MXPA97003669A - Method for the depilation of leather or skins pormedio de enzi - Google Patents

Abstract

The present invention relates to a method for depilating hides or skins by means of enzymes, characterized in that 1) the hides and skins are soaked, 2) the soaked hides or skins are attached to a main soak, and 3) the hides or skins treated in this manner are depilated by the addition of water, exposure to mechanical influence and attachment to at least one protease, characterized in that the hides or skins are attached to at least one protein disulfide redox agent by at least one time during step 1) a

Description

METHOD FOR THE DEPILATION OF LEATHER OR SKIN BY MEANS OF ENZYMES FIELD OF THE INVENTION The invention relates to a method for depilating hides or skins by means of enzymes.

BACKGROUND OF THE INVENTION The depilation of hides or skins aided by enzymes was first described around the mid-to-late 1960's. A typical, representative prior art method is described in U.S. Patent No. 3,840,433 (Aunstrup et al.), Which describes the depilation of hides and skins in a strongly alkaline environment by means of certain resistant, alkaline proteolytic enzymes. A disadvantage with regard to methods for hair removal of this kind, is the fact that perfect depilation can not be obtained, because the leather or skin, shaved, resulting either will be either incompletely depilated (if the amount of enzyme used is small ) or will be damaged in the REF: 24682 outer side of the skin (if the amount of enzyme is high). Another prior art method of this type is described in PCT / DK93 / 00283. Even if it is possible to obtain a complete hair removal without damaging the outer side of the skin with this method of the prior art, it uses sulfur and is thus not environmentally friendly. Until now it has not been possible to produce, in an environmentally friendly manner, a leather or skin completely depilated without damage on the outer side by the use of enzymes.

BRIEF DESCRIPTION OF THE INVENTION It is the purpose of the present invention to solve some of the problems mentioned above by providing an environmentally favorable method for the depilation of hides or skins by means of enzymes, which results in a leather or skin that is completely depilated, and which exhibits an outer side of the leather or skin without damage. Surprisingly, it has now been found that hides or skins can be completely depilated without damaging the outer side thereof by means of an environmentally friendly method. According to the method of the invention for the depilation of hides or skins, it comprises the following steps: 1) the hides or skins are soaked or macerated; 2) the soaked hides or skins are attached to a main soak, and 3) the hides or skins treated in this way are depilated by the addition of water, exposure to mechanical influence and subjection to at least one protease, characterized in that , the hides or skins are attached to at least one protein oxidase reduction (redox) agent at least once during step 1) to 3).

DETAILED DESCRIPTION OF THE INVENTION The present inventors have surprisingly succeeded in finding an environmentally favorable method for plucking leathers or skins by means of enzymes, which results in leathers or skins completely depilated with an undamaged outer side.

The method can be used advantageously for depilating bovine skins or hides and also hides or skins from another source, for example sheep or sheep or goat. According to the method of the invention, the hides or skins 1) are soaked, 2) the soaked hides or skins are subjected to a main soaking, and 3) the hides or skins treated in this way are depilated by the addition of water , exposure to mechanical influence, and attachment to at least one protease, characterized in that the hides or skins are attached to at least one protein disulfide redox agent at least once during step 1) to 3) . Steps 1), 2) and 3) are usually carried out in the same equipment, such as a preparation section drum for tanning, which ensures that the skins or leathers are subjected to sufficient mechanical influence. However, the steps can be carried out on different pieces of equipment. Steps 1), 2) or 3) in which the protein disulfide redox agent in question is added, depends on the optimum pH of the protein disulfide redox agent in relation to the pH of the process. At the optimum pH, the enzyme in question exhibits approximately 80 to 100% of the maximum catalytic activity. If the protein disulfide redox agent has an optimum pH of about 7, it is preferred that it be added during the main soak in step 2), as the main soaking is normally carried out at pH 7 to 9. If the protein disulfide redox agent has an optimum pH at a significantly higher pH (protein disulfide, alkaline, high redox agents) it may be advantageous to add it together with the protease in step 3). This leads to the degradation of keratin immediately after disulfide removal through the bonds. The alkaline, high protein disulfide redox agents are enzymes that show optimum enzymatic activity at pH above 9, preferably in the pH range used for hair removal (step 3)), ie between pH 9 and 13, in most cases between 10 and 12.5.

