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Detergent Enzymes

How safe are they?


Enzymes are defined as organic catalysts which promote specific chemical reactions in the body upon which all life depends. Enzymes are effective in infinitesimal amounts since they are not consumed in the catalyzed chemical reactions and will remain active indefinitely. Naturally occurring enzymes are related to proteins and are largely comprised of amino acids. They are used extensively in the food industry for fermentation in the production of alcoholic beverages and cheese for example.

In the mid-60’s Novozyme began to supply microbial enzymes for use in laundry detergents and dish washing detergents. These protein enzymes were classified as proteases. Today proteases still retain a dominant position in the detergent industry and are often used in combination with other enzymes.

More recently detergent manufacturers began to employ quaternary amines in order to increase the cleaning action of household detergents. These synthetic enzymes greatly increased the cleaning efficiency of common household detergents by accelerating the hydrolysis of animal fats (such as glycerides) and oily food residues (including proteins) so that they could be more rapidly dispersed and emulsified in water. In the scientific literature these quaternary amines are sometimes employed as phase transfer catalysts (1,2). Phase transfer catalysts, as the name suggests, accelerate chemical reactions that take place between insoluble phases, eg. oil and water. Quaternary amines, being soluble in both water and organic liquids, can greatly accelerate certain chemical reactions when added to such a heterogeneous system. These amine additives are highly toxic and are as equally effective as chlorine dioxide disinfectants. This antibacterial activity is considered desirable for maintaining a sterile living environment. These synthetic enzyme catalysts are extremely effective at low concentrations in aqueous solutions (typically 0.003 molar). Quaternary amines are chemically similar to naturally occurring neurotransmitters which are present in virtually all living organisms (including humans) eg. acetylcholine bromide. Neurotransmitters are molecules which control muscle behaviour by transmitting nerve signals. The toxic alkaloid curare (d-tubocurarine) is a quaternary ammonium compound which has been found useful in surgery in order to relax muscles (3).

So far there has been limited information concerning the long term effects of synthetic enzymes on the human population. 

Are genetic disorders a manifestation of DNA specific agents in our environment? 

Can Alzheimer’s and Parkinson’s diseases be attributed to protein fragments generated by enzymatic hydrolysis? 

This paper attempts to establish whether detergent enzymes are potentially dangerous and harmful to the health and reproduction of humans and other forms of life.


Synthetic Enzymes

Detergent enzymes are well established as normal ingredients in both powder and liquid detergents all over the world. The enzymatic hydrolysis of tri-glycerides in alkaline solutions is used as a measure of detergent efficiency (4). Many synthetic enzymes are derived from quaternary ammonium compounds (5,6). Quaternary ammonium compounds are frequently used as pseudo-enzymes to study the catalytic hydrolysis of organic compounds (1,2).

The rate of hydrolysis of food residues can be greatly increased in the presence of phase transfer catalysts such as quaternary ammonium halides and polyols. In phase transfer catalysis (PTC) a substrate in an organic phase is reacted chemically with a reagent present in another phase (which is usually aqueous). Reaction is achieved by means of an enzymatic transfer agent; this agent or catalyst being capable of dissolving in both aqueous and organic phases, the latter in the form of highly reactive ion pairs. The hydrolytic activity of the PTC ion pair is considerably greater in organic media since it is less hydrated. These cationic enzymes will strongly bind to organic substrates including exposed hands and will remain on the skin even after 16 rinses (9).

This raises concern about the danger of employing chemical agents in detergents which may be absorbed by the skin and eventually into the blood stream where these catalysts could continue to randomly degrade protein matter and even interfere with DNA reproductive processes

