WO2016007309A1

WO2016007309A1 - Use of prehydrolysate liquor in engineered wood

Info

Publication number: WO2016007309A1
Application number: PCT/US2015/037736
Authority: WO
Inventors: Gregory Clark Delozier; Henrik Lund; Morten TOVBORG; Pedro Emanuel Garcia LOUREIRO
Original assignee: Novozymes A/S
Priority date: 2014-07-07
Filing date: 2015-06-25
Publication date: 2016-01-14

Abstract

The present invention pertains to the field of wood. More specifically the present invention relates to a method for treatment of wood fibers and/or wood particles and/or wood strands with a wood prehydrolysate liquor and one or more phenol oxidizing enzymes for production of wood composite.

Description

USE OF PREHYDROLYSATE LIQUOR IN ENGINEERED WOOD

REFERENCE TO SEQUENCE LISTING

This application contains a Sequence Listing in computer readable form. The computer readable form is incorporated herein by reference. FIELD OF THE INVENTION

The present invention pertains to the field of engineered wood products. More specifically the present invention relates to a method for treatment of wood fibers and/or wood particles and/or wood strands with a wood prehydrolysate liquor and one or more phenol oxidizing enzymes for production of engineered wood products. BACKGROUND OF THE INVENTION

Wood composite panels are made of refined wood fibers, wood strands and/or wood particles mixed with an adhesive resin and wax, produced under specific conditions to produce more uniform, cost effective and more sustainable panels for furniture, flooring and other industrial applications.

Generally, wood fibers are mixed with binders, shaped and then compressed under heat and pressure. So-called medium density fiberboards (MDF), high density fiberboards (HDF) and low density fiberboards (LDF) and wood fiber insulation materials are ordinarily produced from wood chips from softwood and/or hardwood in a defibering machine, for example, with so-called refiners (for example, according to the TMP method), and brought to the desired fiber size and fiber fineness. The wood fibers are ordinarily glued with adhesive resins in the drying method (so-called "blow line" or "blender method") and dried to the desired wood fiber moisture content. The wood fibers are then spread mechanically in a shaping station on a conveyor belt in the form of a mat and then compressed while hot.

Rising and fluctuating adhesive resin and wax costs can profoundly affect the profitability of the wood composites as the adhesive resin and wax make up 20-30% of the production costs.

Prehydrolysate liquor of kraft-based dissolving pulp production has previously been disclosed (Yang et al, 2012; Acid Hydrolysis of Prehydrolysis Liquor Produced from the Kraft- Based Dissolving Pulp Production Process. Industrial & Engineering Chemistry Research, 13902-13907; Wang et al, 2015; Fractionation and characterization of saccharides and lignin components in wood prehydrosis liquor from dissolving pulp production. Carbohydrate Poly- mers). The present invention reduces the content of adhesive resin in a wood composite by treatment of the wood fibers with a prehydrolysate liquor and one or more phenol oxidizing enzymes.

SUMMARY OF THE INVENTION

The present invention can reduce the content of adhesive resin and/or wax in a wood composite and/or improve the strength of a wood composite by treatment of the wood fibers or particles with a wood prehydrolysate liquor and one or more phenol oxidizing enzymes. The treatment can reduce the content of the adhesive resin and/or the wax in the wood composite while maintaining or improving the properties of the wood composite. Accordingly, the present invention has a significant impact on the profitability in relation to production of wood composite.

DEFINITIONS

Prehydrolysate liquor (PHD: Prehydrolysate liquor (PHL) or wood PHL are used interchangeably herein. PHL is obtained from the pre-hydrolysis kraft cooking process of mixed wood chips. PHL comprises carbohydrates (sugars and oligomers), carbohydrate-derived deg- radation products, lignin and lignin components, defined as aromatic and aliphatic degradation products from lignin (e.g. as described in Yang, 2012; Acid Hydrolysis of Prehydrolysis Liquor Produced from the Kraft-Based Dissolving Pulp Production Process. Industrial & Engineering Chemistry Research, 13902-13907 and Wang et al, 2015; Fractionation and characterization of saccharides and lignin components in wood prehydrosis liquor from dissolving pulp production. Carbohydrate Polymers). PHL is in one embodiment hardwood PHL. In another embodiment the PHL is softwood PHL. In a final embodiment the PHL is mixture of hardwood PHL and softwood PHL.

Wood composite or Engineered wood product: The terms "wood composite" or "engineered wood product" are used interchangeably herein. Engineered wood products are a wood product made of wood fibers and/or wood particles and/or wood strands. Types of wood composite or engineered wood products include particle board (PB), medium-density fiberboard (MDF), oriented strand board (OSB), wafer boards, laminated strand lumber and hardboard, high-density fiberboard, low-density fiberboard and insulation board. Wood composites can be used e.g. in the furniture industry and in the auto industry e.g. to create free-form shapes such as dashboards, rear parcel shelves, and inner door shells. In one embodiment urea- formaldehyde (UF) resins and/or melamine-urea-formaldehyde (MUF) and/or phenol- formaldehyde (PF) resins and/or methylene diphenyl diisocyanate (MDI or pMDI) resins, or any combination thereof are dominantly used as the adhesive resin in the wood composites. The term "wood composite" is in one embodiment understood especially to mean materials that consist mostly of mechanically and/or thermomechanically ground lignocellulose-containing material blended with resin and/or wax, which is shaped, after sizing and/or pressed under temperature and pressure, to wood and/or composite materials. Lignocellulose-containing material: The term "lignocellulose-containing material" especially summarizes all mat-like and non-mat-like materials that contain as main ingredient ground lignocellulose-containing materials, like wood, cereal straw, hemp or flax, which are pressed under temperature and/or pressure after shaping.

Lignin components: The term "Ngnin components" refers to soluble and/or insoluble lig- nin and/or lignin degradation products. The degradation products include lignin monomers

(phenyl propanoids) and derivatives hereof as well as larger fragments of lignin. Lignin components are often aromatic but also include smaller aliphatic compounds e.g. methanol and/or formic acid.

Lignin: The term "Ngnin" refers to both polymeric intact lignin as well as lignin compo- nents as defined herein above.

Wood fibers: The terms "wood fibers" refer to lignin-containing fibers or wood fibers e.g. with a length of≥0.5 mm to <10 mm and a fiber diameter from≥0.05 mm to <3 mm. Fibers with a length from≥1 mm to <6 mm and a fiber diameter of≥0.1 mm to <1 mm are particularly preferred.

Wood particles: The term "wood particles" refers to a form lignocellulosic material or wood which has been cut or milled into a wood mixture containing particles which can pass through a mesh size of 4 mm but are retained a mesh with a size of 0.1 mm, where the length of the particles may be as high as 4 cm.

Wood strands: The term "wood strands" refers to a form of lignocellulosic material or wood which has been cut or stranded or flaked into strands ranging from a thickness >0.5 mm to <0.9 mm with a length ranging from >50 mm to <200 mm and a width ranging from >10 mm to <30 mm.

Prehydrolysis factors (P-factor): The extent of prehydrolysis can be expressed as the P- factor. The P-factor depends on reaction temperature and time. The P-factor can be calculated according to the definition in Handbook of Pulp, Volume 1 , 2006, Ed. H. Sixta, Wiley-VCH Ver- lag GmbH & Co. KGaA (page 343 to 344). Phenol oxidizing enzymes: "phenol oxidizing enzymes" of the present invention function by catalyzing redox reactions, i.e., the transfer of electrons from an electron donor (usually a phenolic compound) to molecular oxygen or hydrogen peroxide (which acts as an electron acceptor) which is reduced to water. Examples of such enzymes are laccases (EC 1.10.3.2), bili- rubin oxidases (EC 1 ,3.3.5), phenol oxidases (EC 1 .14,18,1 ), and catechol oxidases (EC 1 .10.3.1 ).

Peroxidase: A peroxidase according to the invention is a peroxidase enzyme comprised by the enzyme classification EC 1 .1 1 .1.7, or any fragment derived therefrom, exhibiting peroxidase activity. Laccases: Laccases (EC 1 .10.3.2) are copper-containing oxidase enzymes, or any fragment derived therefrom, exhibiting laccase activity.

SEQ ID NO 1 : Myceliophthora thermophila Laccase

QQSCNTPSNR ACWTDGYDIN TDYEVDSPDT GWRPYTLTL TEVDNWTGPD GWKEKV LV 60

NNSIIGPTIF ADWGDTIQVT VINNLETNGT SIHWHGLHQK GTNLHDGANG ITECPIPPKG 120

GRKVYRFKAQ QYGTSWYHSH FSAQYGNGW GAIQINGPAS LPYDTDLGVF PISDYYYSSA 180

DELVELTKNS GAPFSDNVLF NGTAKHPETG EGEYANVTLT PGRRHRLRLI NTSVENHFQV 240

SLVNHT CII AADMVPVNA TVDSLFLGVG QRYDVVIEAN RTPGNYWFNV TFGGGLLCGG 300

SRNPYPAAIF HYAGAPGGPP TDEGKAPVDH NCLDLPNLKP WARDVPLSG FAKRADNTLD 360

VTLDTTGTPL FVWKVNGSAI NIDWGRAVVD YVLTQNTSFP PGYNIVEVNG ADQWSYWLIE 420

NDPGAPFTLP HP HLHGHDF YVLGRSPDES PASNERHVFD PARDAGLLSG ANPVRRDVS 480

LPAFGWWLS FRADNPGAWL FHCHIAWHVS GGLGVVYLER ADDLRGAVSD ADADDLDRLC 540

ADWRRYWPTN PYPKSDSGLK HRWVEEGEWL VKA 573

SEQ ID NO 2: Coprinopsis cinerea Laccase

QIVNSVDT T LTNANVSPDG FTRAGILVNG VHGPLIRGGK NDNFELNWN DLDNPT LRP 60

TSIHWHGLFQ RGTNWADGAD GVNQCPISPG HAFLYKFTPA GHAGTFWYHS HFGTQYCDGL 120

RGP VIYDDN DPHAALYDED DENTIITLAD WYHIPAPSIQ GAAQPDATLI NGKGRYVGGP 180

AAELSIVNVE QGKKYR RLI SLSCDPNWQF S IDGHELTI I EVDGQLTEPH TVDRLQI FTG 240

QRYSFVLDAN QPVDNYWIRA QPNKGRNGLA GTFANGVNSA ILRYAGAANA DPTTSANPNP 300

AQLNEADLHA LIDPAAPGIP TPGAADVNLR FQLGFSGGRF TINGTAYESP SVPTLLQI S 360

GAQSANDLLP AGSVYELPRN QWELWPAG VLGGPHPFHL HGHAFSWRS AGSSTYNFVN 420

PVKRDVVSLG VTGDEVTIRF VTDNPGPWFF HCHIEFHL N GLAIVFAED ANTVDANNPP 480

VEWAQLCE IY DDLPPEATSI QTWRRAEPT GFSAKFRREG L 521

SEQ ID NO 3: Coprinus cinereus Peroxidase

QGPGGGGSVT CPGGQSTSNS QCCVWFDVLD DLQTNFYQGS KCESPVRKIL RIVFHDAIGF 60

SPALTAAGQF GGGGADGSII AHSNIELAFP ANGGLTDTVE ALRAVGINHG VSFGDLIQFA 120

TAVG SNCPG SPRLEFLTGR SNSSQPSPPS LIPGPGNTVT AILDR GDAG FSPDEWDLL 180

AAHSLASQEG LNSAIFRSPL DSTPQVFDTQ FYIETLLKGT TQPGPSLGFA EELSPFPGEF 240

R RSDALLAR DSRTACRWQS TSSNEV GQ RYRAAMAK S VLGFDRNALT DCSDVIPSAV 300

SNNAAPVIPG GLTVDDIEVS CPSEPFPEIA TASGPLPSLA PAP 343 SEQ ID NO 4: Armoracia rusticana Peroxidase

