Fermentation processes, extractive

Lactic acid-producing bacteria associated with fermented dairy products have been found to produce antibiotic-like compounds caUed bacteriocins. Concentrations of these natural antibiotics can be added to refrigerated foods in the form of an extract of the fermentation process to help prevent microbial spoilage. Other natural antibiotics are produced by Penicillium wqueforti the mold associated with Roquefort and blue cheese, and by Propionibacterium sp., which produce propionic acid and are associated with Swiss-type cheeses (3). 

By-Products. The biomass from the fungal fermentation process is called mycellium and can be used as a supplement for animal feed since it contains digestable nutrients (25,26). The lime-sulfuric purification and recovery process results in large quantities of calcium sulfate cake, which is usually disposed of into a landfill but can find limited use in making plaster, cement, waUboard, or as an agricultural soil conditioner. The Hquid extraction purification and recovery process has the advantage of Htde soHd by-products. 

Biotechnological processes may be divided into fermentation processes and biotransformations. In a fermentation process, products are formed from components in the fermentation broth, as primary or secondary metabolites, by microorganisms or higher cells. Product examples are amino acids, vitamins, or antibiotics such as penicillin or cephalosporin. In these cases, co-solvents are sometimes used for in situ product extraction. 

The long fermenting process converts several glucosides into glucose, vanillin, and other complex aromatic flavors. The vanilla beans can be further processed by extracting soluble compounds in ethanol and water mixtures, resulting in vanilla extract. 

Amino adds find apphcations as ingredients of infiision solutions for parenteral nutrition and individnally for treatment of specific conditions. They are obtained either by fermentation processes similar to those used for antibiotics or in cell-fiee extracts employing enzymes isolated fiom bacteria (Table 25.1). Details of the mar and varied... 

In conclusion, the rates and efficiencies of hydrogen production by systems directly using photosynthesis fall short of even plausible economic feasibility. Since organic substrates are the ultimate source of hydrogen in photofermentations or indirect biophotolysis processes, it can be argued that it should be simpler and more efficient to extract the hydrogen from substrates using a dark fermentation process, an approach which is discussed next. 

Another fermentation process is described by Fayolle et al.14 In this work, processes producing lactic acid bacteria were studied. Samples were extracted from the reactor and assayed by conventional methods and scanned in the IR. Equations were generated, using PLS, for lactose, galactose, lactic acid, and biomass. The SEP for each of these constituents was, respectively, 3.4, 1.5, 0.9, and 0.9 g/1. 

A large spectrum of berries and fruits are used in the production of fruit juice products. The range of products is substantially extended by an additional (fermentation) process to produce alcohol, and transform the fruit into wine. Enzymes, some of them proteolytic, are used to increase the yield of fruit juice during extraction, and to produce the required degree of clarity for the final product. 

The enzyme acts stereoselectively to produce only the required L-isomer (Figure 4.10). Originally a fermentation process for the production of L-aspartic acid was established. This was modified into an immobilised enzyme process, but since the extracted enzyme is not very stable, an efficient continuous process was not possible. Therefore an immobilised cell system was developed with a very long operational lifetime. Another raw material for L-aspartic acid is maleic anhydride, which is first converted... 

Figure 7.7 Plant cell fermentation and extraction process.

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