EP0943032A1

EP0943032A1 - Multicomponent system for modifying, decomposing or bleaching lignin, lignin-containing materials or similar substances, and process for using the same

Info

Publication number: EP0943032A1
Application number: EP97952038A
Authority: EP
Inventors: Johannes Freudenreich; Jürgen STOHRER; Manfred Amann; Robert Müller
Original assignee: Consortium fuer Elektrochemische Industrie GmbH
Current assignee: Consortium fuer Elektrochemische Industrie GmbH
Priority date: 1996-12-09
Filing date: 1997-12-05
Publication date: 1999-09-22
Anticipated expiration: 2017-12-05
Also published as: JP2000505844A; EP0943032B1; DE59702358D1; DE19651099A1; AU719140B2; AU5560398A; ATE196331T1; RU2154704C1; WO1998026127A1; ES2150797T3; PT943032E; CA2271937A1; BR9714387A; CN1240008A

Abstract

A multicomponent system for modifying, decomposing or bleaching lignin, lignin-containing materials or similar substances contains (a) if required at least one oxidation catalyst, (b) at least one appropriate oxidising agent, and (c) at least one mediator characterised in that it is selected from the group composed of hydroxypyridine, aminopyridine, hydroxyquinoline, aminoquinoline, hydroxyisoquinoline, aminoisoquinoline, with nitroso or mercapto substituents at the ortho or para position with respect to the hydroxy or amino groups. Also disclosed are tautomers of said compounds, as well as their salts, ethers and esters.

Description

Multi-component system for changing, breaking down or bleaching lignin, lignin-containing materials or similar substances as well as processes for its use

The present invention relates to a multi-component system for changing, breaking down or bleaching lignin, lignin-containing materials or similar substances, and methods for its use.

The sulfate and sulfite processes are the main processes used today for pulp production. Both methods produce pulp under cooking and under pressure. The sulfate process works with the addition of NaOH and Na ₂ S, while Ca (HSθ3) ₂ + S0 _{2 is used} in the sulfite process.

The main aim of all processes is to remove the lignin from the plant material, wood or annual plants used.

The lignin, which is the main constituent of the plant material (stem or stem) with cellulose and hemicellulose, must be removed, otherwise it will not be possible to produce non-yellowing and mechanically heavy-duty papers.

The wood-based production processes work with stone grinders (wood sanding) or with .Refiners (TMP), which defibrillate the wood after grinding (chemical, thermal or chemical-thermal).

These wood materials still contain a large part of the lignin. You will v. a. used for the production of newspapers, magazines, etc.

For some years now, the possibilities of using enzymes for lignin degradation have been researched. The mechanism of action Such lignolytic systems were only elucidated a few years ago when it was possible to obtain sufficient amounts of enzyme from the white rot fungus Phanero-chaete chrysosporiu through suitable cultivation conditions and inductor additives. The previously unknown lignin peroxidases and manganese peroxidases were discovered. Since Phanerochaete chrysosporium is a very effective lignin degrader, attempts were made to isolate its enzymes and to use them in purified form for lignin degradation. However, this did not succeed because it turned out that the enzymes primarily lead to a repolymerization of the lignin and not to its degradation.

The same applies to other lignolytic enzyme species such as laccases, which oxidatively break down the lignin using oxygen instead of hydrogen peroxide. It was found that similar processes occur in all cases. This is because radicals are formed which react with one another again and thus lead to polymerization.

Today there are only processes that work with in vivo systems (mushroom systems). The main focus of optimization attempts is so-called biopulping and biobleaching.

Biopulping is the treatment of wood chips with living mushroom systems.

There are 2 types of application forms:

1. Pretreatment of wood chips before refining or grinding to save energy in the manufacture of wood materials (e.g. TMP or wood pulp).

Another advantage is the mostly existing improvement in the mechanical properties of the fabric, a disadvantage the poorer final whiteness.

2. Pretreatment of wood chips (Softwood / Hardwood) before cellulose cooking (power process, sulfite process). The goal here is to reduce cooking chemicals, improve cooking capacity and "extended cooking".

As an advantage, improved kappa reduction after cooking compared to cooking without pretreatment is also achieved.

Disadvantages of these procedures are clearly the long treatment times (several weeks) and especially the unresolved

Risk of contamination during treatment if you want to forego the inefficient sterilization of the wood chips.

Biobleaching also works with in-vivo systems. The boiled pulp (Softwood / Hardwood) is inoculated with the fungus before bleaching and treated for days to weeks. Only after this long treatment time does a significant decrease in kappa number and increase in whiteness become apparent, which makes the process uneconomical for an implementation in the usual

Bleaching sequences.

Another application, which is usually carried out with immobilized fungal systems, is the treatment of pulp wastewater, in particular bleaching wastewater to decolorize it and reduce the AOX (reduction of chlorinated compounds in the wastewater that cause chlorine or chlorine dioxide bleaching stages).

It is also known that hemicellulases, etc. Xylanases,

Use mannanases as "bleach boosters".

These enzymes are said to act primarily against the reprecipitated xylan, which partially covers the residual lignin after the cooking process, and by breaking it down, increase the accessibility of the lignin for the bleaching chemicals used in the subsequent bleaching sequences (especially chlorine dioxide). The savings in bleaching chemicals demonstrated in the laboratory have been reflected in on a large scale has only been partially confirmed, so that this type of enzyme can at best be classified as a bleaching additive.

In addition to the lignolytic enzymes, chelating substances (siderophores such as ammonium oxalate) and biosurfactant are assumed to be the cofactor.