QLNATFYSGT CPNASAIVRS TIQQAFQSDT RIGASLIRLH FHDCFVDGCD ASILLDDSGS 60

IQSEKNAGPN ANSARGFNW DNIKTALENT CPGWSCSDI LALASEASVS LTGGPSWTVL 120

LGRRDSLTAN LAGANSAIPS PFEGLSNITS KFSAVGLNTN DLVALSGAHT FGRARCGVFN 180

NRLFNFSGTN GPDPTLNSTL LSSLQQLCPQ NGSASTITNL DLSTPDAFDN NYFANLQSNN 240

GLLQSDQELF STLGSATIAV VTSFASNQTL FFQAFAQS I N GNISPLTG SNGEIRLDCK 300 KVDGS 305

SEQ ID NO 5: Soybean Peroxidase

QLDPSFYRDT CPRVHSIVRE WRNVSKKDP R LASLIRLH FHDCFVQGCD ASVLLNNTAT 60

IESEQQALPN NNSLRGLDW NYIKTAVEKA CPGWSCADI LTLASQISSV LGGGPHWKVP 120

LGRRDSLTAN RNLANQNLPA PFFNLSRLKA AFAVQGLDTT DLVALSGAHT FGRAHCNFIL 180

DRLYNFSGTG KPDPTLDTTY LQQLRQICPN GGPNNLVNFD PVTPDKIDRV YFSNLQVKKG 240

LLQSDQELFS TPGADTIPIV NRFSSDQKVF FDAFEAS IK GNIGVLTGK KGE IRKHCNF 300

VNKKSVEVDI ASVASEESST EGMVTSI 327

SEQ ID NO 6: Roystonea sp. Peroxidase

DLQIGFYNTS CPTAESLVQQ AVAAAFANNS GIAPGLIR H FHDCFVRGCD ASVLLDSTAN 60

NTAEKDAIPN NPSLRGFEVI TAAKSAVEAA CPQTVSCADI LAFAARDSAN LAGNI TYQVP 120

SGRRDGTVSL ASEANAQIPS PLFNATQLIN SFANKTLTAD E VTLSGAHS IGVAHCSSFT 180

NRLYNFNSGS GIDPTLSPSY AALLRNTCPA NSTRFTPITV SLDIITPSVL DN YYTGVQL 240

TLGLLTSDQA LVTEANLSAA VKANA NLTA WASKFAQA V K GQIEVLTG TQGEIRTNCS 300

WNS 304

SEQ ID NO 7: Microdochium nivale Carbohydrate oxidase

LVTRGAIEAC LSAAGVPID I PGTADYERD VEPFNIRLPY IPTAIAQTQT TAHIQSAVQCA 60

KKLNLKVSAK SGGHSYASF GFGGENGHL VQLDR IDVI SYNDKTGIAH VEPGARLGHLA 120

TVLNDKYGRA ISHGTCPGV GISGHFAHGG FGFSSH HGL AVDSWGVTV VLADGRIVEAS 180

ATENADLFWG IKGAGSNFG IVAVWKLATF PAPKVLTRFG VTLNWKNKTS ALKGIEAVEDY 240

ARWVAPREVN FRIGDYGAG NPGIEGLYYG TPEQWRAAFQ PLLDTLPAGY WNPTTSLNWI 300

ESVLSYSNFD HVDFITPQP VENFYAKSLT LKSIKGDAVK NFVDYYFDVS NKVKDRFWFYQ 360

LDVHGGKNSQ VTKVTNAET AYPHRDKLWL IQFYDRYDNN QTYPETSFKF LDGWVNSVTKA 420

LPKSDWG YI NYADPR DR DYATKVYYGE NLARLQKLKA KFDPTDRFYY PQAVRPVK 477

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a method for producing an engineered wood product made from wood strands and/or wood particles and/or wood fibers comprising the steps of a) treating the wood strands and/or wood particles and/or wood fibers with a prehydrolysate liquor;

b) treating the wood strands and/or wood particles and/or wood fibers with one or more phenol oxidizing enzymes; and

subsequently forming the engineered wood product from the treated wood strands and/or wood particles and/or wood fibers. The method typically comprises addition of resin to the treated the treated wood strands and/or wood particles and/or wood fibers before forming of the engineered wood product.

The one or more phenol oxidizing enzymes can be selected from the group consisting of iaccases, phenol oxidases, peroxidases, haloperoxidases, bilirubin oxidases, catechol oxidases, Mn-peroxidases, lignin peroxidases, ligninases, or any combination thereof. Any phenol oxidizing enzyme mentioned elsewhere herein can also be used in step b). In one embodiment the one or more phenol oxidizing enzymes is one or more peroxidases and carbohydrate oxidase is included in the treatment.

In one embodiment step b) is performed as a wet treatment with a dry matter content of from 1 % to 50%. The dry matter content in step b) can be selected from the group consisting of from 1 % to less than 5%, from 5% to less than 10%, from 10% to less than 15%, from 15% to less than 20%, from 20% to less than 25%, from 25% to less than 30%, from 30% to less than 35%, from 35% to less than 40%, from 40% to less than 45%, from 45% to less than 50%, or any combination of these intervals.

In another embodiment step b) is performed as a dry treatment with a dry matter content of from 50% to 95%. The dry matter content in step b) can be selected from the group consisting of from 50% to less than 55%, from 55% to less than 60%, from 60% to less than 65%, from 65% to less than 70%, from 70% to less than 75%, from 75% to less than 80%, from 80% to less than 85%, from 85% to less than 90%, from 90% to less than 95%, or any combination of these intervals.

Steps a) and step b) in the method according to the invention / claim 1 can be performed simultaneously. Steps a) and step b) is however preferably performed sequentially in any order. It is even more preferred that step a) is performed prior to step b). In a specific embodiment a mixture of the PHL and the phenol oxidizing enzyme is pre-incubated for a fixed time period (pre-incubation time) prior to addition to the wood strands and/or wood particles and/or wood fibers. The pre-incubation time can e.g. be from 1 minute to 1 hour, such as from 1 minute to 5 minutes, for example from 5 minutes to 10 minutes, such as from 10 minutes to 15 minutes, for example from 15 minutes to 20 minutes, such as from 20 minutes to 30 minutes, for example from 30 minutes to 40 minutes, such as from 40 minutes to 50 minutes, for example from 50 minutes to 60 minutes, or any combination of these intervals.

The treatment in step a) is preferably performed at room temperature. In another embodiment step a) is performed at a temperature range selected from the group consisting of from 10°C to 20°C, from 20°C to 25°C, from 25°C to 30°C, from 30°C to 35°C, from 35°C to 40°C, from 40°C to 50°C, from 50°C to 60°C, from 60°C to 70°C, from 70°C to 80°C, from 80°C to 90°C, or any combination of these intervals.

The treatment in step b) can be performed at room temperature. However, step b) is preferably performed at or around the optimal temperature for the one or more phenol oxidizing enzymes. In one embodiment step a) is performed at a temperature range selected from the group consisting of from 10°C to 20°C, from 20°C to 25°C, from 25°C to 30°C, from 30°C to 35°C, from 35°C to 40°C, from 40°C to 50°C, from 50°C to 60°C, from 60°C to 70°C, from 70°C to 80°C, from 80°C to 90°C, or any combination of these intervals.

The treatment in step a) is preferably performed without incubation time. However, step a) can comprise an incubation time such as an incubation time selected from the group consisting of from 5 minutes to 15 minutes, from 15 minutes to 30 minutes, from 30 minutes to 45 minutes, from 45 minutes to 60 minutes, from 1 hour to 2 hours, from 2 hour to 3 hours, or any combination of these intervals.

The treatment in step b) preferably comprise an incubation time such as an incubation time selected from the group consisting of from 5 minutes to 15 minutes, from 15 minutes to 30 minutes, from 30 minutes to 45 minutes, from 45 minutes to 60 minutes, from 1 hour to 2 hours, from 2 hour to 3 hours, or any combination of these intervals.

In one embodiment the treatment in step a) comprises use of 0.01 % to 5% dry matter of wood PHL such as an interval selected from the group consisting of from 0.01 % to 0.05%, from 0.05% to 0.1 %, from 0.1 % to 0.2%, from 0.2% to 0.4%, from 0.4% to 0.6%, from 0.6% to 0.8%, from 0.8% to 1 %, from 1 % to 1.2%, from 1.2% to 1 .4%, from 1.4% to 1.6%, from 1.6% to 1.8%, from 1 .8% to 2%, from 2% to 2.2%, from 2.2% to 2.4%, from 2.4% to 2.6%, from 2.6% to 2.8%, from 2.8% to 3%, from 3% to 3.2%, from 3.2% to 3.4%, from 3.4% to 3.6%, from 3.6% to 3.8%, from 3.8% to 4%, from 4% to 4.2%, from 4.2% to 4.4%, from 4.4% to 4.6%, from 4.6% to 4.8%, from 4.8% to 5%, or any combination of these intervals.

The treatment in step a) and/or step b) can comprise spraying of the prehydrolysate liquor and/or the one or more phenol oxidizing enzymes onto the wood strands and/or wood particles and/or wood fibers. The spray addition is preferably performed in the blowline and/or in the dryer. Any other suitable method such as pouring can be used for administering of the prehy- drolysate and/or the one or more phenol oxidizing enzymes onto the wood strands and/or wood particles and/or wood fibers.

