Bioreactor Media,Microbial Growth,Inorganic Nutrients,Antibiotic Production,Autotrophs,Rapid Cell Growth

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	Bioreactor Media - The medium composition is as critical to product yields as high producing strains of microorganisms. The medium not only provides the nutrients needed for microbial growth but also for the metabolite production. The organisms vary greatly in their nutrient requirements from autotrophs, which produce all the biochemicals required from simple inorganic nutrients deriving their energy from oxidation of some inorganic component of the medium to the difficult organisms like lactic acid bacteria, which require many organic compounds for their growth.
The various media may be grouped into two broad categories: (i) synthetic and (ii) complex. A synthetic or chemically defined medium is desirable for various studies, but product yields from such media are generally low. Foaming is not a problem with such media. The complex media contain undefined constituents like soybean meal, molasses, corn steep liquor, etc., and give much higher yields of metabolites. Carbon source can be simple, e.g., sugar, alcohol, etc., or complex carbohydrates, proteins, molasses, potatoes, sweet potatoes, etc. In many processes, precursors need to be provided, e.g., phenylacetic acid for penicillin G, inorganic cobalt for vit. B12.
Buffers are also added to prevent drastic changes in pH, and anti foam would often be needed when complex media are used. For much fermentation, e.g., antibiotic production, medium suited for rapid cell growth is unsuitable for product formation. In such cases, specialized media for production have to be devised.