title: Structural elucidation of inhomogeneous lignins from bamboo.
abstract: A better understanding of the inhomogeneous molecular structure of lignin from bamboo is a prerequisite for promoting the "biorefinery" technologies of the bamboo feedstock. A mild and successive method for fractionating native lignin from bamboo species was proposed in the present study. The molecular structure and structural inhomogeneity of the isolated lignin polymers were comprehensively investigated by elemental analysis, carbohydrate analysis, state-of-the-art NMR and analytical pyrolysis techniques (quantitative (13)C NMR, (13)C-DEPT 135 NMR, 2D-HSQC NMR, (31)P NMR, and pyrolysis-GC-MS). The results showed that the proposed method is effective for extracting lignin from bamboo. NMR results showed that syringyl (S) was the predominant unit in bamboo lignin over guaiacyl (G) and p-hydroxyphenyl (H) units. In addition, the lignin was associated with p-coumarates and ferulates via ester and ether bonds, respectively. Moreover, various substructures, such as β-O-4, β-β, β-5, β-1, and α,β-diaryl ether linkages, were identified and quantified by NMR techniques. Based on the results obtained, a proposed schematic diagram of structural heterogeneity of the lignin polymers extracted from the bamboo is presented. In short, well-defined inhomogeneous structures of native lignin from bamboo will facilitate further applications of bamboo in current biorefineries.
authors.affiliation: Beijing Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, No. 35, Qinghua East Road, Beijing 100083, China.
authors.forename: Jia-Long
authors.initials: JL
authors.lastname: Wen
authors.affiliation: Beijing Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, No. 35, Qinghua East Road, Beijing 100083, China.
authors.forename: Shao-Long
authors.initials: SL
authors.lastname: Sun
authors.affiliation: Beijing Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, No. 35, Qinghua East Road, Beijing 100083, China.
authors.forename: Bai-Liang
authors.initials: BL
authors.lastname: Xue
authors.affiliation: Beijing Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, No. 35, Qinghua East Road, Beijing 100083, China. Electronic address: rcsun3@bjfu.edu.cn.
authors.forename: Run-Cang
authors.initials: RC
authors.lastname: Sun
mesh_terms: D018533:Biomass; D008031:Lignin / Q000737:chemistry*; D008970:Molecular Weight; D006109:Poaceae / Q000737:chemistry*
chemical_list: D008031:Lignin
keywords: Bamboo lignin; NMR; Structural elucidation