DD262447A1 - SOFT METHOD OF CONSERVED BEAUTY - Google Patents

Abstract

The invention relates to a soft process of Rohhaeuten or preserved Rohhaeuten. These Rohhaeute are to be brought into the original swelling state, in the subsequent reaction steps such as depilation, skin disruption, tanning, etc. over the surface of the skin almost uniformly obtained product with higher surface yield. The soft process is carried out with water with the addition of a pretreated Abproduktloesung from the cultivation of the microorganism Streptomyces griseus with addition to the microbial growth inhibiting substances and the enzymes stabilizing compounds.

Description

Field of application of the invention

The invention relates to a soft process of raw hides or preserved raw hides, which are to bring in the water workshop of the tannery in the original swelling state in order to evenly depilate them in the subsequent reaction steps of pelvic extraction and optionally by skin pulping the basis for a later required softness and elasticity to lay. These processes lie solely in the area of the leather-producing industry.

Characteristic of the known state of the art

For the living body, microorganisms are not foreign bodies. You take z. B. part of metabolic processes. The skin on the living animal is also covered by microorganisms (bacteria and fungi) which are essentially useful as long as the skin is alive. This condition immediately changes on the dead skin. The beneficial microorganisms exhibit extensive growth in the breakdown and destruction of the skin substance. This is the reason why animal skins, which can not be incorporated in the tannery immediately after skinning, must be preserved. By the preservation, z. B.

by drying or salting, the microorganisms are deprived of the necessary moisture for propagation. By reducing the humidity, however, the collagen fibers move closer together via polar groups until the material stiffens and hardens. In order to produce leather, the original swelling state must be restored, which is generally not to do without aids. Apart from the necessary swelling process of the skin, the switch also serves for skin cleansing. To facilitate skin swelling, the pH is changed to the acidic or alkaline range.

According to J. A. Wilson (Chemistry of Leather Manufacture, Vienna 1930, p.213) swelling maxima are at pH 2.4 and 11.6, respectively. This is based on the use of acidic or alkaline "Anschärfmittel" in soft water.

By Otto Röhm (DE 268873 - Dehairing and cleansing of hides and skins by treatment with an optionally alkaline solution of tryptases and DE 288095 - Process for softening hides and skins by treatment in an aqueous solution of fat and protein-splitting enzymes of the pancreas if necessary in the alkaline range), the proposal is to accelerate the softening process by adding controlled amounts of tryptic enzymes. These developments date back to 1910 and 1914.

As late as 1948, F. Stather writes that O. Röhm's proposal to speed up the softening process by adding controlled amounts of tryptic enzymes has received little input into practice and repeats this statement as late as 1966 (Gerbereichemie and Gerbereitechnologie, Akademie-Verlag, Berlin 1967, p. 159).

Since then, with increasing industrialization of leather production, the enzyme crossover has been introduced and enforced. This is evidenced by the many inventions in this field.

Initially, due to the state of emergency of the First World War, the recommendation was made to add proteins or protein degradation products to the soft water (DE 298322, later also SU 55069.56549 and 56631). This recommendation may have damaged rather than benefited the development of an enzymatic switch. F. Stather (see above, page 157) writes:

Regardless of the fact that bacteria enzymes favorably influence the softening process, the formerly common use of "rotten" turnouts, ie heavily bacteria-containing, repeatedly used softened waters, must be rejected as completely inappropriate, since in such switches the skin material is damaged by uncontrollable bacterial action.

The later inventions related to the use of defined products in their enzymatic activity with both bacterial protease and fungal protease and other enzymes. In DE 1022350, the use of bacterial proteases, optionally together with other proteases, has generally been protected for diversification.

DE 1022748 protects the use of the proteolytic enzymes formed by molds or bacteria together with the carbohydrases formed by microorganisms for the purpose of softening skins and skins, whereby the protein-splitting enzymes produced by the pancreas are included. The moldyptylase originates from Aspergillus crycae.

