The essential part of media designing is to be considering the stoichiometry of growth and formation of desired product which is given below:

Carbon and energy source + Nitrogen source + O2 + Other requirements ----> Biomass + Products + CO2 + H2O+ Heat

Essential characteristics of formulated media:
It should produce the maximum yield, maximal concentration with maximal rate of production of desired biomass, of consistent quality which is always readily available. It should also have minimal problems during media desiginging. It should have minimal problems during recovery of desired product/ biomass especially during aeration and agitation, extraction, purification and waste treatment.

Medium formulation is done by changing one of independent variables such as nutrient, antifoam, pH, temperature, etc. by fixing rest of others at specific level which requires at least 36 (729) trials or allow more than one variable to be changed at a time to estimate the optimal concentration of target variable. A cost of media formulation is usually higher than those for microbial cells. Animal cell media is initially used which contained about 10% calf serum along with required organic and inorganic components such as carbohydrates, amino acids, vitamins, nucleic acids, etc. Serum is also good source for media formulation especially for animal cell culture to in vivo production of recombinant proteins and antibody. Serum-free media supplements can be used for media formulation such as albumin, insulin, transferrin, ethanolamine, selenium and β-mercaptoethanol. Protein-free media may be good supplement to design the media for animal cell culture and microbial culture.

The advantages of using serum and protein free supplements include:
1. These are more consistent for medium composition to reduce batch variation.
2. These should be also responsible to reduced potential contamination to make sterilized media easily.
3. Potential cost savings is easily achieved because of these cheaper replacement components.
4. These are simplified the downstream processing during the recovery of desired product because of reduced total protein/serum content of the formulated media.

The role of trace elements (Iron, Zinc, Copper, Selenium, Manganese & Molybdenum) in medium formulation might be quite significant. The concentration of NaCl is needed to adjust the osmolarity of media and pH is commonly maintained by CO2-bicarbonate system. Best example of non-nutritional media supplements is 0.1% sodium carboxy methyl cellulose to minimize mechanical damage caused by the stirrer shear force generated by the impeller during the production phase in bioreactor.

About Author / Additional Info:
Dr. Kirti Rani Sharma,
Assistant Professor (II),
Amity Institute of Biotechnology,
Amity University, sec-125, Gautam Buddha Nagar, Noida-201303 (UP), India.
Office Phone no: +91-120-4392946
Mobile No: +91-9990329492
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