国立研究開発法人 国際農林水産業研究センター | JIRCAS

Structural Modification of Lignin in Peat during Peat Formation at Tropical Swamp

JARQ : Japan Agricultural Research Quarterly
ISSN
00213551
書誌レコードID(総合目録DB)
AA0068709X
本文フルテキスト

Peat samples from typical tropical peat swamp around Narathiwat Province, southern Thailand, were collected from various depths of peat profile (from surface to 210 cm depth), of which dates were established using an accelerator mass spectrometry from 0 to 2600 years BP. The samples were analysed to discuss changes in structural characteristics of lignin in peat samples during peat formation. The samples were fractionated based on pH adjustment into dilute alkali soluble (ALsol) and insoluble (ALinsol) fractions. Only glucosyl and xylosyl residues were detected in ALinsol fraction, but no monosaccharide in ALsol fraction. Lignin contents of ALinsol fraction of the peat samples ranged from 73.0 to 83.3%. Lignin was significantly modified during peat formation. The progress of condensation reactions, introduction of carboxyl groups and partially loss of methoxyl groups, cleavage of arylglycerol-β-aryl ether linkage, were confirmed by alkaline nitrobenzene oxidation, functional group analysis and analytical ozonation, respectively, due to the microbial activities.
Lignin of the peat samples was isolated by Bj?rkman's procedure to discuss structural feature in detail using spectrometrical procedures as the first trial in the field of geochemistry. The signals around 6.6 and 6.9 ppm in 1H-NMR were considerably weak compare with those of lignin from fresh wood, suggesting high condensation. The most peaks originating from lignin of fresh wood were also detected in the FTIR spectrum. The ionization difference (ΔEi) spectrum clearly showed the presence of unconjugated and conjugated phenolic hydroxyl groups. Thus, lignin in peat was modified significantly by microbial activities. It is expected that further modified fragments of lignin would be soluble in water and flow-out to ocean through rivers.

刊行年月2009-01-01
作成者JIN ZhenfuSHAO ShunliuKATSUMATA Kyoko S.ISHIDA TomoyasuIIYAMA Kenji
著者キーワード

analytical ozonation

arylglycerol-β-aryl ether linkage

biological modification of lignin

公開者Japan International Research Center for Agricultural Sciences
データ作成日2009-01-01
国立情報学研究所メタデータ主題語彙集(資源タイプ)Journal Article
43
1
開始ページ71
終了ページ79
DOI10.6090/jarq.43.71
権利Japan International Research Center for Agricultural Sciences
言語eng