In general fiberboards including MDF can be made by steam cooking and refining wood chips to produce fibers. These fibers are typically propelled by hot air, through a blow line, where they are mixed with resin and wax, then dried, formed and finally pressed.

In more detail, a fiber board such as MDF is typically being produced by a process much similar to a Thermo Mechanical Pulping (TMP) process, where the wood chips are steamed and pressurized in a disk refiner to separate the individual fibers in the wood. The refined fibers are then blended with adhesive resin (typically urea formaldehyde, 10-12% w/w) and wax and dried in a tube dryer. After a short holding time the fiber-mat is formed and hot-pressed which causes the resin to polymerize and harden and the board is ready for further processing.

The high temperature used during refining causes the breakage to appear in the lignin rich middle lamella between the fibers, and results in a surface that contains high amounts of lignin available for oxidation by phenol oxidizing enzyme such as one or more laccases. The mechanism for the laccase activation of lignin involves an electron oxidation of the phenolic hy- droxyl groups present in the lignin, generating relatively stable phenoxy radicals on the surface of the fibers. During the hot pressing of the activated fibers the phenoxy radicals undergo coupling reactions that form water-resistant cross-linkages between the fibers and hereby increases the strength and reduces the water absorption of the final boards. These improvements allow for less resin and/or wax to be added to the boards in order to meet specifications requirements.

The administration of wood PHL followed by administration of one or more phenol oxidizing enzymes (such as one or more laccases) onto wood fibers and/or wood particles and/or wood strands can result in an adhesive resin reduction of at least from 10% to 60% in the pro- duction of the wood composites compared to fibers without administration of wood PHL and one or more phenol oxidizing enzymes. This resin reduction can be selected from the group consisting of from about 10% to about 12%, from about 12% to about 14%, from about 14% to about 16%, from about 16% to about 18%, from about 18% to about 20%, from about 20% to about 22%, from about 22% to about 24%, from about 24% to about 26%, from about 26% to about 28%, from about 28% to about 30%, from about 30% to about 32%, from about 32% to about 34%, from about 34% to about 36%, from about 36% to about 38%, from about 38% to about 40%, from about 40% to about 42%, from about 42% to about 44%, from about 44% to about 46%, from about 46% to about 48%, from about 48% to about 50%, from about 50% to about 52%, from about 52% to about 54%, from about 54% to about 56%, from about 56% to about 58%, from about 58% to about 60%, or any combination of these intervals.

The administration of wood PHL followed by administration of one or more phenol oxidizing enzymes (such as one or more laccases) onto wood fibers and/or wood particles and/or wood strands can result in a wax reduction of at least from 10% to 60% in the production of the wood composites compared to fibers without administration of wood PHL and one or more phe- nol oxidizing enzymes. This wax reduction can be selected from the group consisting of from about 10% to about 12%, from about 12% to about 14%, from about 14% to about 16%, from about 16% to about 18%, from about 18% to about 20%, from about 20% to about 22%, from about 22% to about 24%, from about 24% to about 26%, from about 26% to about 28%, from about 28% to about 30%, from about 30% to about 32%, from about 32% to about 34%, from about 34% to about 36%, from about 36% to about 38%, from about 38% to about 40%, from about 40% to about 42%, from about 42% to about 44%, from about 44% to about 46%, from about 46% to about 48%, from about 48% to about 50%, from about 50% to about 52%, from about 52% to about 54%, from about 54% to about 56%, from about 56% to about 58%, from about 58% to about 60%, or any combination of these intervals.

The administration of wood PHL followed by administration of one or more phenol oxidizing enzymes (such as one or more laccases) onto wood fibers and/or wood particles and/or wood strands can result in an adhesive resin and/or wax reduction of at least from 10% to 60% in the production of the wood composites compared to fibers without administration of wood PHL and one or more phenol oxidizing enzymes. This adhesive resin and/or wax reduction can be selected from the group consisting of from about 10% to about 12%, from about 12% to about 14%, from about 14% to about 16%, from about 16% to about 18%, from about 18% to about 20%, from about 20% to about 22%, from about 22% to about 24%, from about 24% to about 26%, from about 26% to about 28%, from about 28% to about 30%, from about 30% to about 32%, from about 32% to about 34%, from about 34% to about 36%, from about 36% to about 38%, from about 38% to about 40%, from about 40% to about 42%, from about 42% to about 44%, from about 44% to about 46%, from about 46% to about 48%, from about 48% to about 50%, from about 50% to about 52%, from about 52% to about 54%, from about 54% to about 56%, from about 56% to about 58%, from about 58% to about 60%, or any combination of these intervals.

In one aspect the adhesive resin reduction is possible while maintaining or improving the properties of the wood composite. The product properties include one or more properties selected from the group consisting of increased overall strength of the wood composite, increased internal bond strength, increased adhesion between strands, fibers or particles, reduction of the water absorption, reduction of thickness swelling, reduction of moisture absorption, improved bending strength, reduced edge swelling, reduction in mold growth and improvement with respect to formaldehyde emission.

In one aspect administration of wood PHL followed by administration of one or more phenol oxidizing enzymes (such as one or more laccases) onto wood fibers and/or wood parti- cles and/or wood strands can result in an increase of the internal bond strength of the wood composite of from 5% to 60% compared to untreated wood fibers/particles/strands. The increase of the internal bond strength can e.g. be selected from the group consisting of from about 5% to about 10%, from about 10% to about 15%, from about 15% to about 20%, from about 20% to about 25%, from about 25% to about 30%, from about 30% to about 35%, from about 35% to about 40%, from about 40% to about 45%, from about 45% to about 50%, from about 50% to about 55%, and from about 55% to about 60%, or any combination of these intervals.

In one aspect administration of wood PHL followed by administration of one or more phenol oxidizing enzymes (such as one or more laccases) onto wood fibers and/or wood particles and/or wood strands results in a reduction in the water absorption of the wood composite of from 10% to 50% compared to wood composite made of untreated fibers/particles/strands. The reduction in the water absorption can e.g. be selected from the group consisting of from about 10% to about 15%, from about 15% to about 20%, from about 20% to about 25%, from about 25% to about 30%, from about 30% to about 35%, from about 35% to about 40%, from about 40% to about 45%, from about 45% to about 50%, or any combination of these intervals.

In one aspect the administration of the wood PHL is performed by spraying in the blow- line and/or in the dryer.

In a preferred embodiment the wood prehydrolysate liquor comprises lignin components, acetic acid and furfural. In an even more preferred embodiment the acetic acid content is from 5% to 20% of drymatter in the wood prehydrolysate liquor and the furfural content is from 1 % to 10% of drymatter in the wood prehydrolysate liquor. Preferably the PHL further comprises oligosaccharides, monosaccharides, formic acid and 5-hydroxymethyl furfural. In a preferred embodiment the monosaccharide composition in the PHL is defined by a ratio of xylose to glucose of at least 0.5 such as from 0.5 to 1 , for example from 1 to 2, such as from 2 to 3, for example from 3 to 4, such as from 4 to 5, for example from 5 to 6, such as from 6 to 7, for example from 7 to 8, such as from 8 to 9, for example from 9 to 10, or any combination of these intervals. The wood prehydrolysate liquor is typically derived from a kraft-based dissolving pulp production process.

The invention further relates to wood fibers and/or wood particles and/or wood strands for manufacture of wood composite treated with the method or manufactured using the method according to the invention.

The present invention further relates to an engineered wood product obtained or obtainable by the method according to the invention. Furthermore use of a prehydolysate liquor and one or more phenol oxidizing enzymes for reducing the resin content and/or improving the properties of a engineered wood product is also encompassed by the present invention.

Wood Prehydrolysate liquor Prehydrolysate liquor (PHL) from the pre-hydrolysis kraft cooking e.g. of mixed hardwood chips is used for impregnation of wood strands and/or wood particles and/or wood fibers in manufacture of engineered wood products such as wood composite (i.e. step a) in the method described herein above).

Prehydrolysis is carried out for producing dissolving pulp in kraft process to remove hemicelluloses. More specifically, the prehydrolysis step is utilized in dissolving pulp production to degrade the major portion of the hemicelluloses which become soluble in the subsequent alkaline steps (cf. e.g. Sixta, 2006; Handbook of Pulp. Weinheim: Wiley-VCH Verlag GmbH).

The PHL can be collected after depressurizing the digester of a pre-hydrolysis kraft dis- solving pulp mill.

Prehydrolysis is carried out for producing dissolving pulp in kraft process to efficiently remove hemicelluloses. During the prehydrolysis step of such a process, hemicelluloses and other organics are dissolved in the prehydrolysate liquor (PHL). The major reactions include: (i) depolymerization and dissolution resulting in the formation of sugars and/or oligomers, (ii) fur- ther degradation of sugars to form monosaccharides and sugar decomposition products such as furfural and hydroxymethylfurfural hydroxymethylfurfural, and (iii) acetic acid is generated by the cleavage of acetyl groups in wood, which is responsible for the decrease in pH during the prehydrolysis, and thus facilitate the hemicelluloses removal.

The PHL from the kraft-based dissolving pulp production process typically contains both mono- and oligosugars along with lignin, acetic acid, and some degradation products. PHL preferably mainly comprises oligosugars with a minor amount of monosugars.

The content of the PHL depend on the raw material type (composition of wood types) and on the operational conditions. The amount of sugars recovered from the raw material is dependent on the reaction time, the temperature and the acid concentration. The acid concentra- tion is typically the most important parameter affecting sugar yield, while for the formation of sugar degradation products, such as furfural, the temperature typically has the highest impact. An example of raw material could be a composition comprising 70 wt% maple, 20 wt % poplar and 10% birch. An example of operational conditions could be steaming at 170°C for 30 minutes. The operational conditions are further exemplified herein below.

The temperature for the PHL production is typically from 100 °C to 250 °C, such as a temperature selected from the group consisting of from 100 °C to 1 10 °C, from 1 10 °C to 120 °C, from 120 °C to 130 °C, from 130 °C to 140 °C, from 140 °C to 150 °C, from 150 °C to 160 °C, from 160 °C to 170 °C, from 170 °C to 180 °C, from 180 °C to 190 °C, from 190 °C to 200 °C, from 200 °C to 210 °C, from 210 °C to 220 °C, from 220 °C to 230 °C, from 230 °C to 240 °C, from 240 °C to 250 °C, and any combination of these intervals. The reaction time for the production of the PHL is typically from 10 minutes to 200 minutes, such as a reaction time selected from the group consisting of from 10 minutes to 20 minutes, from 20 minutes to 30 minutes, from 30 minutes to 40 minutes, from 40 minutes to 50 minutes, from 50 minutes to 60 minutes, from 60 minutes to 70 minutes, from 70 minutes to 80 minutes, from 80 minutes to 90 minutes, from 90 minutes to 100 minutes, from 100 minutes to 1 10 minutes, from 1 10 minutes to 120 minutes, from 120 minutes to 130 minutes, from 130 minutes to 140 minutes, from 140 minutes to 150 minutes, from 150 minutes to 160 minutes, from 160 minutes to 170 minutes, from 170 minutes to 180 minutes, from 180 minutes to 190 minutes, from 190 minutes to 200 minutes, or any combination of these intervals.