Quaternary Ammonium Enzymes

The annual production of all purpose cleaners is greater than one million tons. Tetraalkyl ammonium halides are often added to these surfactants as disinfectants (7). These quaternary compounds are known to be toxic to virtually all living organisms (including bacteria, aquatic life, animals, amphibians, and humans) and are said to be just as effective as chlorine compounds for disinfecting purposes (9). Of the many quaternary ammonium compounds in commercial use, alkyldimethylbenzyl ammonium chloride, is perhaps the most widely used cationic agent in domestic surfactants. The hydrolytic efficiency of a quaternary ammonium base is dependent upon its relative solubility in organic substrates (characterized by the hydrophilic/lipophilic balance). Alkyl dimethylbenzyl ammonium chloride is a powerful catalyst which greatly accelerates the hydrolysis of esters and amides, the major components of all living organisms (8). This quaternary compound is widely used as a synthetic enzyme for accelerating many other types of reactions. They are often used as phase transfer catalysts due to their ability to transfer reagents from an aqueous phase into an organic phase. In the presence of trace amounts of such catalytic agents, the detergent can become extremely corrosive and will promote rapid hydrolysis and degradation of organic tissues. This is not surprising since modern detergents are designed to rapidly hydrolyze residual fats and oils in food. The active ingredient, quaternary ammonium hydroxide, can adsorb on the skin and diffuse into the body. Vegetable or animal fats and greases comprise triglycerides, which are esters of glycerol. Since skin comprises keratin (a protein) and fatty esters, these tissues are just as susceptible to hydrolysis as animal food residues. The rate of hydrolysis of denatured proteins by detergents containing protease enzymes at various temperatures has been investigated (4). Virtually 100 percent hydrolysis was obtained in 30 minutes at 400C which is evidence of the strong catalytic activity of these synthetic enzymes. It is not clear what effect these powerful enzymes might have on the human neurological system if they should invade the body by absorption or ingestion. However in one reported case, a patient in a hospital went into shock and died as a result of a spinal fluid injection. Subsequent investigation showed that the hypodermic syringe had been previously washed with a detergent containing a synthetic enzyme. The residue left on the syringe was sufficient to cause death.

The composition of a general purpose cleaning agent is provided from a Material Safety Data Sheet (10) in Table 1.

Table 1. Composition of Typical General Purpose Cleaning Agent

1.         Tetrasodium ethylenediamine tetraacetate (chelating agent)
2.         Alkyldimethylbenzyl ammonium chloride (hydrolysis catalyst)
3.         Non-Ionic Surfactant (emulsifier)
4.         d-Limonene (a hydrocarbon fragrance)
5.         Non-volatile substances (8 percent - unspecified)
6.         Water

Tetrasodium ethylenediamine tetraacetate is a chelating agent which dissolves calcium deposits or other inorganic residues. Under alkaline conditions alkyldimethylbenzyl ammonium chloride exists largely in its basic form, ie.

R4+ OH-

Quaternary ammonium hydroxide base

In this state the quaternary compound becomes a powerful catalyst which can greatly accelerate hydrolysis reactions, causing rapid degradation of animal or human tissues. The same action occurs when cleaning agents are employed to remove food residues which contain both fats (glycerides) and proteins (polypeptides). Without the quaternary ammonium hydroxide catalyst these hydrolysis reactions would be very much slower.

Cleaning agents containing quaternary ammonium compounds such as alkylbenzyldimethyl ammonium chloride can be found in most grocery stores and supermarkets under a variety of brands. Some typical cleaning agents are listed in Table 2. It should be noted that most detergents do not reveal their composition on the label.



Table 2.   Typical Enzyme Detergents

Cleaning Agent         pH      Comments

Pearl Plus (Flexo)       10      Active ingredient alkyl dimethyl
                                                            benzylammonium chloride

            Pine Scented                9      Corrosive to skin and eyes.
            Household Cleaner               Use rubber gloves. Contains
                                                            quaternary ammonium chlorides.

Lysol                                         8        Corrosive. Contains alkyl               
                                                                       dimethylbenzyl ammonium chloride
Use rubber gloves.


Unlike microbial enzymes, quaternary amines are foreign substances that are chemically stable and not readily biodegradable. In an acidic pH environment quaternary amines are relatively inert but become powerful hydrolysis catalysts under basic conditions. Since the pH of blood is slightly basic, the presence of quaternary amines in the body can be potentially dangerous. Enzymes have been implicated in certain forms of leukemia. Neurotransmitter enzymes are responsible for the transmission of signals to muscle nerves. Parkinson’s disease is attributed to the slow deterioration of nerve signals which are triggered by quaternary enzymes (ie. acetylcholine). Studies have concluded that Parkinson’s disease is probably caused by unknown environmental triggers (12).  

