E fermentation

C, chemical synthesis Enz, enzymatic synthesis Ext, extraction E, fermentation. Ref. 219. 

Starkenstein, E., Ferment action and the influence upon it of neutral salts, Biochem. Z., 24, 210-218, 1910. 

There are two principal ways for utilization of microorganisms (yeasts, fungi, bacteria) for the production of flavouring substances, i.e. fermentation (de novo biosynthesis) and biotransformation (Tab. 3.7). Fermentation products are usually complex (see 3.2.2.4.). Nevertheless, there are some single flavouring substances that are produced by fermentation, such as acetic, butyric, and propionic acids and others (Tab. 3.8). For biotransformations by microorganisms, suitable substrates are necessary. Some examples are given in Tab. 3.9 and Fig. 3.5. 

Wack, G. Nagy, L. Szekely, D. Szolnoky, J. Udvardy-Nagy, E. Zsoka, E. Fermentation Process for the Preparation of Ergot Alkaloids 1975 US 3,884,762... 

Solubility. Solubility is an important functional property per se, i.e. in fluid products, and is essential for other functionalities since insoluble proteins can not perform useful functions in foods. The caseins are, by definition, insoluble at their isoelectric points, i.e. in the pH range c. 3.5-5.S the insolubility range becomes wider with increasing temperature. Insolubility in the region of the isoelectric point is clearly advantageous in the production of acid casein and is exploited in the production of two major families of dairy products, i.e. fermented milks and fresh cheeses. However, such insolubility precludes the use of casein in acid liquid foods, e.g. protein-enriched fruit juices or carbonated beverages. Acid-soluble casein can be prepared by limited proteolysis or by interaction with certain forms of pectin. 

Thus, indol and scatol result from the progressive transforma-tiort of tryptophane. F. Hopkins and W. Cole have verified this experimentally by showing that the action of the bacteria on tryptophane that is added to a gelatin undergoing putrefaction gives indol, scatol, scatol-carbonic acid, and scatol-acetic acid. If th.e fermentation is well carried out, the scatol may reach 65 per cent of the theoretical yield. Moreover, E. and H. Salkowski lia.d. already previously recogni2ied that the basic material for the production of scatol is scatol-carbonic add, which they had isolated from products of putrefaction of albuminoids. 

The last trophic level begins at Eh less than —0.25 V when most available electron recipients become either organic compounds themselves or CO. In the former case as donor (reducer) and acceptor (oxidizer) of electrons serve the ends of broken bonds in the organic compoimd itself, i.e., fermentation. As a result, one end is oxidized, and another one is reduced. In the latter case the donor is H, and the acceptor is carbon. These two processes run with the participation of enzymatic bacteria and archaebacteria, which amend one another. The final outcome of the activity of these syntrophlc microorganism groups on the last trophic level is not oxidizing but reduction of CO carbon with the formation of methane. 

Acetoclastic methanogenesis is associated with the reaction of disproportionation, i.e., fermentation of the acetate. It includes the CH formation at the expense of acetic acid methyl group ... 

The chemistry by which they obtain energy or recharge the oxidative capacity of the cell (i.e., fermentation or respiration) and the terminal electron acceptors used (e.g., oxygen, ferric ion, sulfate, and organic compounds). 

Fermenter. Fermentations were carried out in a BIOSTAT E fermenter (B Braun Mel-sungen) with a working volume of 10 1. 

Li SY, Srivastava R, Suib SL, Li Y, Pamas RS. (2011). Performance of batch, fed-batch, and continuous A-B-E fermentation with pH-control. Bioresour Technol, 102, 4241 250. 

For example, enantiomerically pure amino acids can be prepared from simple reagents with the aid of enzymes (Figure 16.1). Enzymes can be used in two forms either they are added in the pure form after being extracted from the organism that produced them, or they may be added in the form of a whole microrganism. We are all familiar with the catalytic conversion of sugars into ethanol by yeast cells, i.e. fermentation, and this... 

Dioxin, M. Ebb, E. Ferments. Mir, Moscow, 1966, p. 277 Cerkovnik, J. , Eizen, E. Roller, J. Plesni ar, B. Evidence for HOOO. radicals in the formation of alkyl hydrotrioxides (ROOOH) and hydrogen trioxide (HOOOH) in the ozonation of C-H. bonds in hydrocarhons. Journal of the American Chemical SodetylQQl, 124(3), 404-409. Kamogitzkii, V. Organic Peroxides. IL, Moscow, 1961, p. 115. 

Although PLA is synthesized from renewable resources such as starch, the production up to the polymeric form requires much energy and many steps (Fig. 9.1] i.e., fermentation and purification of lactic acid, condensation for oligomerization, thermal degradation into lactide, and polymerization [9], if a highly selective depolymerization of PLA to the cyclic monomer, lactide, can be achieved with high efficiency, it will then be possible to reproduce PLA via the shortest and most energy efficient route. 

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