Presentation on theme: "Media for Industrial Fermentation"— Presentation transcript:
1 Media for Industrial Fermentation Chapter 7Media for Industrial Fermentation
2 Steps to Medium Development Design – nutritional requirements for growth and product formationFormulation – mass composition of cells, stoichiometry of growth and product formationOptimization
3 Media must meet the following criteria It will produce a maximum yield of product at biomass per gram of substrate used.It will produce a maximum concentration of product or biomass.It will permit the maximum rate of product formation.It will be the minimum yield of undesired product.It will be cheap and of a consistent quality and is readily available throughout the year.It will cause minimal problem in other aspects of production and agitation, extraction, purification and waste treatment.
4 MacroelementsConstitutes 90-95% of the dry weight of microbial biomassC, N, O, S, P, K, MgMicroorganisms are heterotroph (obtain the cell carbon from organic compound) and autotrophs (obtain cell carbon from CO2)Assimilated to provide cell carbon and energy – to synthesize cell material, osmotic work, cell motilityEg Penicillin production: of the total amount of glucose consumed, 10% for carbon in biomass, 10% for energy for biomass synthesis, 10% penicillin carbon and energy, 70% for maintenance energy
5 Macroelements [cont]Range of C compounds: carbohydrates, alcohols, organic acids, hydrocarbons, organic nitrogen compoundsN requirements: generally supplied as (NH4)2SO4Protein and peptides can be utilized if the microbes are able to hydrolyzeYeast extract function??
6 Microelements Ca, Mn, Fe, Cu, Co and Zn are essential B, Cr and Mo are rarely requiredCommonly added as mineral saltsTrace elements deficiencies in batch cultures are reflected by limitation of the growth rateIn continuous culture, by the decrease observed in the steady state biomass conc.Must consider the interactions because optimum conc of any ion is dependent on the conc of the others.
7 Growth FactorsSome microbes require specific nutritional factors which they cannot synthesize - growth factors3 groups – vitamins, amino acids and miscellaneous compoundsWater soluble vitamins – mostly coenzymesIn complex media, eg cane molasses already contain several vitamins
8 Other AdditivesPrecursors, eg phenylacetic acid in penicillin biosynthesisStimulants, eg methanol in citric acid productionProtectantsAntifoamsChelators – eg EDTAStabilizers – to avoid the loss of plasmidsNeutralizing agent – eg. Phosphate buffers
9 Influence of Physical Factors Temperature and water activityEg. To grow S.cereviciae at 37C instead of 30C, the pantothenic acid content must be increased.Pasteurella pestis requires more amino acids and vitamins for growth at 37C than at 28C.
10 The medium selected will affect the design of the fermenter to be used. A laboratory medium may not ideal in a large fermenter with a low gas-transfer pattern.Media with a high viscosity will also need a higher power input for effective stirring.Besides the requirement for growth and product formation, medium may also influence pH variation, foam formation, oxidation-reduction potential and the morphological form of the organisms.It may also be necessary to provide precursors or metabolic inhibitors.
12 Guide to Design and Formulation for Plant Cell Suspension Media The use of two-step process, first using a growth medium and second, a production mediumC source – sucrose is preferred.Add phytohormones to improve yield or productivityAdding precursors to enhance secondary metabolite formation
13 Growth Medium Select a basal medium such as MS, B5 or other Test the medium in shake flasks and in a bioreactor and optimize it for maximal biomass production
14 Production MediumMaintain the same carbohydrate conc of the growth media and then test the following:Reduce the phosphate and nitrogen contentModify the vitamins and iron (chelated) contentFind adequate phytohormones level and their ratiosAdd a precursor and find the correct time for its additionTest a biotic or an abiotic elicitorOptimize the medium by fractional factorial statistical methodology
15 Large Scale Media Take into account: - fermenter size - fermentation time- purification procedure- medium compositionbefore implementation!!
16 Can you detect the differences between plant and animal culture media?