AU645412B2 - Enzymatically supported methods for liming and bating - Google Patents

Abstract

The invention relates to a process for the production of pelts ready for tanning, from hides and skins, using proteolytic and lipolytic enzymes in the beam house, wherein in at least one of the part-steps in the beam house consisting of a) the lime in the pH range 11.5 - 14 and the b) bate in the pH range 5 - 11.5 in the aqueous liquors corresponding to these part-steps, alkaline lipases (E.C.3.1.3.) with an activity optimum in the pH range 9 - 11 are employed.

Description

0PI DATE 02/11/92 AOJP DATE 10/12/92 I NTE INTL APPLN. ID 14247 92 PCT NUMBER PCT/DE92/00233 BER DIE NS (PCT) (51) Internationale Patentklassirikation 5 (11) Internationale Vcrdffentlichungsnurnmer: 'WO 92/17613 C14C 1/08 Al (43) Internationales Verbiffentlichungsdatum: 15. Oktober 1992 (15.10.92) (21) Internationales Aktcnzeichen: PCT/DE92/00233 (74) Gemeinsamer Vertreter: RO~HM GMBH; Patentabteilung, Kirschenallee, D-6 100 Darmstadt (DE).

(22) Internationales Anmeldedatum: 19. M'Arz 1 992 (19,03.92) (81) Bestimmungsstaaten: AU, BR, CS, H-U, JP, KR, PL, RU, Prioritlitsdaten: US.

P 41 09 826.9 26. Miirz 1 (26.03.91) DE Veroffentlicht (71) Anelder (ftir alic Bestirnungsstaaten ausser US): R(5H M Mit internationalemn Reclierclienbericlu.

GMBH [DE/DE]; Kirschenallee, D-6100 Darmstadt

(DE).

(72) Erfinder; and Erfinder/Anmelder (hur ffir US) CHRISTNER, Jflrgen [DE/DE]; Tannenstralle 7 B, D-6104 Seeheim-Jugenhelm TAEGER, Tilman [DE/DE]; Breslauer Stra-4 5A A" R~e 35, D-6 104 Seeheim-Jugenheim WICK, Gertrud [DE/DE]; Aumlihlenweg 36, D-6100 Darmstadt 12

(DE).

L~rz~.4rr(A cak v.rLJ M~hA YFirL'IFIL if L J WI ~I (54)Title: Ht1-1fl*MING1 MN/RN!N-RCESUIGEZ -ES J 4j (54) Bezeichnung: ENZYMATISCH UNTERSTOTZTE ASCH ER- UND BEIZVERFAHREN (57) Abstract The invention concerns a process for the production of ready-to-tan skins and hides, the process using proteolytic and lipolytic enzymes at the water-bath stage. In at least one of the operations carried out at the water-bath stage, alkaline lipases with a maximum effective action in the PH range 9 to I I are used in the aqueous baths used in these operations, i.e.

the liming bath at pH 11.5 to 14 and the drenching bath at pH 5 to 11.5.

(57) Zusamnmenfassung Die Erfindung betrifft ein Verfahren zur Herstellung gerbfertiger BU5I9en aus Hduten und Fellen unter Verwendung von proteolytischen und Iipolytischen Enzymen in der Wasserwerkstatt, wobei bei wenigstens einem der Teilschritte der Wasserwerkstatt bestebend aus demn Ascher im pl--Bereich 11,5-14 und der Beize im pI--Bereich 5-11,5 in den diesen Teilschritten entsprechenden w~iIrigen Flotten alkalische Lipasen mit einem Wirkungsoptimumn im pH-Bereich 9-11 eingesetzt werden.

1 58055.321 The invention relates to enzymatically supported liming and bating processes wherein alkaline lipases are used, preferably in combination with proteolytic enzymes.

State of the art The planned use of enzymes in leather preparation began with the introduction of the enzymatic bate by Dr.

Otto R6hm in 1907 (DE-PS 200 519). From this time onward against a background of increasing ecological awareness the use of proteases in different partial operations in the beamhouse has been proposed and also realized in practice (cf. E. Pfleiderer and R. Reiner in Biotechnology, editor Rehm, pp 729 -743, VCH 1988).

