The Detergent Industry
To most people, the best known application of enzymes is in the manufacture of enzymatic washing agents (‘biological’ detergents). There are two major reasons for this.
Firstly, since the mid60s the use of enzymes in detergents has been the largest of all enzyme applications.
Secondly, consumers of washing agents are actually users of an enzymatic product. In the vast majority of other applications, enzymes are used as auxiliary agents at some point in the manufacturing process and are not, as a rule, present in the finished product – at any rate not in an active form.
Proteases are the most widely used enzymes in the detergent industry. They remove protein stains such as grass, blood, egg and human sweat.
These organic stains have a tendency to adhere strongly to textile fibres. The proteins act as glues, preventing the waterborne detergent systems from removing some of the other components of the soiling, such as pigments and street dirt.
The inefficiency of nonenzymatic detergents in removing proteins can result in permanent stains due to oxidation and denaturing caused by bleaching and drying. Blood, for example, will leave a rustcoloured spot unless it is removed before bleaching.
Proteases hydrolyze proteins and break them down into more soluble polypeptides or free amino acids. As a result of the combined effect of surfactants and enzymes, stubborn stains can be removed from fibres.
Novozymes’s first detergent protease was Alcalase® developed in the 1960s.
Several other enzymes have been developed by Novozymes for removing protein stains: Esperase®, Savinase® and Everlase® are suited to detergent formulations with pH values above 9. At low wash temperatures, Savinase is particularly suitable. For bleach-containing formulations, Everlase is recommended.
Though protein stains can easily be digested by enzymes, oily and fatty stains have always been troublesome to remove. The trend towards lower washing temperatures has made the removal of grease spots an even bigger problem. This applies particularly to materials made up of a blend of cotton and polyester.
But in 1988 Novo launched Lipolase® for the detergent industry – the first industrial enzyme developed by the application of genetic engineering. Lipolase is capable of removing fatty stains such as lipstick, frying fats, butter, salad oil, sauces and the tough stains on collars and cuffs.
The detergent industry had for many years been asking for a suitable lipase. Lipolase has now been incorporated into a great number of major detergent brands around the world, and a secondgeneration Lipolase called Lipolase Ultra with enhanced wash performance was launched in 1994.
In 1998 LipoPrime® was launched as a protein-engineered variant of Lipolase. LipoPrime shows superior fat-removing efficasy in comparison to Lipolase and Lipolase Ultra in most detergent formulations.
Amylases are used to remove residues of starchy foods such as mashed potatoes, spaghetti, oatmeal porridge, custards, gravies and chocolate. This type of enzyme, e.g. Termamyl®, can be used in laundry detergents as well as in chlorinefree automatic dishwashing detergents.
For bleach-containing formulations, Duramyl® is recommended.
The development of detergent enzymes has focused mainly on enzymes capable of removing stains. However, a cellulase complex from Novozymes called Celluzyme® has properties enabling it to modify the structure of cellulose fibrils such as those found on cotton and cotton blends.
When added to a detergent, it has the following effects:
When a garment made of cotton or cotton blends has been washed several times, it tends to get a ‘fluffy’ look and the colours become duller. This effect is due to the formation of microfibrils that become partly detached from the main fibres. The light falling on the garment is reflected back to a greater extent giving the impression that the colour is duller. These fibrils, however, can be degraded by the cellulase enzyme, restoring a smooth surface to the fibre and restoring the garment to its original colour.
The enzyme also has a significant softening effect on the fabric, probably due to the removal of the microfibrils.
Particulate soil removal
Some dirt particles are trapped in the network of microfibrils and are released when the microfibrils are removed by the enzyme.
The effect of celluzyme on the fabric is cumulative. In other words, each time a garment is washed, the enzyme produces a further improvement in its appearance.
Recently another cellulase with superior colour brightening properties was launched: Carezyme®.
The enzymes added to detergents in the 1960s were powders. Under unfavourable circumstances, dust from the powders could cause allergic reactions among the staff working in the enzyme plant or in detergent factories.
At Novozymes, a major project was started with the aim of developing dustfree preparations. A technique called prilling was introduced in 1970, whereby dust was virtually eliminated. The techniques for making dustfree enzymes have been improved over the years, and the most recent type is called the Tgranulate. The enzyme is coated in an inert substance and is therefore highly resistant to both abrasion and impact, and has a minimal tendency to form dust.
