Carbohydrates fermentation and

Armstrong WG (1960b) Reaction in vitro of sound dentine with glucose, glucosamine and carbohydrate fermentation and degradation products. Arch Oral Biol 5, 179-189. 

Ibanez et al. (1995) compared dry-fermented sausages formulated so that part of the NaCl was replaced with KCl from the standpoint of their effects on carbohydrate fermentation and nitrosation. Both sausages attained similar final pH and a values, at pH 5.06 and 4.99 and a 0.85 and 0.88 for the control NaCl and the KCl-containing sausage. Final values were achieved in less than 20 days and were well below the a value of <0.90, which is required for stability of IM meats. 

J. (1995). Partial replacement of sodium chloride with potassium chloride in dry fermented sausages Influence on carbohydrate fermentation and the nitrosation process. Meat Sci. 40,45. 

Sophisticated models attempt to relate microbial yield to the rate of carbohydrate fermentation and rate of passage, the theoretical growth rate, the energy cost of bacterial maintenance and the form of nitrogen available to the rumen microorganisms. Many of the relationships involved in such calculations are based on laboratory characterisation of the food, and the value of the model will depend on the validity of the relationships between the laboratory determinations and the values used in the models. 

Ethanol is prepared by carbohydrate fermentation and by hydration of ethene (addition reaction) ... 

Until World War 1 acetone was manufactured commercially by the dry distillation of calcium acetate from lime and pyroligneous acid (wood distillate) (9). During the war processes for acetic acid from acetylene and by fermentation supplanted the pyroligneous acid (10). In turn these methods were displaced by the process developed for the bacterial fermentation of carbohydrates (cornstarch and molasses) to acetone and alcohols (11). At one time Pubhcker Industries, Commercial Solvents, and National Distillers had combined biofermentation capacity of 22,700 metric tons of acetone per year. Biofermentation became noncompetitive around 1960 because of the economics of scale of the isopropyl alcohol dehydrogenation and cumene hydroperoxide processes. 

Some of the economic hurdles and process cost centers of this conventional carbohydrate fermentation process, schematically shown in Eigure 1, are in the complex separation steps which are needed to recover and purify the product from the cmde fermentation broths. Eurthermore, approximately a ton of gypsum, CaSO, by-product is produced and needs to be disposed of for every ton of lactic acid produced by the conventional fermentation and recovery process (30). These factors have made large-scale production by this conventional route economically and ecologically unattractive. 

Uses of lactose production by appHcation include baby and infant formulations (30%), human food (30%), pharmaceuticals (25%), and fermentation and animal feed (15%) (39). It is used as a diluent in tablets and capsules to correct the balance between carbohydrate and proteins in cow-milk-based breast milk replacers, and to increase osmotic property or viscosity without adding excessive sweetness. It has also been used as a carrier for flavorings. 

The nature of the diet sets the basic pattern of metabohsm. There is a need to process the products of digestion of dietary carbohydrate, lipid, and protein. These are mainly glucose, fatty acids and glycerol, and amino acids, respectively. In ruminants (and to a lesser extent in other herbivores), dietary cellulose is fermented by symbiotic microorganisms to short-chain fatty acids (acetic, propionic, butyric), and metabohsm in these animals is adapted to use these fatty acids as major substrates. All the products of digestion are metabohzed to a common product, acetyl-CoA, which is then oxidized by the citric acid cycle (Figure 15-1). 

The presence of unusual carbohydrate fermentation patterns (particularly for lactose), and the ability to use citrate among Enterobacteriaceae has hindered, and sometimes jeopardized, the identification of pathogenic strains including Salmonella typhi. 

Reeves, A.R., Britain, I.A., Cemota, W.H. et al. (2006) Effects of methylmalonyl-CoA mutase gene knockouts on erythromycin production in carbohydrate-based and oil-based fermentations of Saccharopolyspora ery-thraea. Journal of Industrial Microbiology and Biotechnology, 33, 600-609. 

Mammalian cell culture is more technically complex and more expensive than microbial cell fermentation. Therefore, it is usually only used in the manufacture of therapeutic proteins that show extensive and essential post-translational modifications. In practice, this usually refers to glycosylation, and the use of animal cell culture would be appropriate where the carbohydrate content and pattern are essential to the protein s biological activity, its stability or serum half-life. Therapeutic proteins falling into this category include EPO (Chapter 10), the gonadotrophins (Chapter 11), some cytokines (Chapters 8-10) and intact monoclonal antibodies (Chapter 13). 

The study of the reactions with the participation of glycosyl bonds is important not only for the theoiy of carbohydrates structure and reactional ability of carbohydrates. They represent a significant interest and solution for a number of important problems of organic, bioorganic chemistry, and molecular biology, fermentative catalysis, since the glycosyl bond is one of the most important structural elements of many biologically active compounds. 

Lignocellulose biomass is a mixture of phenolic lignin and carbohydrates -cellulose and hemi-cellulose. It grows abundantly on earth and is largely available as agricultural and forestry residues. Lignocellulose can be converted via four major routes pyrolysis, gasification, hydrolysis and fermentation. 

Due to fermentation of hitherto undigested carbohydrates by the cecal and colonic bacteria (the large bowel contains concentrations of bacteria of up to 10lo-1012 bacteria/ mL), the pH in the proximal colon is usually lower than that of the ileum. This is reflected in the composition of SCoF, which is essentially an acetate buffer. The use of acetate is appropriate as it is known that the products of carbohydrate fermentation include very short chain acids (acetate, propionate, and butyrate are typical). 

Fermentation tests are based on the ability of yeast to oxidize the sugar to yield ethanol and carbon dioxide, although only the D-isomers are fermentable and only relatively few of these. Modem chromatographic techniques are, however, much more acceptable and paper and thin-layer techniques are useful for routine separation and semi-quantitation of carbohydrate mixtures, although GLC or HPLC techniques may be necessary for the more complex samples or for quantitative analysis. 

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