Media for Industrial Biotechnology

Dr.Jitender Kumar

Department of Biotechnology

HMV,Jalandhar

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Basic components

• All microorganisms require water, sources of energy, carbon, nitrogen, mineral elements.
• And also require vitamins plus oxygen if aerobic.
• On a small scale it is relatively simple to devise a medium containing pure compounds, but the resulting medium, although supporting satisfactory growth, may be unsuitable for use in a large scale process.

Nutrients requirement

• On a large scale production one must normally use sources of nutrients to create a medium which will meet as many as possible of the different nutritional requirements of the organism.
• Important one includes carbon and nitrogen.

Undesired products

• There will be the minimum yield of undesired products.
• It will be of a consistent quality and be readily available throughout the year.
• It will cause minimal problems during media making and sterilization.
• It will cause minimal problems in other aspects of the production process particularly aeration and agitation, extraction, purification, and waste treatment.

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Effect of media components

• It will produce the maximum yield of product or biomass per gram of substrate used.
• It will produce the maximum concentration of product or biomass.
• It will permit the maximum rate of product formation.
• There will be the minimum yield of undesired products.

Carbon and Nitrogen sources

• The use of cane molasses, beet molasses, cereal grains, starch, glucose, sucrose, and lactose as carbon sources
• Ammonium salts, urea, nitrates, corn steep liquor, soya bean meal, slaughter-house waste, and fermentation residues as nitrogen sources, have tended to meet most of the above criteria for production media because they are cheap substrates.
• However, other more expensive pure substrates may be chosen if the overall cost of the complete process can be reduced because it is possible to use simpler procedures.

Design of fermenter

• Medium selected will affect the design of fermenter to be used for example, the decision to use methanol and ammonia in the single cell protein process developed the design of a novel fermenter design.
• Batch fermentations.

Solid-state fermentation

• Solid-state fermentation is an alternative to deep aqueous (submerged) culture methods, which can have significant advantages such as higher yields of enzymes and secondary metabolites.
• Indeed some enzymes and secondary metabolites can only be produced economically by solid-state fermentation though the reasons for this are not fully understood.

Development a microbial process

• The problem of developing a process from the laboratory to the pilot scale, and subsequently to the industrial scale, must also be considered.
• A laboratory medium may not be ideal in a large fermenter with a low gas-transfer pattern.
• A medium with a high viscosity will also need a higher power input for effective agitation.

Scale up

• This will become more significant as the scale of the fermentation increases.
• Besides meeting requirements for growth and product formation, the medium may also influence ph variation, foam formation, the oxidation–reduction potential, and the morphological form of the organism.
• It may also be necessary to provide precursors or metabolic inhibitors.
• The medium will also affect product recovery and effluent treatment.

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Undefined complex media

• Historically, undefined complex natural materials have been used in fermentation processes because they are much cheaper than pure substrates.
• However, there is often considerable batch variation because of variable concentrations of the component parts and impurities in natural materials which cause unpredictable biomass
• and/or product yields.

Growth factors

• Yeast extract is commonly used in many fermentations as a complex but inexpensive source of carbon and nitrogen which is rich in various amino acids, peptides, vitamins, growth factors, trace elements, and carbohydrates.
• However, batch-to-batch variations in composition of yeast extract can significantly affect the productivity of a fermentation process.

Undefined media

• As a consequence of these variations in composition small yield improvements are difficult to detect.
• Undefined media often make product recovery and effluent treatment more problematical because not all the components of a complex nutrient source will be consumed by the organism.
• The residual components may interfere with recovery and contribute to the biochemical oxygen demand of the effluent

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The carbon substrate

• The carbon substrate has a dual role in biosynthesis and energy generation.
• The carbon requirement for biomass production under aerobic conditions may be estimated

from the cellular yield coefficient (Y) which is defined as:

• Quantity of cell dry matter produced
• Quantity of carbon substrate utilized
• More details of Y values for different microorganisms and substrates can be calculated

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Role of water

• Water is the major component of almost all fermentation media, and is needed in many of the ancillary services such as heating, cooling, cleaning, and rinsing. Clean water of consistent composition is therefore required in large quantities from reliable permanent sources.
• When assessing the suitability of a water supply it is important to consider pH, dissolved salts, and effluent contamination.

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References

• Biotechnology: Expanding Horizon – B.D. Singh (Kalyani Publication)
• Biophysical and Biochemical Technology – Wilson and Walker (Cambridge University Press)
• Principle of Gene Manipulation and Genomics – Primrose (Blackwell Publication)
• General Microbiology – R.P. Singh (Kalyani Publication)
• General Microbiology – R.Y. Stanier
• Animal Cell Culture and Technology – Michael Butler

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Thank You