WO1998005818A1

WO1998005818A1 - Multi-component system for modifying, decomposing, or bleaching lignin, lignin-containing materials or similar substances and process for its application

Info

Publication number: WO1998005818A1
Application number: PCT/EP1997/004173
Authority: WO
Inventors: Johannes Freudenreich; Jürgen STOHRER; Manfred Amann; Robert Müller
Original assignee: Consortium für elektrochemische Industrie GmbH
Priority date: 1996-08-01
Filing date: 1997-07-31
Publication date: 1998-02-12
Also published as: AU3850697A; DE19631131A1

Abstract

This invention concerns a process for modifying, decomposing 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 by the fact that the mediator is chosen from the group of vicinal nitroso-substituted aromatic alcohols of general formulas (Ia) or (Ib), as well as their salts, ethers, or 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 (HS0 ₃ ) 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 the cellulose and He icellulose, must be removed, otherwise it is not possible to produce non-yellowing and mechanically heavy-duty papers.

The wood fabrication processes work with stone grinders (wood sanding) or with refiners (TMP), which defibrillate the wood by grinding after appropriate pretreatment (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 chrysosporium 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 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 implementation in the usual bleaching sequences.

Another application that 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. Use xylanases, 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 Large scale confirmed only to a limited extent, so that one can classify this enzyme type as a bleaching additive at best.

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

The application PCT / EP87 / 00635 describes a system for removing lignin from lignin-cellulose-containing material with 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 be 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 materials which do not have the disadvantages mentioned or to a lesser extent.

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

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 of vicinally nitroso-substituted aromatic alcohols of the general formulas la or ib

and their salts, ethers or esters, where

R ¹ , R ² , R ³ and R ^{4 are the} same or different and are hydrogen, halogen, hydroxy, formyl, carbamoyl, carboxy, ester or salt of carboxy, sulfono, ester or salt of sulfono, sulfamoyl, Nitro-, nitroso-, cyano, amino-, phenyl-, aryl-C ₁ -C ₅ -alkyl-, C ₁ -C ₁₂ -alkyl-, C- _{j ^} -Cg-alkoxy-, ^C _l -C ₁₀ - Carbonyl, ^arDon y ¹ ~ ^c ι " ^c ₆ ~ ^al * ^: y ¹ "'phospho-, phosphono-, Mean phosphonoxy residue, ester or salt of the phosphonoxy residue,

where carbamoyl, sulfamoyl, amino and phenyl radicals can be unsubstituted or substituted one or more times with a radical R ⁵ and the aryl-C - ^ - Cg-alkyl, C- _L -C ₁₂ alkyl, C _{j ^} -CG alkoxy, C ₁ -C ₁₀ ^carboxylic ~ y ¹ ~ 'carbonyl-C - ^ - Cg-alkyl radicals can be saturated or unsaturated, may be branched or unbranched, and with a radical R ⁵ or can be substituted several times, wherein

R ^{5 is the} same or different and is hydroxyl, formyl, carboxy, ester or salt of carbox, carbamoyl, sulfono, sulfamoyl, nitro, nitroso, amino, phenyl, C - ^ - Cg-alkyl- , C- _{j ^} - C ₅ -alkoxy radical means or

the radicals R - ^ - R ⁴ are linked in pairs to form a ring [-CR ⁶ R ⁷ -] _ln , where m is an integer and has a value from 1 to 4, or to form a ring [-CR ⁸ = CR ⁹ -] _{n are} linked, where n is an integer and means a value from 1 to 3, and

R ⁶ , R ⁷ , R ⁸ and R ^{9 are the} same or different and have the meanings given for R ¹ to R ⁴ .

Aromatic alcohols are preferably to be understood as meaning phenols or higher-condensed derivatives of phenol.