The application PCT / EP87 / 00635 describes a system for removing lignin from lignin-cellulose-containing material under simultaneous bleaching, which works with lignolytic enzymes from white rot fungi with the addition of reducing and oxidizing agents and phenolic compounds as mediators.

In DE 4008893C2, in addition to the Red / Ox system, “mimic substances” which simulate the active center (prosthetic group) of lignolytic enzymes are added. In this way, a significant improvement in performance could be achieved.

In the application PCT / EP92 / 01086, a redox cascade is used as an additional improvement with the aid of phenolic or non-phenolic aromatics "matched" in the oxidation potential.

In all three processes, the limitation for large-scale use is the applicability with low consistencies (up to a maximum of 4%) and with the last two applications the risk of "leaching out" of metals when using the chelate compounds, which, above all, in the case of downstream peroxide bleaching stages can lead to the destruction of the peroxide.

Methods are known from WO / 12619, WO 94/12620 and WO 94/12621 in which the activity of peroxidase is promoted by means of so-called enhancer substances.

The enhancer substances are characterized in WO 94/12619 on the basis of their half-life. According to WO 94/12620, enhancer substances are characterized by the formula A = NN = B, where A and B are each defined cyclic radicals.

According to WO 94/12620, enhancer substances are organic chemicals which contain at least two aromatic rings, at least one of which is substituted with defined radicals.

All three applications relate to "dye transfer inhibition" and the use of the respective enhancer substances together with peroxidases as a detergent additive or detergent composition in the detergent sector. In the description of the application, reference is made to the usability for treating lignin, but our own experiments with the substances specifically disclosed in the applications showed that they had no effect as mediators for increasing the bleaching effect of the peroxidases when treating materials containing lignin!

WO 94/29510 describes a method for enzymatic delignification, in which enzymes are used together with mediators. Compounds with the structure NO, NOH or HRNOH are generally disclosed as mediators.

Of the mediators listed in WO 94/29510

1-Hydroxy-lH-benzotriazole (HBT) the best results in delignification. However, HBT has several disadvantages:

It is only available at high prices and not in sufficient quantities.

It reacts to lH-benzotriazole under delignification conditions. This compound is relatively poorly degradable and can represent a considerable environmental burden in larger quantities. To some extent, it causes damage to enzymes. Its delignification rate is not too high. It is therefore desirable to provide systems for changing, breaking down or bleaching lignin, lignin-containing materials or similar substances which do not have the disadvantages mentioned or to a lesser extent.

The present invention therefore relates to a multi-component system for changing, breaking down or bleaching lignin, lignin-containing materials or similar substances containing a. optionally at least one oxidation catalyst and b. at least one suitable oxidizing agent and c. at least one mediator, characterized in that the mediator is selected from the group hydroxypyridines, aminopyridines, hydroxyquinolines, aminoquinolines, hydroxyisoquinolines, aminoisoquinolines, with nitroso or mercapto substituents ortho or para to the hydroxyl or amino groups, tautomers of the compounds mentioned and their salts, ethers and esters.

It has surprisingly been found that the multicomponent system according to the invention with the mediators mentioned does not have the disadvantages of the multicomponent systems known from the prior art.

Preferred mediators in the multicomponent system according to the invention are compounds of the general formula (I), (II) or (III)

(D (II) (III)

as well as tautomers, salts, ethers or esters of the compounds mentioned, where in the formulas I, II or III, two radicals R ^{1 which} are ortho or para to one another are hydroxyl and nitroso or hydroxyl and mercapto or nitroso and amino and the rest R ¹ radicals are the same or different and are selected from the group consisting of hydrogen, halogen, hydroxy, mercapto, formyl, cyano, carbamoyl, carboxy, ester and salt of carboxy, sulfono, ester and salt of sulfo norests, sulfamoyl, nitro, nitroso, amino, phenyl, aryl-C ₁ -C ₅ alkyl, C ₁ -C ₁₂ alkyl, C ₁ -C ₅ alkoxy, CLCL _Q carbonyl -, Carbonyl-CL-Cg-alkyl, phospho-, phosphono-, phosphono-oxy, ester and salt of the phosphonooxy and and where carbamoyl, sulfamoyl, amino, mercapto and phenyl residues are unsubstituted or one or more times with a radical R ² may be substituted and the aryl-C ₁ -C ₅ -alkyl-, C ₁ -C ₁₂ -alkyl-, C ₁ -C ₅ -alkoxy-, CLCL _Q -carbonyl-, carb onyl-C - ^ - Cg-alkyl radicals can be saturated or unsaturated, branched or unbranched and can be substituted one or more times with a radical R ² , where R ^{2 is the} same or different and hydroxyl, formyl, cyano, carboxy radical , Ester or salt of carboxy, carbamoyl, sulfono, sulfamoyl, nitro, nitroso, amino, phenyl, C ₁ -C ₅ alkyl, CL-Cς alkoxy or CL-Cς alkylcarbonyl and each two radicals R ¹ or two radicals R ² or R and R can be linked in pairs via a bridge [-CR ³ R ⁴ -] _m with m equal to 1, 2, 3 or 4 and R ³ and R ^{4 are the} same or different and are carboxy, ester or salt of carboxy, phenyl, C ^ _^ -Cς alkyl, C ₁ -C ₅ alkoxy or CLC ₅ alkylcarbonyl and one or more non-adjacent groups [-CR ³ R ⁴ -] by oxygen, sulfur or an imino radical optionally substituted with C ₁ -C ₅ alkyl- and two adjacent groups [-CR ³ R ⁴ -] by a group [-CR = R ⁴ -] can be replaced.