In certain cases it is advantageous to add the protein redox agent during the initial soaking (step 1)) or the main soaking (step 2)), and in other cases simultaneously with or in the arbitrary sequence with the protease in step 3) . It is also completed, according to the invention, to add a protein disulfide redox agent during the main soaking and additionally simultaneously with or in arbitrary sequence with the protease. The protein disulfide redox agent (s), when added, can be the same or two different protein disulfide redox agents. It should be understood that if the two enzymes, the protein disulfide redox agent and the protease, respectively, exhibit the optimum pH, which are too different, they will have to be added sequentially and with a pH adjustment. The initial soaking is done to remove dirt, blood or other impurities from the hides or skins. In industrial practice, hides or skins will always need the initial soaking. However, if the hides or skins have already been cleaned, the first step is less important and even in some cases not necessary.

The initial soaking and main soaking are generally done in water. According to the chemical substances of the invention, which are conventionally used during soaking and depilation steps, they can be used, and usually, advantageously, they can also be used in the method according to the invention, for example, preservatives. , detergents and soda during soaking, and quicklime during waxing. A soaking enzyme is often used during the main soak in step 2) to soften the hides and skins. For soaking, broad spectrum proteases can be used, such as Aquaderm ™ (available from Novo Nordisk A / S). However, if the skins or leathers are of poor quality, the soaking enzymes should be used with caution. One possible explanation for the surprising effect, obtained by the method of the present invention, is that the protein disulfide redox agent prepares the hair roots for protease treatment. The preparation of the roots of the hair causes the removal of some of the bonds through disulfide in the soft keratin (having only a few bonds through disulfide) that leads to an even softer keratin, similar to the type of keratin present in the epidermis. The treatment with the protease degrades both the epidermis and the roots of the hair resulting in a complete depilation of the hides or skins. Protein disulfide redox agents catalyze the general reaction: Ri-S-S-R + EbZred - Ri-SH + R2-SH + Enzox (reaction I) wherein Ri and R2 represent protein entities that are the same or different, either within the same polypeptide or in two polypeptides, Enz "is a protein disulfide redox agent in the oxidase state, and Enzred is an agent of protein disulfide redox in the reduced state. Group EC 5.3.4.1 (Enzyme Nomenclature, Academic Press, Inc., 1992) refers to enzymes capable of catalyzing the rearrangement of -SS- bonds in proteins and groups E 1.6.4.4 and E 1.8.4.2 are examples of enzymes that catalyze the reaction with NA (P) H and glutathione as a mediator, respectively.

In accordance with the invention, all of the protein disulfide redox agents, and mixtures thereof, can be used. Examples such include protein disulfide redox agents selected from the group comprising protein disulfide reductases, protein disulfide isomerases, protein disulfide oxidases, protein disulfide oxidoreductase, protein disulfide transhydrogenases, sulfhydryl oxidase and thioredoxins, including protein disulfide redox agents according to with pending patent applications WO 94/00264 and WO 94/00265 (Novo Nordisk A / S). Preferred protein disulfide redox agents are protein disulfide isomerases (PDI), thioredoxins (TRX) or disulfide bond formation proteins, such as DsbA and DsbC, or variants thereof. TRX is a 12 kDa protein that has a redox-active disulfide / dithiol and catalyzes thiol-disulfide exchange reactions (Edman et al., (1985), Nature, 317, p. 267-270; Holmgren, ( 1985), Annu Rev. Biochem., 54, pp. 237-271, Holmgren, (1989), J. Biol. Chem., 264, pp. 13963-13966).

PDI is a 57 KDa protein that normally consists of two subunits. This has a disulfide / dithiol redox-active and catalyzes the exchange reactions of thiol-disulfide (acting as an oxidase and protein disulfide isomerase) (Yamauchi et al, (1987), Biochem. Biophys. Res. Commun., 146, p 1485-1492), Chicken (Parkkonen et al., (1988), Biochem. J. 256, p.1005-1011), Human (Rapilaj aniemi et al., (1987), EMBO J., 6, p.643 -649), Mouse (Gong et al., (1988), Nucleic Acids res., 16, p.1203), Rabbit (Fliegel et al., (1990), J. Biol. Chem., 265, p.15496-15502 ), and Rata (Ed an et al., (1985), Nature, 317, pp. 267-270). PDI has also been isolated from yeast (Tachikawa et al, J. Biochem., 110, pp. 306-313). DsbA is a known 21 kDa protein that is capable of reducing insulin disulfide bonds and common activity for disulfide oxidoreductases (Bardwell et al., (1991), Cell, Vol. 67, p 581-589). BsbC is a known 23 kDa protein that exhibits disulfide oxidase and disulfide isomerase activity (Missiakas et al., (1994), The EMBO journal, vol 13, No. 8, p.2012-2020).