Preferred mediators in the multicomponent system according to the invention are compounds of the general formula Ia or Ib, the synthesis of which can be attributed to the nitrosation of substituted phenols. Examples of such compounds are 2-nitrosophenol, 3-methyl-6-nitrosophenol, 2-methyl-6-nitrosophenol, 4-methyl-6-nitrosophenol, 3-ethyl-6-nitrosophenol, 2-ethyl-6-nitrosophenol, 4 -Ethyl-6-nitrosophenol, 4-isopropyl-6-nitrosophenol, 4-tert.butyl-6-nitrosophenol, 2-phenyl-6-nitrosophenol, 2-benzyl-6-nitrosophenol, 4-benzyl-6-nitrosophenol, 2 -Hydroxy-3-nitrosobenzyl alcohol, 2-hydroxy-3-nitrosobenzoic acid,

4-hydroxy-3-nitrosobenzoic acid, 2-methoxy-6-nitrosophenol, 3, 4-dimethyl-6-nitrosophenol, 2, 4-dimethyl-6-nitrosophenol, 3, 5-dimethyl-6-nitrosophenol, 2, 5- Dimethyl-6-nitrosophenol, 2-nitrosoresorcinol, 4-nitrosoresorcinol, 2-nitrosoorcinol, 2-nitrosophloroglucin and 4-nitrosopyrogallol, 4-nitroso-3-hydroxyaniline, 4-nitro-2-nitrosophenol.

Also preferred as mediators are o-nitroso derivatives of higher condensed aromatic alcohols. Examples of such compounds are 2-nitroso-1-naphthol, 1-methyl-3-nitroso-2-naphthol and 9-hydroxy-10-nitroso-phenanthrene.

Particularly preferred mediators are 1-nitroso-2-naphthol, 1-nitroso-2-naphthol-3, 6-disulfonic acid, 2-nitroso-1-naphthol-4-sulfonic acid,

2,4-dinitroso-l, 3-dihydroxybenzene and esters, ethers or salts of the compounds mentioned.

Surprisingly, it has been found that compounds from the class of the 2-nitroso-phenols or higher condensed analogs or the tautomeric o-quinone monoximes present in aqueous systems, when used as mediators in a multicomponent system, do not have any of the disadvantages mentioned in the prior art Have mediators in a multi-component system.

The multicomponent system according to the invention contains mediators which are less expensive than HBT.

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

The invention thus also relates to the use of mediators mentioned in claim 1 as component c) for changing, breaking down or bleaching lignin, lignin-containing materials or similar substances. 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.

The multicomponent system according to the invention can be used as the enzyme

Oxidoreductases of classes 1.1.1 to 1.97 according to the International Enzyme Nomenclature, Committee of the International Union of Bioche istry and Molecular Biology (Enzyme Nomenclature, Acade ic Press, Inc., 1992, pp. 24-154) are used.

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 accept 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).

The enzymes of this class are particularly preferred

Class 1.1.5 with quinones as acceptors and the enzymes of class 1.1.3 with oxygen as acceptors.

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

Enzymes of class 1.2 are also preferred. This enzyme class includes those enzymes that oxidize aldehydes to the corresponding acids or oxo groups. The acceptors can be NAD ⁺ , NADP ⁺ (1.2.1), Cytochro e (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), cytochrome (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 is particularly preferred

and (1.8.5) with quinones as acceptors.

Also preferred are class 1.9 enzymes which act as donors on heme groups and oxygen as acceptors

(0 ₂ ) (1.9.3), N0 ₂ compounds (1.9.6) and others (1.9.99).

Group 1.9.3 with oxygen is particularly preferred here

(0 ₂ ) as acceptor (cytochrome oxidases).

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

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. Ceruloplas in) are particularly preferred here.

Further preferred enzymes are those of group 1.17 (action on CH ₂ groups which are oxidized to -CHOH-), 1.18 (action on reduced ferredoxin as donor), 1.19 (action on reduced flavodoxin as donor) and 1.97 (others Oxidoreductases).

The enzymes of group 1.11 are also particularly preferred. which act on a peroxide as an acceptor. This only subclass (l.ll.l) 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, with 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. Basically, 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 oxidizing agent. Examples of oxidizing agents are air, oxygen, ozone, H ₂ 0 ₂ , organic peroxides, peracids such as peracetic acid, performic acid, persulfuric acid, persitric acid, metachloroperoxybenzoic 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 ⁺ ), dioxiranes, dioxetanes or fremy radicals can be used.

Preferably oxidizing agents are used which can either be generated by the corresponding oxidoreductases e.g. Dioxiranes from laccases plus carbonyls or which can chemically regenerate the mediator or 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 2+ ions are present in addition to the components mentioned. The Mg 2+ ions can be used as a salt, such as MgS0 ₄ , at.spi.elswei.se. The concentration is in the range of 0.1-2 mg / g lignin-containing. Material, preferably at 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 24 ions also complexing agents such as e.g. Contains ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), hydroxyethylenedia diacetic acid (HEDTA), diethylenetriapentamethylenephosphonic 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, in that the components a) to c) mixes 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 preferred 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 of 20 to 95 ° C., preferably 40-95 ° C. , and a consistency of 0.5 to 40%.