Amylases, particularly in combination with proteases, have similarly also entered the bating operation of the beamhouse 4,273,876). The concurrent use of lipases and amylases (in the form of pancreatin) in the presence of desoxycholic acid is known from Hungarian Patent 3325 (Chem. Abstr. 77, 7341k). Because of their natural properties lipases are used for the degreasing of skins and hides, particularly pigskins and sheepskins with a high fat content, and also of scraps. The recommendations for their use for degreasing L.H.

Posorske, J. Am Oil Chem. Soc. 61 (11) 1758 1760 (1984); K. Yeshodha et al., Leather Sci. (Madras) 25 (2) 77 86 (1978), Chem Abstr. 89, 199097; T. Nielsen, Fette, Seifen, Anstrichm. 87 15 19 (1985)] are countered by negative experiences, e.g. with respect to pickled and delimed unhaired sheepskins [cf. A Vulliermet et al., Technicuir 16 64 76 (1982), Chem. Abstr.

97, 57467q; Chem. Abstr. 82, 113205g]. In the literature reference mentioned last, an enzymatic decomposition of fat with lipases or enzyme preparations containing lipase in a pH range below 8, preferably in a moderately acid pH range, is considered.

2 In Biotechnology, editor Rehm, vol. 7a, loc.cit. p.644, it is noted that microbial and pancreatic lipases cannot be used as enzymes for washing agents because of their notorious instability under alkaline conditions, quite apart from their price.

The decomposing effect of proteases on proteins, as demonstrated by the lipases, argues against a concurrent use of lipases and proteases.

Recently, an enzymatically supported soaking method for hides and skins has been recommended, in which the soaking floats contain A) lipases having an acitivity optimum in the pH range of from 9 to 11, B) proteases having an acitivity in the pH range of from 9 11, and C) surface active agents, wherein the pH value of the soaking float is in the range of from 9 to 11 (cf. German patent application P 39 22 748.0). For this, enzymes obtained from Aspergillus species and from certain special genetically altered strains have been found to be especially suitable, for example an alkaline lipase obtained by recombination from an Aspergillus orvzea strain, having a pronounced activity optimum between pH 9 and 11, as well as a lipase commercially available under the name "LIPOLASE 100 T" (Novo Industri A/S, Bagsvaerd, 2880 Denmark).

Problem and solution.

The processing of raw material which is very rich in fat (such as pigskins, sheepskins, scraps, etc.) still presents difficult problems to leather manufacturers.

These problems may be listed in short as: insufficient liming and freedom of the dehaired skins from scud after opening of the hide structure, as well as the formation of interfering calcium soaps, which can lead to unpleasant smears on the skins.

Also, the bating of fatty dehaired hides presents difficulties because an adherent fatty surface film 3 hinders penetration of the bating enzymes and can counteract the optimum loosening of scud.

The teaching of aforementioned German patent application P 39 22 748.0 does not extend beyond the use of certain lipases in soaking, i.e. in a pH region of 9 11. Since, according to the instructions of their manufacturers, these enzymes have their pH optimum in the range of from 10 11, it appears that the recommendation for use, according the the aforementioned German patent application, refers, at least as far as this parameter is concerned, to a range which it is sensible to consider.

Exceeding this pH range appeared ab initio hardly to promise success; on the contrary, the skilled man must expect considerably less efficiency and decreased stability, the farther removed he is from the aforementioned range.

It has now been found that, surprisingly, alkaline lipases which characteristically have a pH optimum from about 9 11, particularly from 10 11, can advantageously be used in the beamhouse in the aqueous floats appropriate to the steps of a) liming in the pH range from 11.5 14, particularly 12 13.5, and especially from 12 13, and b) bating in the pH range from 5 11.5, particularly 7 9.5, and especially 8 9.

The effect is particularly pronounced if the aforementioned lipases are used in an enzyme combination (EC) together with neutral or alkaline proteases (P) chosen to correspond to the step in question.

Preferably, this involves those proteases normally used in industry.