Enzymes have been implicated in the growth of cancerous tumors and certain forms of leukemia (13).

Scientists have recently discovered that Alzheimer’s disease is attributed to particular protein fragments (amyloid betapeptides) which have been cut off or cleaved from a larger amyloid protein molecule by a particular protease enzyme referred to as BACE (11). While the chemistry of this reaction may be quite different from that of quaternary amines, it does emphasize that people who are exposed to chemicals that cleave proteins invite a serious health risk. The origin of Alzheimer’s disease has been attributed to the cleavage of proteins in the body, the same type of cleavage reaction that detergent enzymes promote in order to increase cleaning efficiency. Since detergent residues are normally present on dishes, drinking glasses, and eating utensils, the possibility of ingestion exists for all individuals. Laundry detergents leave residual detergents on clothes which may be subsequently absorbed by the body after contact with the skin. Hence most if not all individuals are exposed to these chemicals on a daily basis, both internally and externally.



It is clear that our health is dependent upon a delicate balance of chemistry between enzymes, hormones, vitamins and genes. Whereas the interdependence between these four organic species is highly complicated and not too well understood, minor disturbances can lead to catastrophic results. The introduction of a highly reactive biochemical agent such as a detergent enzyme into the human body may disrupt these complex reactions that are essential to good health and survival.

It is known that synthetic enzymes such as alkylbenzyldimethyl ammonium chloride are powerful phase transfer catalysts which can greatly accelerate the hydrolytic attack of glycerides, proteins, lipids, and genetic molecules. These additives are extremely toxic to virtually all living organisms. This observation raises concerns about the safety of using detergents which contain pseudo-enzymes such as quaternary ammonium compounds. Tonnage quantities of these lethal agents are being dispersed in the environment without a clear understanding of their potential effects on humans or other living species. The increasing number of genetic disorders and the increasing incidence of cancers in the general population and especially in children, mostly of unknown origin, should be a warning that we should be more wary of introducing potentially life threatening biological agents into the environment, and especially into cleaning agents. Further research is needed to ascertain whether certain detergent enzymes are consistent with a healthy environment. A known toxic additive that is so ubiquitous within our society should be carefully reviewed for potential adverse effects on human health.


  1. E. V. Dehmlow, S. S. Dehmlow, Phase Transfer Catalysis, VCH Publishers, 1993.
  2. C. M. Starks, C. L. Liotta, M. E. Halpern, Phase Transfer Catalysis, Chapman & Hall, 1994.
  3. A. Streitwieser, C. H. Heathcock, E. M. Kosower, Introduction to Organic        Chemistry, MacMillan Publishing, 1992. pp. 740-742.
  4. P. N. Christensen, K. Thomsen, S. Branner, Development of Detergent           Enzymes, Proceedings Second World Conference on Detergents, American Oil Chemists Society, p. 182, 1987.
  5. W. G. Cutler, E. Kissa, Detergency - Surfactant Science Series Vol. 20, 1987.
  6. J. M. Richmond, Cationic Surfactants, ibid, Vol. 34, 1990 (see also Vol. 53).
  7. B. Davis, Recent Developments in the Technology of Surfactants, Critical Reports on Applied Chemistry, Volume 30, Elsevier Applied Science, pp.     78-83.
  8. J. Albrizzio, J. Archila, T. Rodulfo, E. H. Cordes, J. Org. Chem. 37 (6), 871     (1972).
  9. E. Jungermann, Cationic Surfactants, Marcel Dekker, 1970.
  10. Material Safety Data Sheet for Pearl Plus, Flexo Products Limited., Toronto.
  11. Science, 286:650-651, 735-740 (1999).
  12. The Toronto Star, January 29, 1999, p. F8 (published in the Journal of the American Medical Association).
  13. The Toronto Star, March 16, 1999, p. A3 (Proceedings of the National Academy of Sciences).

Toronto, Ontario                                                                    Raymond T. Woodhams
September 2, 2001