2 FERMENTATIONMicrobiologists consider fermentation as any process for the production of a product by means of mass culture of micro-organismsBiochemists consider fermentation as an energy generating process in which organic compounds act as both electron donors and acceptorsFermentation is any of a group of chemical reactions induced by living or non-living ferments that split complex organic compounds into relatively simple substances
3 FERMENTATIONThe process of deriving energy from the oxidation of organic compounds, such as carbohydrates, using an endogenous electron acceptor, which is usually an organic compound End-products Obtained by Fermentation • Microbial cells • Microbial metabolites • Recombinant products
5 STERILIZATION loss of productivity Outgrow contaminate the final productcontaminant may degrade the desired productContamination of a bacterial fermentation with phage could result in the lysis of the culture
6 STERILIZATION Sterilizing the medium to be employed Sterilizing the fermenter vesselSterilizing all materials to be added to the fermentation during the processMaintaining aseptic conditions during the fermentation
7 STERILIZATION MEDIUM STERILIZATION filtration, radiation, ultrasonic treatment, chemical treatment or heatSTERILIZATION OF THE FERMENTERheating jacket or coils with steam 15 psi
8 FACTORS INFLUENCING MICROBAL GROWTH pHOptimum pH for bacteria is , yeasts 4-5, molds 4-7. The pH of the medium should be maintained at optimum level for the micro-organism being employed to ensure better product yieldTemperatureOptimum temperature for most of the bacteria is 370C and the optimum temperature for most fungi is 250CNutrientsMicro-organisms require optimum concentrations of nutrients like nitrogen, vitamins, and minerals for maximum growth rate. This will be different for each of the different types
9 FACTORS INFLUENCING MICROBAL GROWTH MineralsCalcium, chlorine, magnesium, phosphorous, potassium and sulfur are the essential minerals for all media. Other minerals like copper, cobalt, iron, manganese, molybdenum, and zincGrowth FactorsVitamins, amino acids, and fatty acids are used as growth factors in the fermentation
10 FACTORS INFLUENCING MICROBAL GROWTH Chelating AgentsChelating agents prevent formation of insoluble metal precipitates. They form complexes with the metal ions present in the medium and can be utilized by the microorganismsEDTA (ethylene diamine tetraacetic acid) is able to form six bonds with a metal ion.Other chelating agents are citric acid and pyrophosphates
11 FACTORS INFLUENCING MICROBAL GROWTH Carbon SourcesProduct formation is directly dependent on the rate at which the carbon source is metabolized; also the main product of fermentation determines the type of carbon source to be used.CarbohydratesThese are the most commonly used carbon sources in the fermentation process.Starch – maize, cereals, and potatoesIt is widely used in alcohol fermentation.Malt and beer - barley grains contain high concentrations of different carbohydrates like starch, sucrose, cellulose and other sugarsSucrose - sugar cane and molasses
12 FACTORS INFLUENCING MICROBAL GROWTH Oils and FatsThey also have anti-foaming properties but are generally used as additives rather than as the sole carbon source. Examples are olive oil, cotton seed oil, soya bean oil, linseed oil, and lard (animal fat).HydrocarbonsC12-C18 alkanes can be used as carbon sources. They are cheap, and have more carbon and energy content per weight than sugars. They can be used in organic acids, amino acids, antibiotics, enzymes, and proteins fermentation.
13 FACTORS INFLUENCING MICROBAL GROWTH Nitrogen SourcesAmmonia, ammonium salts, and urea are the most commonly used nitrogen sources in the fermentation process. Ammonia also serves the purpose of pH control.Other substances used as nitrogen sources are corn-steep liquor, soya meal, peanut meal, cotton seed meal, amino acids, and proteins.
14 FACTORS INFLUENCING MICROBAL GROWTH BuffersBuffers are used to maintain the pH of the medium as microbial growth is affected by the pH changes. Optimum pH for most microorganisms is 7.0. Commonly used buffers are calcium carbonate, ammonia, and sodium hydroxideAntifoaming AgentsCommonly used antifoaming agents are stearyl alcohol, cotton seed oil, linseed oil, olive oil, castor oil, soy bean oil, cod liver oil, silicones, and sulphonates