"Liming" should be understood to refer to the known process for swelling the epidermis and loosening hairs and guard hairs to the point of removal under the influence of alkaline liming chemicals (cf. F. Stather, Gerbereichemie und Gerbereitechnologie, pp 166 199, Akademie-Verlag 1967; Ullmann's Encyclopedia of Industrial Chemistry, 5th edition, vol. A15, pp 259 4 282, VCH 1990). Depending on how the process is carried out, the liming can be arranged to retain hair or to destroy it. Liming is generally carried out in the pH range from 12 13, either in the form of the so-called "hydroxyl liming", where, in particular, calcium hydroxide, as well as alkali metal hydroxide, ammonia, and other hydroxides of alkaline earth metals, are used, or in the form of the so-called sulphide liming, the active components of which are alkali metal sulphides or alkaline earth metal sulphides, optionally in admixture with other basic alkalis or alkaline earth metals. The liming process of the present invention extensively follows the method of the state of the art (cf. Ullmann's Encyclopedia of Industrial Chemistry, 5th edition, vol.

15A, pp 259 282, VCH (1990); Ullmanns Enzyklopadie der Technischen Chemie, 4th edition, vol. 16, pp 119 120, Verlag Chemie (1978), 3rd edition, vol. 11, p 609, Urban Schwarzenburg The liming procedure according to the present invention can be performed with a float length of 50 250, preferably 80 to 150, percent of water by weight of the hides.

In general, the liming process requires 12 to 36 hours, particularly 16 to 20 hours.

In the steps of deliming and bating, which follow liming in the beamhouse, the hides and skins are neutralized and enzymatically bated. In so doing, the hides and skins are firstly washed and delimed, preferably using weak acids, for example organic acids such as lactic acid, formic acid, acetic acid, butyric acid, propionic acid, or dicarboxylic acids or the like, or using weakly acidic inorganic compounds such as sodium bisulphite, sulfophthalic acid, ammonium sulphate, or even carbon dioxide. In general, during deliming it is important to see that a pH range results, which will be favourable for the subsequent use of enzymes for bating.

For pancreatic enzymes, the pH values range from 7.5 8.2. The subsequent bating serves to remove residues of 5 epidermis and hair and further to open the hide structure. As a rule, the enzymatic bating component, especially enzymes of the pancreatic complex, is added after a certain time. The enzymes of the pancreatic complex may also include lipases (DE-A 37 04 465). The range between 32 and 37"C has proved to be a suitable bating temperature. Bating generally lasts 1 to 3 hours.

Preferably, the enzymatic preparation mixtures, particularly those involving the enzyme combination EC, also contain sequestering agents SM, mainly to avoid calcium soaps.

Further, the addition of substances acting as emulsifiers ES has proved to lead to a particularly satisfactory emusification of fat. The float length corresponds to that for carrying out liming.

The alkaline lipases AL The lipases to be used according to the invention are, in agreement with the usual definitions, esterases, which hydrolyze glycerin esters of the fatty acids in aqueous emulsion Cleavage of the triglyceride preferably takes place in the 1,3-position.

In contrast to the lipases normally used according to the state of the art, with an applicational range from pH 6 9, the lipases according to the present invention have a pronounced activity optimum towards olive oil or tributyrin) between pH 9 and 11. Such alkaline lipases were specially developed for the detergent industry.

They are of microbiological origin. Potential sources for such strains of microorganisms, which may, optionally, be genetically altered, are, in particular, fungi and bacteria. Certain alkaline lipases occur, for example, in Pseudomonas strains. Rhizopus sp., Candida sp., Chromobacterium sp., can also be considered as producing lipases. Further important lipase producers are Geotrichium sp., Aspergillus sp., Mucor sp., Penicillium sp., Corynebacterium sp., Propionibacterium sp., and Achromobacter sp.. Special mention must be made 6 of Rhizopus arrhizus and Rh. oryzae, Candida cyclindracea, Chromobacterium viscosum, Geotrichium candidum, Mucor miehi, Mucor pusillus, Penicillium roqueferti and P. cyclopium, Corynebacterium acne, Propionibacterium shermanii, Achromobacter lipolyticum, Aspergillus niqer, especially Aspergillus oryzae.

Certain genetically altered strains have also been found to be particularly suitable, e.g. an alkaline lipase of an Aspergillus oryzae strain obtained by recombination and having an outstanding activity optimum between pH 9 and 11, or a lipase commercially available under the name of "®LIPOLASE TM 30 T" (Novo Industri A/S, DK 2800 Bagsvaerd, Denmark).

