Some enzymes only work in the presence of a non-protein substance called a cofactor. A cofactor tightly bound into its enzyme is called a prosthetic group. They may be organic (carbon containing) or inorganic. Inorganic cofactors are named activators, they include metal atoms and may attach on to active sites to make its shape more efficient. Organic cofactors are named coenzymes, many of which are vitamins or vitamin compounds. Some transfer chemical groups, atoms of electrons from one enzyme to another.
Incubation time is the length of time over which a reaction has taken place. As the incubation time increases the average (not initial) rate of reaction generally decreases because the enzyme gradually becomes denatures with time, even when there is an excess of substrate present. As the protein molecule becomes deformed, it loses its effectiveness as an enzyme.
Enzyme inhibitors slow down the rate of reaction. Competitive inhibitors have a similar shape to the substrate and compete for the active site, so reduces the bonding for the reaction to take place because the inhibitor occupies the active site. The only way this can be overcome is to add more substrate to increase the chance of a substrate occupying the active site. A non-competitive inhibitor is not similar in shape to a substrate; it binds to the enzyme-but not at the active site. A competitive inhibitor causes the shape of the enzyme and the active site to alter. A deformation of the active site disallows the substrate to be able to attach, or it binds, but no product is formed. Therefore, addition of more substrate will not reduce this inhibition. (Advanced Biology and Revise AS Biology)
Enzymes can also be denatured and precipitated with salts, organic solvents and other reagents, which often have to be used in industrial processes. They also work best at atmospheric pressures. Other problems include that they are expensive to produce and that they have to be safe (e.g. non pathogenic) for the use of humans and animals. Most enzymes can be improved. One way is to improve the enzyme’s stability by causing its 3D structure to be maintained under a wider range of conditions. Enzymes are fairly unstable, as displayed previously and can be denatured during industrial process environments. But some organisms such as the thermophillic bacteria have evolved to live in the hot conditions of volcanic springs. They produce thermostable enzymes, which can with stand hot temperatures of up to 75°C, they also display tolerance to organic solvents and pH extremes. The gene from these bacterium has been isolated and transferred to Bacillus subtilis, a microbe that can be used in industrial processes, enabling a thermostable version of the desired enzyme to be made. The enzyme can also be improved through immobilisation. Unstable enzymes are immobilised. This means binding it to or trapping it in, a matrix of networks of fibres that can easily be recovered later in processing, or a silica gell lattice, polymer microspheres or alginate beads. The enzyme can then be reused so greatly reduces cost and the need for the purification of the product of the reaction. Immobilisation makes the enzyme more stable, possibly by restricting its ability to change shape and denature as a result in changes of pH, temperature and solvents. Also, because they are held in an unreactive matrix, the reaction products are not contaminated by the enzyme. Continuous production is also made easier by passing the reactants over the enzyme and collecting the product at the end. The best example of a successful process involving immobilised enzymes is the production of high fructose corn syrup. It requires enzymes with optimum temperatures of 115°C. They are thermostable. The benefits of thermostable enzymes include that they are able to speed up reactions at higher temperatures so the overall reaction is quicker. More product is produced more quickly. Temperature of the fermenter/ reactor doesn’t need to be monitored as closely because they are not as delicate as ordinary enzymes. The production cost then becomes more efficient.
Fructose is widely used as a sweetener in the USA and Japan in mainly fruit drinks, because it is cheaper than sucrose and less is needed as it is sweeter. They have also been used in the manufacture of semisythetic penicillin’s from natural penicillin’s. The immobilised enzyme chemically modifies one of the side groups on the basic penicillin structure, which increases the antibiotic activity.
One of the properties of enzymes that make them so important as diagnostic and research tools is the specificity that they exhibit relative to the reactions they catalyse. Some enzymes show absolute specificity; that is they will catalyse only one particular reaction. Other enzymes will be specific for a particular type of functional group, such as amino, phosphate and methyl groups-these are known as enzymes with group specificity. Linkage specificity is when the enzyme will act on a particular type of chemical bond regardless of the rest of the molecular structure. When the enzyme will act on a particular steric or optical isomer, it is stereo chemical specificity.(Collins advanced science-Biology)
There are many uses for enzymes. The main categories are medicine and industry. Worldwide sales of enzymes now exceed 1 billion dollars per year, through a wide range of applications.