Particularly preferred mediators in the multicomponent system according to the invention are compounds of the general formula (I) or (II) and their tautomers, salts, ethers or esters, in the formulas (I) and (II) particularly preferably two radicals which are ortho-oriented to one another R ^{1 is} hydroxy and nitroso or hydroxy and mercapto or nitroso and amino and the other R ^{1 are the} same or different and are selected from the group consisting of hydrogen, hydroxy, mercapto, formyl, carbamoyl and carboxy, Esters and salt of carboxy, sulfono, esters and salt of sulfo, sulfamoyl, nitro, nitroso, amino, phenyl, aryl-C- _| _-C ₅ -alkyl-, C ₁ -C ₅ -alkyl-, C ₁ -C ₅ -alkoxy-, CL-Cg-carbonyl-, carbonyl- C- _{j ^} -Cg-alkyl-, phospho- / phosphono- , Phosphonooxy radical, ester and salt of the phosphonooxy radical, where carbamoyl, sulfamoyl, amino, mercapto and phenyl radicals can be unsubstituted or substituted one or more times with a radical R ² and the aryl-C ₁ -C ₅ - alkyl, C ₁ -C ₅ alkyl, CL-Cg-alkoxy, C ₁ -C ₅ carbonyl, carbonyl-CL-Cg-alkyl radicals may be saturated or unsaturated, branched or unbranched and with a radical R ² can be substituted one or more times, where R ^{2 has} the meanings already mentioned and two radicals R ¹ can be linked in pairs via a bridge [-CR ³ R ⁴ -] _m with m equal to 2, 3 or 4 and R ³ and R ^{4 have} the meanings already mentioned and one or more non-adjacent groups [-CR ³ R ⁴ -] can be replaced by oxygen or an imino radical which may be substituted by CL-Cg-alkyl. Examples of compounds which can be used as mediators (component c) in the multicomponent system according to the invention are 2, 6-dihydroxy-3-nitrosopyridine, 2, 3-dihydroxy-4-nitrosopyridine,

2, 6-dihydroxy-3-nitrosopyridine-4-carboxylic acid, 2, 4-dihydroxy-3-nitrosopyridine, 3-hydroxy-2-mercaptopyridine, 2-hydroxy-3-mercaptopyridine, 2, 6-diamino-3-nitrosopyridine, 2, 6-diamino-3-nitrosopyridine-4-carboxylic acid, 2-hydroxy-3-nitrosopyridine, 3-hydroxy-2-nitrosopyridine, 2-mercapto-3-nitrosopyridine, 3-mercapto-2-nitrosopyridine, 2- Amino-3-nitrosopyridine, 3-amino-2-nitrosopyridine, 2, 4-dihydroxy-3-nitrosoquinoline, 8-hydroxy-5-nitrosoquinoline, 2, 3-dihydroxy-4-nitrosoquinoline, 3-hydroxy-4-nitrosoisoquinoline,

4-hydroxy-3-nitrosoisoquinoline, 8-hydroxy-5-nitrosoisoquinoline and tautomers of these compounds.

Preferred mediators are 2,6-dihydroxy-3-nitrosopyridine, 2,6-diamino-3-nitrosopyridine,

2, 6-dihydroxy-3-nitrosopyridine-4-carboxylic acid, 2, 4-dihydroxy-3-nitrosopyridine, 2-hydroxy-3-mercaptopyridine, 2-mercapto-3-pyridinol, 2, 4-dihydroxy-3-nitrosoquinoline, 8-hydroxy-5-nitrosoquinoline, 2, 3-dihydroxy-4-nitrosoquinoline and tautomers of these compounds.

The multicomponent system according to the invention contains mediators which are less expensive than the mediators known from the prior art, in particular less expensive than HBT.

In addition, an increase in the rate of delignification is achieved when using the mediators according to the invention.

The multicomponent system according to the invention preferably comprises at least one oxidation catalyst. Enzymes are preferably used as oxidation catalysts in the multicomponent system according to the invention. For the purposes of the invention, the term enzyme also encompasses enzymatically active proteins or peptides or prosthetic groups of enzymes.

Oxidoreductases of classes 1.1.1 to 1.97 according to the International Enzyme Nomenclature, Committee of the International Union of Biochemistry and Molecular Biology (Enzyme Nomenclature, Acade ic Press, Inc., 1992, pp. 24-154) can be used as the enzyme in the multicomponent system according to the invention become.

Enzymes of the classes mentioned below are preferably used:

Class 1.1 enzymes, which comprise all dehydrogenases which act on primary, secondary alcohols and semiacetals, and which are accepted as NAD ⁺ or NADP ⁺ (subclass 1.1.1), cytochrome (1.1.2), oxygen (0 ₂ ) (1.1.3), disulfides (1.1.4), quinones (1.1.5) or the other acceptors (1.1.99).

From this class, the enzymes of class 1.1.5 with quinones as acceptors and the enzymes of class 1.1.3 with oxygen as acceptors are particularly preferred.

Cellobiose: quinone-1-oxidoreductase (1.1.5.1) is particularly preferred in this class.

Enzymes of class 1.2 are also preferred. This class of enzymes includes those enzymes that oxidize aldehydes to the corresponding acids or oxo groups. The acceptors can be NAD ⁺ , NADP ⁺ (1.2.1), cytochrome (1.2.2), oxygen (1.2.3), sulfides (1.2.4), iron-sulfur proteins (1.2.5) or other acceptors (1.2 .99).

