Ethanol Production and Acetone - Ethanol Fermentation by Microorganisms

 

Ethanol Production and Acetone - Ethanol Fermentation by Microorganisms

Ethanol Production and Acetone - Ethanol Fermentation by Microorganisms

Ethanol Production: 

Ethanol is a component of alcoholic beverages and microorganisms are required for the fermentation of ethanol.

Process of Ethanol Production: 

Ethanol Production or Fermentation is an anaerobic process. It may be also called brewing.

Ethanol is produced by yeast using any fermentable carbohydrate as a substrate such as corn, molasses, sugar beet, grape, potatoes are some common raw materials used for alcoholic fermentation. 

The reaction takes place via EMP (Embden-Mayerhof-Parnas) pathway, in which glycolysis occurs. Glucose is broken down into two pyruvate molecules during glycolysis.

      C6H12O6    ===>   2(CH3CH2OH)      +        2(CO2)    +   ATP

      Sugar     ===>       Alcohol             +   Carbon dioxide (gas) + ATP

   (Glucose)               (Ethanol)

Microorganisms used in Ethanol Production:

The selected yeast strain must have the following characteristics -

Grow rapidly. 

Produce large amount of ethanol.

Have a high tolerance of ethanol.

In ethanol fermentation, all types of yeasts are not suitable for brewing. 

Selected stains of yeast Saccharomyces cerevisiae are commonly used. Other yeast is Saccharomyces carslbergensis.

Functions of yeast:

a)     Converts sugar into alcohol and carbon dioxide. 

b) Produces changes in proteins and other amino acid constituents, which modify flavor of alcoholic beverages.

Uses of Ethanol Fermentation:

1. Common solvent used in the production of dye, soap, plastic, rubber, polishes.

2. used as a raw material in the industry. 

3. used in the production of ether, acetaldehyde, butanol and acetic acid.

4. The byproducts produced in the production of ethanol used in the production - carbon dioxide, isoamyl alcohol, butyl alcoholic are collectively known as fused oil.

Acetone - Ethanol Fermentation

Raw materials: 

Carbohydrate ( corn, potato, molasses, corn cob, oat and peanut). 

Temperature required: 40 - 43℃ 

pH required: optimum 8-9. 

But highest yield at a pH of 6-8.

Time: about six days. 

Microorganism required: Bacillus acethylicus.

Fermentation of corn cob: 

In this method, corn cobs are hydrolyzed for one hour at a steam pressure of 20lb. The hydrolysate obtained is then neutralized with calcium hydroxide and pressure and then the residue is washed.

The ratio of the weight of water, corn cob and sulphuric acid used for the hydrolysis is 200:50:4.

The sugar content of the mash is adjusted to a 3% concentration. 

The reaction of the fermentation is maintained at pH range of 7.6-8.4.

Sufficient calcium carbonate is then added to neutralize the acid formed.

Acetone - Ethanol Fermentation differs from Acetone - Butanol Fermentation by these factors:

a) the type of organisms used.

b) the optimum pH

c) the end product 

d) respect to qualities of butyric acid and butanol formed.

e) the use of calcium carbonate

f) the time required for the completion of the fermentation.

Uses of Acetone - Ethanol Fermentation:

a) a powerful solvent in plastic industry 

b) cleaning agent

c) used as paint thinners.

The Daily Youth- tdy24.com Presents

" Ethanol Production and Acetone - Ethanol Fermentation by Microorganisms"

Written By

Sadia Akhtar

Student of Department of Microbiology

Jagannath University.

Email- sadiabd810@yahoo.com