In the pre-hydrolysis kraft cooking of e.g. mixed hardwood chips steam prehydrolysis of the wood chips is normally carried out with saturated steam at adjusted prehydrolysis factors (P- factors). In one embodiment the P-factor can be in the range from 100 to 2000, such as from 200 to 1500, such as from 300 to about 1000. A P-factor of 300 and 1000 corresponds to 30 minutes and 100 min at 170°C, respectively. In another embodiment the P-factor can be select- ed from the group consisting of from 100 to 200, from 200 to 300, from 300 to 400, from 400 to 500, from 500 to 600, from 600 to 700, from 700 to 800, from 800 to 900, from 900 to 1000, from 1000 to 1500, and from 1500 to 2000, or any combination of these intervals.

The PHL typically comprises one or more carbohydrates (including sugars and/or oligomers), one or more carbohydrate-derived degradation products and lignin (cf. e.g. Yang, 2012; Acid Hydrolysis of Prehydrolysis Liquor Produced from the Kraft-Based Dissolving Pulp

Production Process. Industrial & Engineering Chemistry Research, 13902-13907 and Wang et al, 2015; Fractionation and characterization of saccharides and lignin components in wood prehydrosis liquor from dissolving pulp production. Carbohydrate Polymers). The soluble lignin portion in the PHL is of interest in this invention as a source of mediators for one or more oxi- doreductases when applied to different lignocellulosic substrates such as wood strands and/or wood particles and/or wood fibers.

The PHL is preferably produced by steam or water hydrolysis of wood chips and often deacetylation of xylan governs its efficiency thereby lowering the pH of the liquor. Compared to other types of processes generating water streams from mechanical treatment of wood in a re- fining step, as disclosed in WO 98/31875, the PHL is rather obtained by a harsh chemical process (a typical prehydrolysis intensity in dissolving kraft pulp production is 1 h at 170°C which corresponds to a P-factor of 597) leading to the chemical degradation of carbohydrate and lignin fraction in the wood, not only via acid-catalysed depolymerization but also decomposition reactions. For example, xylan is depolymerized into oligomeric and monomeric fractions that further decompose into decomposition products, such as furfural. Likewise, lignin is partially degraded into different types of water soluble aromatic structures (lignin components) (Sixta, 2006; Handbook of Pulp. Weinheim: Wiley-VCH Verlag GmbH) that can serve as a source of mediators for oxidoreductase enzymes.

Besides lignin-degradation products (lignin components), xylan-derived furfural and ace- tic acid are always present and constitute major components in the PHL in contrast to the composition of other water streams derived from less harsh processes such as wood refining processes, e.g. as described in WO 98/31875. Furthermore it is described that up to 4% of wood is commonly solubilized during the refining process, but in a typical steam pre-hydrolysis step within kraft dissolving pulp production, 8% of the wood is lost. If the neutralization step after pre- hydrolysis is considered, the portion of wood components that is solubilized is much greater. In one embodiment the PHL comprises sugar (including mono- and oligosaccharides) and/or solid content (wood components) and/or lignin and/or acetic acid and/or furfural. The amounts of these components are exemplified herein below.

The solid content (wood components) of the PHL is typically from 2 g/L to 200 g/l, such as a solid content selected from the group consisting of from 2 g/L to 10 g/L, from 10 g/L to 20 g/L, from 20 g/L to 30 g/L, from 30 g/L to 40 g/L, from 40 g/L to 50 g/L, from 50 g/L to 60 g/L, from 60 g/L to 70 g/L, from 70 g/L to 80 g/L, from 80 g/L to 90 g/L, from 90 g/L to 100 g/L, from 100 g/L to 1 10 g/L, from 1 10 g/L to 120 g/L, from 120 g/L to 130 g/L, from 130 g/L to 140 g/L, from 140 g/L to 150 g/L, from 150 g/L to 160 g/L, from 160 g/L to 170 g/L, from 170 g/L to 180 g/L, from 180 g/L to 190 g/L, from 190 g/L to 200 g/L, or any combination of these intervals.

The lignin content of the PHL is typically from 0.1 g/L to 100 g/L, such as a ligning content selected from the group consisting of from 0.1 g/L to 1 g/L, from 1 g/L to 2 g/L, from 2 g/L to 4 g/L, from 4 g/L to 6 g/L, from 6 g/L to 8 g/L, from 8 g/L to 10 g/L, from 10 g/L to 12 g/L, from 12 g/L to 14 g/L, from 14 g/L to 16 g/L, from 16 g/L to 18 g/L, from 18 g/L to 20 g/L, from 20 g/L to 25 g/L, from 25 g/L to 30 g/L, from 30 g/L to 40 g/L, from 40 g/L to 50 g/L, from 50 g/L to 60 g/L, from 60 g/L to 70 g/L, from 70 g/L to 80 g/L, from 80 g/L to 90 g/L, from 90 g/L to 100 g/L, or any combination of these intervals. Due to the relatively harsh process conditions of the pre- hydrolysis step the lignin fraction is considerably more soluble at acidic and neutral conditions compared to less harsh conditions of typical TMP processes. The lignin content of the PHL is typically from 1 % to 30% of drymatter, for example from 1 % to 5%, such as from 5% to 10%, for example from 10% to 15%, such as from 15% to 20%, for example from 20% to 25%, such as from 25% to 30%, or any combination of these intervals. The lignin in the PHL preferably has an acid soluble fraction of at least 10% of lignin drymatter such as from 10% to 15%, for example from 15% to 20%, such as from 20% to 25%, for example from 25% to 30%, such as from 30% to 35%, for example from 35% to 40%, such as from 40% to 45%, for example from 45% to 50%, such as from 50% to 60%, for example from 60% to 70%, such as from 70% to 80%, or any combination of these intervals.

The acetic acid content of the PHL is typically from 0.1 g/L to 100 g/L, such as an acetic acid content selected from the group consisting of from 0.1 g/L to 1 g/L, from 1 g/L to 2 g/L, from 2 g/L to 4 g/L, from 4 g/L to 6 g/L, from 6 g/L to 8 g/L, from 8 g/L to 10 g/L, from 10 g/L to 12 g/L, from 12 g/L to 14 g/L, from 14 g/L to 16 g/L, from 16 g/L to 18 g/L, from 18 g/L to 20 g/L, from 20 g/L to 25 g/L, from 25 g/L to 30 g/L, from 30 g/L to 40 g/L, from 40 g/L to 50 g/L, from 50 g/L to 60 g/L, from 60 g/L to 70 g/L, from 70 g/L to 80 g/L, from 80 g/L to 90 g/L, from 90 g/L to 100 g/L, or any combination of these intervals. The acetic acid drymatter content of the PHL is typically from 5% to 25%, such as from 5% to 10%, for example from 10% to 15%, such as from 15% to 20%, for example from 20% to 25%, or any combination of these intervals. The furfural content of the PHL is typically from 0.1 g/L to 20 g/L, such as an furfural content selected from the group consisting of from from 0.1 g/L to 0.2 g/L, from 0.2 g/L to 0.4 g/L, from 0.4 g/L to 0.6 g/L, from 0.6 g/L to 0.8 g/L, from 0.8 g/L to 1 g/L, from 1 g/L to 1.2 g/L, from 1.2 g/L to 1.4 g/L, from 1.4 g/L to 1.6 g/L, from 1.6 g/L to 1.8 g/L, from 1.8 g/L to 2 g/L, from 2 g/L to 4 g/L, from 4 g/L to 6 g/L, from 6 g/L to 8 g/L, from 8 g/L to 10 g/L, from 10 g/L to 12 g/L, from 12 g/L to 14 g/L, from 14 g/L to 16 g/L, from 16 g/L to 18 g/L, from 18 g/L to 20 g/L, or any combination of these intervals. The furfural content of the PHL is typically from 0.1 % to 15% drymatter, for example 0.1 % to 0.5%, such as from 0.5% to 5%, for example from 5% to 10%, such as from 10% to 15%, or any combination of these intervals.

As mentioned above the PHL typically comprises monosaccharides and oligosaccha- rides. The total content of sugar (i.e. monosaccharides and oligosaccharides) in the PHL is typically from 1 g/L to 250 g/L, such as a total sugar content selected from the group consisting of from 1 g/L to 10 g/L, from 10 g/L to 20 g/L, from 20 g/L to 30 g/L, from 30 g/L to 40 g/L, from 40 g/L to 50 g/L, from 50 g/L to 60 g/L, from 60 g/L to 70 g/L, from 70 g/L to 80 g/L, from 80 g/L to 90 g/L, from 90 g/L to 100 g/L, from 100 g/L to 150 g/L, from 150 g/L to 200 g/L, from 200 g/L to 250 g/L, or any combination of these intervals. In one embodiment the total drymatter content of sugar (i.e. monosaccharides and oligosaccharides) in the PHL is from 40% to 80% drymatter, such as from 40% to 50%, for example from 50% to 60%, such as from 60% to 70%, for example from 70% to 80%, or any combination of these intervals. The total content of oligosaccharides in the PHL is typically from 1 g/L to 200 g/L, such as a total oligosaccharide content selected from the group consisting of from 1 g/L to 10 g/L, from 10 g/L to 20 g/L, from 20 g/L to 30 g/L, from 30 g/L to 40 g/L, from 40 g/L to 50 g/L, from 50 g/L to 60 g/L, from 60 g/L to 70 g/L, from 70 g/L to 80 g/L, from 80 g/L to 90 g/L, from 90 g/L to 100 g/L, from 100 g/L to 150 g/L, from 150 g/L to 200 g/L, or any combination of these intervals. In one embodiment the total drymatter content of oligosaccharides in the PHL is from 30% to 80% drymatter, for example from 30% to 40%, such as from 40% to 50%, for example from 50% to 60%, such as from 60% to 70%, for example from 70% to 80%, or any combination of these intervals. The total content of monosaccharides in the PHL is typically from 1 g/L to 150 g/L, such as a total monosaccharide content selected from the group consisting of from 1 g/L to 10 g/L, from 10 g/L to 20 g/L, from 20 g/L to 30 g/L, from 30 g/L to 40 g/L, from 40 g/L to 50 g/L, from 50 g/L to 60 g/L, from 60 g/L to 70 g/L, from 70 g/L to 80 g/L, from 80 g/L to 90 g/L, from 90 g/L to 100 g/L, from 100 g/L to 150 g/L or any combination of these intervals. The monosaccharides drymatter content of the PHL is typically from 1 % to 20% drymatter, such as from 1 % to 5%, for example from 5% to 10%, such as from 10% to 15%, for example from 15% to 20%, or any combination of these intervals.

