Micro-organisms used for fermentation process grow on or in growth medium which satisfies the nutritional needs of microbes. Complete analysis is needed to be done to establish the most favourable medium for the growth of the microbe used for fermentation. Formulating medium at lab scale can be done by adding main ingredients like water, carbon source, nitrogen source, minerals and other supplements in pure form and in required quantities is very easy which supports the growth of the microbe whereas, the same may not support the satisfactory growth of the same organism at industrial level.
Following criteria need to be satisfied for the material to be treated as medium at industrial level.
It should give maximum yield of product.
It should give minimum yield of undesired product.
It should be consistently available throughout the year.
It should be cheap.
Generally carbohydrates are used as carbon sources for fermentations at lab level. But, at industrial level cane molasses, corn steep liquor, sugar beet juice which are inexpensive sources are utilised. On contrary, some sensitive fermentation makes use of glucose, sucrose and other carbohydrates in their pure form which ensures the purity and quality of the final product. Sometimes starch will be added to the medium for the specific production of amylases.
At lab level, peptone or tryptone or beef extract which is a partially digested hydrolysate, which is utilised in synthesis of proteins, components of nucleic acids and other essential cellular components. But at industrial level it is supplemented with soy meal or ammonia or nitrate salts to supplement the nitrogen source.
Other elements include growth factors, vitamins, anti-foaming agents, precursors, inducers chelating agents, trace elements such as Fe, Cu, Mn, Mo and Co, are added to the fermentation medium. Where growth factors, vitamins, precursors, inducers and trace elements directly supports the growth of microbe and anti-foaming agents are added to prevent the foam formation, in case of presence of higher concentrations of metal ions which is not preferable chelating agents are added.
Last date updated on July, 2014