The determination of the activity of lipases is carried out in the usual way with olive oil as the substrate, but also with triacetin and tributyrin. [Cf.

M. Semeriva et al., Biochemistry 10, 2143 (1971); Pharmaceutical Enzymes, edited by R. Ruyssen and A.

Lauwers, 1978, If the fat cleaving activity is expressed in kilo-lipase units (one unit KLCA), tributyrin is used as a substrate working under the standard conditions at 40°C. (Cf. M. Semeriva, loc.cit..) For the purposes of the present invention, lipase activity is given in LCA units, measured, however, at pH According to the invention, the lipases are so employed that a lipase activity of 100 100,000 LCA, preferably 2,000 4,000 LCA, is present in a float per kg of skins at pH The proteolytic enzymes P The use in liming of proteases which display a sufficient proteolytic activity in the pH range between 9 and 13 is known. These are neutral (E.C.3.4.24), particularly alkaline proteases (E.C.3.4.21) [cf. Kirk- Othmer, Encyclopedia of Chemical Technology, 3rd edition, pp 199 202, J. Wiley 1990; Ullmann's Encyclopedia of Industrial Chemistry, vol. A9, pp 409 414, VCH 1987; L.

7 Keay, in Process Biochemistry, 17 21 (1971).] In detail, these are Alkaline proteases which display their activity optimum approximately in the pH range of from 8.5 13.

These include alkaline bacterial proteases, which for the most part are of the serine type, and alkaline fungal proteases. Mention must be made of mainly the proteases from Bacillus strains such as B.subtilis, B.

licheniformis, B. firmus, B. alcalophilus, B. polymixa, B. mesentericus, as well as Streptomyces strains like S.

alcalophilus. The most favourable working temperature with alkaline bacterial proteases is, in general, 60°C and with fungal proteases 20 40*C. The alkaline fungal proteases include those from Aspergillus strains, such as A. oryzae, from Penicillin strains such as P.cvanofulvum, or from Paecilomyces persicinus, and the like. The activity of the alkaline fungal proteases is primarily in the pH range of 8.0 11.0. As a rule of thumb, one can proceed from an enzyme activity which is between 8,000 and 10,000 L6hlein-Volhard Units (LVU) per gramme of enzyme.

Neutral proteases having an activity optimum in the range of from pH 6.0 9.0. These include, in particular, neutral bacterial proteases, which belong, as a rule, to the metallo enzymes, and fungal proteases, for example neutral Bacillus proteases such as B. subtilis, B. natto, and B. polymixa, Pseudomonas proteases, Streptomyces proteases, Aspergillus proteases from A.

orvzae, A. parasiticus, and Penicillium qlaucum. Neutral bacterial proteases display their optimum activity at working temperatures of 20 50"C., whereas the most favourable working temperatures for neutral fungal proteases is 35 The proteolytic activity of the enzymes is usually determined according to the Anson haemoglobin method Anson, J. Gen. Physiol, 22, 79 (1939)] or according to the L6hlein Volhard method [modified by TEGEWA in Leder, 22, 121 126 (1971)]. According to the latter, 8 one L6hlein Volhard Unit (LVU) is that amount of enzyme which, in 20 ml of casein filtrate, causes an increase of the hydrolysis product corresponding to an equivalent of 5.75 (10- 3 ml of 0.1 N NaOH under test conditions (1 hour, 37"C). The protease activity in general is between 1,000 and 60,000 LVU per kg of hides, preferably between 2,000 and 14,000 LVU per kg of hides.

Depending on activity, amounts of protease between 0.05 and 0.8 or as a rule of thumb about 0.1 0.25 wt%, based on the weight of the hides and skins, are sufficient according to the invention.

As (synthetic) surface active substances, the usual emulsifiers, for example, can be used, particularly those suitable for the emulsification of fat in water. (Cf.