The enzymes of group (1.2.3) with oxygen as the acceptor are particularly preferred here.

Enzymes of class 1.3 are also preferred. This class includes enzymes that act on the CH-CH groups of the donor.

The corresponding acceptors are NAD ⁺ , NADP ⁺ (1.3.1), cytochroe (1.3.2), oxygen (1.3.3), quinones or related compounds (1.3.5), iron-sulfur proteins (1.3. 7) or other acceptors (1.3.99).

Bilirubin oxidase (1.3.3.5) is particularly preferred.

The enzymes of class (1.3.3) with oxygen as acceptor and (1.3.5) with quinones etc. as acceptor are also particularly preferred here.

Also preferred are class 1.4 enzymes which act on CH-NH ₂ groups of the donor.

The corresponding acceptors are NAD ⁺ , NADP ⁺ (1.4.1), cytochrome (1.4.2), oxygen (1.4.3), disulfides (1.4.4), iron-sulfur proteins (1.4.7) or others Acceptors (1.4.99).

Enzymes of class 1.4.3 with oxygen as the acceptor are also particularly preferred here.

Also preferred are class 1.5 enzymes which act on CH-NH groups of the donor. The corresponding acceptors are NAD ⁺ , NADP ⁺ (1.5.1), oxygen (1.5.3), disulfides (1.5.4), quinones (1.5.5) or other acceptors (1.5.99).

Enzymes with oxygen (0 ₂ ) (1.5.3) and with quinones (1.5.5) as acceptors are also particularly preferred here.

Enzymes of class 1.6 which act on NADH or NADPH are also preferred. The acceptors here are NADP ⁺ (1.6.1), heme proteins (1.6.2), disulfides (1.6.4), quinones (1.6.5), N0 ₂ groups (1.6.6), and a flavin (1.6.8 ) or some other acceptors (1.6.99).

Enzymes of class 1.6.5 with quinones as acceptors are particularly preferred here.

Also preferred are class 1.7 enzymes which act as donors on other N0 ₂ compounds and acceptors cytochrome (1.7.2), oxygen (0 ₂ ) (1.7.3), iron-sulfur proteins (1.7.7 ) or others (1.7.99).

Class 1.7.3 with oxygen as the acceptor is particularly preferred here.

Also preferred are class 1.8 enzymes which act as donors on sulfur groups and acceptors NAD ⁺ , NADP ⁺ (1.8.1), cytochromes (1.8.2), oxygen (0 ₂ ) (1.8.3), disulfides (1.8. 4), quinones (1.8.5), iron-sulfur proteins (1.8.7) or others (1.8.99).

Class 1.8.3 with oxygen 0 ₂₎ and (1.8.5) with quinones as acceptors is particularly preferred.

Also preferred are class 1.9 enzymes which act as donors on heme groups and have oxygen (0 ₂ ) (1.9.3), NO ₂ compounds (1.9.6) and others (1.9.99) as acceptors.

Group 1.9.3 with oxygen (0 ₂ ) as acceptor (cytochrome oxidases) is particularly preferred here.

Also preferred are class 1.12 enzymes which act on hydrogen as a donor.

The acceptors are NAD ⁺ or NADP ⁺ (1.12.1) or others (1.12.99). Enzymes of class 1.13 and 1.14 (oxigenases) are also preferred.

Preferred enzymes are also those of class 1.15 which act as acceptors on superoxide radicals.

Superoxide dismutase (1.15.1.1) is particularly preferred here.

Enzymes of class 1.16 are also preferred.

NAD ⁺ or NADP ⁺ (1.16.1) or oxygen (0 ₂ ) (1.16.3) act as acceptors.

Enzymes of class 1.16.3.1 (ferroxidase, e.g. ceruloplasmin) are particularly preferred here.

Further preferred enzymes are those from group 1.17 (action on CH ₂ groups which are oxidized to -CHOH-), 1.18 (action on reduced ferredoxin as donor), 1.19

(Effect on reduced flavodoxin as donor) and 1.97 (other oxidoreductases).

The enzymes of group 1.11 are also particularly preferred. which act on a peroxide as an acceptor. This only subclass (1.11.1) contains the peroxidases.

The cytochrome C peroxidases (1.11.1.5), catalase (1.11.1.6), the peroxidase (1.11.1.6), the iodide peroxidase (1.11.1.8) and the glutathione peroxidase (1.11.1.9) are particularly preferred here. , the chloride peroxidase (1.11.1.10), the L-Ascorbat-peroxidase (1.11.1.11), the phospholipid-hydroperoxide-glutathione-peroxidase (1.11.1.12), the manganese peroxidase (1.12.1.13), the Diarylpropane peroxidase (ligninase, lignin peroxidase) (1.11.1.14).

Enzymes of class 1.10 which act on biphenols and related compounds are very particularly preferred. They catalyze the oxidation of biphenols and ascorbates. NAD ⁺ , NADP ⁺ (1.10.1), cytochrome (1.10.2), oxygen (1.10.3) or others (1.10.99) act as acceptors.

Of these in turn, class 1.10.3 enzymes with oxygen (0 ₂ ) as the acceptor are particularly preferred.

Of the enzymes in this class, the enzymes are catechol oxidase (tyrosinase) (1.10.3.1)., L-ascorbate oxidase (1.10.3.3), o-aminophenol oxidase (1.10.3.4) and laccase (benzenediol: oxigen oxidoreductase) (1.10. 3.2) is preferred, the laccases (benzene diol: oxigen oxidoreductase) (1.10.3.2) being particularly preferred.

