Converted starches cyclodextrins

Prior to 1939, however, it was not known whether the cyclodextrins were products of the synthetic metabolism of Bacillus macerans, and therefore, perhaps, quite different from the components of starch, or whether they were formed by a single enzyme and therefore closely related to the starch structure. Then, Tilden and Hudson announced the discovery of a cell-free enzyme preparation from cultures of Bacillus macerans which had the ability to convert starch into the Schardinger dextrins without the production of maltose, glucose, or any other reducing sugars. They thus concluded that the Schardinger dextrins were either the true components of starch or closely related to such true components. 

Cyclodextrin glycosyltransferase catalyzes the breakdown of starch and linear maltodextrin substrates to produce CDs, while a-amylase converts starch into linear oligosaccharides, resulting in a rapid decrease in viscosity [37]. 

The conversion of starch into cyclohepta-amylose by soluble or immobilized cyclodextrin D-glucanotransferases and the ability of a-amylases to convert starch into some products by a non-hydrolytic (transglycosylation) pathway have been reported.The production of single-cell protein from starchy wastes has been discussed. 

Cyclodextrin D-Glucanotransferases.—The neutral cyclodextrin D-glucano-transferase from an alkaliphilic Bacillus species has been purified by adsorption onto starch, ion-exchange chromatography, gel filtration, and polyacrylamide gel electrophoresis. The enzyme (mol. wt. 8.5—8.8 x 10 in the presence of sodium dodecyl sulphate) is most active at pH 7 and 50 °C, is thermally stable, and converts starches and glycogens principally into cyclohepta-amylose. 

A purified extracellular cyclodextrin D-glucanotransferase (pH optimum 4.6, pi 5A, mol. wt. 8.8 x 10 ) from an alkaliphilic Bacillus species has been shown to be a single homogeneous protein by polyacrylamide gel electrophoresis and ultracentrifugation. The Km values for cyclohexa-, cyclohepta-, and cyclo-octa-amyloses at a constant concentration of sucrose are 5.88, 0.39, and 0.25 mmol 1, respectively. The enzyme converted starch, amylopectin, glycogen, and amylopectin j8-limit dextrin into cyclodextrins. 

Starch-Modifying Enzymes Starch is one of the most abundant carbohydrates in terrestrial plants and the most important polysaccharide used by humankind. This polymer is normally processed and used in a variety of products such as starch hydrolysates, starch or maltodextrin derivatives, fructose, glucose syrups, and cyclodextrins [148, 149]. In addition, starch is widely used as a raw material in the paper industry, in polyol production, and as economic substrate for many microbial fermentations [149]. Starch consists of a large number of glucose units that can be linearly attached as hehcal amylose [ 99% a-(l-4) and 1% a-(l-6) bonds] or branched as amylopectin [ 95% a-(l-4) and 5% a-(l-6) bonds] [69]. In nature, four types of starch-converting enzymes exist (i) endoamylases (ii) exoamylases (iii) debranching enzymes and (iv) transferases. 

Cycloamyloses.—Starch has been converted into cyclohepta-amylose by soluble, immobilized forms of cyclodextrin o-glucanotransferase. ... 

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