GB-PS 586,540, DE-PS 894,142, FR-PS 899,983, FR-PS 918,523). First of all, non-ionogenic emulsifiers are suitable, for example of the following kinds: I. Polyglycol derivatives (exemplary commercial products given in parentheses) a) fatty acid polyglycols (EMULPHOR B) fatty alcohol polyglycol ethers (DEHYDOL 7) alkylphenol polyglycol ethers (EMULGIN 6) fatty acid ethanolamido polyglycol ethers 286, FLUIDOL W 100

MARLOPHEN,

IGEPAL (C FORYL KW

EMULGIN)

(TEGOMOLS example, of the II. Glycerin derivatives a) fatty acid monoglycerides B) fatty acid polyglycerin esters.

Further anionic emulsifiers are, for following kinds: III. Sulphates R OSO 3 Na a) fatty alcohol sulphates, primary (EPPOL DL and secondary conc.®,PERAMIT I I I 9 3) fatty alcohol ether sulphates monoglyceride sulphates 6) sulphation products of unsaturated oils and fatty acids IV. Sulphonates R S03Na a) alkylbenzene sulphonates

(ABS,TPS)

B) alkyl sulphonates 7) fatty acid condensation products 6) petroleum sulphonates E) sulphitation products of unsaturated fatty oils and fatty acids short-chained alkylbenzene sulphonates, e.g. of cumene, toluene, or xylene.

ML TEEPOL®) (TEXAPON Q (VEL

(LEDEROLINOR

DKMS (MARLOPON MARLON (MERSOLAT (IGEPONA IGEPONT (contained in: GRASSAN B (CUTISAN BS Cationic emulsifiers, e.g. of the following types, are less

V.

advantageous: Amine salts R NR!, R 2 Hx (SAPAMIN SOROMIN (REPELLAT VI. Quaternary Ammonium Salts RNeR 3 Xe a) ammonium salts P) pyridinium salts, wherein tne group R is a long-chained alkyl group having 8 24 carbon atoms, the groups R 1

R

2 or R 3 as a rule represent short-chained alkyl groups having up to 6 C-atoms.

10 The emulsifiers usable according to the invention have an HLB value (O/W emulsion) of 8 18, preferably 9 15, especially 12 15. (Cf. Ullmanns Encyklopddie der Technischen Chemie, 4th edition, vol. 19).

Combinations of emulsifiers can also advantageously be used, particularly of non-ionic and anionic emulsifiers.

Emulsifier combinations ES of the following kinds are specially mentioned (EO degree of ethoxylation): x% C1 C 1 3 fatty alcohols ethoxylates having 6 10 EO preferably 8 9 EO y% C15 C 17 paraffin sulphonate Na salt z% C1 C 18 fatty alcohol amine ethoxylate having 7 moles of ethylene oxide, quaternized water to 100% wherein x 10 50 percent by weight y 10 50 percent by weight z 1 50 percent by weight The content of emulsifiers in the floats is as a rule from 0.1 to 1 percent depending on type of the salted weight or 'reen weight of the skins or hides.

Remarkably, the precipitates which are to be expected with the above composition do not occur when using the preferred combinations. Also, the floats can still contain known sequestering agents. The sequestering agents are chosen from the group formed by the polyphosphates, the phosphonates, the polycarboxylates, ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid, diethylenetriaminopentaacetic acid. The content of sequestering agents in the soak float can be from 0 to percent by weight, preferably 0.05 to 0.15 percent by weight. (Cf. Kirk-Othmer, Encyclopedia of Chemical Technology, 3rd edition, vol. 5, pp 344 345, J Wiley 1979).

In detail, the method of the invention can be carried out as follows: 11 The lipases used correspond to the designations given above, as do the proteases.

Liming method In a hair jellification method, the enzymes or enzyme combinations are added to the soaked hides or skins at the beginning of the process. Enzyme combinations EC of the following composition have proved particularly useful: 100 1,000 KLVU alkaline bacterial protease, e.g. from B. subtilis, B.

licheniformus 0.1 5 lipase having an activity of 5,000 LVU/mg 20 Na tripolyphosphate to 100 Na sulphate The product is conventionally dosed in the range from 0.05 1 percent by weight of the salted or green hides.

As a guide value for the float length, 150 percent is given; the temperature is preferaby 28*C.

Although sulphur liming is involved, the liming bath contains relatively small amounts of the liming chemicals, typically sodium hydrosulphide as a guide value about 0.6 percent by weight and sodium sulphide as a guide value about 0.2 percer: by weight as well as hydrated lime guide value about percent by weight based on the hides, at a pH value of 12.8.

