Classifications

• • C—CHEMISTRY; METALLURGY
  • C14—SKINS; HIDES; PELTS; LEATHER
  • C14C—CHEMICAL TREATMENT OF HIDES, SKINS OR LEATHER, e.g. TANNING, IMPREGNATING, FINISHING; APPARATUS THEREFOR; COMPOSITIONS FOR TANNING
  • C14C1/00—Chemical treatment prior to tanning
  • C14C1/08—Deliming; Bating; Pickling; Degreasing

Definitions

• the invention relates to enzymatically supported liming and pickling processes in which alkaline lipases, preferably in combination with proteolytic enzymes, are used.
• Aspergillus species for example an alkaline lipase from an Aspergillus oryzae strain obtained by recombination with a pronounced optimum activity between pH 9 and 11 and one under the name "LIPOLASE 100 T "commercially available lipase (NOVO INDUSTRI A / S, DK 2880 Bagsvaerd).
• the effect is particularly pronounced when the lipases mentioned are used in an enzyme combination EK together with neutral or alkaline proteases P, which are selected according to the sub-step in question. These are preferably the proteases used in technology.
• the liming is understood to mean the well-known process of swelling and loosening of the epidermis up to the removal of hair and awns under the action of alkaline liming chemicals (see F. Stather, Gerschenemie und Gerfertechnologie, pp. 166 - 199, Akademie-Verlag 1967; Ullmann's Encyclopedia of Industrial Chemistry 5th Ed. Vol., A15, 259-282, VCH 1990).
• the liming device can be designed to preserve or destroy hair.
• the liming is in the generally carried out in the pH range 12-13, either in the form of the so-called "hydroxyl ash", where calcium hydroxide in particular is used in addition to alkali hydroxide, ammonia and other alkaline earth hydroxides, or in the form of the so-called sulfide ash, the active components of which are alkali metal or alkaline earth metal sulfides, optionally in a mixture with others are basic alkalis or alkaline earths.
• the liming process according to the invention very largely follows the processes of the prior art (Ullmann's Encyclopedia of Industrial Chemistry 5th Ed. Vol. 15A, 259-282, VCH (1990); Ullmanns Enzyklopadie der Techn.
• the liming operation can be carried out according to the invention with a liquor length of 50-250%, preferably 80-150%, water, based on the weight of the skins. In general, the liming process takes 12 to 36 hours, in particular 16 to 20 hours.
• the hides and skins are neutralized and enzymatically ashed.
• the hides or skins are first washed and preferably using weak acids, for example organic acids such as lactic acid, formic acid, acetic acid, butyric acid, propionic acid, or dicarboxylic acids and the like. or weakly acidic inorganic compounds such as sodium bisulfite, sulfophthalic acid, ammonium sulfate or also carbonic acid.
• weak acids for example organic acids such as lactic acid, formic acid, acetic acid, butyric acid, propionic acid, or dicarboxylic acids and the like.
• weakly acidic inorganic compounds such as sodium bisulfite, sulfophthalic acid, ammonium sulfate or also carbonic acid.
• this range is at pH 7.5 - 8.2.
• the enzymatic pickling component in particular enzymes of the pancreatic complex
• Enzymes of the pancreatic complex can also include lipases (DE-A 37 04 465).
• the pickling temperature the range between 32 and 37 degrees C has proven to be expedient.
• the pickling time generally ranges from 1 hour to 3 hours.
• the enzymatic batches, especially the sequestering agents SM known per se with the enzyme combination EK, preferably contain in advance in order to avoid lime soaps.
• the addition of emulsifying substances ES has proven itself, which leads to particularly good fat emulsification.
• the length of the liquor corresponds to that of the liming.
• the lipases to be used according to the invention are esterases which hydrolyze glycerol esters of the fatty acid in an aqueous emulsion (EC 3.1.1.3.).
• the triglycerides are preferably cleaved in the 1,3 position.
