Fermentation

• Fermentation is any microbial process controlled by humans that produces useful products.
• Louis Pasteur showed that fermentation is directly caused by life processes of minute organisms.
• Molds have multicellular filaments and increase vegetative growth.
• Yeast are unicellular, 0.004-0.01 mm in diameter, and multiply by budding.
• Bacteria are unicellular, 0.007 mm in diameter, and multiply by binary fission.
• 1880 - production of lactic acid
• 1914 - production of acetone and n-butanol
• 1920-1940 - production of citric and gluconic acid
• 1939 - production of penicillin
• Oxidation:

  • Alcohol to acetic acid
  • Sucrose to citric acid
  • Dextrose to gluconic acid
• Reduction:

  • Aldehyde to alcohol
  • Sulfur to hydrogen sulfide
• Hydrolysis:

  • Starch to glucose
  • Sucrose to glucose and fructose, and to alcohol
• Esterification:

  • Hexose and Phosphoric acid to Hexose Phosphate
• Prerequisites for a Good Fermentation Process

  1. A microorganism that forms a desired end product. This organism must be readily propagated and be capable of maintaining biological uniformity, thereby giving predictable yields.
  2. Economical raw materials for substrate
  3. Acceptable yields
  4. Rapid fermentation
  5. A product that is readily recovered and purified
• Critical factors

  1. pH
  2. Temperature
  3. Aeration-Agitation
  4. Pure-culture Fermentation
  5. Uniformity in yields
• Greatest Yields, Least By-Product, and at Lowest Cost
• Industrial Alcohol

  Denatured Alcohol or alcohol containing impurities that adds bad smell and taste. All this being rendered to make the alcohol unfit for human consumption.
• In industrial nomenclature it refers to ethyl alcohol, or ethanol (CH2OH), which contains 95% C2H2OH or more, and 5 % H2O or less.
• To every 100 gal of ethyl alcohol of not less than 160 proof add:

  • 0.125 gal of Pyronate or a similar compound
  • 0.50 gal of acetaldol (8-hydroxybutyraldehyde)
  • 2.50 gal of methyl isobutyl keton
  • 1.00 gal of kerosene
• Become important by virtue of its economically useful properties as a solvent and for the synthesis of other chemicals.
• In absolute alcohol, Ethanol (CH2OH), which contains 99.5% C2H2OH or more.
• Octane Booster for Gasoline
• Malt Liquors:

  • malted (germinated) grain to make carbohydrates fementable
• Fermented Wines

  • yeast action on sugars of fruit
• Distilled Liquors

  • fermented liquors that are distilled to increase alcohol content
• Malt Liquor: Beer

  • 2-7% alcohol content, raw materials are cereal with hops
• Fermented Wines:

  • 7-14% alcohol content, raw materials are grapes
• Distilled Liquors are fermented beverages that have undergone distillation and aging.
• Butyl Alcohol and Acetone are used as a solvent
• The process was able to produce Riboflavin which is an antioxidant that fight free radicals, inhibit bacteria, viruses, parasites, and fungi in the body.
• Acetic Acid refers to fermented dilute alcohol and Vinegar (5% Acetic Acid) is a flavored acetic acid solution.
• Citric Acid is the most versatile organic acid. Its major use is as an acidulant. It is manufactured by aerobic fermentation of crude sugar by aspergillus niger.
• Lactic Acid:

  Fermentation of milk sugar by streptococcus lactis. Used as acidulant and in deliming leather and tanning.
• Miscellaneous Compounds

  1. Monosodium Glutamate - obtained from fermentation of carbohydrates with Brevibacterium divaricatum
  2. L-Lysine
  3. Dihydroxyacetone
• Production of enzymes by fermentation has many advantages. It allows ensuring a constant quality of the product and a high production yield. It also helps to obtain enzymes specifically targeted to perform specific tasks under required conditions