The enzymes mentioned are commercially available or can be obtained by standard methods. Plants, animal cells, bacteria and fungi, for example, come into consideration as organisms for the production of the enzymes. In principle, both naturally occurring and genetically modified organisms can be enzyme producers. Parts of unicellular or multicellular organisms are also conceivable as enzyme producers, especially cell cultures.

For the particularly preferred enzymes, such as those from group 1.11.1, but especially 1.10.3, and in particular for the production of laccases, white rot fungi such as pleurus, phlebia and trametes are used, for example.

The multi-component system according to the invention comprises at least one oxidation agent. Examples of oxidizing agents that can be used are air, oxygen, ozone, H ₂ 0 ₂ , organic peroxides, peracids such as peracetic acid, performic acid, persulfuric acid, persitric acid, metachloroperoxibenzoic acid, perchloric acid, perborates, peracetates, persulfates, peroxides or oxygen species and their radicals such as OH, OOH, singlet oxygen, superoxide (0 ₂ ^" ), ozonide, dioxygenyl cation (0 ₂ ⁺ ), dioxirane, dioxetane or fremy radicals can be used. Oxidizing agents are preferably used which can either be generated by the corresponding oxidoreductases, for example dioxiranes from laccases plus carbonyls, or which can chemically regenerate the mediator or can implement it directly.

The invention also relates to the use of substances which, according to the invention, are suitable as mediators for changing, breaking down or bleaching lignin, lignin-containing materials or similar substances.

The effectiveness of the multi-component system when changing, breaking down or bleaching lignin, lignin-containing materials or similar substances is often further increased if Mg ions are also present in addition to the components mentioned.

The Mg ions can be used, for example, as a salt, such as MgSO ₄ . The concentration is in the range of 0.1-2 mg / g of material containing lignin, preferably 0.2-0.6 mg / g.

In some cases, a further increase in the effectiveness of the multicomponent system according to the invention can be achieved in that the multicomponent system in addition to the Mg ions also complexing agents such as e.g. Contains ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), hydroxyethylenediaminetriacetic acid (HEDTA), diethylenetriaminepentamethylenephosphonic acid (DTMPA), nitrilotriacetic acid (NTA), polyphosphoric acid (PPA) etc. The concentration is in the range of 0.2-5 mg / g of lignin-containing material, preferably 1-3 mg.

The use of the multicomponent system according to the invention in a process for treating lignin takes place, for example, by mixing the respectively selected components a) to c) according to claim 1 simultaneously or in any order with an aqueous suspension of the lignin-containing material. A process using the multicomponent system according to the invention is preferably carried out in the presence of oxygen or air at atmospheric pressure up to 10 bar and in a pH range from 2 to 11, at a temperature from 20 to 95 ° C., preferably 40-95 ° C. and a consistency of 0.5 to 40%.

A finding that is unusual and surprising for the use of enzymes in pulp bleaching is that when the multicomponent system according to the invention is used, increasing the consistency enables a significant increase in the kappa reduction.

For economic reasons, a process according to the invention is preferably carried out at consistencies of 8 to 35%, particularly preferably 9 to 15%.

Surprisingly, it was also found that an acidic wash (pH 2 to 6, preferably 4 to 5) or Q stage (pH 2 to 6, preferably 4 to 5) before the enzyme mediator stage in some pulps led to a considerable reduction in the kappa number Comparison to treatment without this special pretreatment leads. The substances used for this purpose (such as EDTA, DTPA) are used as chelating agents in the Q stage. They are preferably used in concentrations of 0.1% to 1% (w / w based on dry cellulose), particularly preferably 0.1% to 0.5% (w / w based on dry cellulose).

In the process according to the invention, preferably 0.01 to 100,000 IU enzyme per g lignin-containing material are used. 0.1 to 100 IU of enzyme per g of lignin-containing material are particularly preferably used (1 U corresponds to the conversion of 1 μmol

2,2'-Azino-bis (3-ethyl-benzothiazoline-6-sulfonic acid diammonium salt) (ABTS) / min / ml enzyme In the process according to the invention, preferably 0.01 mg to 100 mg of oxidizing agent per g of lignin-containing material is used. 0.01 to 50 mg of oxidizing agent per g of lignin-containing material are particularly preferably used.

In the method according to the invention, 0.5 to 80 mg of mediator per g of lignin-containing material is preferably used. 0.5 to 40 mg of mediator per g of lignin-containing material is particularly preferably used.

At the same time, reducing agents can be added which, together with the oxidizing agents present, serve to set a certain redox potential.

Sodium bisulfite, sodium dithionite, ascorbic acid, thio compounds, mercapto compounds or glutathione etc. can be used as reducing agents.

In the case of laccase, for example, the reaction takes place with air or oxygen supply or oxygen or air overpressure, with the peroxidases (e.g. lignin peroxidases, manganese peroxidases) with hydrogen peroxide. For example, the oxygen can also be generated in situ by hydrogen peroxide + catalase and hydrogen peroxide by glucose + GOD or other systems.

In addition, radical formers or radical scavengers (trapping, for example, OH or OOH radicals) can be added to the system. These can improve the interaction within the Red / Ox and radical mediators.

Other metal salts can also be added to the reaction solution.