• the lipases used according to the invention have one pronounced optimum effect (eg against olive oil or tributyrin) between pH 9 and 11.
• Such alkaline lipases have been specially developed for the detergent industry. They are of microbiological origin. Potential sources of such, possibly genetically modified, microorganism strains are in particular fungi and bacteria.
• Certain alkaline lipases occur, for example, in Pseudomonas strains. Rhizopus sp., Candida sp., Chromobacterium sp. as a lipase supplier. Other important lipase producers are Geotrichium sp., Aspergillus sp., Mucor sp., Penicillium sp., Corynebacterium sp., Propionibacterium sp. and Achromobacter sp. Rhizopus arrhizus and Rh.
• Candida cyclindracea Chromobacterium viscosum, Geotrichium Candidum, Mucor miehi, Mucor pusillus, Penicillium roqueferti and P. cyclopium, Corynebacterium acne, Propionibacterium asymillium, especially lipion, asymptomium, bacterium shermiobacterium shermi Aspergillus oryzae.
• Certain genetically modified strains were also found to be particularly suitable, for example an alkaline lipase from an Aspergillus oryzae strain obtained by recombination with a pronounced optimum activity between pH 9 and 11 or a lipase commercially available under the name ® Lipolase TM 30 T (NOVO INDUSTRI A / S, DK 2880 Bagsvaerd, Denmark).
• the activity determination of lipases is carried out in a conventional manner with olive oil as a substrate, furthermore with triacetin and tributyrin. [See. M. Semiva et al. Biochemistry 10, 2143 (1971); Pharmaceutical Enzymes, edited by R. Ruyssen and A. Lauwers 1978, (FIP)].
• lipase activity is given in LCA units, but is measured at pH 9.5.
• the lipases are used in such a way that a lipase activity of 100-10,000 LCA, preferably 2,000 to 4,000 LCA, per kg skin is present in the liquor at pH 9.5.
• the proteolytic activity of the enzymes is customarily determined using the Anson hemoglobin method [ML Anson, J. Gen. Physiol, 22, 79 (1939)] or according to the Löhlein-Volhard method [modified according to TEGEWA in Leder 22 , 121 - 126 (1971)).
• the protease activity is generally between 1,000 and 60,000 LVE per kg skin, preferably between 2,000 and 14,000 LVE per kg skin.
• the process according to the invention usually requires amounts of proteases between 0.05 to 0.8% by weight, as a rule of thumb about 0.1-0.25% by weight, based on the weight of the hides and skins used.
• Examples of (synthetic) surface-active substances are per se conventional emulsifiers, in particular those which are suitable for emulsifying fat in water. (See GB-PS 586 540, DE-PS 894 142, FR-PS 899 983, FR-PS 918 523). Primarily suitable are non-ionic emulsifiers, for example of the following types:
• anionic emulsifiers for example of the following types:
• alkylbenzenesulfonates ABS, TPS
• MARLOPON ®, MARLON ® alkyl sulfonate
• MERSOLAT ® alkyl sulfonate
• IGEPONA ®, IGEPONT ® petroleum sulfonates
• GRASSAN B ® Sulfitation products of unsaturated fatty oils and fatty acids
• CUTISAN BS ® short chain alkylbenzenesulfonates, e.g. of cumene, toluene or xylenol
• Cationic emulsifiers are less advantageous e.g. of types:
• radical R above is a long-chain alkyl radical with 8-24 carbon atoms
• radicals R1, R2 or R3 are generally short-chain alkyl radicals with up to 6 carbon atoms.
• the emulsifiers which can be used according to the invention have an HLB value (O / W emulsion) of 8-18, preferably 9-15, especially 12-15 (cf. Ullmanns Encyklopadie der Techn. Chemie, 4th edition, vol. 19). Combinations of emulsifiers can also advantageously be used, in particular nonionic and anionic emulsifiers.