Enzymes are used in all areas of medicine ranging from diagnosis to treatment. Using enzymes is critical in understanding causes of disease. Most genetic diseases result in enzyme deficiency of a specific enzyme. Some bacteria are more pathogenic because of the enzyme activity possessed. The majority of reactions that occur in living organisms are enzyme controlled. Without them, the rate of reactions would be slow to the extent of causing serious damage. Without enzymes toxins would soon build up and the supply of respiratory substrate would decrease. It can often be very difficult to find out about the uses of enzymes in medicine as clinical diagnostics and pharmaceutical industries tend to work privately until they wish to publicise a positive discovery. The applications of enzymes in medicine fundamentally include Analytical tests; Glucose is always measured by an enzyme-based test. Diabetics use strips of paper to monitor their blood sugar. When blood is added to the paper a series of reactions produce a colour change that is proportional to the amount of glucose. The enzyme utilises glucose oxidase, for a prompt reading. A similar test involving a test strip containing enzymes is used to detect the presence of heroin. The areas of red dye on the strip indicate a positive response to pin-prick samples. This is mainly used in illicit drug detection rather than medicine, but it again shows how enzymes are able to recognise specific types of molecule. The gel on the test strip contains two enzymes. The first of which comes from the bacterium Rhondococcus-it can break down heroin to morphine. The second enzyme from the bacterium Pseudomonas breaks down the morphine to cause a colourless dye to turn red.
Another area in which the presence of enzymes is vital, is in diagnosing of disease. An example being when the liver is diseased or damaged, enzymes that are only specific for within the liver leak into the blood stream. Testing the blood for these activities is confirmation of liver damage.
Enzymes are often used in prescription medicines to replace any enzyme deficiencies in patients. For example blood-clotting factors are used to treat haemophilia, or in the opposite case of where proteases are used to degrade fibrin. Use of proteases can prevent the formation of dangerous blood clots. The enzyme trypsin can dissolve blood clots. Tissue plasminogen activator is the protease used in the therapy of thromboembolic diseases such as myocardial infarction, embolisms and deep venous thronmosis, where as previously anti-coagulants have had to be relied on-such as heparin and coumarin, to slow down the formation of fibrin clots. Nucleus is considered as a possible therapy for cystic fibrosis, but it is unclear of its success. Proteases are also used in wound therapy. They are called debriding agents and are used to clean a wound and quicken the process of healing. Some proteases are used as anti-inflammatory reagents. The enzyme named superperoxide dismutase is also available as an anti inflammatory agent, but how successful it has been as a commercial product is unclear.
Within drug manufacturing the chemical synthesis of complex drugs is often difficult and companies use enzymes to perform chemical conversions. There has even been a company set up to investigate pharmaceutical manufacture, for the use of enzymes.
Enzymes are even used to aid digestion, in humans and animals. They are used to supplement natural amylase, lipase and protease produced by the pancreas. Within some ethnic groups, on aging they lose the enzyme lactase (converts lactose into glucose and galactose)-they are lactose intolerant. They cannot ingest milk or dairy products. Giving these people supplements of lactase prevents stomach upsets, abdominal pain and diarrhoea. Milk is an important dietary component and can be made lactose free by passage down a column packed with yeast lactase immobilised on fibres of cellulose acetate.
There is very rarely a top athlete that has not received enzyme therapy. They are recommended supplements to aid quick recovery after injury.
