Understanding the structural features of lignin (L) and lignin-carbohydrate complexes (LCC) in bamboo (Phyllostachys pubescens Mazel) is important in order to expand the use of bamboo biomass. In this study, L and LCC were isolated from four-year-old mature bamboo using an organic solvent as an extractant. The structural features of L and LCC were characterized via UV-vis, FT-IR, NMR, sugar composition analysis, and alkaline nitrobenzene oxidation. L and LCC contained almost the same structural units: guaiacyl (G), syringyl (S), p-hydroxybenzoate substructures (PB), β-O-4' substructures (A), 3-O-acetyl-(1>4)-linked-B-D-xylopyranosyl (βXyl3), (1>4)-linked-α(β)-D-xylopyranosyl (α(β)Xyl), and 4-O-methyl-α-D-glucuronic acid (MeGlcA(1>4)). The contents of the units varied between L and LCC. Carbohydrates linked with lignin in L and LCC mainly consisted of xylans. The sugar units of carbohydrates linked with lignin in LCC were determined to be of xylose (76.98%), arabinose (4.08%), glucose (6.47%), mannose (6.34%), altrose (3.69%), galactose (1.75%), and ribose (0.69%). The S (75.80%) and G (24.20%) units with a high S/G ratio of 3.13 were the main structural elements of lignin associated with carbohydrates in LCC.
Bibliographical noteFunding Information:
The authors are grateful for the financial support of the Natural Science Foundation of China (21306076, 30960304, and 21266022), the Natural Science Foundation of the Ministry of Education of Jiangxi Province of China (GJJ13089), the postdoctoral research project of China (2013M540537), the postdoctoral research project of Jiangxi Province of China (2013KY41), and the Open Fund of the Engineering Research Center of Biomass Materials, Ministry of Education, Southwest University of Science and Technology (12zxbk09).
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- Bamboo (Phyllostachys pubescens Mazel)
- Lignin-carbohydrate complexes
- Structural features