FERMENTATION PRODUCTS

(PICTURE TAKEN FROM WWW.BIOS.NIU.EDU)

The diversity of fermentation products produced by the microorganisms is a reflection of the metabolic diversity of the microorganisms used in the fermentation process. Many fermentation books classify the fermentation products into four basic groups:
1 Primary metabolites
2 Secondary metabolites
3 Biomass ( or production of microbial cells)
4 Bioconversions , which in fact is not a product but a microbial transformation activity

PHYSICAL LOCATION OF FERMENTATION PRODUCTS
We can locate these fermentation products physiologically or physically with respect to the microbial cell. Physical location indicates the exact location where the products are formed or accumulated. Such products may be intracellular or extracellular or it maybe excreted into the fermentation broth.
1 Intracellular products may be in the cytoplasm or in the organelles.
2 Extracellular location may occur as deposition outside the cells of the products secreted. Exopolysaccharide and extracellular enzymes are fermentation products located out side the cell.
3 Secreted fermentation products are released by the cell into the broth after they are formed. Most of these secreted products are soluble metabolic waste products such as alcohol.

The physical location of the fermentation products us important in determining the ease or difficulty of extracting and concentrating the products during downstream activities

PHYSIOLOGICAL LOCATION OF FERMENTATION PRODUCTS

There is another way of looking at the fermentation products, that is by the physiological location of the fermentation products. In physiological location of fermentation products we look at the formation of the products as function of the microbial growth curve. Certain fermentation products are formed throughout the growth of the microorganisms while there are other fermentation products formed only at the onset or during the stationary phase.

Primary metabolites and biomass are maximally produced at the log phase of the growth curve. Antibiotics and secondary metabolites are only produced at the onset of the stationary phase