The largest application of biosensors at present is in medicine. A biosensor is an electronic monitering device, which uses biological material (receptors), such as an immobilised cell, enzyme or antibody, to detect or measure a chemical compound. Enzymes and antibodies are particularly useful because they are so specific and can pick out particular molecules in a complex mixture. The reaction between the biological material and the substrate brings about a change which is converted into an electrical signal by an appropriate transducer. This is designed to detect and respond to the change. The electrical signal in the biosensor is amplified to give some form of read-out, such as a digital display or print out. The receptor uses the biochemical reaction to detect a substance or condition and as well as medicine is used in forensic science, agriculture, and environmental science to monitor specific chemicals accurately and rapidly. The blood glucose devices used by diabetics as mentioned previously is also a biosensor. The immobilised enzymes on the filter paper (glucose oxidase and a peroxidase) with a colourless hydrogen donor catalyse the conversion of the glucose in the blood sample to gluconic acid and hydrogen peroxide. A coloured compound formed indicates the concentration of blood glucose. Biosensors are small, accurate, rapid in response, safe, sensitive-so only small samples are needed and can be mass produced. However, they are not very robust, they are not very stable and they are not sterilisable. Though the annual market of biosensors is growing 30%, because of these disadvantages the market is still relatively small-worth less than £50 million in 1992.
Within industry enzymes are also widely used, even more so than within medicine. The study of industrial enzymes and their uses is enzyme technology. The detergent, food and starch processing industries still account for 75% of the ‘bulk’ enzyme use.
Enzymes have been used in the detergent industry since the mid 1960's and is probably the best known application of industrial enzymes especially in laundry products - the so-called "biological" washing powders. However allergic reactions to the detergents within factories caused a withdrawal in the 1970’s in the USA. An inert wax was then added to prevent the fine dust particles becoming air born. The liquids and tablets also overcame the problem.
The main enzyme activity in biological laundry detergents is protease ( subtilisin, from the bacterium bacillus subtilis, was developed by Denmark to withstand hot conditions) which acts on organic stains such as grass, blood, egg and human sweat and other protein residues. However, it has become more common in recent years to include a "cocktail" of enzyme activities including lipases and amylases. Lipases are effective on stains resulting from fatty products such as oils and fats whilst amylases help remove starchy food deposits. This is where thermostable enzymes are very adequate because of the wide range of temperatures, pH extremes and the presence of high levels of phosphate found in some detergents.
More recently, colour enhancing and "anti-bobbling" washing powders have been developed which contain cellulases. It is thought that the mode of action of such cellulases is to remove detached cellulose fibrils, which cause a progressive dulling of the colour as dirt is trapped on the rough surface of the fabric. Enzymes have become particularly important in products developed for the pre-soaking or spot application onto laundry. In these cases soils are loosened by enzyme action prior to the main wash in a detergent. Such products result in reduced detergent costs and the ability to save energy by lower temperature washing. The use of enzymes in automatic dishwashing detergents is also becoming popular. Typical enzyme activities are protease and amylase to remove food particles. Such new products are more environmentally friendly as they contain less bleaching agents and phosphates.
The Food and Drink industry is another application upon which enzymes are relied heavily. Enzymes can be used to modify raw materials and aid in the processing or cooking stages. The roles of enzymes include: enhancement of flavour and aroma, removal of unwanted flavours and taints, enhancement of digestibility, modification of texture to aid processing and final product appearance, upgrading raw materials. The main enzyme activity utilised in food processing applications is protease. However, applications utilising lipases and carbohydrate degrading activities are also becoming widespread. Meat is mainly muscle protein. Muscles are bundles of protein fibres wrapped in blocks by connective tissue. Connective tissue also contains structural proteins, particularly collagen and elastin. The meat can be tenderised (made easier to chew) by pre-digesting some of the connective tissue proteins and some of the muscle fibres. The fibres become shorter and more easily separated thus breaks down more easily. The enzymes used to tenderise meat are papain and trypsin. To allow the enzyme to work the meat has to be left to marinate in the juices before cooking, as denaturation takes place when cooking commences. In countries other than the UK papain is sometimes injected into the blood of the animals to make the meat more tender. A similar process of tenderisation that occurs naturally in the meat after death is where the lysosomes in dying cells break down and release digestive enzymes to digest the meat. It is known as autolysis and is why meat should be hung in cold storage for a few days before use. Baby foods are also pre-digested by trypsin before they are sold. Enzymes are also applied in the production of meat extracts and play a large part in pet food manufacture.