It should be understood that a redox partner or pair must also be present in conjunction with the protein disulfide redox agent. This partner or redox couple exhibits an effect on the protein disulfide redox agent, not on the leathers or skins. According to the method of the invention, all the redox partners or pairs can be used. Mate or couple redox may be an organic reducing agent or mineral selected from the group comprising glutathione, L-cysteine, dithiothreitol (DTT), 2-mercaptoethanol, thioglycolic acid, ethyl ester L-cysteine, beta-mercaptoethylamine, mercaptosuccinic acid , ß-mercaptopropionic acid, dimercapto adipic acid, thiomalic acid, tioglicoamidas thioglycolate, glycol, glyceryl thioglycolate, thiolactic acid and salts thereof, sulfite and bisulfite. However, weak redox partners or partners such as glutathione and dithiothreitol (DTT) are preferred. Even the hair removal palette itself exhibits weak redox potential. With respect to step 3) it should be noted that any proteolytic enzyme or mixtures thereof can be used.

The protease may be serine proteases, aspartic proteases, cysteine proteases and metallo proteases, respectively. Suitable enzymes also include truncations, mutations and / or variants of the enzyme groups listed above. Examples of serine proteases are for example, trypsins, chymotrypsins and subtilisins. Preferred are the bacillus sp. alkalin serine protease derivatives. It has been found experimentally that an enzyme of this kind gives rise to a satisfactory depilation without damage to the outer side of the skin. Examples of such are subtilisin BPN ', subtilisin amilosacchariticus, subtilisin 168, subtilisin mesentericopeptidase, subtilisin Carlsberg, subtilisin DY, subtilisin 309, subtilisin 147, thermitasa, aqualisin, Bacillus PB92 protease, proteinase K, Protease TW7, and Protease TW3, truncations, mutations and variants thereof. In the context of this invention a variant of subtilisin or subtilisin mutant protease means a subtilisin that has been produced by an organism which is expressing a mutant gene derived from a main parent microorganism or has a parent or original gene that produces an enzyme mother corresponding, the parent gene having been used in order to produce the mutant gene from which the subtilisin protease used was produced when expressed in a suitable host. References for such enzymes and / or methods for producing truncations, variants and mutations include European Patent No. 130,756 (Genentech), European Patent No. 479,870 (Novo Nordisk A / S), European Patent No. 214,435 (Henkel), WO 87/04461 (Amgen), WO 81/05050 (Genex), European Patent Application no. 87303761 (Genentech), EP 260.105 No. (Genencor), WO 88/06624 (Gist-Brocades NV), WO 88/07578 (Genentech), WO 88/08028 (Genex), WO 88/08033 (Amgen), WO 88/08164 (Genex), Tho et al., (1985), Nature, 318, p. 375-376; Thomas et al., (1987), J. Mol. Biol., 193, p. 803-813; Russel and Fersht, (1987), Nature 328, p. 496-500. Other methods well established in the art can also be used. Examples of cysteine poteases are for example papain and bromelain. For the group of metallo proteases are for example Neutrase8 (available from Novo Nordisk A / S) and collagenase.

Examples of acidic aspartic proteases are for example pepsin A, pepsin B, pepsin C, chemosin, cathepsin B and renin. The activity of the proteases mentioned above can be determined in general as described in "Methods of Enzymatic Analysis", Third Edition, Vol. 5 (1984), Verlag Che ie, Winheim. Preferred examples of enzymes, which can be used according to the invention, comprise alkaline proteases as described in WO 92/17576, WO 89/06279, WO 91/00345, and PCT / DK93 / 00074. A specific example of an easily available, suitable protease is NUE (from Novo Nordisk A / S). In a preferred embodiment of the method according to the invention, the protease exhibits a pH activity curve with a maximum pH above 9, according to the KNPU activity determination method (the KNPU activity determination method which uses casein as a substrate is described in AF 277, which is available at the request of Novo Nordisk A / S, Novo Alie, DK-2880 Bagsvaerd Denmark). In this way a very satisfactory hair removal is obtained without damaging the outer side of the skin. An embodiment of the method according to the invention comprises that the fleshing or cleaning of the untanned skin is carried out between step 2) and 3). The untanning of untanned skin is done to remove fat that can interfere with hair removal. In this modality the following advantages are obtained: 1) the enzymatic action during depilation is improved due to the reduced amount of fat in the hair removal blade and in the hides or skins, and 2) the wastewater contains less fat and this way is more acceptable from an environmental point of view. However, it is also contemplated according to the invention, to carry out a necking after the depilation step, instead of fleshing the untanned skin. In step 3) water is added in an amount which satisfactorily provides rubbing between the individual leathers or skins and the mechanical influence is usually secured by preparation for tanning of the skin and leathers, for example in a drum of preparation section for the tanned or similar.