The monosugars in the PHL can comprise rhamnose and/or arabinose and/or galactose and/or glucose and/or xylose and/or mannose. The content of rhamnose in the PHL can be from 0.1 g/L to 10 g/L such as a content selected from the group consisting of from 0.1 g/L to 0.2 g/L, from 0.2 g/L to 0.4 g/L, from 0.4 g/L to 0.6 g/L, from 0.6 g/L to 0.8 g/L, from 0.8 g/L to 1 g/L, from 1 g/L to 1.5 g/L, from 1.5 g/L to 2 g/L, from 2 g/L to 3 g/L, from 3 g/L to 4 g/L, from 4 g/L to 5 g/L, from 5 g/L to 6 g/L, from 6 g/L to 7 g/L, from 7 g/L to 8 g/L, from 8 g/L to 9 g/L, from 9 g/L to 10 g/L, or any combination of these intervals. The drymatter content of rhamnose in the PHL is typically from 0.1 % to 4%, such as from 0.1 % to 0.5%, for example from 0.5% to 1 %, such as from 1 % to 2%, for example from 2% to 3%, such as from 3% to 4%, or any combination of these intervals.

The content of arabinose in the PHL can be from 0.1 g/L to 10 g/L such as a content selected from the group consisting of from 0.1 g/L to 0.2 g/L, from 0.2 g/L to 0.4 g/L, from 0.4 g/L to 0.6 g/L, from 0.6 g/L to 0.8 g/L, from 0.8 g/L to 1 g/L, from 1 g/L to 1.5 g/L, from 1.5 g/L to 2 g/L, from 2 g/L to 3 g/L, from 3 g/L to 4 g/L, from 4 g/L to 5 g/L, from 5 g/L to 6 g/L, from 6 g/L to 7 g/L, from 7 g/L to 8 g/L, from 8 g/L to 9 g/L, from 9 g/L to 10 g/L, or any combination of these intervals. The drymatter content of arabinose in the PHL is typically from 0.1 % to 4%, such as from 0.1 % to 0.5%, for example from 0.5% to 1 %, such as from 1 % to 2%, for example from 2% to 3%, such as from 3% to 4%, or any combination of these intervals.

The content of galactose in the PHL can be from 0.2 g/L to 25 g/L such as a content selected from the group consisting of from 0.2 g/L to 1 g/L, from 1 g/L to 2 g/L, from 2 g/L to 3 g/L, from 3 g/L to 4 g/L, from 4 g/L to 5 g/L, from 5 g/L to 6 g/L, from 6 g/L to 7 g/L, from 7 g/L to 8 g/L, from 8 g/L to 9 g/L, from 9 g/L to 10 g/L, from 9 g/L to 10 g/L, from 10 g/L to 12 g/L, from 12 g/L to 14 g/L, from 14 g/L to 16 g/L, from 16 g/L to 18 g/L, from 18 g/L to 20 g/L, from 20 g/L to 22 g/L, from 22 g/L to 25 g/L, or any combination of these intervals. The drymatter content of galactose in the PHL is typically from 0.1 % to 4%, such as from 0.1 % to 0.5%, for example from 0.5% to 1 %, such as from 1 % to 2%, for example from 2% to 3%, such as from 3% to 4%, or any combination of these intervals.

The content of glucose in the PHL can be from 1 g/L to 80 g/L such as a content selected from the group consisting of from 1 g/L to 80 g/L, such as a total sugar content selected from the group consisting of from 1 g/L to 10 g/L, from 10 g/L to 20 g/L, from 20 g/L to 30 g/L, from 30 g/L to 40 g/L, from 40 g/L to 50 g/L, from 50 g/L to 60 g/L, from 60 g/L to 70 g/L, from 70 g/L to 80 g/L, or any combination of these intervals. The drymatter content of glucose in the PHL is typically from 0.1 % to 4%, such as from 0.1 % to 0.5%, for example from 0.5% to 1 %, such as from 1 % to 2%, for example from 2% to 3%, such as from 3% to 4%, or any combination of these intervals. The content of xylose in the PHL can be from 5 g/L to 250 g/L, such as a xylose content selected from the group consisting of from 5 g/L to 10 g/L, from 10 g/L to 20 g/L, from 20 g/L to 30 g/L, from 30 g/L to 40 g/L, from 40 g/L to 50 g/L, from 50 g/L to 60 g/L, from 60 g/L to 70 g/L, from 70 g/L to 80 g/L, from 80 g/L to 90 g/L, from 90 g/L to 100 g/L, from 100 g/L to 150 g/L, from 150 g/L to 200 g/L, from 200 g/L to 250 g/L, or any combination of these intervals. The xy- lose content of the PHL is typically from 1 % to 15% drymatter, such as from 1 % to 5%, for example from 5% to 10%, such as from 10% to 15%, or any combination of these intervals.

The content of mannose in the PHL can be from 0.2 g/L to 250 g/L such as a content selected from the group consisting of from 0.2 g/L to 1 g/L, from 1 g/L to 2 g/L, from 2 g/L to 3 g/L, from 3 g/L to 4 g/L, from 4 g/L to 5 g/L, from 5 g/L to 6 g/L, from 6 g/L to 7 g/L, from 7 g/L to 8 g/L, from 8 g/L to 9 g/L, from 9 g/L to 10 g/L, from 9 g/L to 10 g/L, from 10 g/L to 12 g/L, from 12 g/L to 14 g/L, from 14 g/L to 16 g/L, from 16 g/L to 18 g/L, from 18 g/L to 20 g/L, from 20 g/L to 22 g/L, from 22 g/L to 25 g/L, from 25 g/L to 30 g/L, from 30 g/L to 40 g/L, from 40 g/L to 50 g/L, from 50 g/L to 60 g/L, from 60 g/L to 70 g/L, from 70 g/L to 80 g/L, from 80 g/L to 90 g/L, from 90 g/L to 100 g/L, from 100 g/L to 150 g/L, from 150 g/L to 200 g/L, from 200 g/L to 250 g/L or any combination of these intervals. The drymatter content of mannose in the PHL is typically from 0.1 % to 4%, such as from 0.1 % to 0.5%, for example from 0.5% to 1 %, such as from 1% to 2%, for example from 2% to 3%, such as from 3% to 4%, or any combination of these intervals. In a preferred embodiment the PHL comprises an elevated ratio of monosaccharides originating form hydrolysis of hemicellulose. Preferential hydrolysis of hemicellulose increases the relative amount of e.g. xylose and mannose to that of e.g. glucose, primarily present in cellulose. The ratio of xylose to glucose in PHL is typically at least 0.5, 0.75, 1 , 2, 3, 4, 5, 6, 7, 8, 9 or 10. The ratio of xylose to glucose in PHL can be selected from the group of ranges consisting of from 1-2, such as from 2-3, such as from 3-4, such as from 4-5, such as from 5-6, such as from 6-7, such as from 7-8, such as from 8-9, such as from 9-10, or any combination of these ranges.

Phenol oxidizing enzymes The one or more phenol oxidizing enzymes of the present invention function by catalyzing redox reactions, i.e., the transfer of electrons from an electron donor (usually a phenolic compound) to molecular oxygen or hydrogen peroxide (which acts as an electron acceptor) which is reduced to water.

The enzyme system used in the invention consists of a suitable oxidase together with 0₂ or a suitable peroxidase together with H₂0₂. Suitable enzymes are those, which oxidize and polymerize aromatic compounds such as phenols and lignin.

The one or more phenol oxidizing enzymes can be selected from the group consisting of laccases (EC 1 .10.3.2), phenol oxidases (EC 1 .14.18.1 ), peroxidase (EC 1.1 1.1.7), haloperoxi- dases, bilirubin oxidases (EC 1.3.3,5), catechol oxidases (EC 1 .10.3.1 ), Mn-peroxidases, lignin peroxidases, ligninases, or their mixtures.

The amount of peroxidase can in one embodiment be in the range 10-10,000 PODU per g of dry substance (PODU unit of peroxidase activity defined below). The amount of laccase can in one embodiment be in the range 0.001 -1000 units per g of dry substance (unit of laccase activity defined below).

Laccase Laccases are one preferred type of phenol oxidizing enzymes. A laccase according to the invention is any laccase enzyme comprised by the enzyme classification EC 1.10.3.2 as set out by the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (IUBMB), or any fragment derived therefrom exhibiting laccase activity, or a compound ex- hibiting a similar activity, such as a catechol oxidase (EC 1 .10.3.1 ), an o-aminophenol oxidase (EC 1 .10.3.4), or a bilirubin oxidase (EC 1 .3.3.5).

Preferred laccase enzymes are enzymes of microbial origin. The enzymes may be derived from plants, bacteria or fungi (including filamentous fungi and yeasts).

Suitable examples from fungi include a laccase derivable from a strain of Aspergillus, Neurospora, e.g., N. crassa, Podospora, Botrytis, Collybia, Fomes, Lentinus, Pleurotus, Trametes, e.g., T. villosa and T. versicolor, Rhizoctonia, e.g., R. solani, Coprinopsis, e.g., C. cinerea, C. comatus, C. friesii, and C. plicatilis, Psathyrella, e.g., P. condelleana, Panaeolus, e.g., P. papilionaceus, Myceliophthora, e.g., M. thermophila, Schytalidium, e.g., S. thermophi- lum, Polyporus, e.g., P. pinsitus, Phlebia, e.g., P. radiata (WO 92/01046), or Coriolus, e.g., C. hirsutus (JP 2238885).

Suitable examples from bacteria include a laccase derivable from a strain of Bacillus.

A laccase derived from Coprinopsis or Myceliophthora is preferred; in particular a laccase derived from Coprinopsis cinerea or Myceliophthora thermophila. Preferably, the amino acid sequence of the laccase has at least 80% identity, more preferably at least 85%, more preferably at least 90%, more preferably at least 95%, and most preferably 100% identity to the Myceliophthora thermophila laccase shown as SEQ I D NO:1 , or the Coprinopsis cinerea laccase shown as SEQ ID NO:2.