An unusual and surprising finding for the use of enzymes in cell pulp bleaching is that when the multicomponent system according to the invention is used, an increase in 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 acid 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 led to a considerable degree in some pulps Lowering the kappa number compared 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. It is particularly preferred to use 0.1 to 100, particularly preferably 1 to 40 IU enzyme per g lignin-containing material (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 are used per g of lignin-containing material. 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 existing oxidizing agents, 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 24-, Fe3 + '

Mn ²⁺ , Mn ³⁺ , Mn ⁴⁺ , Cu ²⁺ , Ca ²⁺ , Ti ³⁺ , Cer ⁴⁺ , Al ³⁺ .

The chelates present in the solution can also act as mimic substances for the enzymes, for example for the

Laccases (copper complexes) or for the lignin or manganese peroxidases (heme complexes). Mimic substances are to be understood as substances that the prosthetic groups of

(here) simulate oxidoreductases and e.g. Can 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 a 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 serve, inter alia, to achieve better access to lignin by breaking down the extensin C present in the wood, hydroxyproline-rich protein. Amino acids, simple sugars, oligomer sugars, PEG types of the most varied molecular weights, polyethylene oxides, polyethyleneimines and polydimethylsiloxanes can be considered as further protective colloids.

The method according to the invention can be used not only in the delignification (bleaching) of sulfate, sulfite, organosol, etc. Pulp and wood pulp are used, but also in the production of pulp 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, an acid 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

Enzymatic bleaching with l-nitroso-2-naphthol 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 are mixed with 65 mg l-nitroso-2-naphthol with stirring, the pH Value with 0.5 mol / 1 H ₂ S0 ₄ solution. so adjusted 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 μ ol 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 μ) 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 2

Enzymatic bleach with 2-nitroso-l-naphthol 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 of tap water are mixed with 65 mg of 2-nitroso-l-naphthol 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 Trameses 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 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.

Example 3

Enzyme bleach with 2,4-dinitroso-l, 3-dihydroxybenzene and

Softwood sulfate pulp

A) 20 ml tap water with 63 mg

2,4-Dinitroso-l, 3-dihydroxybenzene added with stirring, the pH with 0.5 mol / 1 H S0 ₄ solution. adjusted so that pH 4.5 results after adding the pulp and the enzyme.

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 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

Enzyme bleach with 2-nitroso-l-naphthol-4-sulfonic acid and Softwood sulfate pulp

A) 20 ml tap water with 47 mg

2-nitroso-l-naphthol-4-sulfonic acid mixed with stirring, the pH with 0.5 mol / 1 H S0 ₄ solution. adjusted so that pH 4.5 results after adding the pulp and the enzyme.

B) 5 ml of tap water are mixed with the amount of Laccase from Trameses versicolor that an activity of 35 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 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 5 Enzymatic bleaching with l-nitroso-2-naphthol-3,6-disulfonic acid 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 are mixed with 61.5 mg l-nitroso-2-naphthol-3, 6- disulfonic acid 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 traces versicolor laccase that results in an activity of 35 U (1 U = conversion of 1 μmol ABTS / min / ml enzyme) per g of pulp.

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.

Table 1

Results Example 1 to 5

Substance Mediatordosage Enzyme dosage Incubation time Lignin degradation

[mg / S g pulp] [g / g pulp] [h] [%] l-nitroso-2-naphthol 65 15 2 17.6

2-nitroso-l-naphthol 65 15 2 8.2

2,4-dinitroso-1,3-dihydroxybenzene 63 15 2 22.1

2-nitroso-l-naphthol-4-sulfonic acid 47 35 4 25.0 l-nitroso-2-naphthol-3, 6-disulfonic acid 61, 5 35 4 31, 7