• the amount of emulsifiers in the liquors is - depending on the type - generally 0.1 to 1% by weight based on the salt or green weight of the hides or skins.
• the liquors may also contain sequestering agents known per se.
• the sequestering agents are selected from the group consisting of the polyphosphates, phosphonates, polycarboxylates, ethylenediaminetetraacetic acid (EDTA); Nitrilotriacetic acid, diethylenetriamineopentaacetic acid.
• the content of the sequestering agents in the soft liquor can be 0 to 0.5% by weight, preferably 0.05 to 0.15% by weight.
• the lipases used correspond to the labeling given above, as do the proteases.
• Enzyme combinations EK with the following composition have proven particularly useful: 100 - 1,000 KLVE alkaline bacterial protease, for example: from Bac.subtilis, Bac.licheniformis 0.1 - 5% by weight Lipase with the activity 5,000 LU / mg 1.0-20% by weight Na tripolyphosphate ad 100% by weight Sodium sulfate
• the dosage of the product is usually in the range of 0.05-1% in terms of salt weight or fresh weight of the skins.
• 150 ⁇ 50% are given as a guideline for the fleet length; the temperature is preferably 28 degrees C.
• sulfur liming contains the liming broth relatively small proportions of liming chemicals, typically sodium sulfate (72%) - as a guideline approx. 0.6% by weight - and sodium sulfide (60%) - as Guide value approx. 0.2% by weight, as well as hydrated lime - Guide value approx. 1.5% by weight - based on the skins at a pH of 12.8. You move about 1 1/2 hours under these conditions before using the enzymes, especially the enzyme combination EK-II- as a guideline in proportions of approx.
• the skins or furs are softened as usual. It has been found that hides and skins which are pretreated or soaked with an alkaline protease at pH 8-11 for 4-20 hours and are then mixed with the alkaline lipase in the same or a new bath at the same pH value for 2-6 hours , are excellently prepared for subsequent proteolytic hair removal.
• the switch is followed by a hair immunization step in which - based on DE-A 38 02 640 - hydrated lime and organic thio compounds together with amines in approx. 80% water at approx. PH 12 can be used. This is usually followed by a level of hair loosening.
• sulfide for example 0.4% by weight sodium sulfhydrate (72%) based on the skins.
• sodium sulfhydrate 72%) based on the skins.
• the skins are hairless.
• the fleet is then drained off and further processing is continued in the usual manner.
• fleshing and splitting of the skins can follow the liming process.
• the skin material prepared in the usual way e.g. Fleshed and split pelts are usually first washed and descaled in the usual way (see above).
• about the same amount of water is again added, preferably at 35 ° C., and the enzymes are preferably added as the enzyme combination EK.
• Enzyme combinations EK of the following typical composition are generally used: 50 - 1 00 KLVE Pancreatic enzyme complex 0.5 - 5% by weight alkaline lipase with the activity 5,000 LU / mg 1.0 - 30% by weight Na tripolyphosphate ad. 100% by weight Na sulfate or ammonium sulfate
• the product according to the invention is used at 30-35 degrees C for 20-120 minutes at 0.5-2% based on the pelt weight after decalcification.
• Emulsifier combination ES
• Fat content in the fleet 0.6 g / l Fat content in the nakedness: 0.25% in terms of dry weight
• Fat content in the fleet 0.4 g / l Fat content in the nakedness: 0.4% in terms of dry weight
• Treatment with the enzyme product according to the invention makes it possible to dispense with the post-purifier. Digestion of the skin is optimal after a process duration of 16-18 hours.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Treatment And Processing Of Natural Fur Or Leather (AREA)
• Cosmetics (AREA)
• Preparation Of Compounds By Using Micro-Organisms (AREA)
• Immobilizing And Processing Of Enzymes And Microorganisms (AREA)
• Enzymes And Modification Thereof (AREA)
• Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
• Materials For Medical Uses (AREA)

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• 1991
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• 1992
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