Dr. N. BANUVels University

Microbe requiresWaterEnergyCarbonNitrogenMineral elementsVitaminsOxygen

MEDIA FORMULATION

Max. yieldMax. conc. Of productMin. yield of undesired productStable productMin. problems during media making and

sterilizationMin. problems of production processes

(aeration, agitation, extraction, purification and waste treatment.

Criteria for nutrients for a medium

Major component of all fermentation.Ancillary services : heating, cooling, cleaning

and rinsing.Suitable water:pH, dissolved salts, effluent contamination.Brewing: mineral content of the water.Reuse of water after fermentation –

Methylophilus methylotrophus

WATER

Carbon &energy source + nitrogen + others

STOICHIOMETRY OF GROWTH AND PRODUCT FORMATION

BIOMASS + PRODUCTS + CO2 +H2O+ HEAT

Oxidation of the medium components (carbohydrates, lipids and proteins,

light

ENERGY SOURCE

Carbohydrates Oils and fats Hydrocarbon and their derivativesCarbohydrates:Starch from maize, cassava, cereals, potatoesBarley grains – malt.Sucrose from sugar cane and sugar beet.Molasses – high volume, low-value product.Lactose and crude lactoseCorn steep liquor.

Carbon sources

First used as carriers for antifoams in antibiotic processes.

Vegetable oils – olive, maize, cotton seed, lin seed, soybean, etc. Used as carbon substrates.

Also provides antifoaming property.Methly oleate – sole ‘c’source in

cephalosporin production.

Oils and fats

Methane, methanol and n-alkanes – substrates for biomass production.

N-alkanes – for the production of organic acids, amino acids, vitamins and co-factors, nucleic acids, antibiotics, enzymes and proteins.

Scp from hydrocarbons:BP plc developed Toprina from yeast grown on n-

alkanes.ICI plc developed pruteen from bacteria grown on

methanol.Hoechst/UBHE (protein from bacteria on methanol)Shell plc (bacteria on methane).

Hydrocarbons and their derivatives

Inorganic source and organic sourceInorganic Nitrogen:

1. Ammonia gas2. Ammonium salts3. NitratesOrganic nitrogen:4. Amino acids5. Protein 6. UreaProtenaceous nitrogen compounds:CSL, soya meal, peanut meal, cotton-seed

meal, distiller’s solubles, meal and yeast extract.

Nitrogen sources

Penicillin Bacitracin Riboflavin Novobiocin Rifomycin

CSL Peanut granules Pancreatic digest

of gelatine Distillers solubles Pharmamedia,

soybean meal, (NH4)2 SO4.

Best N source for some sec. metabolites

KH2 PO4 MgSO4. 7H20 KCl CaCO3 FeSo4. 4H2O ZnSO4. 8H20 MnSo4. H2O CuSO4.5H2O Na2MoO4. 2H20

1.0-4.0 0.25-3.0 0.5-12.0 5-17 .01-.1 .1-1 .01-.1 .003-.01 .01-.1

Minerals

Trace elements influencing primary and secondary metabolism

Product Trace elements

Bacitracin Protease Gentamicin Riboflavin Chloramphenicol Citric acid Penicillin Patulin

Mn Mn Co Fe, Co Fe, Zn Fe, Zn, Cu Fe, Zn, Cu Fe, Zn

Vitamins Amino acids, Fatty acids Sterols. Calcium pantothenate – Vinegar production Biotin – glutamic acid production.

Growth factors

Calcium carbonate Phosphates Balanced use of C/N ratio controls pH pH controlled externally by adding ammonia

or sodium hydroxide and sulfuric acid.

Buffers

Penicillin production – phenlyacetic acid – precursor.

Inducers: amylase – starch, maltose. Pullulanase – maltose. Penicillin acylase – phenlyacetic acid Proteases – various proteins Cellulase – cellulose Pectinases - pectin

Precursors and inducers

Influence of medium for oxygen availability: Fast metabolism: The culture may become

oxygen limited because sufficient O2 cannot be made available in the fermentor if certain substrates, like rapidly metabolized sugars which leads to a high oxygen demand, are available in high conc.

Rheology: The individual components of the medium can influence the viscosity of the final medium and its subsequent behaviour with respect to aeration and agitation.

Antifoams: Act as surface active agents and reduce the o2 transfer rate.

Oxygen requirement

Foaming due to component of the medium / protein in the medium – leads to problem.

Characteristics of antifoams: Should disperse readily and have fast action on an

excisting foam. Should be active at low conc. Should be long acting in preventing new foam

formation. Should not be metabolized by the microorganisms. Should be non-toxic to the microbe,humans and

animals. Should not cause any problems in the downstreaming Should not cause any handling hazards. Should be cheap. Should have no effect on oxygen transfer Should be heat sterilizable.

Antifoams

Alcohols; stearyl and octyl decanol Esters Fatty acids and derivatives (glycerides)

linseed oil, cottonseed oil, olive oil, castor oil, sunflower oil, rapeseed oil and cod liver oil.

Silicones Sulphonates Alkaterge C, oxazaline, poly-propylene

glycol.

Antifoams examples