In a preferred embodiment of the method according to the invention, water is added in an amount between 50 and 200% relative to the dry weight of the hides or skins, preferably between 70 and 120% thereof. With an amount of water less than 50%, the abrasion of the hides or skins can be damaged, and with an amount of water above 200%, the mechanical impact is usually also low, and also the water consumption will be undesirably high. The temperature range for carrying out the method according to the invention is selected in consideration of the optimal activity of the enzymes for example the contraction properties of the hides or skins. A suitable temperature range is 5 ° C to 60 ° C, preferably 10 ° C to 40 ° C, especially 22 ° C to 32 ° C. In one embodiment of the invention, the protein disulfide redox agent, the redox partner or pair and the protease are added simultaneously in step 3). In this case the two enzymes should exhibit approximately the same optimum pH. In this way, this mode is simple, because the addition of the enzyme is carried out as a step of the process.

A preferred embodiment of the method according to the invention comprises that in step 3), the protein disulfide redox agent and the protease are added sequentially such that the protein disulfide redox agent is added first, and subsequently the protease. It has been found that a very effective depilation can be obtained together with an outer side of the perfect skin, because in this case a protease with a high, optimum pH can be used, such proteases are usually the best depilation enzymes. A preferred embodiment of the method according to the invention comprises that the protein disulfide redox agent is added in an amount of between 25 and 1000 g of pure enzyme protein / kg of salty leather or skin and the protease is added in a amount of between 5 and 50 mg of pure enzyme protein / kg of leather or salty skin, and that the total hair removal time is maximum 24 hours. It has been found that the desired result can be obtained with the activities and times indicated. With the enzymes in less quantities and with shorter times, a less satisfactory result can be obtained. With enzymes in larger quantities and with longer times, the method will not be economical and / or the outer side of the skin may be damaged. A preferred embodiment of the method according to the invention comprises that the hairs are removed from the depilation liquor by continuous filtration during depilation. If continuous filtration is not carried out, the hairs will tend to adhere to the fatty tissue on the back of the leather or skin. The method according to the invention will be illustrated by the following examples. The effect of hair removal is caused by the decomposition of the keratin of the epidermis. In this way, if a more considerable decomposition of the keratin of the epidermis can be demonstrated, a better depilation effect is demonstrated simultaneously. Although the present invention is illustrated in the following examples, many alterations and modifications are possible in the practice of this invention without departing from the spirit and scope thereof. Accordingly, the scope of the invention should be constructed in accordance with the substance defined by the following claims.

METHODS AND MATERIALS Substrate: Celestial blue keratin, Sigma K-8500, LOT 33H3614 (a keratin stained with partially denatured blue) Enzymes: 5 mg of PDI dissolved in 1.5 ml of 0.1 M K2HP0 (produced as described in WO 94/00264 and available from Novo Nordisk A / S). NUE 12.0 MP (Activity 8.37 KNPU (E) / g) (available from Novo Nordisk A / S). Eusapon-S (detergent) Arazit KF (preservation agent) Redox partner or partner: Dithiothreitol (DTT) Shock absorber: K2HP0 0.1 M (pH 7.0) Methods: Determination of protease activity NUE The determination of KNPU activity is made as described in AF-277 (available at the request of Novo Nordisk A / S).

Determination of PDI activity Insulin from Novo Nordisk A / S is used as a substrate. Insulin, which contains two disulfide bonds (-S-S-), becomes cloudy when the disulfide bonds are removed. This can be determined spectrophotometrically at 650 nm. Insulin (sparingly soluble) is suspended in water and 0.1 M HC1 is added until the insulin dissolves. Using weak NaOH, the solution was triturated to turbidity and a drop of HC1 was added. Water was added until the insulin concentration was 1.3 mM.

