Factor affecting industrial fermentation media

Dr.Jitender Kumar

Department of Biotechnology

HMV,Jalandhar

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Introduction

• Most suitable medium for an individual fermentation process, but certain basic requirements must be met by any such medium.
• All microorganisms require water, sources of energy, carbon, nitrogen, mineral elements, and possibly 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.

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Sources of nutrients

• On a large scale one must normally use sources of nutrients to create a medium which will meet as many as possible of the following criteria:
• 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.
• 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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Different nutrients

• The use of cane molasses, beet molasses, cereal grains, starch, glucose, sucrose, and lactose as carbon sources, and ammonium salts, urea, nitrates, corn steep liquor, soya bean meal, slaughter-house waste, and fermentation residues as nitrogen sources.
• Media are designed 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 media

• Other criteria are used to select suitable sporulation and inoculation media.
• It must be remembered that the 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 by ICI plc necessitated the design of a novel fermenter design
• The microbial oxidation of hydrocarbons is a highly aerobic and exothermic process.

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Solid-state fermentation

• Fermenter had to have a very high oxygen transfer capacity coupled with excellent cooling facilities.
• Equally, if a fermenter is already available this will obviously influence the composition of the medium.
• Solid-state fermentation is an alternative to deep aqueous (submerged) culture methods, which can have significant

Advantages

• 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.

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A laboratory medium

• 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.

Factors

• Medium with a high viscosity will also need a higher power input for effective agitation.
• 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.

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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.

Batch-to-batch variations

• 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. As a consequence of these variations in composition small yield improvements are difficult to detect.

Typical media�

• Development of some recipes for some typical media for submerged culture fermentations.
• These examples are used to illustrate the range of media in use, but are not
• necessarily the best media in current use.

Media purification

• Thus, although manufacturers have been reluctant to use defined media components because they are more expensive, pure substrates give more predictable yields
• from batch to batch and recovery, purification, and effluent treatment are much simpler and therefore cheaper.

Process improvements

• Process improvements are also easier to detect when pure substrates are used.
• The use of glycerophosphate in a defined media for the commercially important yeast Pichia pastoris.Glycerophosphate as a phosphorous source overcomes problems caused when a complex media is formulated.

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Medium formulation�

• Medium formulation is an essential stage in the design of successful laboratory experiments,pilot-scale development, and manufacturing processes.
• The constituents of a medium must satisfy the elemental requirements for cell biomass and metabolite production and there must be an adequate supply of energy for biosynthesis and cell division

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Reference

• Biotechnology expanding horizon by B.D.Singh
• General Microbiology by Stainier
• 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