1993 Fiscal Year Final Research Report Summary
Structure and Bio-degradation of Chlorinated Lignin
| Project/Area Number |
04660177
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
林産学
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| Research Institution | The University of Tokyo |
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Principal Investigator |
MATSUMOTO Yuji The University of Tokyo Faculty of Agriculture, Associate Professor, 農学部, 助教授 (30183619)
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| Project Period (FY) |
1992 – 1993
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| Keywords | pulp / chlorine bleaching / organic chlorine / lignin / lignin peroxidase / methylation / AOX / effluent |
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| Research Abstract |
When unbleached kraft pulps are subjected to chlorine bleaching, residual lignin in hardwood kraft pulps become soluble in water more easily than that in softwood kraft pulps. Majority of adsorbable organic chlorine (AOX), and total organic carbon (TOX), produced from hardwood kraft pulps, were found to be present in chlorine stage (C-stage) effluent rather than in E-stage effluent, which makes a contrast to those of softwood kraft pulp. By oxygen treatment, a considerable part of residual lignin in kraft pulp was converted to a part which is highly reactive to chlorine. A organic chlorine produced in such a reactive lignin forms a unstable organic chlorine, which is easily removed by an attack of a nucleophile. AOX method does not give an accurate value for organic chlorine content of C-stage effluent. The reason for this was attributable to the presence of unstable organic chlorine in C-stage effluent.
Methylation reaction and oxidation (dehydrogenation) reaction of phenolic hydroxyl group are competing reaction when phenolic compounds such as a chlorinated guaiachol, a typical chloroorganic found in bleaching effluent, is treated by Phanerochaete chrysosporium. Methylation reaction is active throughout the fungus life, while phenol oxidation activity is visible only during a secondary metabolism.
Veratryl alcohol oxidation activity of ligninperoxidase is inhibited completely when phenolic compound are present in a reaction system.
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