In many countries, there has been an increasing interest in liquid household washing detergents.
It is more difficult to preserve the stability of the enzyme in liquid detergents than in washing powders.
Novozymes enzymes are now formulated in a liquid form that can be used in practically all types of liquid detergent.
Automatic dishwashing detergents (ADDs)
There are many differences between washing laundry and washing dishes. The formulations therefore tend to differ widely between laundry detergents and ADDs. The traditional ADD formulations in Europe and North America contain metasilicate, phosphates and chlorine bleach, but no enzymes.
However, in the last few years, particularly in Europe, the use of enzymes in ADDs has taken off. The metasilicate has been replaced by disilicate, so reducing the pH. The chlorine bleaching agents and phosphates have been replaced in many European formulations, mainly for environmental reasons.
Normally, if phosphates and chlorine are taken away and the pH is reduced, the wash performance will suffer. Enzymes can be added to restore performance in such cases. In fact, tests by Novozymes show that, despite the lower pH and lack of chlorine, new enzymatic ADDs are often better at removing starch and protein stains than traditional ADDs.
Unless starch films are removed, they can build up and give plates a dull appearance. Protein spots, another type of soil, are also a problem, particularly with glassware and cutlery. Though dishes and glasses may look clean to the naked eye, protein spots often remain on the surface and attract white deposits of lime in hard water areas unless a water softener is used. Enzymes can be used to remove both these types of troublesome soil.
One of the big advantages of enzymes is that they remove soils efficiently even when the wash temperature is low.
In recent years, the application of enzymes for washing purposes has been given further impetus by endeavours to save energy. By optimizing application parameters, a satisfactory effect can be achieved even at very low temperatures, either by increasing the application time (presoaking) or by increasing the enzyme concentration (prespotting). In fact, it has been proven that presoaking with an enzymatic washing agent followed by a wash at a low temperature can give results that are as good or better than a normal wash at a high temperature without presoaking.
A procedure that has given promising results is prespotting: before washing, the parts of laundry with particularly stubborn stains, such as shirt collars and cuffs, are moistened with an undiluted liquid enzymatic washing agent.
The standard Product Range for the Detergent industry looks as follows. Most products are available in liquid as well as solid form, and in different concentrations. Please contact your local sales office for further details as well as with inquiries about special products not listed here.
Please note that all products listed are not necessarily available in all countries. Contact your local sales office for details.
A bacterial protease effective under neutral and mildly alkaline conditions (pH 7-10). Suitable for soaking preparations and liquid as well as powder detergents.
A bacterial protease which is effective under alkaline conditions (pH 8-11). Besides it is characterized by being very effective under medium-temperature wash conditions.
A protein-engineered variant of Savinase characterized by having an excellent storage stability in bleach-containing detergents.
A bacterial protease which is effective under strongly alkaline conditions (up to pH 12 approximately) even at high temperatures. Esperase is also effective in less alkaline solutions and at lower temperatures.
A fungal lipase. The first enzyme on the market for industrial application produced by recombinant DNA techniques. Lipolase is effective under alkaline conditions (up to pH 12 approximately) and at a broad temperature range.
A protein-engineered variant of Lipolase. In general, the washing performance of Lipolase Ultra is superior to that of Lipolase at high ionic strength, low temperatures and high pH, and various combinations of these conditions.
A protein-engineered variant of Lipolase. LipoPrime shows superior fat-removing efficacy in comparison to Lipolase and Lipolase Ultra in most detergents.
A bacterial amylase which is able to work at relatively high (alkaline) pH values (up to pH 11) and at high temperatures (up to 100ºC).
BAN (Bacterial Amylase Novo)
A traditional bacterial amylase which is effective at neutral and mildly alkaline conditions and at low and moderate wash temperatures. (Only available as a co-granulate with Savinase).
A fungal enzyme product containing a cellulase complex active in the neutral to moderately alkaline region. This special enzyme has three effects: colour brightening, softening and removal of particulate soil. The overall effect is that Celluzyme helps to preserve the nice appearance of new fabric and restores old fabric so that it looks new again. It works on garments made from cellulosic fibres, for example cotton and cotton blends.
A monocomponent cellulase showing remarkable colour brightening benefits. Preserves the attractive appearance of new fabric. Restores the appearance of used and worn garments. Removes pills. Works on cotton and cotton-containing blends.