Yeast, commercial production

Yeast. Several yeast species, including Saccharomjces cerevisiae (baker s yeast) and Klujveromjces lactis are good candidates for the production of certain industrial enzymes, although their abiUty to secrete is much inferior to Bacilli 2in.d Yispergilli. The best-known example of K. lactis is used for commercial production of chymosin [9001-98-3]. 

Bioprocess plants are an essential part of food, fine chemical and pharmaceutical industries. Use of microorganisms to transform biological materials for production of fermented foods, cheese and chemicals has its antiquity. Bioprocesses have been developed for an enoimous range of commercial products, as listed in Table 1.1. Most of the products originate from relatively cheap raw materials. Production of industrial alcohols and organic solvents is mostly originated from cheap feed stocks. The more expensive and special bioprocesses are in the production of antibiotics, monoclonal antibodies and vaccines. Industrial enzymes and living cells such as baker s yeast and brewer s yeast are also commercial products obtained from bioprocess plants. 

The aim is to produce biomass or a mass of cells such as microbes, yeast and fungi. The commercial production of biomass has been seen in the production of baker s yeast, which is used in the baking industry. Production of single cell protein (SCP) is used as biomass enriched in protein.6 An algae called Spirulina has been used for animal food in some countries. SCP is used as a food source from renewable sources such as whey, cellulose, starch, molasses and a wide range of plant waste. 

Many plants have been constructed in Europe to utilize the sugars in sulfite liquor for the production of ethyl alcohol or food yeast. Some of these have been in commercial production 35 to 40 years, and have supplied alcohol for motor fuel and protein food for humans and animals. 

Dextrans are bacterial and yeast polysaccharides made up of (a 1—>6)-linked poly-D-glucose all have (al—>3) branches, and some also have (al—>2) or (al—>4) branches. Dental plaque, formed by bacteria growing on the surface of teeth, is rich in dextrans. Synthetic dextrans are used in several commercial products (for example, Sephadex) that serve in the fractionation of proteins by size-exclusion chromatography (see Fig. 3-18b). The dextrans in these products are chemically cross-linked to form insoluble materials of various porosities, admitting macromolecules of various sizes. 

In the more abundant a chitin the chains in alternate sheets have opposite orientations,101102 possibly a result of hairpin folds in the strands. Native chitin exists as microfibrils of 7.25 nm diameter. These contain a 2.8-nm core consisting of 15-30 chitin chains surrounded by a sheath of 27-kDa protein subunits. The microfibrils pack in a hexagonal array, but the structure is not completely regular. Several proteins are present some of the glucosamine units of the polysaccharide are not acetylated and the chitin core is often calcified.103 The commercial product chitosan is a product of alkaline deacetylation of chitin but it also occurs naturally in some fungi.102 Chitin is also present in cell walls of yeasts and other fungi. It is covalently bonded to a P-l,3-linked glycan which may, in turn, be linked to a mannoprotein (see Section D,2)97... 

Piovesta s alcohol oxidase, from the yeast Pichia pastor is. Described as "equally active on methanol and ethanol" (D. Ranasiak arid T. Hopkins, Provest a, personal communication) it is "one-third as active no ethanol than on methanol.." on an enzyme electrode (Hopkins and Muller (in )). The commercial product is virtually devoid of catalase and has a pH stability profile (5. -8. 3) that see/n.s to rule out its use in beer or wines. Alcohol oxidase is still of interest... 

Buckholz, R.G. and Gleeson, M.A. (1991). Yeast systems for commercial production of heterologous proteins. Bio/ Technology 9, 1067 1072. 

Provitamin D2. Ergosterol is isolated exclusively from plant sources. The commercial product is ca 90—100% pure and often contains up to 5 wt % of 5,6-dihydroergosterol. Usually, the isolation of provitamin D2 from natural sources iavolves the isolation of the total sterol content, followed by the separation of the provitamin from the other sterols. The isolation of the sterol fraction iavolves extraction of the total fat component, its saponification, and then reextraction of the unsaponifiable portion with an ether. The sterols are ia the unsaponiftable portion. Another method is the saponification of the total material, followed by isolation of the nonsap onifiable fraction. Separation of the sterols from the unsap onifiable fraction is done by crystallization from a suitable solvent, eg, acetone or alcohol. Ethylene dichloride, alone or mixed with methanol, has been used commercially for recrystallization. In the case of yeasts, it is particularly difficult to remove the ergosterol by simple extraction, thereby obtainiag only ca 25% recovery. Industrially, therefore, the ergosterol is obtaiaed by preliminary digestion with hot alkaUes or with amiaes (28—33). Variations of the isolation procedure have been developed. Eor example, after saponification, the fatty acids may be precipitated as calcium salts, which tend to absorb the sterols. The latter are then recovered from the dried precipitate by solvent extraction. 

Give reasons why a requirement for 1) yeast extract and 2) vitamins is undesirable for commercial production of exopolysaccharide. 

Derivation (commercial product) From yeast nucle-... 

Derivation (Commercial product) Isolation from nucleic acid of yeast or pancreas also made synthetically. 

Source (Food) Milk, green leafy vegetables, egg yolk, liver, enriched flour, yeast (commercial) distiller s residues, fermentation solubles, synthetic production (indirectly from dextrose, lactose, yeast, and whey). 

Monascus spp. have been used as foods and medicines in the Orient for over 1000 years (Wong, 1982). In China and Taiwan, it has been called "Hong Qu," "Hon-Chi," "Anka," or "Ang-kak" using the Chinese or Taiwanese phonetic alphabet. The Japanese use the name "Beni Koji" or "red Koji." In the United States and Europe, it has been called "red rice," "red-mold rice," or "red Chinese rice." Many publications and commercial products use "red yeast rice," which is not an appropriate name for filamentous fungi. 

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