THE PRESENCE OF LIGNIN IN DISSOLVED ORGANIC MATTER OBTAINED FROM PEAT SWAMP WATER
Lignin plays important roles in the accumulation of organic carbon in peat. Lignin has highly resistance against biological attack, whereas polysaccharides are easily digested by microorganisms. Some portions of lignin in peat would be modified by microorganisms. Significantly modified lignin is expected to dissolve easily in water. In this study, dissolved organic matters (DOM) were isolated from water drained out of Bibai and To Daeng peat swamp and structural features of DOMs were investigated. Broad signal of aromatic protons at around 7 ppm was recorded in H-NMR spectrum of DOM isolated from water collected at Bibai swamp (Bibai DOM), which was methylated with diazomethane followed by acetylation prior to the 1H-NMR measurement. This result proved that the Bibai DOM contains aromatic structure. Total yield of the alkaline nitrobenzene oxidation products were slightly detectable in Bibai DOM, suggesting that lignin in plant residues was modified significantly in structural features, but detectable in DOM. Methoxyl groups of DOM increased by 0.12 mol/C mol after diazomethane methylation. The content of methoxyl group increased by diazomethane treatment due to methylation of carboxyl and phenolic hydroxyl groups. Acid/aldehyde ratio of alkaline nitrobenzene products of the Bibai DOM was considerably higher than that of the peat sample obtained at To Daeng swamp. Total yield of alkaline nitrobenzene oxidation products and methoxyl group in DOM were significantly less than those of peat sample. These results suggest that the lignin containing in the DOM is highly oxidized than the lignin in the peat sample. Average molecular weight of Bibai DOM was MW 1600. DOM would be originated from lower molecular weight part of peat sample, in which hydrophilic functional groups was highly introduced by biological modification, to be dissolved in water.
peat swamp dissolved organic matter (DOM) lignin
Kyoko S. Katsumata Zhenfu Jin Kenji Iiyama
Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Zhejiang Agriculture & Forestry University, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, Japan, 113-8657 Japan International Research Center for Agricultural Sciences, 1-1-1 Yayoi, Bunkyo-ku, Tokyo,Japan,
国际会议
16th International Symposium on Wood,Fiber and Pulping Chemistry(第十六届木材、纤维及制浆化学国际会议)
天津
英文
311-314
2011-06-08（万方平台首次上网日期，不代表论文的发表时间）