Substrate before use: 100 μl of 1 M K2HP04, pH 7 100 μl of insulin 1.3 Mm 3.3 μl of 100 M DTT 800 μl of water 5 mg of PDI are diluted in 1.5 ml of buffer, pH 7.0, with 100 μl of phosphate of 0.1 M sodium and 263 μl of 1 M EDTA, pH 7.0, at approximately 100 U / ml. 0-10-20-40-60-80-100 μl of PDI was filled into microtiter plates and the buffer was added to 100 μl. 100 μl of the insulin substrate was added. As a measure of the enzyme activity, the absorbance is monitored at 650 nm.

EXAMPLES Example 1 mg of celestial blue keratin are placed in a small container with a lid. Light blue keratin is added with 10 ml of 0.1 M K2HP0 (pH 7.0) and varying amounts of 100 mM DTT. A small magnetic stirrer is introduced into the container. Subsequently, the varying amounts of PDI (protein disulfide redox agent) are added as appears from the table below, and the mixture is heated to 60 ° C and subjected to magnetic stirring for 19 hours. Then the temperature is lowered to 30 ° C, and varying amounts of NUE protease are added, and the mixture is stirred for 52 hours. Subsequently, the liquids were filtered, and the color development was measured spectrophotometrically at 595 nm. The higher the absorption, the blue celestial keratin decomposes more.

Table 1 Step 1 Step 2 Shows Absorbance No. mg of PDI per μl of DTT per gram of at 595 nm vessel container proteases (20 mg of (20 mg of pure NON keratin keratin per g of celestial blue) blue light) blue keratin 1 0.25 5 200xl0"5 0.664 2 0.50 5 200xl0"5 0.838 3 1.50 5 200xl0-5 0.998 4 0.25 5 200xl0"5 0.585 5 5 2 00x l 0" J 0. 270 6 5 0 0. 137 00 0 0. 257 The experiment indicates that a protease (NUE) alone, and in addition a redox partner or pair (DTT) alone, does not significantly decompose the hair (celestial blue keratin), while the combination of a protease and a disulfide redox agent protein, in the presence of a redox partner or partner, decomposes hair proportionally with the increase in the amount of protein disulfide redox agent.

Example 2 50 kg of bovine hair were depilated using PDI enzyme as protein disulfide redox agent, DTT as the redox partner or pair, and NUE as the protease.

Initial soaking - step 1) O h 300% (150 kg) of water with a temperature of approximately 25 ° C. 0.1% Eusapon-S (0.05 kg) (detergent) Start - 10 rp (turns per minute) The pH was in the range of between 7 and 0:30 h Detention Main soak - step 2) 0:45 h 125% (67.5 kg) of water with a temperature of approximately 28 ° C. 1) 0.1% Eusapon-S (0.05 kg) (detergent) 2) 0.01% Arazit KF (0.005 kg) (preservative) 3) 0.003% AquadermMR B (0.0015 kg) (soaking enzyme) 4) 0.1 % of PDI product (0.050 kg) 10 mg of active PDI protein / gram of PDI product. 10 rpm (turns per minute) The pH was in the range between 7 and 8. 5:45 h Detention Depilation - step 3) 6:00 h 80% (40 kg) of water with a temperature of approximately 28 ° C. 2.5% lime (1.25 kg) 6:15 h 0.06% NUE (0.03 kg) 12.0 MP (protease) 11:00 h Drum operation at 5 minutes of operation followed by a 25 minute interval 24: 00 detention The flesh was removed after the waxing step.

Bovine hides are completely depilated and had a grainy surface without damage.

Conclusion: Previous experiments show that skins and leathers can be depilated in an environmentally friendly manner (without sulfur) by means of a protein disulfide redox agent. The above examples are model experiments. However, it has been found that the hides or skins depilated by means of the method according to the invention are completely depilated without any damage on the outer side of the skin whatever it may be.

It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Having described the invention as above, the content of the following claims is claimed as property.

Claims (28)

1. A method for the depilation of hides or skins by means of enzymes, characterized in that 1) the hides and skins are soaked 2) the soaked hides or skins are subjected to a main soaking, and 3) the hides or skins treated in this manner are depilate by the addition of water, exposure to mechanical influence and attachment to at least one protease, characterized in that the hides or skins are attached to at least one protein disulfide redox agent for at least one time during passage 1) to 3).