In DE 1034317 the effect of powder or. pasty-shaped enzyme products protected from previously dilute solutions. In one example, the combined use of mold fungus tryptase, bacterial protease and carbohydrase from Bacillus subtilis has been proposed.

In the older patents, the softening of hides and skins using yeast cultures or self-digested yeast in the presence of wetting agents, e.g. As non-tanning acting aromatic simple or condensed sulfonic acids, fatty alcohol sulfonates, alkyl sulfates, fatty acid condensation products u. a. possibly with the concomitant use of acids containing S, N or P or aliphatic primary or secondary amines or salts of organic dibasic acids (DE 710789, DE 721 885).

Only recently has been proposed in SU 1147759 for switching pet fur skins the concomitant use of anionic surfactants together with protosubtiline G 3h, with an antiseptic (formaldehyde) in the soft process is used. Even in SU 423843 the co-use of an antiseptic is protected. DD 138479 describes the sequential use of formaldehyde and enzyme.

The co-use of papain and other enzymes of the Carica papaya or of Bromelin when switching dates back to GB 474991. The same is protected by DE 1800891, while according to DE 2113214 and 2161824 a papain and pancreatin blending enzyme is used together with a mixture of different amino acids, in particular cysteine and / or cysteine hydrochloride.

Urease, another enzyme from the plant kingdom (bean seeds) is used to switch according to US 2212750.

ImDE 1282838 states that the processes known so far have not been quite satisfactory using proteolytic enzymes, and reducing substances such as hydrazine are used to improve the situation for shedding skins and skins with proteolytic enzymes alone or together with carbohydrases.

According to DE 2059453 and also DE 2308967, the switch of skins and hides is carried out by means of proteolytic enzymes in liquors adjusted to alkalinity, at a pH of between 10 and 12. It should be noted that also in the patents DE 288095, DE 369587 and GB 474991 alkaline was softened. In the newer methods, an undesirable skin swelling is avoided compared to the older methods.

While proteolytic enzymes have generally been used in the processes mentioned hitherto and the processes according to the invention have generally been characterized by additives or by conditions of use, in the following patents the origin of the enzymes, possibly with the accession number of the strain, is protected.

This includes

SU 331091 Aspergillus avamori US 4,288,556 Streptomyces caligosus DE 2836824 Rhizopus rhizopodiformis DD 224870 Bacillus licheniformis

The latter involves the utilization of collagenolytic side activities.

The listed soft processes using enzymatic auxiliaries all require industrial production of the enzymes for use in leather production. Exempted from this is DE 298322, wherein proteins or decomposition products thereof are added to the soft water. It was found to be an uncontrolled enzyme process that did more harm than good to the introduction of the enzymatic switch.

The use of enzymes for the switch must be controlled and interrupted. If prolonged, it may lead to hair loosening, but certainly to skin disintegration, which blends into a breakdown of skin substance.

After all, however, several processes are designed in such a way that the essential waterworks partial steps are to a certain extent carried out enzymatically "in one go." This is proposed in DE 1282838, DE 1800891, DE 2301 591 and DE 2307603.

However, it must be remembered that enzymatic processes in leather production get more and more out of control the longer they are used.

Object of the invention

The use of enzymes is costly because the controlled use proteolytic enzymes must be obtained by breeding bacterial strains or fungal cultures. It is an object of the invention to bring enzymes used, which are not intended for leather production, but already produced, so require virtually no special effort to manufacture and thus are inexpensive. It is a further object of the invention to obtain an effect on the leathers by application of the enzymes in terms of yield gain and also smoother pelts with less pronounced fattening folds and less scar pull.

Explanation of the essence of the invention

The invention has for its object to make an existing product containing proteolytic enzymes, suitable by a treatment for use as a soft assistant for raw hides or preserved raw hides to prepare for the production of leather.