Suitable laccases may, for example, be derived from a strain of Polyporus sp., in particular a strain of Polyporus pinsitus (also called Trametes villosa) or Polyporus versicolor, or a strain of Myceliophthora sp., e.g. M. thermophila or a strain of Rhizoctonia sp., in particular a strain of Rhizoctonia praticola or Rhizoctonia solani, or a strain of Scytalidium sp., in particular S. thermophilium, or a strain of Pyricularia sp., in particular Pyricularia oryzae, or a strain of Coprinus sp., such as a C. cinereus.

The laccase may also be derived from a fungus such as Collybia, Fomes, Lentinus, Pleurotus, Aspergillus, Neurospora, Podospora, Phlebia, e.g. P. radiata (WO 92/01046), Coriolus sp., e.g. C. hirsitus (JP 2-238885), or Botrytis. In a preferred embodiment of the invention the laccase is derived from a strain of Polyporus sp., especially the Polyporus pinsitus laccase (in short: PpL). The laccase enzyme may furthermore be one which is producible by a method comprising cultivating a host cell transformed with a recombinant DNA vector which carries a DNA sequence encoding said laccase as well as DNA sequences encoding functions permitting the expression of the DNA sequence encoding the laccase, in a culture medium under conditions permitting the expression of the laccase enzyme, and recovering the laccase from the culture.

In further particular embodiments of the method and use of the invention, the laccase and/or compound exhibiting laccase activity is used in an amount of 0.005-50 ppm (mg/l), or 0.01 -40, 0.02-30, 0.03-25, 0.04-20, 0.05-15, 0.05-10, 0.05-5, 0.05-1 , 0.05-0.8, 0.05-0.6, or 0.1- 0.5 ppm. The amount of enzyme refers to mg of enzyme protein.

Determination of Laccase Activity (LAMU)

Laccase activity may be determined from the oxidation of syringaldazine under aerobic conditions. The violet colour produced is measured at 530 nm. The analytical conditions are 19 mM syringaldazine, 23 mM Tris/maleate buffer, pH 7.5, 30°C, 1 min. reaction time. One laccase unit (LAMU) is the amount of enzyme that catalyses the conversion of 1.0 mmole syringaldazine per minute at these conditions.

Source of Oxygen

The source of oxygen required by the laccase may be oxygen from the atmosphere or an oxygen precursor for in situ production of oxygen. In many industrial applications, oxygen from the atmosphere will usually be present in sufficient quantity. If more 0₂ is needed, additional oxygen may be added, e.g. as pressurized atmospheric air or as pure pressurized 0₂. Alternatively, oxygen precursors such as peroxides may be inherently present and/or added to the effluent and which, upon dissociation or reduction, reduction (e.g. by one or more enzymes such as by one or more catalases), provide an in situ source of oxygen. Suitable peroxides may be provided as described below.

Peroxidase Enzymes

Peroxidases are one preferred type of phenol oxidizing enzymes. EC-numbers may be used for classification of enzymes. Reference is made to the Recommendations of the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology, Academic Press Inc., 1992.

It is to be understood that the term enzyme, as well as the various enzymes and enzyme classes mentioned herein, encompass wild-type enzymes, as well as any variant thereof that retains the activity in question. Such variants may be produced by recombinant techniques. The wild-type enzymes may also be produced by recombinant techniques, or by isolation and purification from the natural source.

In a particular embodiment the enzyme in question is well-defined, meaning that only one major enzyme component is present. This can be inferred e.g. by fractionation on an ap- propriate size-exclusion column. Such well-defined, or purified, or highly purified, enzyme can be obtained as is known in the art and/or described in publications relating to the specific enzyme in question. A peroxidase according to the invention is a peroxidase enzyme comprised by the enzyme classification EC 1.1 1.1 .7, or any fragment derived therefrom, exhibiting peroxidase activity.

Preferably, the peroxidase according of the invention is a plant peroxidase (e.g. horserad- ish peroxidase (see SEQ ID NO:4), soybean peroxidase (see SEQ ID NO:5), or royal palm tree peroxidase (see SEQ ID NO:6)), or a fungal or bacterial peroxidase.

Some preferred fungi include strains belonging to the subdivision Deuteromycotina, class Hyphomycetes, e.g., Fusarium, Humicola, Tricoderma, Myrothecium, Verticillum, Arthromyces, Caldariomyces, Ulocladium, Embellisia, Cladosporium or Dreschlera, in particular Fusarium ox- ysporum (DSM 2672), Humicola insolens, Trichoderma res/7, Myrothecium verrucaria (IFO 61 13), Verticillum alboatrum, Verticillum dahlie, Arthromyces ramosus (FERM P-7754), Caldariomyces fumago, Ulocladium chartarum, Embellisia alii or Dreschlera halodes.

Other preferred fungi include strains belonging to the subdivision Basidiomycotina, class Basid- iomycetes, e.g., Coprinus, Phanerochaete, Coriolus or Trametes, in particular Coprinus cinere- us microsporus (IFO 8371 ), Coprinus macrorhizus, Phanerochaete chrysosporium (e.g. NA- 12) or Trametes (previously called Polyporus), e.g., T. versicolor (e.g. PR4 28-A).

Further preferred fungi include strains belonging to the subdivision Zygomycotina, class Mycoraceae, e.g., Rhizopus or Mucor, in particular Mucor hiemalis.

Some preferred bacteria include strains of the order Actinomycetales, e.g. Streptomyces spheroides (ATTC 23965), Streptomyces thermoviolaceus (IFO 12382) or Streptoverticillum ver- ticillium ssp. verticillium.

Other preferred bacteria include Rhodobacter sphaeroides, Rhodomonas palustri, Streptococcus lactis, Pseudomonas purrocinia (ATCC 15958), Pseudomonas fluorescens (NRRL B- 1 1 ) and Bacillus strains, e.g. Bacillus pumilus (ATCC 12905) and Bacillus stearothermophilus.

Further preferred bacteria include strains belonging to Myxococcus, e.g., M. virescens.

The peroxidase may in one embodiment be derived from a strain of Coprinus, e.g. C. cinerius or C. macrorhizus, or of Bacillus, e.g. B. pumilus, from soy bean or horse radish.

It may be preferable to use two or more different phenol oxidizing enzymes together.

The peroxidase may furthermore be one which is producible by a method comprising cul- tivating a host cell transformed with a recombinant DNA vector which carries a DNA sequence encoding said peroxidase as well as DNA sequences encoding functions permitting the expres- sion of the DNA sequence encoding the peroxidase, in a culture medium under conditions permitting the expression of the peroxidase and recovering the peroxidase from the culture.

Particularly, a recombinantly produced peroxidase is a peroxidase derived from a Coprinus sp. (also referred to as Coprinopsis sp.), in particular C. macrorhizus or C. cinereus (see e.g. SEQ ID NO:3).

In a preferred embodiment, the peroxidase of the methods and compositions of the invention comprises an amino acid sequence which has at least 80% identity, such as at least 85% identity, at least 90% identity or at least 95% identity, to SEQ ID NO:3, SEQ ID NO:4, SEQ ID NO:5, or SEQ ID NO:6.

In another preferred embodiment, the peroxidase of the methods and compositions of the invention consists of an amino acid sequence which has at least 80% identity, such as at least 85% identity, at least 90% identity or at least 95% identity, to SEQ ID NO:3, SEQ ID NO:4, SEQ ID NO:5, or SEQ ID NO:6.

In another preferred embodiment, the peroxidase of the methods and compositions of the invention comprises or consists of an amino acid sequence which has one or several (such as 1 -10 or 1 -5) amino acid substitutions compared to the amino acid sequence of SEQ ID NO:3, SEQ ID NO:4, SEQ ID NO:5, or SEQ ID NO:6.

In another preferred embodiment, the peroxidase of the methods and compositions of the invention comprises an amino acid sequence selected from the group consisting of the amino acid sequence of SEQ ID NO:3, SEQ ID NO:4, SEQ ID NO:5, and SEQ ID NO:6.

In another preferred embodiment, the peroxidase of the methods and compositions of the invention consists of an amino acid sequence selected from the group consisting of the amino acid sequence of SEQ ID NO:3, SEQ I D NO:4, SEQ ID NO:5, and SEQ ID NO:6.

In the context of this invention, compounds possessing peroxidase activity comprise pe- roxidase enzymes and peroxidase active fragments derived from cytochromes, haemoglobin or peroxidase enzymes.

Determination of Peroxidase Activity (POXU)

One peroxidase unit (POXU) is the amount of enzyme which catalyze the conversion of one μηηοΐβ hydrogen peroxide per minute at 30°C in a mixture containing:

0.1 M phosphate buffer, pH 7.0;

0.88 mM hydrogen peroxide; and 1.67 mM 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS).

The reaction is continued for 60 seconds (15 seconds after mixing) while the change in absorb- ance at 418 nm is measured. The absorbance should be in the range of 0.15 to 0.30. Peroxidase activity is calculated using an absorption coefficient of oxidized ABTS of 36 mM^"1 cm^"1, and a stoichiometry of one μηηοΐβ H₂0₂ converted per two μηηοΐβ ABTS oxidized.

Source of Hydrogen Peroxide

The source of hydrogen peroxide required by the peroxidase, or compounds exhibiting peroxidase activity, may be provided as an aqueous solution of hydrogen peroxide or a hydro- gen peroxide precursor for in situ production of hydrogen peroxide. Any solid entity which liberates upon dissolution a peroxide which is useable by peroxidase can serve as a source of hydrogen peroxide. Compounds which yield hydrogen peroxide upon dissolution in water or an appropriate aqueous based medium include but are not limited to metal peroxides, percar- bonates, persulphates, perphosphates, peroxyacids, alkyperoxides, acylperoxides, peroxyes- ters, urea peroxide, perborates and peroxycarboxylic acids or salts thereof.

Another source of hydrogen peroxide is a hydrogen peroxide generating enzyme system, such as an oxidase together with a substrate for the oxidase. Examples of combinations of oxidase and substrate comprise, but are not limited to, amino acid oxidase (see e.g. US 6,248,575) and a suitable amino acid, glucose oxidase (see e.g. WO 95/29996) and glucose, lactate oxidase and lactate, galactose oxidase (see e.g. WO 00/50606) and galactose, and aldose oxidase (see e.g. WO 99/31990) and a suitable aldose.

By studying EC 1 .1.3.-, EC 1 .2.3.-, EC 1.4.3.-, and EC 1 .5.3.- or similar classes (under the International Union of Biochemistry), other examples of such combinations of oxidases and substrates are easily recognized by one skilled in the art.