Enzyme application happens within cheese making. Rennet is responsible for curd production from milk, many flavours in cheeses are a result of protease action, the flavours are also due to the amount of lactic acid bacteria added. These covert lactose to lactic acid. Rennet contains chymosin. Chymosin breaks down the milk protein casein to Paracasien that combines with calcium to form calcium paracaseinate, which separates out. Milk fat and some water become incorporated into the mass, forming curds. The remaining liquid is whey. The milk is then said to be coagulated-curdled. Enzymes are also used in the production of baby milk formulas from cows milk and Soy sauce production. Production of hydrolysed vegetable protein also involves the application of enzymes as does Gelatine hydrolysis.
Many sweeteners in the modern world are derived from starch rather than sugar cane or beet. The enzymatic treatment of starch has become more popular than the acid hydrolysis. Mainly due to more efficiency from the enzymes which can be reused and they lower the energy needed. They are also faster. Many sweet syrups are formed that are needed throughout the food and drink industry. Three stages can be identified in starch modification. Firstly, amylases free "maltodextrin" by the liquefaction process. Such maltodextrins are not very sweet as they contain dextrins and oligosaccharides. The dextrins and oligosaccharides are further hydrolysed by enzymes such as pullulanase and glucoamylase in a process known as saccharification. Complete saccharification converts all the limit dextrans to glucose, maltose and isomaltose. The resulting syrups are moderately sweet and are frequently modified further. Treatment of glucose/maltose syrups with glucose isomerase converts a large proportion of the glucose to fructose, which is sweeter than glucose. High fructose syrups contain fairly equal portions of fructose and glucose. The high fructose syrups are in greater demand than pure glucose as food and drink sweeteners, because fructose is sweeter than glucose. Thus when glucose can be converted in to fructose its value significantly increases. Fructose is used in diet foods rather than glucose because it is sweeter so less is needed, reducing the calorie content.
Enzymes produced by yeast have been used fore thousands of years in brewing and baking. The word enzyme even means ‘in yeast’. Bread baking is the most common food processing technique in the world even though there are so many type and forms of bread produced. The main method of making bread is wheat flour with added water, salt and yeast. Sugar, fats and flavourings are often added to the bread. The wheat flour is mainly composed of starch, protein and fibre. The natural occurring enzymes within the wheat flour modify these contents and fibre fraction of the flour when water is added to the flour to make the dough. Just as the yeast has its own natural enzymes that ferment the maltose and other sugars releasing carbon dioxide, causing the bread to rise.
The minute bread leaves the oven, the breakdown of the bread begins. It is the bread's starch content that is "hard to please"; starch feeds on moisture, which is why bread becomes hard and unfit for consumption within a few days. By adding Novozymes' enzymes to the flour, it is possible to alter the structure of the starch in the bread so that it retains moisture better. This means that the bread remains soft for a longer period of time. Other enzymes make dough-handling much easier for the baker. Enzymes make the dough less sticky, which is a major benefit if you are making hundreds of loaves every morning. If you have ever wondered why bread from the bakers is larger and more airy, enzymes are once again the answer. Specialized enzymes can make the gluten of bread retain naturally-occurring gases that would otherwise disappear. Also in order to produce consistent products for the consumer and to make operations more efficient, enzymes are used as supplements in the bread making process. These include xylanase, -amylase, protease, glucose oxidase and lipase. These are blended into the dry flour and (like the wheat enzymes) are activated when the water is added to make the dough. These supplements enable better handling of dough, and control of characteristics in the finished bread such as taste, loaf volume, and crumb texture. But it is important that these enzymes remain thermostable due to the high cooking temperatures. Enzymes are often used in confectionary in the production of soft centred sweets and chocolates. The chocolate or sweet coating is poured over a solid mixture which contains sucrose and an enzyme. The coating sets, and the enzyme breaks down the sucrose into glucose and fructose. These smaller sugar molecules are much more soluble than the sucrose and dissolve in the small amount of water in the original mixture.
