A special test, called Clinistix, which contains a chemical indicator, toluidine, and an enzyme, glucose oxidase; the enzyme converts, if present, the glucose in urine to hydrogen peroxide and gluconic acid. It is then the amount of hydrogen peroxide that will react with the toluidine that will produce a spectrum of colours, that can be compared to a booklet given by the manufacturer, that will determine, to a mediocre level of accuracy, the extent to which the diabetes is affecting the patient. (3) This approach has some clear disadvantages, however, notably that it is costly, especially for less economically developed countries where it is common to cut the strips into smaller ones to save money. They are also at risk of being contaminated, particularly if the patient has taken Vitamin C tablets. However it has replaced the cruder method of using Benedict's Solution to test for the presence of reducing sugars, which can be swayed by simple drugs such as antibiotics and painkillers, also it reacted with any other reducing sugars that could be present in the urine, possibly giving false positives. (4)
Enzymes are used to great extent in the laundry and washing powder industry, where biological washing powders contain a variety of enzymes to eliminate common household stains. Enzymes are used to reduce the wash time and temperature, to make a wash more environmentally friendly by using less energy. The environmental impact of enzymes is much reduced in the fact that they are fully biodegradable and therefore will not hurt the environment if released into the water cycle (7). They also need to be non toxic, as well as to not react with other things put in the wash such as fabric conditioner or anti-limescale products; enzymes are also compatible with anionic and nonionic surfactants, which reduces the surface tension between water and oil.
Protease is found in washing powders as it can convert protein stains, for example egg, bodily fluids, and milk; this enzyme will then convert the proteins, by hydrolysis, into shorter chain amino acids, which can be washed away easily. (5) Carbohydrases such as amylase, break down starch containing foods such as potatoes or gravy, and convert them into simple hexose sugars, such as glucose, which can be easily washed away. The alpha-amylase used also, conveniently, helps prevent the reccurance of starch stains in garments. Lipases are found in washing powder that break down lipids such as grease or butter, this means that all the common biological molecules found in foods can be converted into others which are easier to wash away and less likely to stay on the clothes. Cellulose is also used to eliminate the cotton microfibrils that can be found on the exterior of garments after repeated wear and washing, this property also softens the cotton and keeps it a bright colour. (6)
Enzymes are not just used to keep clothes clean, however, they are also used in the denim industry, a $700 billion global industry. Stonewashed jeans used to be made by tumbling denim items in a washing machine, to give them a used, softer feel, but this not only held some big impracticalities, it held some serious environmental and health implications. Pumice stoning, often used in conjunction with an acid wash, could not be recycled and reused, instead, it turned the water into a thick, gritty sludge. The pumice stones were also not selective, they would wear away at anything, including the washing machine drum, rivets and areas like the hem of jeans, which lead to a proportion of the finished product being discarded. The pumice grit would endanger employees health by getting into their lungs as dust, and the employees would also be faced with the thankless task of finding small stones in jeans and discarding them; all these issues made stonewashed jeans more expensive and worse for the environment, however thankfully a solution was found, one containing the miraculous molecule once more, the enzyme. Cellulase is an enzyme, that will bind to the exposed cellulose on the exterior of the denim and break some of the molecular bonds, releasing some dye, but without being abrasive and by using a lot less. The reason this breakthrough only occurred in the last decade was because biologists only then found out how to isolate the cellulase from the fungus, Trichoderma Ressei, and then put this to numerous industrial and medicinal uses (8). Another bonus of biostoning is the fact that if other fabrics, such as nylon or polyester are appliquéd or sewn onto the fabric before washing, they will not be affected at all by the enzymes, making designer style jeans easier to create and replicate in high street stores. Biostoning also increases productivity by up to 50% (8) as the room that was previously filled with pumice in the washing machine can now be filled with more jeans, and workers spend no time fishing out wayward pumice from the denim fabric. There was only one dilemma facing the team working with biostoning, and that was the issue of 'back staining', this being when the released dye rebinds with the surface of the denim, or other fabrics attached to the denim, however this problem was hastily fixed when it was worked out that it did not occur at the enzyme's optimum pH, being 7-8.
- en.wikipedia/wiki/Diabetes_Mellitus
- en.wikipedia/wiki/Glucosuria
- Diabetes: Control In Your Hands ISBN 8122307493 Pustak Mahal 2001
- Key Stage 4 Science: Industrial Enzymes Channel 4, first broadcast 1999.
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