Chemistry: molecular biology and microbiology – Micro-organism – tissue cell culture or enzyme using process... – Preparing heterocyclic carbon compound having only o – n – s,...
Patent
1994-12-01
1997-09-09
Mullis, Jeffrey C.
Chemistry: molecular biology and microbiology
Micro-organism, tissue cell culture or enzyme using process...
Preparing heterocyclic carbon compound having only o, n, s,...
527400, 527401, C12P 712
Patent
active
056655738
DESCRIPTION:
BRIEF SUMMARY
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a national stage application of PCT/DK93/00217 filed Jul. 2, 1993, which is incorporated herein by reference.
TECHNICAL FIELD
The present invention relates to a method of enzymatic polymerization and/or modification of lignin or lignin containing materials. The invention also relates to the use of this method in the manufacture of wood composites or wood laminates.
BACKGROUND ART
Wood composites such as fibre board and particle board are made by binding the material (e.g. wood fibres or wood particles) with a suitable binder and pressing, usually with heating. Conventional chemical binders for this purpose are e.g. urea-formaldehyde resin and phenol-formaldehyde resin.
Binders made from enzymatically treated lignin are also known. Thus, it has been suggested to use a binder made from peroxidase treated lignin (vide e.g. U.S. Pat. No. 4,432,921), but the use of a peroxidase has not previously been demonstrated.
For wood composites, e.g. for use in construction, a high physical strength is generally important. In order to obtain high physical strength it is essential that an optimal polymerization/modification takes place during binding of the material.
As a liquid binder material is believed to be a prerequisite for optimal polymerization, enzymatic polymerization processes, due to the reaction pH of the enzymes hitherto employed, optionally involve the addition of organic solvents in order to solubilize lignin (vide e.g. EP Patent Application No. 354,485).
Another way of improving the strength of the composite board involves addition of chemical polymerization agents, e.g. polydiphenylmethyldiisocyanate (PMDI), (vide e.g. EP Patent Specification No. 275,544).
SUMMARY OF THE INVENTION
It is the object of this invention to provide a method of polymerization of lignin or lignin containing materials that allows for optimal polymerization/modification at elevated pH without need for organic solvents to be added.
We have now surprisingly found that peroxidases are able to polymerize lignin or lignin containing material at elevated pH values, by which there is no need for organic solvents to be added to the reaction mixture, provided the polymerization is conducted by a controlled addition of hydrogen peroxide during the reaction.
The invention provides a method of enzymatic polymerization/modification of lignin or lignin containing materials, the method being improved in respect of polymerization and exploitation of the lignin. Moreover, the method does not require the addition of organic solvents or chemical polymerization agents.
Due to the extent of the polymerization achieved by this method, it is especially advantageous for implementation in the manufacture of wood composites or laminated wood products of which high physical strength is required.
Accordingly, the invention provides a method of enzymatic polymerization and/or modification of lignin or lignin containing material by treatment of the lignin or lignin containing material with an aqueous solution of peroxidase at elevated pH values, and under a controlled addition of hydrogen peroxide, in the absence of organic solvents.
In another aspect, the invention provides a glue or active binder obtained by subjecting lignin sulphonate to the method of the invention.
In yet another aspect, the invention relates to the use of the method of the invention in the preparation of a glue or an active binder for use in the manufacture of wood composites e.g. wood fibre materials such as chipboards, fibre boards, or particle boards, or in the manufacture of laminated wood products, such as laminated beams and plywood.
BRIEF DESCRIPTION OF DRAWINGS
The present invention is further illustrated by reference to the accompanying drawings, in which:
FIGS. 1A-1D shows polymerization of Indulin.TM., determined by average molecular weight (MW.times.1000), by use of SP 502.TM. (4000 PODU/ml) and 10 mM H.sub.2 O.sub.2. (A Start; B 5 min; C 30 min; D 60 min; E 65 min; F 90 min);
FIG. 1A Standard: 4000 POD
REFERENCES:
patent: 4432921 (1984-02-01), Haars et al.
Popp et al. "Incorporation of p-cResol into Lignins Via Peroxidase-Catalysed Copolymerization in Nonaqueous Media", Enzyme Microb. Technol., 1991, vol. 13, (Dec.).
Harrington, Esq. James
Mullis Jeffrey C.
Novo Nordisk A S
Zelson Esq. Steve T.
LandOfFree
Polymerization of lignin at alkaline pH does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Polymerization of lignin at alkaline pH, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Polymerization of lignin at alkaline pH will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-68972