The soft method according to the invention for raw hides or preserved hulls, especially those which have been made storable by salts, is characterized by the use of a pretreated waste solution from the cultivation of the microorganism Streptomyces griseus, which contains low molecular weight proteases, microbial growth inhibiting substances and the compounds stabilizing proteolytic enzymes, and possibly a wetting agent.

To obtain in the fermentative production of streptomycin, which takes place in stirred and ventilated fermentors using glucose, complex protein-rich substrates such as soybean meal and inorganic salts in a known manner, to obtain a suitable for the soft process of raw hides or preserved raw hides waste product solution, several pre-treatment steps are carried out :

1. Addition of excipients to the culture solution at the end of fermentation

2. Removal of solids, especially biomass

3. Removal of streptomycin

4. Addition of stabilizers of enzymatic activity

5. Removal of impurities by adsorption

At the end of the fermentation, 0.1% to 5% formaldehyde (formalin solution, 35%), 0.5% to 2% kaolin and 0.5 g / l to 1.5 g / l of preneutralized oxalic acid are added to the culture. Subsequently, biomass and solid products are separated at an acidity of pH 5.0 to pH 7.0. The filtrate is largely freed from streptomycin by adsorption on ion exchangers at a pH of 7.5 to 8.0. The passage of the ion exchange columns is treated with 0.1 g / l to 5.0 g / l of anhydrous calcium chloride. The latter increases the thermal stability of the proteases and their activity.

The thus obtained partially pretreated waste product solution can be used in this state to the point of raw hides or preserved raw hides.

In order to remove interfering impurities, for example pigments, the solution is cleaned. For this purpose, it is mixed with 0.5% to 2% pre-swollen, neutralized bentonite and 1% to 2% pre-precipitated and neutralized calcium phosphate. The solution is stirred and then these additives are removed again with the impurities adsorbed on them. The purified, pretreated waste product solution can also be used in this state as a softening agent of preserved hides.

You can still narrow this pretreated waste solution, z. B. in a vacuum evaporator, and use as a conserved waste solution or as a solid.

It has been found that the added formaldehyde to the waste solution does not interfere with the proteolytic activity of the enzyme as would be expected, although formaldehyde is considered to be a fermentation toxin. However, references to this feature are already available from SU 1147759 and from DD 138479.

This peculiarity is probably due to the activity of the advantageous low molecular weight protease fraction. In this context, it should be mentioned that by not applying costly precipitation high activity losses are avoided. It is also the composition of a ferment extremely diverse and not necessarily uniform.

The whole life process can be considered as an ordered activity of enzymes, disease and death as a disorder of this enzyme order or inhibition (J.B. Sumner, JALCA [1950], p. 575). A single cell may contain from 100 to 1000 different enzymes (F. Slather, supra, p.109).

This explains the differentiated composition of the decolorization solution and it can not be assumed that enzymes, such as proteases, have a uniform structure but consist of a difficult-to-understand mixture of different compounds with complementary properties. In this respect, the low molecular weight protease fraction is to be assigned a not to be underestimated importance with regard to the proteolytic activity of the waste product solution. On the other hand, it should also be noted that the formaldehyde, which has tanning properties, does not block the switch of the preserved skin with limited supply.

Advantageously, the addition of formaldehyde affects the shelf life of the waste product solution. It reduces the risk of microbial growth in the waste solutions. The small amount of streptomycin remaining in the waste product solution also counteracts microbial growth.

Optionally, incipient growth can be prevented by adding formaldehyde or other growth inhibiting substances. "^

For the storage of the waste product solution, a pH of 6.0 and a storage temperature of 10 ⁰ C are conducive. It is to be noted with regard to the suitability of the waste product solution for use as Weichhi'fsmittel for raw hides or preserved hides and skins that not only the treatment of the waste product solution is important, but especially the resulting by the process control in the cultivation of the microorganism Streptomyces griseus composition from which the waste product solution, which in turn has a specific composition, is separated off.

