Amylase, (α–amylase) is an enzyme EC 188.8.131.52 that hydrolyses alpha bonds of large, alpha-linked polysaccharides, such as starch and glycogen, yielding glucose and maltose.
- Fungal alpha-amylase:
Fungal Amylase is an alpha-amylase enzyme preparation produced by Aspergillus species. It is available as powder formulation. This rapid-acting hydrolase is active throughout every pH(acidic, neutral and alkaline). It readily degrades polysaccharides like a starch molecule. Fungal alpha-amylase is not extremely heat-resistant compared with enzymes from bacterial sources but exhibits adequate heat resistance for many industries like a distillery and most agricultural applications where its pH range is often complementary to alpha-amylase from bacterial sources.
Fungal Amylase is used in commercial starch modification purpose, cleaning purpose, textile processing, fermentation in a distillery, and animal feed supplements. It can supplement the deficiency of endogenous Amylase of young animals. It can also increase the utilization of feedstuffs bread is the most common hydrolyzing the starch which is contained in feed to generate dextrins and sugars. Besides, this enzyme facilitates contact between the digestive enzymes and chyme to improve nutrient absorption and utilization.
2- Fungal alpha-amylase for bakery:
- The dough for bread, rolls, buns, etc. consists of flour, water, yeast, salt and other ingredients such as sugar and fat. Bread is the most common and traditional foods. But bread has close links with enzymes. For years, enzymes such as malt and fungal alpha-amylase have been used in bread making industries. Due to the changes in the baking industry and the ever-increasing demand for more natural products.Flour consists of gluten, starch, lipids and other polysaccharides etc. In the beginning, the fermentation goes smoothly whether sugar has been added or not because the flour always contains a certain amount of fermentable sugar. But when this has been used up, the fermentation process will cease unless new supplies of sugar are made available to the yeast.Amylases degrade starch and produce small dextrin for the yeast to do work. Gluten is a combination of proteins, which form a huge network during dough formation. This network holds the gas in dough proofing, baking and other processing. The strength of this network is significant for the quality of all bread raised by yeast. Enzymes such as proteases, hemicellulases and lipases directly or indirectly improve the strength of the gluten network and so improve the quality the bread.
3- Bacterial alpha-amylase:
- The starch is first converted to oligosaccharides, maltose and some amount of glucose.Maltose molecules is a naturally occurring disaccharide. Its chemical structure has 4-0-α-Dglucopyronosil-D-glucopyranose It’s main contains maltose sugar syrup. Maltose is widely used as a sweetener and intravenous sugar supplement. It is used in food industries because of the low tendency to be crystallized and is relatively non-hygroscopic. Corn, sweet potato and cassava are used for maltose manufacture. The concentration of starch slurry is adjusted to be 11-20% for production of medical-grade maltose and 23-40% for food grade.
4. High-temperature alpha-amylase:
High-temperature alpha-amylase for starch used in the starch industry for liquidation purpose. Liquefaction is a process of breakdown of insoluble starch granules in aqueous solution followed by partial hydrolysis using high-temperature alpha-amylases. In industrial processes, the starch suspension for liquefaction is generally more than 30 to 35% w/v. Therefore, the viscosity is exceptionally high following gelatinization process. High-temperature alpha-amylase is used as a thinning agent, which brings a reduction in viscosity and partial hydrolysis of starch.
High-temperature alpha-amylase for sugar is used in a sugar mill to breakdown starch or used as a viscosity reducer. This high-temperature alpha-amylase for sugar is used in reaction tank or an evaporation tank. This enzyme is applicable for recovery of sugar.
The amylolytic activity of high-temperature alpha-amylase for grain is to increase the rate and amount of starch utilization and ethanol yields. Moulds high-temperature alpha-amylases for grain is used in alcohol production and brewing industries. The advantages of such systems are uniform enzyme action in mashes, increase rate of saccharification reaction, alcohol percentage and yeast growth cycle. High-temperature Alpha amylases for grains convert the starch into fermentable sugars. Carbohydrates such as grain and potatoes are used as a raw material that helps to produce alcohol. In the presence of high-temperature alpha-amylases for grain, the starch is first converted into fermentable sugars. The use of bacterial enzyme partly replaces malt in the brewing industry, thus making the process more economically significant. Alpha-amylase can also carry out the alcoholysis reaction by using methanol as a substrate.
5- Low-temperature alpha-amylase:
Cold-adapted amylolytic microorganisms produce low-temperature alpha-amylases, which function effectively at low temperatures with high rates of catalysis in comparison to the from medium and high-temperature alpha-amylase, which shows no activity at low temperature.
-manufacturing of maltose
-production of high fructose-containing syrup
-production of maltotetraose syrup.
-manufacturing of high molecule weight branched dextrin.
-removal of starch sizer from textile.
-direct fermentation of starch to ethanol
6- Medium temperature alpha-amylase:
- Medium temperature alpha-amylase work on temperature range between 40 to 60-degree centigrade.application-for production of monosaccharides-for production of beer or using in brewery-starch industries-production of oligosaccharides
Beta Amylase comes from germinated barley sprouts. The enzyme attacks the non-reducing end of linear starch chains breaking them off two units at a time, creating maltose molecule. The enzyme is not capable of cleaving the α-(1-6) linking glycosidic bond. They are used to produce high-maltose syrups. Still, these syrups may have relatively high tri-saccharide levels and other limit dextrins because the enzyme is very slow to break down the starch compared to alpha-amylase. This enzyme is temperature & Ph sensitive.
During the fruit ripening, β-amylase breaks starch into maltose, resulting in the sweet flavour of ripe fruit.
β-amylase is present in an inactive form at the moment of seed germination. Many microbes also produce beta-amylase to degrade extracellular starches.