Fermentation fundamentals

Another area is the production of chemical intermediates from renewable feedstocks. Cargill-Dow and Dupont are just two of the companies beginning to market biobased polymers and plastics to replace petroleum based polymers. Again, the fermentation fundamentals originally developed for food manufacturing continue to apply to a wide variety of products. 

J. E. Bailey and D. F. Ohis, Biochemical Engineering Fundamentals, 2nd ed. McGraw-HiU Book Co., Inc., New York, 1986. A very good treatise describing the apphcation of basic engineering principles to fermentation technology. 

In the interdisciplinary field of biophysics and biotechnology, the bioeffects of electric field have received considerable interest for both fundamental studies on these interaction mechanisms and potential application. However, the effects of pulsed electric field (PEF) on secondary metabolism in plant cell cultures and fermentation processes have been unknown. Therefore, it would be very interesting to find out whether PEF could be used as a new tool for stimulating secondary metabolism in plant cell cultures for potential application to the value-added plant-specific secondary metabolite production. Furthermore, if the PEF permeabilization and elicitation are discovered in a cell culture system, the combination of... 

From this one ancestral fungus each penicillin manufacturer has evolved a particular production strain by a series of mutagenic treatments, each followed by the selection of improved variants. These selected variants have proved capable of producing amounts of penicillin far greater than those produced by the wild strain, especially when fermented on media under particular control conditions developed in parallel with the strains. These strain selection procedures have become a fundamental feature of industrial biotechnology. 

The fundamental difference between this process and bulk fermentation or sponge batter processes is that the dough development is achieved by a combination of high mechanical energy and chemical action. 

Fermentation systems obey the same fundamental mass and energy balance relationships as do chemical reaction systems, but special difficulties arise in biological reactor modelling, owing to uncertainties in the kinetic rate expression and the reaction stoichiometry. In what follows, material balance equations are derived for the total mass, the mass of substrate and the cell mass for the case of the stirred tank bioreactor system (Dunn et ah, 2003). 

Interpretation of the process of fermentation by yeast was one of the most controversial issues for vitalists. Its resolution was fundamental for the future development of biochemistry. In the early nineteenth century fermentation was believed to be related to putrefaction and decay. Liebig considered it to result from the breakdown of a substance (sugar) following the admission of air to the nitrogenous components in yeast juices. After the must of grape juice had fermented, the liquid cleared and the yellow sediment, yeast, was deposited. 

Fundamentally new insights have recently been gained by Kluyver and Schnellen. Making use of a pure culture of methane bacteria, Methanosarcina Barkerii, they converted a mixture of carbon monoxide and hydrogen into methane according to the equation CO - - 3 H2 = H2O -F CH4. This fermentation process actually takes place in two steps (a) CO + H2O = H2 - - CO2 and (b) CO2 + 4 H2 = 2 H2O - -CH4. Many details and references to the older literature can be found in this publication and also in the thesis of Schnellen. ... 

The phase transfer method of protein solubihzation is fundamentally different from the other two methods. In this method, there are two bulk phases (aqueous and organic) which are brought to equihbrium. Under certain conditions, the protein molecules are transferred from the aqueous phase to the surfactant-containing organic phase. Unhke the dry-addition and injection methods, it is difficult to obtain a value for the maximum solubihzation using the phase-transfer method. Moreover, since this method is mainly used for protein extraction, it is desirable to use aqueous phase protein concentrations consistent with those in a typical fermentation broth. For the phase-transfer method, pH of the aqueous phase, the size and isoelectric point of the protein, and the surfactant type were shown to have a significant effect on protein solubilization [145]. 

Kos owski, F. Cheese and fermented milk foods Fundamentals of cheese... 

Twenty-five years ago the only oxygenated aliphatics produced in important quantities were ethyl and n-butyl alcohols and acetone made by the fermentation of molasses and grain, glycerol made from fats and oils, and methanol and acetic acid made by the pyrolysis of wood. In 1927 the production of acetic acid (from acetylene) and methanol (from synthesis gas) was begun, both made fundamentally from coal. All these oxygenated products are still made from the old raw materials by the same or similar processes, but the amount so made has changed very little in the past quarter century. Nearly all the tremendous growth in the production of this class of compounds has come from petroleum hydrocarbons. 

Practical and fundamental aspects of malo-lactic fermentation are given. Conditions which winemakers can use for better control of the fermentation, including detailed procedures for inoculation with Leuconostoc oenos ML 34 and for inhibition with fumaric acid, are presented. New information on the role of malic acid decarboxylation in bacterial metabolism and on the enzymatics of malic acid decarboxylation are reviewed. The malic acid decarboxylation seems to involve two pathways a direct decarboxylation of malic to lactic acid with NAD as a coenzyme and a concurrent but small oxidative decarboxylation to pyruvic acid and NADH. How these pathways can bring about the marked stimulation of bacterial growth rate by the malo-lactic reaction and their negligible effect on growth yield are discussed. 

For the optimum design of a production-scale fermentation system (prototype), we must translate the data on a small scale (model) to the large scale. The fundamental requirement for scale-up is that the model and prototype should be similar to each other. 

Many aspects related to optimization of the ethanol production process have been addressed in previous works. A key to the optimization of a process is a thorough understanding of the system s dynamics, which can be obtained using an accurate model of the process. Atala et al. (1) developed a mathematical model for the alcoholic fermentation based on fundamental mass balances. The kinetic parameters were determined from experimental data and were described as functions of the temperature. The experiments were conducted with high biomass concentration and sugarcane molasses as substrate to simulate the real conditions in industrial units. 

Usually, after alcoholic fermentation, the wine undergoes malolactic fermentation, induced primarily by Oenococcus oeni. Not only can this lactic acid bacterium convert L-malic acid into L-lactic acid but also it is involved in many other transformations fundamental to Amarone quality. 

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