It is assumed that the waste product solution was originally channeled and got into the wastewater and that the solutions of soft processes in raw hides, including soft aids containing, are also fed to the wastewater. Utilization of this treated waste product solution thus not only leads to the saving of equivalent softening agents, it also results in the present invention, a lower supply of waste to the sewage network. The investigations carried out with the pretreated waste solution on cattle hides led to the assessment that the effects known on the use of alkaline proteases on the quality and quantity of the leathers were obtained. In particular, it should be noted that the increase in area due to the enzyme treatment against skin material which occurs without the use of the waste product solution, i. worked according to the usual enzyme-free switch, is between 1% and 2%.

The enzyme treatment led to an altered loosening of the fiber structure of the skin, which is fixed by the tanning, and is reflected in a larger area of the skins.

The enzyme use is known to lead to softer leathers with less pronounced fattening folds and less scar pull. The scar strength was not affected.

Examples

1./2. For the experiments, 20 salt-preserved, pre-stoned, black-colored (SMR) cattle hides (heifers / bullocks / bulls) of the mass class 15 to 19.5 kg green mass ^ were used. The skins were marked individually and halved after tanning.

The used waste solution showed an activity of 1 to 2.5 KE _cas / ml.

Two experiments were carried out parallel to each other, one experiment using the waste product solution, the other running without waste product solution. In the variant with enzyme has been dispensed with the correction of the pH in the most favorable for the activity of the enzyme range, which has been achieved that the difference between the two variants is attributable only to the use of enzymes.

with enzyme without enzyme

Vorweiche 120% water 30 ⁰ C 90 'the like.

Escape yes.

Main switch 100% water 28 ⁰ C 100% water 28 ⁰ C

0.3% wetting agent 0.3% wetting agent

2% pre-treated -

Abproduktlösung

180 '180'

Unwinding and further processing in a barrel

Limestone 200% water 28 ⁰ C

2% Na ₂ S (60%) 2h 2% Ca (OH) ₂ 90 '

Interval switching overnight

After chrome tanning, the skins were split.

The following masses were determined:

1. Rawhide

2. Wet-blue after fixation

3. wet-blue before folding

4. wet-blue after folding

5. Crust

6. Useful gap

The area was also determined by the crust.

On the basis of the determined masses and areas, the following statements result:

Mass wet-blue (%) with enzyme 114.4 ± 5.0 without enzyme 113.5 + 6.5 Mass rawhide mass before folding (%) 138.4 ± 12.0 142.0 + 7.4 Mass after crumple mass crust (%) 50.5 ± 8.5 44.6 + 1.65 Mass after folding mass gap (%) 49.4 ± 4.2 50.3 + 6.1 Mass rawhide basis weight (g / m ² ) 773 ± 54 712 ± 36 Crust surface crust (m ² / 100kg) 18.37 ± 2.64 18.09 ± 1.34 Mass of rawhide

With the enzyme treatment, a higher wet blue mass was obtained from the crude skin mass. For this, changes in the area and thickness of the wet-blue come into question.

The Masserelationen when folding evidence that in the enzyme-treated wet-blue less mass was folded. This ensures that the evaluation of the rawhide by enzyme treatment experiences a more favorable ratio. According to the mass relations between crusts and the wet-blue after folding it is clear that this can be attributed to different compressibilities of the wet-blue during folding. The thicknesses of the finished leathers produced with enzymes were on average 0.1 mm above those of the comparative leathers. Associated with this is a higher basis weight of the crust. The enzyme treatment would thereby inevitably allow lower folding or gap thicknesses. The investigations confirm that the waste product from the cultivation of Streptomyces griseus after a treatment is suitable as an aid for the smoothing of preserved rawhides.