The batch is agitated for about 1 hours under these conditions before the enzymes, particularly the enzyme combination EC II is added as a guide value in amounts of about 0.3 percent by weight preferably with about the same amount of hydrated lime as is already present, and is constantly agitated for a short time at first, and 12 then left to react over a longer period of time, for example about 16 hours, with occasional stirring.

After draining off the float an' ashing, preferably with about 150 percent of water at 2 C, dehaired skins of good quality are obtained. The smoothness and the freedom from scud of the dehaired skins are emphasized.

In a liming process in which hair is retained, the hides or skins are soaked as usual. It was found that hides and skins which have been pretreated or soaked with an alkaline protease at pH 8 11 for 4 20 hours and then are treated at the same pH for 2 6 hours with an alkaline lipase in the same bath, or in a new bath, are extremely well prepared for a subsequent proteolytid removal of hair. Advantageously, a hair immunization step directly follows the soak in which according to DE-A 38 02 640 hydrated lime and organic thio compounds together with amines in about 80 percent of water at about pH 12 can be used. Then, a hair loosening step usually follows. When the enzyme combination EC-II to be added according to the invention is used, a sharply reduced amount of sulphide is sufficient, for example 0.4 percent by weight of sodium hydrosulphide based on the hides. After a relatively short time, for example about 2 hours, the hides are free of hair. Suitably, about 70 percent by weight of water is added together with about 2 percent by weight of hydrated lime and about 0.3 percent by weight of sodium hydroxide solution and the process is continued over a certain period of time, suitably about 14 hours at 28°C with short periods of agitation at moderate intervals. Subsequently the float is drained off and further processing is continued in the manner usual in industry. Normally, the liming procedure can directly follow fleshing and splitting of the hides.

Bating The hide material prepared in the usual way, e.g.

fleshed and split dehaired skins, are washed and delimed 13 (supra). Generally, the addition to a float of about percent and at 30°C of about 2 percent by weight, based on the hide material, of a deliming agent is sufficient, for example in the form of the above-mentioned acids carbon dioxide or dicarboxylic acids in combination with ammonium salts), which are suitably added in two portions each of 1 percent by weight and are each allowed to act for 10 or 20 minutes, whereby the pH decreases to about 8.5. For the bate itself, as a rule about the same amount of water is added, preferably at 35°C, and the enzyme is added, preferably as enzyme combination EC.

As a rule, enzyme combinations EC of the following typical composition are used: 100 KLVU pancreatic complex 0.5 5 alkaline lipase having an activity of 5000 LU/mg 30 Sodium tripolyphosphate to 100 Sodium sulphate or ammonium sulphate.

After deliming, the product according to the invention is added at 30 35°C over 20 120 minutes in an amount of 0.5 2 percent by weight of the dehaired skins.

Suitably, the batch is agitated for about 1 hour at 33 0 C with the pH at about 8 8.5, the guide value being 7.9. Then the float is drained off and the batch is washed, with agitation, with about 200 percent of water at about 22°C. In the fashion conventional in tanneries, pickling and chrome tanning can then follow.

Advantageous effects The methods according to the invention are based on the observation that enzyme preparations which contain one or more lipases whose activity optimum, according to the specification, is in the pH range of 10 11, can be used with outstanding success both under the conditions of liming at a pH of about 13 and in bating in the pH range of 7 9. The effect in combination with 14 corresponding neutral and alkaline proteases is particularly pronounced, as summarized as follows: improved loosening of pigment scud improved degreasing of the dehaired skins fewer grain wrinkles and grain damage performance of a sulphide-free and also a sulphide-deficient smoothing which retains the hair.

With the use of alkaline lipases in the bate at pH 7 9, preferably in combination with pancilatic enzymes, an improved loosening of scud is observed.

The following examples serve to illustrate the invention:

EXAMPLES

Products Used: Product EC-I: Bating agent containing lipase 100 KLVU 1 wt.-% wt.-% wt.-% ad. 100 wt.-% Product EC-II: 500 KLVU 2 wt.-% ad. 100 wt.-% Deliming agent: pancreatic enzyme complex alkaline lipase LIPOLASE 100 T, Novo), 5,000 LU/mg sodium tripolyphosphate sodium sulphate ammonium sulphate.