Claims

claims

1. Containing a multi-component system for changing, breaking down or bleaching lignin, lignin-containing materials or similar substances

a. optionally at least one oxidation catalyst and

b. at least one suitable oxidizing agent and

la Ib

and their salts, ethers or esters, where

R ¹ , R ² , R ³ and R ^{4 are the} same or different and are hydrogen, halogen, hydroxy, formyl, carbamoyl, carboxy, ester or salt of carboxy, sulfono, ester or salt of sulfono, sulfamoyl, Nitro-, nitroso-, cyano-, amino-, phenyl-, aryl-C- _{j ^} -Cg-alkyl-, C ₁ -C ₁₂ alkyl-, C ₁ -C ₅ -alkoxy-, C- _{j ^} - Are C- ^ _Q- carbonyl, carbonyl-C- _{j ^} -Cg-alkyl, phospho-, phosphono-, phosphono-oxy, ester or salt of the phosphonooxy,

where carbamoyl, sulfamoyl, amino and phenyl radicals can be unsubstituted or substituted one or more times with a radical R ⁵ and the aryl-C- ^ Cg-alkyl-, C- ^ C- _j ^ -alkyl-, C- _j ^ Cg-alkoxy, C- _{j ^} -C _jQ- carbonyl, carbonyl-C- _{j ^} -Cg-alkyl radicals may be saturated or unsaturated, branched or unbranched can and can be substituted one or more times with a radical R ⁵ , where

R ^{5 is the} same or different and is hydroxyl, formyl, carboxy, ester or salt of carbox, carbamoyl, sulfono, sulfamoyl, nitro, nitroso, amino, phenyl, C - ^ - Cg- Alkyl, C _j - C ₅ alkoxy radical means or

the residues R- ^ ⁴ are linked in pairs to form a ring [-CR ⁶ R ⁷ -] _{; ffl} , where m is an integer and has a value from 1 to 4, or to form a ring [-CR ⁸ = CR ⁹ -] _n are linked, where n is an integer and has a value from 1 to 3, and

2. Multi-component system according to claim 1, characterized in that it comprises at least one oxidation catalyst.

3. Multi-component system according to claim 1 or 2, characterized in that enzyme is used as the oxidation catalyst.

4. Multi-component system according to one of claims 1 to 3, characterized in that laccase is used as the enzyme.

5. Multi-component system according to one of claims 1 to 4, 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, pernitric, Metachlorperoxibenzosaure, perchloric acid, perborates, peracetates, persulphates, peroxides or oxygen species and their radicals, such as OH ^*, OOH ^*, singlet oxygen, superoxide (° ₂ '~)' ozonide, dioxygenyl cation (0 ₂ ⁺ ), Dioxirane, Dioxetane or Fre y radicals are used.

6. Multi-component system according to one of claims 1 to 5, characterized in that the mediator (component c) is selected from the group of compounds 2-nitrosophenol, 3-methyl-6-nitrosophenol, 2-methyl-6-nitrosophenol, 4- Methyl 6-nitrosophenol, 3-ethyl-6-nitrosophenol, 2-ethyl-6-nitrosophenol, 4-ethyl-6-nitrosophenol, 4-isopropyl-6-nitrosophenol, 4-tert.butyl-6-nitrosophenol, 2- Phenyl-6-nitrosophenol, 2-benzyl-6-nitrosophenol, 4-benzyl-6-nitrosophenol, 2-hydroxy-3-nitrosobenzyl alcohol, 2-hydroxy-3-nitrosobenzoic acid,

4-hydroxy-3-nitrosobenzoic acid, 2-methoxy-6-nitrosophenol, 3, 4-dimethyl-6-nitrosophenol, 2, 4-dimethyl-6-nitrosophenol, 3, 5-dimethyl-6-nitrosophenol, 2, 5- Dimethyl-6-nitrosophenol, 2-nitrosoresorcin, 4-nitrosoresorcin, 2-nitrosoorcin, 2-nitrosophloroglucin, 4-nitrosopyrogallol,

4-nitroso-3-hydroxyaniline, 4-nitro-2-nitrosophenol, 2-nitroso-l-naphthol, l-methyl-3-nitroso-2-naphthol and 9-hydroxy-10-nitroso-phenanthrene.

7. Multi-component system according to one of claims 1 to 6, characterized in that the mediator is selected from the group l-nitroso-2-naphthol, l-nitroso-2-naphthol-3,6-disulfonic acid,

2-nitroso-l-naphthol-4-sulfonic acid, 2,4-dinitroso-l, 3-dihydroxybenzene and esters, ethers and salts of the compounds mentioned.

8. A process for treating lignin, characterized in that the components a) to c) selected in accordance with claim 1 are mixed simultaneously or in any order with an aqueous suspension of the lignin-containing material.

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