Science in the box

Certain enzymes (protease, amylase, lipase, cellulase, mannanase, and pectinase) are very effective, in small amounts, for removing certain target substances (i.e., substrates). When enzymes find their designated stains, they lock on and remove them, then continue to the next stain.Certain enzymes (protease, amylase, lipase, cellulase, mannanase, and pectinase) are very effective, in small amounts, for removing certain target substances (i.e., substrates). When enzymes find their designated stains, they lock on and remove them, then continue to the next stain. The enzymes used in laundry detergents act on materials that make up a variety of stains and soils so that these materials can be washed away more easily. These enzymes are named after the materials they can act upon, for example:

• proteases break down protein based stains,
• lipases break down lipid (fat) based stains,
• amylases break down starches and other carbohydrate based stains (amyl comes from the Greek for starch) and
• pectinase remove fruit and pectin-based stains that traditional detergent ingredients have trouble removing, doing it efficiently at low wash temperatures.

Since one enzyme molecule can act on many substrate (i.e., soil) molecules, a small amount of enzyme added to a laundry detergent can provide a big cleaning benefit to the consumer.

Enzymes fit their target substrates like a key fits a lock.
The active site of the enzyme is open only to specific target substances (i.e., substrates) with a matching chemical and 3-dimensional shape. If the substrate doesn't fit, it can't enter and no reaction occurs. This makes the action of enzymes highly specific for their substrates.
A little enzyme goes a long way!
Like other types of catalysts, an enzyme can complete its chemical reaction without being used up or destroyed, leaving the enzyme protein available for yet another reaction. This means that one enzyme protein molecule can act on many substrate molecules. Eventually, all the substrate is gone and the enzyme stops working and will eventually break down on its own.

Enzymes are proteins, therefore, they are completely biodegradable. They are non-toxic to plants and animals in the environment. They are harmless if accidentally ingested by a child. However, like many other proteins, enzymes can cause respiratory allergy in some people if they are breathed in at very high concentrations, frequently, and for long periods of time. This doesn't pose a safety issue for consumers who use laundry detergents. But this can represent a health issue for people that work in enzyme-making facilities and in detergent production facilities, if enzymes are not handled properly.

What's a respiratory allergy?
Respiratory allergy is a response our bodies can have when we are exposed to proteins such as house dust mites, cat and dog dander, pollens and moulds. Not everyone will develop respiratory allergy to the variety of proteins we are exposed to on a daily basis. As mentioned above, enzymes are proteins. Frequent inhalation of enzymes at high concentrations over a long period of time can lead to respiratory allergy among some people. This can occur among people that have to work with enzymes and when the enzymes are not handled properly. This is why strict procedures are followed to handle enzyme materials safely.

When enzymes were first introduced into detergent products in the 1960s, they were dusty powders. The detergent products were also very dusty so it was easy for the enzymes to become airborne. At that time there were very few controls to limit the amount of detergent powder that could become airborne during the making and packing of detergents. As a result, many employees were exposed to very high levels of airborne enzymes and some of them developed respiratory allergies. Since then, a number of steps have been taken to eliminate the health risk to our employees by reducing the amount of airborne enzymes in the workplace. Some of these steps were:

• Receiving and handling enzymes in completely enclosed systems to further limit exposure.
• Improved engineering and ventilation to minimize the generation of dust.
• Constant monitoring of airborne enzyme levels in the manufacturing plants to allow early
identification of leaks or other problems so that they can be addressed promptly.
• Development of standard practices to clean up spills and perform other tasks in a manner that limits the potential to generate airborne dust.
• A thorough health monitoring programme for each employee to limit the chances of development of respiratory allergy.

• Flindt, M. L. H. 1969. Pulmonary disease due to inhalation of derivatives of Bacillus subtilis containing proteolytic enzyme. Lancet, 1:1177-81.
• Pepys J., J. L., Longbottom, F. E. Hargreave and J. Faux. 1969. Allergic reactions of the lungs to enzymes from Bacillus subtilis. Lancet, 1:1181-4.
• Newhouse M. L., B. Tagg, S. J. Pocock, A. C. McEwan. 1970. An epidemiological study of workers producing enzyme washing powders. Lancet, 1:689-693.
• Juniper, C. P., M. J. How, B. F. J. Goodwin and A. K. Kinshott. 1977. Bacillus subtilis enzymes: a 7-year clinical, epidemiological and immunological study of an industrial allergen. J. Soc. Occup. Med., 27:3-12.
• Flood D. F. S., R. E. Blofeld, C. F. Bruce, J. I. Hewitt, C. P. Juniper and D. M. Roberts. 1985. Lung function, atopy, specific hypersensitivity, and smoking of workers in the enzyme detergent industry over 11 years. Br J Ind Med.,42:43-50.
• Schweigert, MK, MacKenzie, DP and Sarlo, K. 2000. Occupational asthma and allergy associated with the use of enzymes in the detergent industry - a review of the epidemiology, toxicology and methods of prevention. Clinical and Experimental Allergy, 30: 1511-1518.
• Sarlo, K and Kirchner, DB. 2002. Occupational asthma and allergy in the detergent industry: new developments. Current Opinion in Allergy and Clinical Immunology, 2:97-101.
• Sarlo, K. 2003. Control of occupational asthma and allergy in the detergent industry. Annals Allergy, Asthma and Immunology, 90(suppl):32-34.
In addition, a complete literature review on enzymes has been completed by the European Union:
• Aberer, W., M. Hahn, M. Klade, U. Seebacher, A. Spök, K. Wallner and H. Witzani. 2002. Final report: Collection of information on enzymes, European Commission Contract No. B4-3040/2000/27845/MAR/E2