Liming excipient containing lipase alkaline bacterial protease from Bacillus subtilis alkaline lipase LIPOLASE 100 T) sodium sulphate Ammonium sulphate/dicarboxylic acid basis Emulsifier combination ES: wt.-% C 13 -fatty alcohol ethoxylate with 8 mols of ethylene oxide 15 wt.-% 6 wt.-% ad. 100 wt.-%

C

15 -paraffin sulphonate, sodium salt

C

16

-C

18 -fatty amine ethoxylate with 6 mols of ethylene oxide, quaternized water.

Test 1: Preparation of soft shoe-upper leather bating Material: Split dehaired cowhide (2.5 mm). (Data based on the weight of the smoothed hides) Starting material: 100 kg of skin material Washing: 200% water, 30*C, agitate for 10 minutes.

drain float.

Dcliming: 1% 1% water at deliming agent, agitate for 10 minutes deliming agent, agitate for 20 minutes K pH 8.5, colourless water, product EC-I agitate every 60 minutes, pH 8.3, 33°C drain off float Bate: 50% 1% Washing: 200% water, 22"C, agitate for 10 minutes drain float Pickling, Chrome Tanning: As usual in the tannery.

16 Analytical Data: Fat content in the float: 0.6 g/l Fat content in the dehaired hide: 0.25% based on dry weight.

For comparison, a test was carried out with the same product as product 1, but without lipase: Fat content in the float: 0.4 g/l Fat content in the dehaired hide: based on dry weight.

Test 2: Preparation of garment leather (sheepskin) bate (data based on weight of dehaired skins) Starting material: 100 kg unsplit dehaired sheepskins Tanning vat Washing: 200% water, agitate for 10 minutes drain off float.

Deliming: 50.0% water, 30*C, agitate 1.4% deliming agent, agitate for minutes, pH 8.6 Bate: 50.0% water, 0.3% emulsifier ES product EC-1 agitate for 2 hours pH 8.5, 32°C

L

17 drain off float.

Washing: 200.0% water, 22°C run for 10 minutes drain off float.

Pickling/tanning: as usual in the tannery.

Analytical data: Fat content: Float 9.8 g/1 Dehaired hide based on dry weight.

Product 1, but without alklaline lipase, was tested in the same way: Fat content: Float 6.1 g/1 Dehaired hide based on dry weight.

Test 3: Preparation of garment leather (pigskin), bate Material: Pigskin split to 2.0 mm Tanning vat (Data based on weight of dehaired skins) Washing: 200% water, 30 0 C; 10 minutes; drain off float Deliming: water, 18 deliming agent agitate for 30 minutes float, pH 8.6 Bate: 100.0% 0.3% water, emulsifier combination ES product EC-1 agitate for 90 minutes pH 8.3; temperature 33"C.

Washing: 200% water; 22°C agitate for 10 minutes drain off float Pickle/Chrome tanning: as usual in the tannery.

Analytical data: Fat content Float 13.1 g/1 Dehaired hides based on dry weight.

For comparison, product 1, without alkaline lipase, was used in the same working method: Fat content: Float 10.2 g/l Dehaired hides 8.9% based on dry weight.

Enzymatic dehairing of sheepskins Test 4: 19 Material: 200.0% 0.1% water, 28°C non-ionic emulsifier, comprising

