Cup o'Joe-What are enzymes doing in detergents? скачать в хорошем качестве

Cup o'Joe-What are enzymes doing in detergents?

Take a look at the ingredient list on your laundry or dishwasher detergent. There will be “surfactants,” molecules that have one end that is attracted to water (hydrophilic) with the other end (lipophilic) embedding itself in oily stains. Agitating with water results in the surfactant pulling the oily stain off a fabric or dish. But besides surfactants, you are also likely to find “enzymes,” ingredients that have revolutionized the cleaning industry. Enzymes are proteins produced by living organisms that act as catalysts, meaning they speed up chemical reactions. Trypsin, for example, is produced in the small intestine from trypsinogen secreted by the pancreas. It is known as a “protease” because it speeds up the cleavage of proteins into peptides and amino acids that can then be absorbed into the bloodstream. It was back in the early 1900s, that German chemist Otto Rohm isolated trypsin from animal tissue and had the idea of introducing it into washing detergents to remove protein stains such as grass, egg and blood. Trypsin wasn’t very stable, but by the 1950s, methods were discovered to isolate proteases from bacteria, and by the 1980s amylases that break down starch, lipases that break down fat and cellulases to break down cellulose were extracted from various bacteria and fungi. Amylases take care of pasta sauce or gravy stains, lipases of salad dressing spots and body oils, cellulases remove microfibers from the surface of cotton. Enzymes do more than just remove stains. Unlike surfactants that work better in hot water, enzymes are functional in cold water. This can have a huge environmental benefit because heating water requires a great deal of energy and has a huge carbon footprint. And enzyme technology is improving because it is now possible to genetically engineer bacteria to crank out enzymes that are more compatible with other ingredients and have greater stain specificity. A technique that can be used to generate these engineered enzymes is known as DNA shuffling. This is done by isolating from bacteria or a fungus the gene that codes for the protease, amylase, lipase or cellulase. This is then broken down with deoxyribonuclease, yet another enzyme, into fragments that are allowed to randomly join together to form novel genes that are then amplified using the polymerase chain reaction (PCR). The enzymes formed by the mutant genes can be screened for desired properties. Once a gene that gives rise to a desired enzyme is identified, it can be inserted into a species of bacteria that can be cultured in a fermentation tank where they will dutifully produce the enzyme that can be harvested and purified. In a more sophisticated method, the structure of an enzyme is determined by X-ray crystallography and amino acids that are responsible for a weakness are pinpointed. For example, methionine is easily oxidized especially if bleach is present in a detergent reducing the effectiveness of the enzyme. Using the Nobel Prize-winning technique known as CRSPR, methionine can be replaced with alanine or leucine, both of which are resistant to oxidation. As you can surmise, today’s laundry and dishwasher detergents clean better and are more environmentally friendly thanks to biotechnology.