Enzymes are even used in the food processing industry to clear pipes in processing machinery. Especially within the fruit juice industry where the fruit is pulped it can easily accumulate in the pipes and release cellulose. Enzymes such as cellulases are able to break down the cellulose present in plant cell walls, into glucose.
The word enzyme was first used to describe the chemicals that enable yeast to covert sugar into alcohol during fermentation. Wine production involves the fermentation of grape juice. However the juice extraction is a longer and more complex process to receive the strong coloures needed, especially in red wine. The grapes are processed before they have fully ripened. This is so because they contain more amounts of insoluble protopectin which can absorb large quantities of juice during pressing and also result in viscous solutions which are difficult to process. The addition of pectinases during mashing can hydrolyse the pectins in the cell walls, which increases the yield of juice, clarifies the resulting juice and prevents the juice from gelling. Some grapes also contain large amounts of arabinoxylans which can be treated with xylanases to aid processing. Other uses of enzymes in wine producing is the addition of the proteases make the colour stay and to make it stable. Reducing the binding of polymerised tannins to proteins and the use of glycosidases to hydrolyse terpenyl glycosides thereby increasing the aroma of the wine, does this.
Beer brewing essentially is the formation of alcohol via the reaction of yeast and plant materials such as maize, hops and barley. Yeast is able to covert simple sugars into alcohol and carbon dioxide. But a lot of the sugar present in these plant materials is as polysaccarides such as starch. These can not be readily utilised. The nutrients are normally released through the malting in which barley is germinated slightly, at this stage the endogenous enzymes are released which break down starch and protein to simple sugars and amino acids. These can then be utilised by the yeast cells. The malting process is fairly expensive to produce enzymes and ones control is limited. To make the brewing more efficient and economical industrial enzymes including amylase and proteases are added to the barley before malting. The fashion at which the same simple sugars are released is more controlled than within malting. Enzymes are also important as filtration improvers. Slow filtration of the mash or final beer often results from the presence of viscous polysaccharides such as xylans and glucans. If it is previously treated with xylanaes or glucanases these viscouse polysaccarides are broken down, thus increase filtration rates and prevent fouling of filtration membranes.
Enzymatic fruit juice extraction was introduced 20 years ago and today some 5 million tons of non-citrus fruit juice is produced annually throughout the world. During the manufacture of non citrus fruit juice the fruit is firstly crushed. Like any other part of the plant the fruits are made up of cells with cell walls. These contain cellulose and complex polysaccarides called hemilcelluloses. Cell walls are very tough and difficult o break open. In order to improve yields and the quality of the product, cellulases and hemilcelluloses are added during the crushing stage to digest the cellulose and hemilcelluloses in the walls, making them more soluble and ensuring more complete disintegration of the tissues. The enzymes are selected to work at low pH levels as the fruit is acidic. Cell walls of nearly all fruits and berries contain pectins, starch and aribinoxylans. These make the fruit juice viscouse and difficult to extract. During the processing of fruits, pectins tend to be converted to water-soluble pectins and are threrfore present in the juice in solution even if the ‘bits’, the unbroken cells and cell wall debris, are removed. At low temperatures, the pectins start to come out of the solution and form a colloidal suspention in which the particles do not settle. This gives the drink an unattractive feature to some consumers, particularly in the USA and Britain, although it should perhaps be regarded as a sign of high fruit juice content. If the enzymes called pectinases are added to the juice they partially digest the pectin to smaller polysaccarides and sugars which remain in the solution even at low temperatures. The pectinases therefore clarify the drink. Arabinoxylin and starch hazes particularly in apple juice can also be treated by the addition of xylanases and alpha-amylases. The juice is then described as ‘chill proofed’. The source of these pectinases is bacteria. The flavour may also deteriorate if the pectin’s are not hydrolysed using pectinases. Cellulases also play a role in the extraction of juice from berries where juice yield together with extraction of colour and flavour components may be difficult.