These are important in conjunction with chelating agents as radical formers or red / ox centers. The salts form cations in the reaction solution. Such ions include Fe, Fe ³⁺ 'Mn ²⁺ , Mn ³⁺ , Mn ⁴⁺ , Cu ²⁺ , Ca ²⁺ , Ti ³⁺ , Cer ⁴⁺ , Al ³⁺ . The chelates present in the solution can also serve as mimic substances for the enzymes, for example for the laccases (copper complexes) or for the lignin or manganese peroxidases (ham complexes). Mimic substances are substances that simulate the prosthetic groups of (here) oxidoreductases and can, for example, catalyze oxidation reactions.

NaOCl can also be added to the reaction mixture. In combination with hydrogen peroxide, this compound can form singlet oxygen.

Finally, it is also possible to work using detergents. Non-ionic, anionic, cationic and amphoteric surfactants are suitable as such. The detergents can improve the penetration of the enzymes and mediators into the fiber.

It may also be beneficial for the reaction to add polysaccharides and / or proteins. Glucans, mannans, dextrans, levans, pectins, alginates or plant gums and / or proprietary polysaccharides formed by the fungi or produced in the mixed culture with yeasts are to be mentioned here in particular as polysaccharides and gelatin and albumin as proteins.

These substances mainly serve as protective colloids for the enzymes.

Other proteins that can be added are proteases such as pepsin, bromelin, papain, etc. These can include serve to achieve better access to lignin by breaking down the extensin C present in the wood, a protein rich in hydroxyproline.

Other protective colloids are amino acids, simple sugar, oligomer sugar, and PEG types of the most varied Molecular weights, polyethylene oxides, polyethyleneimines and polydimethylsiloxanes in question.

The method according to the invention can be used not only in the delignification (bleaching) of sulfate, sulfite, organosol, etc. Cellulose and wood pulp are used, but also in the production of cellulose in general, whether from wood or annual plants, if defibrillation by the usual cooking methods (possibly connected with mechanical processes or pressure) i.e. a very gentle cooking up to kappa numbers, which can be in the range of approx. 50 - 120 kappa, is guaranteed.

In the bleaching of cellulose as well as in the production of cellulose, the treatment can be repeated several times, either after washing and extraction of the treated material with NaOH or without these intermediate steps. This leads to kappa values which can be reduced still further and to substantial increases in whiteness. Likewise, a 0 ₂ stage can be used before the enzyme / mediator treatment or, as already mentioned, a clean wash or Q stage (chelate stage) can be carried out.

The invention is explained in more detail below with the aid of examples:

example 1

Enzy atic bleach with 8-hydroxy-5-nitrosoquinoline and Softwood sulfate pulp

5 g dry cellulose (Softwood 0 delignified), consistency 30% (approx. 17 g moist) are added to the following solutions: A) 20 ml tap water are mixed with 65.3 mg 8-hydroxy-5-nitrosoquinoline with stirring, the pH -Value with 0.5 mol / 1 H ₂ S0 ₄ solution. adjusted so that pH 4.5 results after addition of the pulp and the enzyme.

B) 5 ml of tap water are mixed with the amount of Laccase from Trame- tes versicolor that an activity of 15 U (1 U = conversion of 1 μmol ABTS / min / ml enzyme) results per g of pulp.

Solutions A and B are added together and made up to 33 ml. After adding the pulp, mix with a dough kneader for 2 min.

The substance is then placed in a reaction bomb preheated to 45 ° C. and incubated under 1-10 bar oxygen pressure for 1-4 hours. The material is then washed over a nylon sieve (30 μm) and extracted for 1 hour at 60 ° C., 2% consistency and 8% NaOH per g of pulp.

After washing the fabric again, the kappa number is determined. Result cf. Table 1

Example 2

Enzymatic bleaching with 2, 4-dihydroxy-3-nitrosopyridine and

Softwood sulfate pulp

5 g dry cellulose (Softwood 0 ₂ delignified), consistency 30% (approx. 17 g wet) are added to the following solutions:

A) 20 ml tap water with 61.2 mg

2, 4-Dihydroxy-3-nitrosopyridine added with stirring, the pH with 0.5 mol / 1 H ₂ S0 ₄ solution. adjusted so that pH 4.5 results after addition of the pulp and the enzyme.

B) 5 ml of tap water are mixed with the amount of Laccase from Trame- tes versicolor that an activity of 15 U (1 U = conversion of 1 μmol ABTS / min / ml enzyme) results per g of pulp. Solutions A and B are added together and made up to 33 ml.

After adding the pulp, mix with a dough kneader for 2 min. The substance is then placed in a reaction bomb preheated to 45 ° C. and incubated under 1-10 bar oxygen pressure for 1-4 hours.

The material is then washed over a nylon sieve (30 μm) and extracted for 1 hour at 60 ° C., 2% consistency and 8% NaOH per g of pulp.

After washing the fabric again, the kappa number is determined. Result see Table 1

Example 3

Enzyme bleach with 3-hydroxy-2-mercaptopyridine and Softwood sulfate pulp

5 g dry cellulose (Softwood 0 ₂ delignified), consistency

30% (approx. 17 g moist) are added to the following solutions:

A) 20 ml tap water with 47.7 mg

3-Hydroxy-2-mercaptopyridine added with stirring, the pH with 0.5 mol / 1 H ₂ S0 ₄ solution. adjusted so that pH 4.5 results after addition of the pulp and the enzyme.

After adding the pulp, mix with a dough kneader for 2 min.

Then the substance is placed in a reaction bomb preheated to 45 ° C and under 1 - 10 bar oxygen pressure for 1 -

Incubated for 4 hours.