2. The method according to claim 1, characterized in that the protein redox agent is added during soaking in step 2).

3. The method according to claim 1, characterized in that the protein redox agent is added simultaneously with or in arbitrary sequence with the protease.

4. The method according to claim 1, characterized in that the protein redox agent is added during the main soaking and a protein disulfide redox agent is added simultaneously with or in arbitrary sequence with the protease.

5. The method according to claim 4, characterized in that the protein disulfide redox agents, added, first, are the same as the protein disulfide redox agent added in the second term.

6. The method according to claim 4, characterized in that the first protein disulfide redox agents are different from the protein disulfide redox agent added in the second term.

7. The method according to claims 3 and 4, characterized in that the protein disulfide redox agent and the protease are added simultaneously.

8. The method according to claims 3 and 4, characterized in that the protein disulfide redox agent and the protease are added sequentially in a manner such that the protein disulfide redox agent is added first and subsequently the protease.

9. The method according to claims 1 to 8, characterized in that the protein disulfide redox agent can be added during step 1), 2) or 3).

10. The method according to any of claims 1 to 9, characterized in that the soaking enzyme is added during the main soaking in step 2).

11. The method according to any of claims 1 to 10, characterized in that a fleshing of the untanned skin between steps 2) and 3) is carried out.

12. The method according to claims 1 to 11, characterized in that the amount of water added to the hides or skins treated in step 3) is between 50 and 200% in relation to the dry weight of the hides or skins, preferably between 70 and 120% of it.

13. The method according to claims 1 to 12, characterized in that the protein disulfide redox agent is added in an amount of between 25 and 1000 mg of pure enzyme protein / kg of leather or salty skin and the protease is added in an amount between 5 and 50 mg of pure enzyme protein / kg of leather or salty skin, and that the total hair removal time is maximum 24 hours.

14. The method according to claims 1 to 13, characterized in that the protein disulfide redox agent is selected from the group of compounds comprising protein disulfide reductases, protein disulfide isomerases, protein disulfide oxidases, protein disulfide oxidoreductase, protein disulfide transhydrogenases, sulfhydryl oxidase, thioredoxins and disulfide bond formation proteins.

15. The method according to claim 14, characterized in that the protein disulfide redox agent is a disulfide isomerase protein (PDI), or variants thereof.

16. The method according to claim 14, characterized in that the protein disulfide redox agent is a thioredoxin (TXR), or variants thereof.

17. The method according to claim 14, characterized in that the protein disulfide redox agent is a disulfide bond formation protein or variants thereof.

18. The method according to claim 17, characterized in that the disulfide redox agent of the protein is DsbA.

19. The method according to claim 17, characterized in that the protein disulfide redox agent is DsbC.

20. The method according to any of claims 1 to 19, characterized in that the protease is selected from the group of serine proteases, aspartic proteases, cysteine proteases and metallo proteases, or truncations, mutations or variants thereof.

21. The method according to claim 20, characterized in that the protease is a serine protease, including trypsins, chymotrypsins and subtilisins.

22. The method according to any of claims 20 and 21, characterized in that the protease is a Bacillus sp. derived from serine alkaline proteases.

23. The method according to claim 22, characterized in that the protease exhibits a pH activity curve with a maximum above pH 9, according to the method of determining KNPU activity.

24. The method according to claim 21 or 23, characterized in that the protease is selected from the group comprising subtilisin BPN ', subtilisin amylosacchariticus, subtilisin 168, subtilisin mesentericopeptidase, subtilisin Carlsberg, subtilisin DY, subtilisin 309, subtilisin 147, thermitase, aqualisin, Bacillus PB92 protease, Proteinase K, Protease TW7 and Protease TW3, truncations, mutations and variants thereof.

25. The method according to claim 20, characterized in that the cysteine protease is from the group including papain and bromelain.

26. The method according to claim 20, characterized in that the metallo protease is from the group comprising Neutrase® and collagenase.

27. The method according to claim 20, characterized in that the aspartic protease is selected from the group comprising pepsin A, pepsin B, pepsin C, chymosin, cathepsin B and renin.

28. The method according to claims 1 to 27, characterized in that the hair is removed from the depilation liquor by continuous filtration during depilation.