymase and invertase. These two enzymes perform the following conversions given below:

If the concentration of ethanol exceeds 15 %, the enzyme gets inhibited. This whole process is carried out in the absence of air under anaerobic condition. In aerobic condition(in presence of oxygen) ethanol is oxidized to produce ethanoic acid.