Method and enzymatic preparation for treatment of cellulose pulps
AssigneeValtion Teknillinen Tutkimuskeskus
InventorsMATTI SIIKA-AHO, JOHANNA BUCHERT, TAPANI VUORINEN, ANITA TELEMAN, MAIJA TENKANEN, MICHAEL BAILEY, LIISA VIIKARI
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Abstract
The present invention concerns a method for enzymatic treatment of lignocellulosic materials which contain xylan-polymers, such as cellulose kraft pulps. According to a method of the present kind, at least a part of the hexenuronic acid groups present in the material is selectively removed in order to remove metal ions from the pulp, to change the surface charge thereof, to improve the brightness stability of the pulp and to render the material more suitable for enzymatic treatment.
Claims25
A method for modifying lignocellulosic materials, in particular cellulosic pulps, characterized in that at least a part of the hexenuronic acid groups of the pulp is selectively removed.
5 The method according to any one of claims 3 to 4, wherein the pulp is contacted with a hexenuronidase preparation derived from a microorganism strain selected from the group essentially consisting of microorganisms of the genera Trichoderma (e.g. T. reesei), Aspergillus (e.g. A. niger, A. awamori, A. terreus, A. oryzae), Schizophyllum (e.g. S. commune), Aureobasidium (e.g. A. pullulans), Phanerochaete (e.g. P. chrysosporium), Fusarium (e.g. F. oxysporum), Agaricus (e.g. A. bisporus), Penicillium (e.g. P. janthinellum, P. digitatum), Streptomyces (e.g. S. olivochromogenes, S. flavogriseus), Bacillus (e.g. B. subtilis, B. circulans), and Xanthobacter (e.g. X. autotrophicus).
13 The method according claim 2, wherein the pulp is first treated with an enzyme preparation having an essential hexenuronidase and optionally glucuronidase activity and subsequently contacted with an enzyme preparation having a hemicellulase, cellulase and/or ligninase activity.
The method according to any of the previous claims, wherein the pulp is treated simultaneously with an enzyme preparation having hexenuronidase activity and an enzyme preparation having hemicellulase, cellulase and/or lignin modifying activity.
An enzyme preparation useful for treatment of lignocellulosic materials, in particular cellulose pulps, characterized in that it contains an essential amount of hexenuronidase activity together with suitable adjuvents used in enzyme preparations intended for a application in the pulp and paper industry.
The enzyme preparation according to claim characterized in that it also contains an essential amount of glucuronidase enzyme activity.
A method of isolating microbial strains capable of producing hexenuronidase, comprising the steps of
- collecting samples of microorganism-containing organic matter from a pulp mill or the vicinity thereof or any other potential source containing material with this carbohydrate structure,
- suspending the samples in a suitable liquid or buffer, e.g. in a physiological salt solution,
- inocculating media containing as a carbon source oligomers containing hexenuronic acid with aliquots of the diluted suspension or the collected material,
- incubating te inocculated medium in a suitable container, e.g. shake flask or fermentor, in conditions which favour microbial growth. until more than appr. 50% of the carbon source containing HexA is consumed,
- collecting the microbial cells from the cultivation liquid
- optionally repeating the cultivation, and
- optionally purifying the colonies or storing the possible mixed microbial population using standard microbiological methods.
Dependencies are inferred from the claim text.