Fermentation Products Overview

Fermentation Products

• Major groups of commercial fermentation products include microbial biomass or cells, enzymes, metabolites, and bioconversion/biotransformation.

Microbial Biomass or Cells

• Production methods include baker's yeast (Saccharomyces cerevisiae), single-cell protein (SCP) from Spirullina, Candida, Saccharomyces (yeast), and Lactobacillus (bacteria).

Microbial Enzymes

• Microbial enzymes have advantages in production due to large quantities produced through fermentation techniques.
• Different industries utilize various enzymes from multiple sources (e.g., Aspergillus, Bacillus, Rhizopus, Corynebacterium, Micrococcus).
• Examples include Amylase (baking, flavors), Protease (beer), Lipase (laundry detergents), Catalase (dairy), Lactase (pharmaceutical & clinical), Amylase (pharmaceutical & clinical), Streptokinase (pharmaceutical & clinical), and Pectinase (fruit juice).

Microbial Metabolites

• Primary metabolites are produced during the growth phase and are crucial for life processes. Examples include amino acids, nucleotides, vitamins, solvents, and organic acids.
• Secondary metabolites are formed during the later stages of growth and play ecological roles, with functions like antimicrobial activity, enzyme inhibition, and pharmacological properties. Examples include antibiotics, pesticides, pigments, and toxins.

Organic Acid Production

• Organic acids, like citric acid, are produced through fermentation.
• Citric acid, a natural plant substance since 1893, can now be produced mostly through microbial fermentation by Aspergillus niger, and other species.
• The application of citric acid includes food preservative, cosmetic ingredients, cleaning agent and water softener.

Amino Acid Production

• Amino acids like glutamic acid, used as flavor enhancers, are produced through fermentation.
• The bacteria Corynebacterium glutamicum and related species are important in industrial glutamic acid production.

Commercial Uses of Amino Acids

• Amino acids are used in the food industry (flavor enhancers, antioxidants, low-calorie sweeteners), pharmaceuticals (medicines), and chemicals (various compounds).

Microbiological Methods of Production

• Three main approaches include direct fermentation, conversion of inexpensive intermediates, and use of enzymes or immobilized cells.

Glutamic Acid

• Predominantly produced by microbial means.
• Production of D,L-glutamic acid is through chemical synthesis, while industrial production involves Micrococcus glutamicus and Brevibacterium flavum.

Vitamins

• Vitamins can be defined as essential micronutrients and these are not synthesized by mammals.
• Some examples of vitamins are Riboflavin (Vitamin B2).

Secondary Metabolites (Antibiotics)

• Antibiotics, secondary metabolites of microorganisms, act on other organisms in low concentrations. Examples include Penicillins (produced by Penicilliumchrysogenum) and Streptomycins (produced by Streptomyces species).

Biotransformation or Bioconversion

• Microbial transformation is a biological process that modifies organic compounds into new substances.
• Microbial transformation is used in industries because it is more specific, requires mild conditions and doesn't need heavy metals.
  • Biotransformation examples include the industrial production of cortisone from progesterone using Rhizopus nigricans.