The fabric is then washed over a nylon sieve (30 μm) and extracted for 1 hour at 60 ° C., 2% fabric density and 8% NaOH per g of pulp. After washing the fabric again, the kappa number is determined. Result see Table 1 Example 4

Enzymatic bleach with

2, 6-dihydroxy-3-nitrosopyridine-4-carboxylic acid and Softwood

Sulfate pulp

A) 20 ml tap water with 69.1 mg

2, 6-dihydroxy-3-nitrosopyridine-4-carboxylic acid mixed with stirring, the pH with 0.5 mol / 1 H ₂ S0 ₄ solution. adjusted so that pH 4.5 results after addition of the pulp and the enzyme.

Incubated for 4 hours.

After washing the fabric again, the kappa number is determined. Result see Table 1 Example 5 Enzymatic bleaching with 2, 6-diamino-3-nitrosopyridine and Softwood sulfate pulp

5 g dry cellulose (Softwood 0 ₂ delignified), consistency 30% (approx. 17 g moist) are added to the following solutions: A) 20 ml tap water with 51.8 mg

2, 6-diamino-3-nitrosopyridine were added with stirring, the pH with 0.5 mol / 1 H ₂ S0 ₄ solution. adjusted so that pH 4.5 results after addition of the pulp and the enzyme. B) 5 ml of tap water are mixed with the amount of Laccase from Trame- tes versicolor that an activity of 15 U (1 U = conversion of 1 μmol ABTS / min / ml enzyme) results per g of pulp. Solutions A and B are added together and made up to 33 ml.

The material is then washed over a nylon sieve (30 μm) and extracted for 1 hour at 60 ° C., 2% consistency and 8% NaOH per g of pulp. After washing the fabric again, the kappa number is determined. Result see Table 1

Example 6 Enzymatic bleaching with 2, 6-dihydroxy-3-nitrosopyridine and Softwood sulfate pulp

5 g dry cellulose (Softwood 0 ₂ delignified), consistency 30% (approx. 17 g moist) are added to the following solutions: A) 20 ml tap water with 52.6 mg

2, 6-dihydroxy-3-nitrosopyridine were added with stirring, the pH with 0.5 mol / 1 H ₂ S0 ₄ solution. adjusted so that pH 4.5 results after addition of the pulp and the enzyme. B) 5 ml of tap water are mixed with the amount of Laccase from Trame- tes versicolor that an activity of 15 U (1 U = conversion of 1 μmol ABTS / min / ml enzyme) results per g of pulp.

Solutions A and B are added together and made up to 33 ml. After adding the pulp, mix with a dough kneader for 2 min. The substance is then placed in a reaction bomb preheated to 45 ° C. and incubated under 1-10 bar oxygen pressure for 1-4 hours.

Example 7

Enzymatic bleaching with 2, -dihydroxy-3-nitrosoquinoline and

Softwood sulfate pulp

5 g dry cellulose (Softwood 0 ₂ delignified), consistency

30% (approx. 17 g moist) are added to the following solutions:

A) 20 ml tap water with 71.3 mg

2, 4-Dihydroxy-3-nitrosoquinoline mixed with stirring, the pH with 0.5 mol / 1 H ₂ S0 ₄ solution. adjusted so that pH 4.5 results after addition of the pulp and the enzyme.

After adding the pulp, mix with a dough kneader for 2 min. Then the substance is placed in a reaction bomb preheated to 45 ° C and under 1 - 10 bar oxygen pressure for 1 -

Incubated for 4 hours.

The fabric is then washed over a nylon sieve (30 μm) and extracted for 1 hour at 60 ° C., 2% fabric density and 8% NaOH per g of pulp. After washing the fabric again, the kappa number is determined. Result see Table 1 Table 1

Results Examples 1 to 7: Enzyme dosage in each case 15 U / g of pulp, incubation time in each case 2 h.

Substance Mediatordosage Lignin degradation [mg / 5g pulp] [%]

8-hydroxy-5-nitrosoquinoline 65.3 11.6 2,4-dihydroxy-3-nitrosopyridine 52.6 22.7 2-mercapto-3-pyridinol 47.7 13.4

2,6-dihydroxy-3-nitrosopyridine -4-carboxylic acid 69.1 15.1

2,6-diamino-3-nitrosopyridine 51.8 9.4 2,6-dihydroxy-3-nitrosopyridine 52.6 20.8 3-nitrosoquinoline-2,4-diol 71.3 38.8

Claims

Claims:

1. Multi-component system for changing, breaking down or bleaching lignin, lignin-containing materials or similar substances containing a. optionally at least one oxidation catalyst and b. at least one suitable oxidizing agent and c. at least one mediator, characterized in that the mediator is selected from the group hydroxypyridines, aminopyridines, hydroxyquinolines, aminoquinolines, hydroxyisoquinolines, aminoisoquinolines, with nitroso or mercapto substituents ortho or para to the hydroxy or amino groups, tautomers of the abovementioned Compounds and their salts, ethers and esters.

