Enzymes starch-liquefying

Amizyme. [FMP Fennentation Prods.] Alpha-amylase enzyme with starch liquefying and heat stability inoperties fw pq)er coatings and sizes. 

Starch Liquefaction. Starch in its natural state is only degraded slowly by CC-amylases. To make the starch susceptible to enzymatic breakdown, it is necessary to gelatinize and liquefy a slurry with a 30—40% dry matter content. Gelatinization temperature depends on the type of starch (67) com is the most common source of industrial starches followed by wheat, tapioca, and potatoes. Liquefaction is achieved by adding a heat-stable a-amylase to the starch slurry. The equipment used for liquefaction may be stirred tank reactors, continuous stirred tank reactors (CSTR), or a jet cooker. Most starch processing plants liquefy the starch with a single enzyme dose in a process using a jet cooker (Fig. 9). 

Starch is first liquefied and hydrolyzed to specific dextrose equivalents with hydrochloric acid. After evaporation to 60 percent solids, a saccharifying enzyme (fungal a-amylase) is added to continue hydrolysis to the desired level. By choosing two or more types of enzymes (such as a-amylase, -amylase, glu-coamylase, pullulanase) and adjusting the initial acid hydrolysis, syrups with different ratios of dextrose, maltose, and higher saccharides can be obtained.92... 

In enzymatic processes, a-amylases, 5-amylases, glucoamylases, and pullulanases are used. First, starch is liquefied and hydrolyzed with acid, with a-amylase, or with a combination acid or enzyme process. 

In contrast to the /S-amylase, the malt a-amylase (and other liquefying amylases) very rapidly lower the viscosity of starch pastes. When the relative viscosity has dropped to half the original value, only about 0.1% of the D-glucosidic linkages in the starch have been hydrolyzed. The malt a-amylase is a typical liquefying enzyme. 

A particularly interesting enzyme is CGTase, which has the unique capability of forming CDs from starch. Commonly CGTase is employed along with a-amylase. First starch is liquefied either by heat treatment or using a-amylase, then CGTase is added for the enzymatic conversion. 

D-Glucose can also be obtained by enzymic conversion of starch or cellulose. Two separate enzymic processes, liquefaction and saccharification, are generally used in the production of D-glucose from starch. The liquefaction process solubilizes the molecules in the starch granules and decreases the viscosity of the starch. In the saccharification step, the liquefied starch is further hydrolyzed to D-glucose by the action of glucoamylase. The majority of starches used for the manufacture of D-glucose contain up to 80% amylopectin 99... 

Saccharification - The meal is mixed with water and an enzyme (alpha-amylase) and kept at 95°C to reduce bacteria levels and to get a pulpy state. The mash is cooled and a secondary enzyme (gluco-amylase) is added to convert the liquefied starch into fermentable sugars (dextrose). 

Bioethanol produced from biomass resources by fermentation is the most promising biofuel and the starting material of various chemicals. Starch is a cheap, clean, nontoxic, renewable Ccirbon source for bioethanol production [1]. In the process currently employed for industrial-scale ethanol production from starchy materials, starch is first hydrolyzed by adding a liquefying enzyme, a-amylase (EC 3.2.1.1), to avoid gelatinization and then... 

Cyclomaltodextrirrs (CDs) are cyclic oligosaccharides that are produced by the action of the CGTase enzyme (CD glucanotransferase, EC 2.4.1.19) on liquefied starch [1-3]. They have... 

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