3. Determination of total proteolytic activity of the waste product solution and the concentrates prepared therefrom: 1 ml of a defined water-diluted waste solution or soft liquor are dissolved with 1 ml of 1% casein solution (1 g of Hammarsten casein dissolved in 100 ml of 0.1 M phosphate buffer, pH 7, 6) and incubated at 35 ° C in a water bath for 20 min. Thereafter, 3 ml of 5% trichloroacetic acid are added to the samples and allowed to stand at room temperature for 30 min. The precipitate is then removed by centrifugation and the extinction at 280 nm in 1 cm cuvettes is measured in the clear sample solutions against corresponding blank samples. The proteolytic activity of 1 Kunitz unit corresponds to the activity causing an extinction change of 1000 under the given conditions in 1 min. To determine the high molecular weight protease activity, 1 ml of the by-product solution is mixed with 1 ml of saturated ammonium sulfate solution. The resulting precipitate is centrifuged off after standing for four hours, the supernatant washed with saturated ammonium sulfate solution and the precipitate dissolved in 1 ml of water. With this solution, the activity determination is performed. The activity is given in Kunitz units / 1 g.

4. Streptomyces griseus is fermented for about 200 hours in a stirred and ventilated stainless steel fermentor of 20 m ³ working volume. The medium contains in 20m ^{3 of} nutrient medium 1 030kg soybean meal, 1600kg glucose, 80kg ammonium sulfate, 4kg potassium hydrogen phosphate, 301 corn oil and 1.51 Antaphron and is sterilized for 30 min. At 12O ⁰ C before inoculation. During the fermentation, the acidity is kept at pH 6.4 by the addition of sodium hydroxide solution. Glucose and ammonium sulfate are replenished as needed. At the end of fermentation, the culture is mixed with 0.2% formalin solution 35%, 1% slurried dry kaolin and 0.5 g / l preneutralized oxalic acid and the biomass and solid products are separated off by separation at pH 6.0. The clear solution is adjusted to pH 7.8 and added via ion exchange columns. The largely streptomycin-free solution, with a Streptomyeinrestgehalt of 400IE / ml, is mixed with 0.5 g / l calcium chloride and adjusted to pH 6. Dropping solids are removed by separation. Total proteolytic activity is 0.85 Kunitz units / ml, of which 42% is precipitable. The thus obtained, partially pretreated solution can already be used as an aid to the switch.

5. To a partially pretreated effluent solution obtained according to Example 4 is added 1% pre-swollen neutralized bentonite and 1.5% pre-precipitated and neutralized calcium phosphate, stirred for 15 min and then the solids removed by separation. Total proteolytic activity is 0.77 Kunitz units / ml, of which 35% is precipitable.

6. 5 m ^{3 of} a obtained according to Example 4, partially pretreated Abprcduktlösung be concentrated at temperatures of 35 ⁰ C in a vacuum circulation evaporator to a volume of 1 m ³ . The total activity after concentration is 3.6 Kunitz units / ml, of which 31% is precipitable.

7. Activity overview at culture filtrates of 8 streptomycin fermentations. A Total activity = high molecular weight + low molecular weight protease moieties B Activity of high molecular weight, ammonium sulfate precipitable proteases in KE / ml C Quotient of total activity and activity of high molecular weight proteases Fermentation A B C

2.04 0,650 3.14 1.60 0.340 4.71 1.57 0,785 2.00 1.55 0,590 2.63 1.80 0,730 2.47 1.10 0.415 2.65 1.55 0,590 2.63 2.24 0.995 2.25

Claims (4)

1. Soft process of raw hides or preserved raw hides to produce a uniform product with higher surface yield, characterized by using a pretreated waste solution from the cultivation of the microorganism Streptomyces griseus containing a proportion of low molecular weight proteases, microbial growth inhibiting substances and proteolytic enzymes stabilizing compounds. 2. The method according to claim!, Characterized by, addition of 0.1% to 5% formaldehyde (as 35% formalin solution) in the partially pretreated waste solution. 3. Process according to claims 1 and 2, characterized by, addition of 0.1 to 5g / l calcium chloride. 4. The method according to claims 1 to 3, characterized by, use of 0.5% to 2% pre-swollen bentonite and 1% to 2% pre-precipitated and neutralized calcium phosphate as adsorbents.