Microorganisms yeast

Deaminases present in many cells are able to deaminate cytosine or its nucleosides or nucleotides to the corresponding uracil derivatives. Cytosine aminohydrolase (deaminase) appears to occur only in microorganisms (yeast and bacteria), but cytidine aminohydrolase is widely distributed in bacteria, plants, and mammalian tissues. A distinct deox-... 

Specific microorganisms, yeasts, and bacteria can also convert sucrose into other alcohols, as well as organic acids, amino acids, and vitamins (Scheme 15). All these biological processes have been improved with the help of modern biotechnology, making them more chemically and economically efficient and to direct them towards new and useful chemical products. The biocracking of carbohydrates has been shown to be a way for the production of biohydrogen. 223... 

This means that fruit which is rotten or mouidy shouid never be sent for processing. Apart from an insipid, putrid flavour, this type of fruit contains a iarge number of unwanted microorganisms (yeasts, mouids and bacteria) and thus a iot of enzymes. This increased microbiai count can subsequentiy iead to difficuities in ciarification, pasteurization or fermentation. 

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. 

Acetyl-CoA carboxylase is a biotin-dependent enzyme. It has been purified from microorganisms, yeast, plants, and animals. In animal cells, it exists as an inactive pro-tomer (M.W. 400,000) and as an active polymer (M.W. 4-8 million). The protomer contains the activity of biotin carboxylase, biotin carboxyl carrier protein (BCCP), transcarboxylase, and a regulatory allosteric site. Each protomer contains a biotinyl group bound in amide linkage to the e-amino group of a lysyl residue. 

Phenolic acids are colorless in a dilute alcohol solution, but they may become yellow due to oxidation. From an organoleptic standpoint, these compounds have no particular flavor or odor. They are, however, precursors of the volatile phenols produced by the action of certain microorganisms (yeasts in the genus Brettanomyces and bacteria) (Section 8.3). Ethyl phenols, with animal odors, and ethyl gaiacols are found in red wines (Figure 6.4). In white wines, vinyl phenols, with an odor reminiscent of gouache paint, are accompanied by vinyl gaiacols. It has been clearly established that these compounds result from the... 

Major Applications Fluorescent probes,4 detecting cells, microorganisms, yeasts, antifungal agent,7 antibacterials agents... 

Like other microorganisms, yeasts require a number of nutrients for growth including carbon (sugars), nitrogen (ammonia and/or amino... 

Tests for microbial limits may also have to be considered depending on the nature of the API, its method of manufacture, and its intended use. Sterility testing may be appropriate for APIs that will be used in parenteral or oral solution products that are sterile. Endotoxin testing may be needed for APIs intended for injectable products. Testing for the total count of aerobic microorganisms, yeasts, and molds and the absence of specific objectionable bacteria, such as Staphylococ-cus aureus, Escherichia coli. Salmonella, and Pseudomonas aeruginosa, may also be required. The tests described in the various compendia are generally used. 

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