Within processing of citrus fruit juices the production of cloudy juice is maximised with enzymes. The problems of extracting juice from citrus pulp and reducing the viscosity of the juice for concentration are similar to those of noncitrus fruit processing. However, citrus juices and in particular orange juice are meant to be cloudy as much or the desired flavour and colour depends on the insoluble, cloudy materials of the pressed juice. Cloud stability is controlled by careful manipulation of the pectin component of the juice. This complex process requires a balance between pectin methyl esterase which will promote cloud formation by increasing pectin / calcium complex formation and polygalacturonase which will break cloud formation by depolymerisation of the pectin before complex formation. (Advanced Biology)
Agriculture utilises enzymes in the production of silage from grass and plant material grown in a field. Lactic acid bacteria are also added. The enzymes partially break down the cell wall of the grass, and is ensiled into soluble sugars. These freed sugars are then metabolised by the natural or applied lactic acid bacteria such as Lactobacilli or Pediococci into lactic acid which reduces the pH and so ensiles the crop. Some enzyme preparations have been reported to improve the utilisation of feeds for important animals on a farm such as cows.
The use of enzymes in arable farming and has not been fully investigated. If so, they could be used for processing major crops and aiding with waste disposal.
Animal Feed consists mainly of plants, especially crops such as maize and corn. These contain carbohydrates which steadily release energy in the animals. They also contain vegetable proteins found in beans, peas, Soya and lupin seeds. Whilst the majority of the starch present in cereals is readily digested by monogastric animals a large proportion of the energy content is present as non-starch polysaccharides (NSP). The NSP's such as arabinoxylans in wheat and rye and ß-gucans in barley and oats are soluble and result in increased viscosity in the gastrointestinal tract of the animal which hinder digestion. Such NSP's are therefore frequently referred to as anti-nutritional factors (ANF). The addition of enzyme activities not present in the animal can overcome the effect of these ANF's. Feed containing predominantly wheat can be improved by the addition of xylanases to degrade the arabinoxylans and feed containing predominantly barley can be improved by the addition of ß-glucanase to degrade the ß-glucans. Such enzyme addition has become very popular. Over 90% of the poultry diets containing wheat and/or barley in the European Community are supplemented with enzymes to degrade the polysaccharide ANF's.
Another application of enzymes within animal feeding is with the addition of Phytase. This aids the release of phosphorus from the phytic acid which is the main store of phosphorus in plant material. This prevents phosphorous supplements being needed and is more efficient because the enzymes can be reused. It also reduces the environmental impact of phosphorus excretion in animal faeces.
All paper is manufactured originally from wood. To pulp this wood either mechanically or chemically, the cellulose fibres must be separated from the lignin and other components. In mechanical pulping a high yield is produced but is poor quality because the lignin components are not significantly solubilised. Such pulps are normally later used for newspapers. Chemical pulping methods use chemicals to dissolve the lignin. The resulting ‘Kraft’ processed pulp is dark in colour due to the presence of dissolved lignin. It then therefore undergoes substantial bleaching with chlorine compounds. The amount of chlorine needed is very high and many ways of reducing it have been tested. The best way has proved to be the use of enzymes. Enzyme treatment of kraft pulps has been shown to remove the hemicelluloses bound to the surface of fibres which makes it easier to remove bound lignin components thereby reducing the requirement for chlorine bleaching. This process has become known as "bleach boosting". When recycling paper the enzyme can break down the surface projections in which the ink is trapped. The paper can then easily be bleeched. Other applications of enzymes in pulp and paper manufacture include pich control, modification of starch for coated papers and cellulsoe fibre modification to produce softer tissue papers.
Cotton treated with enzymes not only looks better, it also lasts longer. Most cotton fabrics tend to be fluffy from the minute they leave the shop. Treating the fabrics with Novozymes' unique Biopolishing enzymes such as cellulase, removes the small hairs or fuzz that protrude from the surface of the yarn, leaving a smoother yarn surface that almost looks like silk. Biopolishing makes your clothes look brand new, even if you've washed them several times. They also look brighter. The same process has recently been adapted and is now included in some washing detergents.