Hydrogen peroxide or a source of hydrogen peroxide may be added at the beginning of or during the process, e.g., typically in an amount corresponding to levels of from 0.001 mM to 25 mM, preferably to levels of from 0.005 mM to 5 mM, and particularly to levels of from 0.01 to 1 mM hydrogen peroxide. Hydrogen peroxide may also be used in an amount corresponding to levels of from 0.1 mM to 25 mM, preferably to levels of from 0.5 mM to 15 mM, more preferably to levels of from 1 mM to 10 mM, and most preferably to levels of from 2 mM to 8 mM hydrogen peroxide. Wood fibers and wood composites

The present invention further relates to wood composites comprising wood fibers and/or wood particles and/or wood strands treated with PHL and one or more phenol oxidizing enzymes.

The wood composite can have similar or improved properties compared to wood composites made of untreated fibers/particles/strands. The similar or improved one or more properties can be selected from the group consisting of increased overall strength of the wood composite, increased internal bond strength, increased adhesion between strands, fibers or particles, reduction of the water absorption, reduction of thickness swelling, reduction of moisture absorp- tion, improved bending strength, reduced edge swelling, reduction in mold growth and improvement with respect to formaldehyde emission.

In one embodiment the wood composite according to the invention can comprise less adhesive resin and/or glue than wood composites with the similar or poorer properties made of unreated fibers/particles/strands.

The wood composites with a reduced adhesive resin content according to the invention maintain their properties or improve their properties. The one or more properties of the wood composites can be selected from the group consisting of overall strength of the wood composite, internal bond strength, adhesion between strands, fibers or particles, water absorption, thickness swelling, moisture absorption, bending strength and edge swelling.

Additional enzymes

Any enzyme having protease, lipase, xylanase, cutinase, oxidoreductase, cellulase en- doglucanase, amylase, mannanase, steryl esterase, and/or cholesterol esterase activity can be used as additional enzymes in the use and process of the invention. Below some non-limiting examples are listed of such additional enzymes. The enzymes written in capitals are commercial enzymes available from Novozymes A S, Krogshoejvej 36, DK-2880 Bagsvaerd, Denmark. The activity of any of those additional enzymes can be analyzed using any method known in the art for the enzyme in question, including the methods mentioned in the references cited.

Examples of cutinases are those derived from Humicola insolens (US 5,827,719); from a strain of Fusarium, e.g. F. roseum culmorum, or particularly F. solani pisi (WO 90/09446; WO 94/14964, WO 94/03578). The cutinase may also be derived from a strain of Rhizoctonia, e.g. R. solani, or a strain of Alternaria, e.g. A. brassicicola (WO 94/03578), or variants thereof such as those described in WO 00/34450, or WO 01/92502. Examples of proteases are the ALCALASE, ESPERASE, SAVINASE, NEUTRASE and DURAZYM proteases. Other proteases are derived from Nocardiopsis, Aspergillus, Rhizopus, Bacillus alcalophilus, B. cereus, B. natto, B. vulgatus, B. mycoide, and subtilisins from Bacillus, especially proteases from the species Nocardiopsis sp. and Nocardiopsis dassonvillei such as those disclosed in WO 88/03947, and mutants thereof, e.g. those disclosed in WO 91/00345 and EP 415296.

Examples of amylases are the BAN, AQUAZYM, TERMAMYL, and AQUAZYM Ultra amylases. An example of a lipase is the RESINASE A2X lipase. An example of a xylanase is the PULPZYME HC hemicellulase. Examples of endoglucanases are the NOVOZYM 613, 342, and 476 enzyme products.

Examples of mannanases are the Trichoderma reesei endo-beta-mannanases described in Stahlbrand et al, J. Biotechnol. 29 (1993), 229-242.

Examples of steryl esterases, peroxidases, laccases, and cholesterol esterases are disclosed in the references mentioned in the background art section hereof. Further examples of oxidoreductases are the peroxidases and laccases disclosed in EP 730641 ; WO 01/98469; EP 719337; EP 765394; EP 767836; EP 7631 15; and EP 788547.

The invention described and claimed herein is not to be limited in scope by the specific embodiments herein disclosed, since these embodiments are intended as illustrations of several aspects of the invention. Any equivalent embodiments are intended to be within the scope of this invention. Indeed, various modifications of the invention in addition to those shown and described herein will become apparent to those skilled in the art from the foregoing description. Such modifications are also intended to fall within the scope of the appended claims. In the case of conflict, the present disclosure including definitions will control.

Various references are cited herein, the disclosures of which are incorporated by refer- ence in their entireties.

Application within specific industries

The present invention pertains to a method for production of lignocellulose-containing molded articles, especially wood composite, comprising administration of PHL and one or more phenol oxidizing enzymes onto the wood fibers and/or wood strands and/or wood particles. The lignocellulose-containing molded articles, especially the wood composite produced using one of the methods according to the invention are also part of this invention. In one embodiment the lignocellulose-containing molded article is especially a wood composite. These products can be used in a number of applications, especially (but not restricted to) one or more of the applications selected from the group consisting of MDF boards for non-bearing purposes in the dry interior area (such as furniture and interior construction), Ve- neer boards such as Veneer-MDF support board-veneer, MDF under decorative paper, MDF under surface coating, HDF for laminate floors, parquet floors, Insulation boards, LDF boards, Molded parts (for example in the sanitary field), and Moldings (for example for automotive internal paneling).

The aforementioned components to be used according to the invention, described and claimed in the practical examples, are not subject to special exceptions in size, shaping, choice of material and technical conception, so that the selection criteria known in the area of application can be used without restriction.

Various references are cited herein, the disclosures of which are incorporated by reference in their entireties.

PREFERRED EMBODIMENTS

One preferred embodiment of the invention is described in the set of items herein below. 1 . A method for producing an engineered wood product made from wood strands and/or wood particles and/or wood fibers comprising the steps of

a) treating the wood strands and/or wood particles and/or wood fibers with a wood prehydroly- sate liquor;

b) treating the wood strands and/or wood particles and/or wood fibers with one or more phenol oxidizing enzymes; and subsequently forming the engineered wood product from the treated wood strands and/or wood particles and/or wood fibers.

2. The method according to item 1 , wherein the one or more phenol oxidizing enzymes can be selected from the group consisting of laccases, phenol oxidases, peroxidases, haloperoxidases, bilirubin oxidases, catechol oxidases, Mn-peroxidases, lignin peroxidases, ligninases, or any combination thereof.

3. The method according to item 2, wherein the one or more phenol oxidizing enzymes is one or more peroxidases and wherein carbohydrate oxidase is included in the treatment.

4. The method according to any of the previous items, wherein step b) is performed as a wet treatment with a dry matter content of from 1 % to 50%.

5. The method according to item 4, wherein the dry matter content can be selected from the group consisting of from 1 % to less than 5%, from 5% to less than 10%, from 10% to less than 15%, from 15% to less than 20%, from 20% to less than 25%, from 25% to less than 30%, from 30% to less than 35%, from 35% to less than 40%, from 40% to less than 45%, from 45% to less than 50%, or any combination of these intervals.

6. The method according to any of the previous items, wherein step b) is performed as a dry treatment with a dry matter content of from 50% to 95%.

7. The method according to item 6, wherein the dry matter content can be selected from the group consisting of from 50% to less than 55%, from 55% to less than 60%, from 60% to less than 65%, from 65% to less than 70%, from 70% to less than 75%, from 75% to less than 80%, from 80% to less than 85%, from 85% to less than 90%, from 90% to less than 95%, or any combination of these intervals.

8. The method according to any of the previous items, wherein steps a) and step b) in item 1 are performed simultaneously. 9. The method according to any of items 1 to 7, wherein steps a) and step b) in item 1 are performed sequentially in any order.

10. The method according to any of items 1 to 7, wherein steps a) and step b) in item 1 are performed sequentially and step a) is performed prior to step b).

1 1. The method according to any of the previous items, wherein the treatment in step b) in item 1 is performed at a temperature range selected from the group consisting of from 10°C to 20°C, from 20°C to 25°C, from 25°C to 30°C, from 30°C to 35°C, from 35°C to 40°C, from 40°C to 50°C, from 50°C to 60°C, from 60°C to 70°C, from 70°C to 80°C, from 80°C to 90°C, or any combination of these intervals.

12. The method according to any of the previous items, wherein the treatment in step b) in item 1 comprises an incubation time selected from the group consisting of from 5 minutes to 15 minutes, from 15 minutes to 30 minutes, from 30 minutes to 45 minutes, from 45 minutes to 60 minutes, from 1 hour to 2 hours, from 2 hour to 3 hours, or any combination of these intervals.

13. The method according to any of the previous items, wherein the treatment in step a) and/or step b) in item 1 comprises spraying of the prehydrolysate liquor and/or the one or more phenol oxidizing enzymes onto the wood strands and/or wood particles and/or wood fibers.

14. The method according to item 13, wherein the spraying is performed in the blowline.

15. The method according to item 13, wherein the spraying is performed in the dryer.

16. The method according to any of the previous items, wherein the wood prehydrolysate liquor comprises lignin components, acetic acid and furfural. 17. The method according to item 16, wherein the acetic acid content is from 5% to 20% of drymatter in the wood prehydrolysate liquor and the furfural content is from 1 % to 10% of dry- matter in the wood prehydrolysate liquor.

18. The method according to any of items 16 and 17, wherein the wood prehydrolysate liquor further comprises oligosaccharides, monosaccharides, formic acid and 5-hydroxymethyl furfural.

19. The method according to item 18, wherein the monosaccharide composition is defined by a ratio of xylose to glucose of at least 0.5 such as from 0.5 to 1 , for example from 1 to 2, such as from 2 to 3, for example from 3 to 4, such as from 4 to 5, for example from 5 to 6, such as from 6 to 7, for example from 7 to 8, such as from 8 to 9, for example from 9 to 10, or any combination of these intervals.

20. The method according to any of the previous items, wherein the wood prehydrolysate liquor is derived from a kraft-based dissolving pulp production process.

21 . The method according to any previous items, wherein the PHL is derived from pre- hydrolysis kraft cooking carried out with prehydrolysis factors (P-factors) of at least 100, such as a P-factor from 100 to 2000.

