Enzyme Glucose Isomerase example essay topic

The food and drink industry depends heavily on enzymes. Enzymes produced by yeast have been used for thousands of years in brewing and baking. High fructose syrup contains fructose and glucose in roughly equal proportions. The high fructose syrup is greater in demand than pure glucose as food and drink sweeteners, because fructose is sweeter than glucose. Therefore, if glucose can be converted into fructose, its commercial value is increased greatly. Biological systems are increasingly being used in the provision of goods and services.

Traditionally they have featured in well-established industries such as brewing, baking, wine-making and cheese manufacture. Modern biotechnology also now includes the use of biological catalysts in products such as washing powders and 'diet' versions of drinks; the recycling or cleaning of waste and remediation of land; and the use of DNA technology to develop new crops and medicines. Enzymatic treatments are a now a major way of producing sweeteners, including syrups derived from sucrose derived from sucrose or starch that contain mixtures of glucose, maltose, fructose, and other sugars. High fructose syrup (HFS) from maize starch has now eclipsed sucrose as the major sweetener used in US food industry. More than eight million of HFS are sold annually. What is HFS HFS stands for High Fructose Syrup.

It is made from a cheap raw material starch. Typically the production of HFS uses four enzymes in three distinct stages: Liquefaction Starch obtained as by-product after valuable oil and protein has been extracted from maize. Starch solution (about 33% starch by mass in water) is boiled and treated with a-amylase, an enzyme from Bacillus licheniformis. At this temperature the enzyme is denatured after a few minutes, but not it broke some of the bonds in the starch molecules. Saccharificariton A cocktail of various fungal is added to the dextrin, depending on the carbohydrate composition required in the finished product. High glucose contents a mixture of a-amylase or pullulanase with syrup with amyloglucosidas.

After 1-3 days at 60 C, these enzymes break down the dextrins progressively to glucose syrup. This solution is sweet, but not sufficiently so to be used in most drinks and other foods. Isomerisation Glucose shares its chemical composition with fructose but has a different molecular structure. This makes glucose about half as sweet as fructose. The enzyme glucose isomerase converts glucose to fructose, thereby increasing the sweetness of the syrup. Several spices of microbe produce glucose isomerase.

Designing Enzymes The conventional method of manufacturing Invert Sugar involves acid hydrolysis of sucrose, the popular and cheap sweetener. However, such acid hydrolysis has a low conversion efficiency, high-energy consumption and thus cost of production is high. The acid-hydrolyses product also contains impurities introduced by uncontrollable parameters during inversion. The said conversion can also be achieved by enzymatic action of invertase on sucrose with a conversion efficiency of almost 100% without the inherent disadvantages of acid hydrolysis. The key to the process developed is a specific enzyme for the continuous production of concentrated Invert Sugar using immobilised yeast cells in an inorganic insoluble matrix.

More traditional enzyme-mediated industrial processes include the production glucose syrup from starch. Cereal-derived starch, inexpensively produced in bulk quantities by modern agronomic techniques, is treated with a combination of amylolytic enzymes, resulting in its degradation to glucose. The glucose can be used for a variety of purposes: it may be sold directly in crystalline form, or used a food ingredient in the production of soft drinks, jams, sweets, confectionary or ice cream. The Enzymes, which are used in sweeteners production 1. a-amyalse: hydrolyses a-1, 4 bonds in glucose polymers, but only within chains, yielding shorter chains (dextrins). Obtained commercially from bacteria (e.g. Bacillus spp.

). 2. B-amylase: hydrolyses a-1, 4 bonds in glucose polymers, breaking off successive maltose units from the (non-reducing) ends of the obtained commercially from barely and malt. 3.

Amyloglucosidase: breaks a-1, 4, cleaving glucose units progressively from the (non reducing) ends of the chain but not slowly. Obtained commercially from the fungi Aspergillus spp. And Rhizopus oryaze. 4. Pullulanase: hydrolyses a-1, 6 bonds.

Obtained commercially from the bacteria Bacillus acidopullulyticus and Klebsiella pneumonia. 5. Glucose isomerase: transforms glucose into its sweeter-tasting isomers fructose. Are there any improved Enzymes Over the last decades scientists have been trying to find better enzymes for HFS production. A Danish scientist introduced some new bacterial a-amylase from Bacillus licheniformis that catalyzed the breakdown of starch at 100 C in 1974. This led to significant improvements in the initial liquefaction process.

Some other range of dextrin-degrading enzymes has also been become available to satisfy the demand for specialised sugar syrup i.e. baby food, diabetic confectionary or for use in brewing and wine making. These investigations took a lot of time and many scientists have been working hard in selection of microorganism. Now scientists are still working trying to find the ideal production strain. Further Investigations Further investigations showed that of the hundreds of amino acids residues making up glucose isomerase, just two were responsible for the weak links. By substituting these amino acids with others that bound more tightly to their neighbours, the proteins were able to produce a more stable enzyme. This was done by altering a small selection of the DNA that coded for glucose isomerase.