C

1 ,-fatty alcohol with 8 mols of ethylene oxide agitate for 20 minutes let stand for 30 minutes agitate for 20 minutes drain off float water, 26°C enzymatic soaking agent comprising proteolytic enzyme from Bacillus licheniformis; 4000 LVU/g pH 9 Main soak: 200.0% 0.2% 0.7% agitate for 260 minutes drain off float Dehairing: 200% 0.005% 0.6 1.1% water, 32"C lipase, alkaline having 5000 LVU/mg soda, pH 8 agitate 3 4 hours 2% proteolytic dehairing enzyme from Aspergillus parasiticus, 40-00 LVU/g agitate for 60 minutes 1 A 20 then agitate for 1 minute per hour for a further 16 24 hours; pH 9.1 temperature 28°C drain off float dehair Washing: 200% water; 26 C agitate 10 minutes drain off float conventional opening of the hide structure with hydrated lime treatment for 4 8 hours Test 5: Liming (sulphide-deficient) of salted cowhides of weight class 30 39 kg for the preparation of furniture leather Tanning vat: Presoak: 150% water, 26 C agitate for 30 minutes let stand for 30 minutes drain off float Soak: 150.0% 0.3% 0.25% water, 26°C non-ionic surfactant comprising proteolytic enzyme product from Bacillus subtilis; 4400 LVU/g sodium hydroxide solution (33%) pH 9.5 21 agitate for 6 hours drain float Liming: 150.0% 0.6% 0.2% 0.3% Washing: 150.0% water, 28°C sodium hydrosulphide (72%) sodium sulphide hydrated lime; pH 12.8 agitate 90 minutes test product EC-II hydrated lime agitate 30 minutes, then for 2 minutes per hour for a further 16 hours drain off float water, 28°C agitate 10 minutes drain off float The dehaired hides are very smooth and free of scud.

Test 6: Hair-retaining liming ofsalted cowhides, weight class 30 39 kg, for preparation of furniture leather Tanning vat: Presoak: 150.0% 0.1% water, 26°C non-ionic surfactant comprising tallow ethoxylate 2 hours (let rest 30 minutes, I 22 agitate 30 minutes) Soak: 150.0% 0.2% 0.25% water, 28"C non-ionic surfactant comprising fatty alcohol ethoxylate proteolytic enzyme product from Bacillus subtilis, 4400 LVT/g bring to pH 9.5 10 with sodium hydroxide solution (33%) agitate for 5 hours drain off float Immunization: 80.0% 1.2% 0.6% 0.3% water, 28°C liming excipient comprising alkanolamine and organic thio compounds hydrated lime agitate 60 minutes sodium hydrosulphide, 72% test product EC-II after 2 hours the hides are free of hair water, 28°C hydrated lime sodium hydroxide solution agitate for 2 minutes per hour for 14 hours drain off float work up further as usual in the tannery 70.0% 0.3% Treatment with the enzyme product according to the invention permits omitting a post-liming. Opening of the L h.~ -23 hide structure is optimum after a processing time of 16 18 hours.

Claims (6)

1. Process for preparing dehaired hides ready for tanning from hides and skins using proteolytic and lipolytic enzymes in the beamhouse, characterised in that in at least one of the partial steps of the beamhouse, consisting of a) liming in the pH range 11.5 14 and b) bating in the pH range 5 11.5, alkaline lipases having an optimum activity in the pH range 9 11 are added to the aqueous floats corresponding to these partial steps.

2. Process according to Claim 1, characterised in that the alkaline lipases are added concurrently with alkaline 15 proteases (E.C.3.4.21) or neutral proteases (E.C.3.4.24).

3. Process according to Claims 1 and 2, characterised in that, as proteases, the proteases of a pancreatic complex ar& added.

4. Process according to Claims 1 3, characterised in 20 that the enzymes are used with surface active substances known per se.

5. Process according to Claims 1 4, characterised in that the liming a) is performed in the pH range 12

13.5. 25 6. Process according to Claims 1 5, characterised in Sthat the bating is carried out in the pH range 8 9. 7. Process according to Claims 1 6, characterised in that the enzymes are used concurrently with sequestering agents known in the art. 8. Process according to Claim 1, characterised in that the float length is 50 250 percent of water by weight of the hides. 9. Process according to Claim 8, c' .dcterised in that the float length is 150 50 percent. DATED this -j day of Ne~'e&Vwer- 1993 RAA ROHM GmbH ,By their Patent Attorney /VT 0 /CALLINAN LAWRIE '~NTA 25 Abstract The invention relates to a method for preparing dehaired hides ready for tanning from hides and skins using proteolytic and lipolytic enzymes in the beamhouse, whereby in at least one of the partial steps of the beamhouse consisting of a) liming in the pH range 11.5 14 and b) bating in the pH range 5 11.5, i0 a C. 3.I.11.3,) alkaline lipases having an optimum activity in the pH range 9 11 are added to the aqueous floats corresponding to these partial steps.