Enzymes also play a major role in the textile industry in the desizing process. After weaving, the starch size has to be removed to prepare the fabric for the finishing steps of bleaching or dyeing. Starch-splitting enzymes are used to desize woven fabrics because of their highly efficient and specific way of desizing without harming the yarn. Natural untreated leather is as stiff as metal. It therefore needs to be softened before use - and enzymes are used for this task.
To make leather pliable, the raw material requires an enzyme treatment called bating, which takes place before tanning. This involves dissolving and washing the protein components that stiffen the leather. The degree of bating depends on the desired properties of the finished leather. Glove leather, for example, should be very soft and pliable and is subjected to strong bating, whereas leather for the soles of shoes is only lightly bated. In the old days, dog excrement was used in the bating process, the bacteria in the excrement producing enzymes to make the leather soft. The use of enzymes in industry today is rather more hygienic.
Hygiene is not the only advantage of using enzymes to treat leather products. Before leather becomes soft it undergoes several different treatments. Each treatment normally requires the use of large quantities of harsh chemicals. When removing hairs and fat from hides, enzymes can reduce the use of sulphide by 40%.
Enzymes are also responsible for major reductions in the amounts of water used, as the replacement of chemicals reduces the rinsing and cleaning processes. Ultimately, a higher quality leather is achieved and the load on the environment is reduced. Stonewashed jeans are the height of fashion and, as the name suggests, the traditional way of producing stonewashed jeans is to wash the jeans with stones. This is a harsh treatment both for the jeans and for the environment. The fabric of the jeans is weakened and may appear flossy, whilst the lifespan of the jeans is far shorter than that of regular blue jeans. By adding enzymes to the process there is no longer any need for stones in the wash. The look of the jeans is the same, but the process no longer damages the fabric and the jeans therefore last much longer. The process even saves on water, one of nature's most precious resources. When using enzymes to get the stonewash look, there is no need for several rinsing processes to get rid of the stones.
The advantages of enzyme technology over whole organism technology is primarily that there is no loss of substrate from the increase in biomas, such as when yeast is used to ferment sugar to alcohol some of the sugar is wasted as it is converted to cell wall material and photoplasm during growth. Secondly, elimination of wasteful side reactions takes place when using enzyme technology over using the whole organism. Whole organisms may convert some of the substrate into irrelevant compounds or even contain enzymes for degrading the desired product into something else. So single enzymes are more predictable and more specific. In whole organisms, the enzymes may have a higher optimum temperature than the organism so would not be working at its full potential. Enzyme technology would allow the enzyme to work at is own optimum conditions and at maximum efficiency. Finally purifying the product is easier when as an enzyme, not as an organism because it can be immobilised more efficiently. Also an enzyme contaminates a product less than an organism.
(Mr Price class biochemistry notes)
In conclusion it is simple to see that life today as we know would be extremely different without the use of enzymes, Infact we would not survive as they are used each day by our bodies to perform important functions. However in regard to industry and medicine the role of enzymes is not a vital, but still huge. They are used in many of the treatments administered to patients and much more. They also play a major role in industry, becoming over the years a billion pound market. Although they go unnoticed and unadvertised as important tools, they are owed great appreciation and gratitude. This is highlighted in the words of Dr. Pavels Ivdra “ Enzymes the unsung heroes” (Medical journal Article-Dr. Pavels Ivdra-1996)
Bibliography.
Internet sites;
www.biology.arizona.edu/biochemistry/problem_sets/energy_enzymes_catalysis/01t.html
(All Visited Dec 2003)
Books/texts;
Advanced Biology (1st Edition). By Michael Kent. Published by Oxford Press in 2000.
Biology-a functional approach (4th Edition). By M.B.V Roberts. Published by Nelson Ltd in 1987.
Understanding Biology (2nd Edition). By Glenn and Susan Toole. Published by ST (P) in 1994.
Complete A-Z biology Handbook (3rd Edition). By Bill Indge. Published by Hodder & Stoughton 2003
Revise AS Biology(1st Edition). By Simon Burch, Graham Read and Ray Skwierczynski. Published by Heinemann in 2001.
Information has been put into my own words to prevent the illegal act of plagiarism.