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Fermentation reactions

There are many reactions in which the products formed often act as catalysts for the reaction. The reaction rate accelerates as the reaction continues, and this process is referred to as autocatalysis. The reaction rate is proportional to a product concentration raised to a positive exponent for an autocatalytic reaction. Examples of this type of reaction are the hydrolysis of several esters. This is because the acids formed by the reaction give rise to hydrogen ions that act as catalysts for subsequent reactions. The fermentation reaction that involves the action of a micro-organism on an organic feedstock is a significant autocatalytic reaction. [Pg.26]

Discuss the cycling of NADH and NAD in glycolysis and the related fermentation reactions. [Pg.637]

An autocatalytic reaction is one in which the reaction rate is proportional to a product concentration raised to a positive exponent. Some of the first articles in the literature of chemical kinetics deal with reactions of this type. For example, in 1857, Baeyer (12) reported that the reaction of bromine with lactose was autocatalytic. The hydrolyses of several esters also fit into the autocatalytic category, since the acids formed by reaction give rise to hydrogen ions that serve as catalysts for subsequent reaction. Among the most significant autocatalytic reactions are the fermentation reactions that involve the action of a microorganism on an organic feedstock. [Pg.338]

Examples of autocatalytic reactions include the decomposition of C2H4I2 either in the gas phase or in solution in CC14 (Arnold and Kistiakowsky, 1933), hydrolysis of an ester, and some microbial fermentation reactions, The first of these may be used to illustrate some observed and mechanistic features. [Pg.187]

Food products Dairy products, General food additives Natural oils and fats Beverages Flavors and fragrances Fermentation reactions Blending control Composition monitoring Raw materials screening Quality control... [Pg.190]

Starch is one of the most abundantly produced carbon sources to be renewable on an annual basis. The chemistry of glucose and the possibility of having starch be the raw material of choice for synthetics has attracted researchers for many years. Fermentation reactions as well as chemical modification continue to be attractive. Economics has been the principal reason for lack of progress in using starch as a carbon source. However, as supplies of natural gas and petroleum decrease, new interest in starch will be found. [Pg.287]

The experimental crystallizer was a 350-mL jacketed glass unit that was provided with sufficient agitation to keep the contents well mixed. The compositions of the charges to the crystallizer were adjusted by adding the amino acids in predetermined ratios concentrations of the amino acid impurities were maintained in ranges comparable to those found in the recovery and purification of L-isoleucine from industrial fermentation reaction masses. The experiments were divided according to the mode of crystallization ... [Pg.88]

The literature on the use of the liquid-solid fluidized bed as a biochemical reactor is vast much of it is devoted to what may be generally termed fermentation reactions. The principle of the fluidized bed bioreactor, whether based on liquid-solid or on gas-solid fluidization, is... [Pg.231]

Molecular intermediates, nonchain mechanism. The general class of enzyme-catalyzed fermentation reactions... [Pg.21]

We have previously encountered examples of chemical autocatalysis, where the reaction accelerates chemically such as in enzyme-promoted fermentation reactions, which we modeled as A + B 2B because the reaction generates the enzyme after we added yeast to initiate the process. The other example was the chain branching reaction such as H. -I-O2 —> OH - -0 just described in hydrogen oxidation. The enzyme reaction example was nearly isothermal, but combustion processes are both chain branching and autothermal, and therefore they combine chemical and thermal autocatalysis, a tricky combination to maintain under control and of which chemical engineers should always be wary. [Pg.422]

The abundance and nontoxic nature of carbon dioxide also make it an attractive carbon feedstock. Potential sources of carbon dioxide include the atmosphere (where it is present in concentrations of approximately 370 ppm), natural reservoirs including natural gas wells and pure CO2 wells, waste streams of fermentation reactions, and flue stacks from power plants, cement production, and so on. Because CO2 is not toxic, development of chemical processes in which CO2 can be used to... [Pg.202]

This process takes place in a lime kiln in the production of precipitated calcium carbonate at temperatures of from 500°C to 900°C. Carbon dioxide is also produced as a by-product in fermentation reactions to produce alcohols. An example is the fermentation of glucose, H to ethanol ( H ) H 2 1. 2C H OH. + 2CO. Carbon dioxide... [Pg.69]

The most important fermentative reaction used in dairy processing is the homofermentative conversion of lactose to lactic acid. The efficient manufacture of high-quality cultured products, including most cheese varieties, yogurt, and cultured buttermilk, requires a rapid and consistent rate of lactic acid production. Lactic acid helps to preserve, contributes to the flavor, and modifies the texture of these products. Nearly all starter cultures used to produce acidified dairy products contain one or more strains of lactic streptococci, because these organisms can produce the desired acidity without causing detrimental changes in flavor or texture. Strains of lactic streptococci can be classified as... [Pg.662]

The values of AGox (Table 6-4) not only give an immediate indication of the relative amounts of energy available from oxidation of substrate with NAD+ but also are very convenient in evaluating AG for fermentation reactions. For example, consider the fermentation of glucose to ethanol (Eq. 6-60) ... [Pg.298]

Microorganisms use a great variety of fermentation reactions for obtaining energy. Could the following reaction be used for such a purpose Explain the reasons for your answer. [Pg.322]

A requirement for all fermentations is the existence of a mechanism for coupling ATP synthesis to the fermentation reactions. In the lactic acid and ethanol fermentations this coupling mechanism consists of the formation of the intermediate 1,3-bisphosphoglycerate by the glyceraldehyde 3-phosphate dehydrogenase (Fig. 10-3, step a). This intermediate contains parts of both the products ATP and lactate or ethanol. [Pg.511]

Glyceraldehyde-3-Phosphate Dehydrogenase and the Generation of ATP in Fermentation Reactions... [Pg.775]


See other pages where Fermentation reactions is mentioned: [Pg.21]    [Pg.251]    [Pg.111]    [Pg.99]    [Pg.378]    [Pg.362]    [Pg.130]    [Pg.217]    [Pg.107]    [Pg.111]    [Pg.120]    [Pg.575]    [Pg.196]    [Pg.256]    [Pg.366]    [Pg.143]    [Pg.11]    [Pg.39]    [Pg.21]    [Pg.674]    [Pg.509]    [Pg.511]    [Pg.661]    [Pg.764]    [Pg.908]    [Pg.918]    [Pg.962]    [Pg.1323]    [Pg.1388]    [Pg.608]   
See also in sourсe #XX -- [ Pg.298 , Pg.510 ]

See also in sourсe #XX -- [ Pg.391 ]




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