2. Multi-component system according to claim 1, characterized in that as mediator (component c) at least one compound selected from the group of compounds of the general formula (I), (II) or (III)

as well as their tautomers, salts, ethers or esters is present, wherein in formulas (I), (II) or (III) two mutually ortho or para radicals R ^{1 are} hydroxy and nitroso or hydroxy and mercapto or nitroso and Amino and the other R ^{1 are the} same or different and are selected from the group consisting of hydrogen, halogen, hydroxy, mercapto, formyl, cyano, carbamoyl, carboxy, ester and salt of carboxy, sulfono , Esters and salt of the sulfone residue, sulfamoyl, nitro, nitroso, amino, phenyl, Aryl-C ₁ -C ₅ -alkyl-, C ₁ -C ₁₂ -alkyl-, C ₁ -C ₅ -alkoxy-, C ₁ -C ₁₀ -carbonyl-, carbonyl-CL-Cg-alkyl-, phospho-, Phosphono, phosphonooxy radical, ester and salt of the phosphonooxy radical and where carbamoyl, sulfamoyl, amino, mercapto and phenyl radicals can be unsubstituted or substituted one or more times with a radical R ² and the aryl C ₁ - C ₅ alkyl, C ₁ -C ₁₂ alkyl, C ₁ -C ₅ alkoxy, C ₁ -C ₁₀ carbonyl, carbonyl-CL-Cg-alkyl radicals can be saturated or unsaturated, branched or unbranched and can be substituted one or more times with a radical R ² , where R ^{2 is} identical or different and is hydroxyl, formyl, cyano, carboxy, ester or salt of carboxy, carbamoyl, sulfono, sulfamoyl, nitro -, nitroso, amino, phenyl, C - ^ - Cς-alkyl, C- _j _-C ₅ alkoxy or CL-Cς alkylcarbonyl radical and two radicals R- ¹ - or two radicals R ^ or Link R and R in pairs over a bridge [-CR ³ R ⁴ -] _m with m equal to 1,2, 3 or 4 t can be and R ³ and R ^{4 are} identical or different and carboxy radical, ester or salt of the carboxy radical, phenyl, C ₁ -C ₅ alkyl,

C- _| _-C ₅ -alkoxy or C ^ -Cg-alkylcarbonyl and one or more non-adjacent groups [-CR ³ R ⁴ -] by oxygen, sulfur or an imino residue optionally substituted with C- _j _-C ₅ -alkyl and two adjacent groups [-CR ³ R ⁴ -] can be replaced by a group [-CR ³ = R ⁴ -].

3. Multi-component system according to one of claims 1 or 2, characterized in that as mediator at least one compound selected from the group 2, 6-dihydroxy-3-nitrosopyridine,

2,3-dihydroxy-4-nitrosopyridine, 2,6-dihydroxy-3-nitrosopyridine-4-carboxylic acid, 2,4-dihydroxy-3-nitrosopyridine, 3-hydroxy-2-mercaptopyridine, 2-hydroxy-3-mercaptopyridine, 2,6-diamino-3-nitrosopyridine, 2,6-diamino-3-nitrosopyridine-4-carboxylic acid,

2-hydroxy-3-nitrosopyridine, 3-hydroxy-2-nitrosopyridine, 2-mercapto-3-nitrosopyridine, 3-mercapto-2-nitrosopyridine, 2-amino-3-nitrosopyridine, 3-amino-2-nitrosopyridine, 2,4-dihydroxy-3-nitrosoquinoline, 8-hydroxy-5-nitrosoquinoline, 2,3-dihydroxy-4-nitrosoquinoline, 3-hydroxy-4-nitrosoquinoline,

4-hydroxy-3-nitrosoisoquinoline, 8-hydroxy-5-nitrosoisoquinoline and tautomers of the compounds mentioned.

4. Multi-component system according to one of claims 1 to 3, characterized in that as a mediator at least one compound selected from the group 2, 6-dihydroxy-3-nitrosopyridine, 2, 3-dihydroxy-4-nitrosopyridine, 2, 6-dihydroxy -3-nitrosopyridine-4-carboxylic acid, 2,4-dihydroxy-3-nitrosopyridine, 3-hydroxy-2-mercaptopyridine, 2-hydroxy-3-mercaptopyridine, 2,6-diamino-3-nitrosopyridine, 2,6-diamino -3-nitroso-pyridine-4-carboxylic acid,

2-hydroxy-3-nitrosopyridine, 3-hydroxy-2-nitrosopyridine,

2-mercapto-3-nitrosopyridine, 3-mercapto-2-nitrosopyridine,

2-amino-3-nitrosopyridine, 3-amino-2-nitrosopyridine,

2, 4-dihydroxy-3-nitrosoquinoline, 8-hydroxy-5-nitrosoquinoline, 2, 3-dihydroxy-4-nitrosoquinoline,

3-hydroxy-4-nitrosoisoquinoline, 4-hydroxy-3-nitrosoisoquinoline and 8-hydroxy-5-nitrosoisoquinoline and tautomers of these compounds are used.

5. Multi-component system according to one of claims 1 to 4, characterized in that it comprises at least one oxidation catalyst.

6. Multi-component system according to claim 5, characterized in that enzyme is used as the oxidation catalyst.

7. Multi-component system according to one of claims 1 to 6, characterized in that laccase is used as the enzyme.

8. Multi-component system according to one of claims 1 to 7, characterized in that the oxidizing agent is air, oxygen, ozone, H ₂ 0 ₂ , organic peroxides, peracids such as peracetic acid, performic acid, persulfuric acid, Persitric acid, metachloroperoxibenzoic acid, perchloric acid, perborates, peracetates, persulfates, peroxides or oxygen species and their radicals such as OH ', 00H ", singlet oxygen, superoxide (0 ₂ " ^~ ), ozonide, dioxygenyl cation (0 ₂ ⁺ ), di- oxirane, dioxetane or fremy radicals can be used.

9. A method for treating lignin, characterized in that the respective components a) to c) as mentioned in claim 1 are mixed simultaneously or in any order with an aqueous suspension of the lignin-containing material.

10. Use of mediators as mentioned in claim 1 as component c for changing, breaking down or bleaching lignin, lignin-containing materials or similar substances.