22. An engineered wood product obtained or obtainable by the method according to any of the previous items.

23. Use of a wood prehydolysate liquor and one or more phenol oxidizing enzymes for reducing the resin content and/or improving the properties of a engineered wood product. EXAMPLES

EXAMPLE 1 - Prehydrolysate impregnation and laccase treatment of wood particles for production and testing of hardwood particle boards

Sample preparation for producing the mini-panels of particle board

A sample of wood prehydrolysate liquor (PHL) from the pre-hydrolysis kraft cooking of mixed hardwood chips was used. In this process, steam prehydrolysis of the wood chips is normally carried out with saturated steam at adjusted prehydrolysis factors (P-factors) ranging from 300 to about 1000, that is 30 to 100 min at 170°C, respectively. This prehydrolysis step is utilized in dissolving pulp production to degrade the major portion of the hemicelluloses which become soluble in the next alkaline steps (Sixta, 2006; Handbook of Pulp. Weinheim: Wiley-VCH Verlag GmbH). The PHL sample was collected after depressurizing the digester of a prehydrolysis kraft dissolving pulp mill.

The composition of the prehydrolysate comprises carbohydrates (sugars and oligomers), carbohydrate-derived degradation products and lignin (Yang, 2012; Acid Hydrolysis of

Prehydrolysis Liquor Produced from the Kraft-Based Dissolving Pulp Production Process.

Industrial & Engineering Chemistry Research, 13902-13907). The soluble lignin portion in this prehydrolysate is of interest in this invention as a source of mediators for oxidoreductases when applied to different lignocellulosic substrates.

Dry hardwood peels from Aspen were comminuted into smaller-size peels using a Wiley mill (Thomas - Wiley Laboratory mill, model 4; with 0.5 cm gaps mounted). The moisture content of the particles was determined and 40 oven dry grams were transferred into a Kautex bottle. Either PHL or water (control trial) was added according to the different trials identified in Table 1 . The container was shaken for 5 min. The Kautex bottles were then inserted into beakers which were then coupled to the Launder-Ometer (SDL Atlas, AATCC model) for better homoge- nization and impregnation of the PHL in the wood chips for 60 minutes at 45°C. 3% PHL (final 3 % PHL drymatter based on wood) was used for the impregnation.

The Launder-Ometer is a laboratory instrument which can provide controlled tempera- ture and agitation for the closed steel beakers containing the desired trial composition.

After the impregnation, 0.5 kg Laccase (Novozym 51003; Myceliopthora thermophile laccase shown as SEQ ID NO: 1 ) / ton (oven dry ton of wood) and Milli-Q water was added to the chips until a final consistency of 70% w/w. The Kautex bottles were then shaken for 5 min and again transferred into the beakers for incubation in the Launder-Ometer- for 60 minutes at 45°C.

Upon incubation, the chips were transferred onto aluminium trays and dried at 140C until 99-100% dryness. The equivalent amount of Milli-Q water for a final consistency of 90% w/w was added and then transferred again into the beakers in the Launder-Ometer- for 60 minutes at 45°C.

Mini-panels production and testing

The equivalent amount of 3% w/w phenol-formaldehyde resin (13D1 18 Powdered Phe- nol Formaldehyde Resin; Arclin Canada Ltd.; chemical name: phenol-Formaldehyde Urea Polymer) was then added and the container was shaken for 5 minutes. For each sample, 3 mini- panels were produced using 12 oven-dry grams of sample.

The equipment for making wood mini-panels consists of three parts: a self-contained control box, the press containing the heated pressure platens and hydraulic jack. The principle for making panels is to heat the lignocellulosic material before/during compression to ultimately form a small, 5 cm wide panel. Prior to loading in the press, the lignocellulosic material is loaded into a brass cylinder that can be subsequently inserted into the press itself prior to compression. It is coupled with a thickness stopper allowing producing panels of similar thickness and thus density. The unit allows the modulation of both temperature and pressure and allows for an un- limited duration of compression.

The PHL-treated wood particles including the control (without PHL) were pressed under 1.88 MPa at 185°C for 5 min. After pressing the panels were cooled to room temperature in a desiccator. Every panel was then weighed and the thickness was measured so that the densities could be calculated.

The panels were afterwards glued with Technomelt Supra 100 adhesive onto metal mounts designed for measuring the internal bond (IB) strength. After being pre-conditioned for 24 hours in a constant relative humidity of 50±2% and temperature of 23±1 °C, the average internal bond strength was measured in the Instron test machine (model 5564) according to ASTM D1037. Effect of the laccase treatment on the PHL-impreqnated wood particles

In Table 1 is observed that the addition of the prehydrolysate in itself increases the internal bond strength of the panels which is further improved when the PHL-impregnated wood particles are pre-treated with laccase (Novozym 51003 Myceliopthora thermophile laccase shown as SEQ ID NO: 1 ; up to 91% improvement in IB).

Table 1. Average density and internal bond of the mini-panels produced.

EXAMPLE 2 - Dosage response of laccase in the PHL-impregnation of wood particles for the production of higher density hardwood particle boards

Similarly to Example 1 , the Aspen wood particles were used after milling. These hardwood particles were impregnated with 3% PHL (final 3 % PHL drymatter based on wood) under the same conditions as in Example 1 except for 50°C and for two dosage levels of Laccase (Novozym 51003 Myceliopthora thermophile laccase shown as SEQ ID NO: 1 - 0.2 and 0.5 kg product / ton of oven dry wood). In this case, more control experiments without PHL- impregnation were made with and without laccase-treatment. Likewise, the mini-panels were produced and tested under the same conditions except for a reduced thickness (increased density).

In Table 2, it is seen that at this higher density level of the mini-panels produced the

PHL-impregnated particles produce stronger boards (up to 86% higher IB) compared to either the laccase or the PHL single treatment. A dosage of 0.2 kg/ton of laccase (Novozym 51003 Myceliopthora thermophile laccase shown as SEQ ID NO: 1 ) was enough to produce a stronger particle board made of PHL-impregnated wood particles. Table 2. Average density and internal bond of the mini-panels produced.

EXAMPLE 3 - Wet incubation of the wood particles with peroxidase and cellobiose oxidase for the production hardwood particle boards

Similarly to Example 1 , the Aspen wood particles were used after milling. The moisture content of the particles was determined and 40 oven dry grams were transferred into a 1 L stainless steel beaker. Distilled water and 3% PHL (final 3 % PHL drymatter based on wood) is added into the beakers considering a final consistency of 10% (400 g suspension). The enzymes (peroxidase - Novozym 51004 (Sequence ID NO: 3) and cellobiose oxidase - LactoY- IELD (Sequence ID NO: 7)) described in Table 3 are added to the suspension and the beakers are then sealed and placed in the Labomat BFA-24 at 45°C for 60 min and rotating speed of 20 rpm with 60 s clockwise followed by 60 s anticlockwise.

The Labomat BFA-24 (Werner Mathis AG, Switzerland) is an instrument which allows controlling temperature, mechanical agitation and treatment time of the reaction systems in the beakers. The instrument is controlled by the Univision S software (Univision S "BFA" Programming Instruction, version 2.0 edition 07/2006 by Werner Mathis AG, Switzerland). Beaker temperature is increased by heat transfer from an infrared-radiation unit. Beakers are cooled down by cooling the air in a heat exchanger with a cooling water supply. The Labomat can be operated by loading a predefined program which defines temperature profiles, agitation and time. The incubated wood particles are then washed with deionized water (40 g / 5 L) and sieved through a fine mesh cloth under vacuum. The washed wood particles are then transferred onto aluminum trays and dried at 140°C until 99-100% dryness. The wood particles were then transferred to Kautex bottles and the equivalent amount of Milli-Q water was added until a final consistency of 90% w/w was reached. The samples were then inserted into steel beakers and placed in the Launder-Ometer at 50°C for 60 min.

The production and testing of the mini-panels of particle board was done as described in Example 1 .

The co-addition of PHL, peroxidase (Novozym 51004) (Sequence ID NO: 3) and the cel- lobiose oxidase (LactoYIELD (Sequence ID NO: 7), providing in-situ generation of hydrogen peroxide) increases the internal bond strength of the produced particle boards up to 47%.

Table 3. Average density and internal bond of the mini-panels produced.

Claims

1. A method for producing an engineered wood product made from wood strands and/or wood particles and/or wood fibers comprising the steps of

subsequently forming the engineered wood product from the treated wood strands and/or wood particles and/or wood fibers.

2. The method according to claim 1 , wherein the one or more phenol oxidizing enzymes can be selected from the group consisting of laccases, phenol oxidases, peroxidases, haloperoxidases, bilirubin oxidases, catechol oxidases, Mn-peroxidases, lignin peroxidases, ligninases, or any combination thereof.

3. The method according to claim 2, wherein the one or more phenol oxidizing enzymes is one or more peroxidases and wherein carbohydrate oxidase is included in the treatment.

4. The method according to any of the previous claims, wherein step b) is performed as a wet treatment with a dry matter content of from 1 % to 50%.

5. The method according to any of the previous claims, wherein step b) is performed as a dry treatment with a dry matter content of from 50% to 95%.

6. The method according to any of the previous claims, wherein steps a) and step b) in claim 1 are performed simultaneously or sequentially in any order.

7. The method according to any of the previous claims, wherein the treatment in step a) and/or step b) in claim 1 comprises spraying of the prehydrolysate liquor and/or the one or more phenol oxidizing enzymes onto the wood strands and/or wood particles and/or wood fibers in the blow- line and/or dryer.

8. The method according to any of the previous claims, wherein the wood prehydrolysate liquor comprises lignin components, acetic acid and furfural.

9. The method according to claim 8, wherein the acetic acid content is from 5% to 20% of dry- matter in the wood prehydrolysate liquor and the furfural content is from 1 % to 10% of drymatter in the wood prehydrolysate liquor.

10. The method according to any of claims 8 and 9, wherein the wood prehydrolysate liquor further comprises oligosaccharides, monosaccharides, formic acid and 5-hydroxymethyl furfural.

1 1. The method according to claim 10, wherein the monosaccharide composition is defined by a ratio of xylose to glucose of at least 0.5 such as from 0.5 to 1 , for example from 1 to 2, such as from 2 to 3, for example from 3 to 4, such as from 4 to 5, for example from 5 to 6, such as from 6 to 7, for example from 7 to 8, such as from 8 to 9, for example from 9 to 10, or any combina- tion of these intervals.

12. The method according to any of the previous claims, wherein the wood prehydrolysate liquor is derived from a kraft-based dissolving pulp production process.

13. The method according to any previous claims, wherein the PHL is derived from pre- hydrolysis kraft cooking carried out with prehydrolysis factors (P-factors) of at least 100, such as a P-factor from 100 to 2000.

14. An engineered wood product obtained or obtainable by the method according to any of the previous claims.

15. Use of a wood prehydolysate liquor and one or more phenol oxidizing enzymes for reducing the resin content and/or improving the properties of a engineered wood product.