Structural Differences between the Lignin-Carbohydrate Complexes (LCCs) from 2- and 24-Month-Old Bamboo (Neosinocalamus affinis).

Pan-Pan Yue,Gen-Que Fu,Run-Cang Sun,Chang-Xia Sun,Ya-Jie Hu,Feng Peng,Ming-Fei Li

doi:10.3390/ijms19010001

Pan-Pan Yue, Gen-Que Fu + Show 5 more

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https://doi.org/10.3390/ijms19010001

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Abstract

The lignin-carbohydrate complex (LCC) was isolated from milled wood lignin of 2- and 24-month-old crude bamboo (Neosinocalamus affinis) culms using acetic acid (AcOH) and then characterized. The results have shown that the LCC preparation from 2-month-old bamboo (L2) exhibited a slightly lower molecular weight than the LCC preparation from the 24-month-old bamboo (L24). Further studies using Fourier transform infrared spectroscopy (FT-IR) and heteronuclear single quantum coherence (2D-HSQC) NMR spectra analyses indicate that the LCC preparations included glucuronoarabinoxylan and G-S-H lignin-type with G>S>>H. The content of the S lignin units of LCC in the mature bamboo was always higher than in the young bamboo. Combined with sugar composition analysis, the contents of phenyl glycoside and ether linkages in the L24 preparation were higher than in the L2 preparation; however, there was a reverse relationship of ester LCC bonds in L2 and L24. Lignin–xylan was the main type of LCC linkage in bamboo LCCs. Lignin–lignin linkages in the LCC preparations included β-β, β-5 and β-1 carbon-to-carbon, as well as β-O-4 ether linkages, but β-1 linkages were not present in L2.

Highlights

Bamboo, an abundant renewable biomass resource, consists of cellulose, hemicelluloses, and lignin, which are associated with one another through physical binding and chemical linkages to form complex structures [1,2]
The result shows that the percentage of acid-soluble lignin of lignin-carbohydrate complex (LCC) in young bamboo culms was relatively higher than in the mature bamboo culms, similar to what was reported by our group [20]
To verify the LCC linkages in bamboo, the sugar composition of the LCC preparations and the dimethyl sulfoxide (DMSO)-soluble hemicelluloses are summarized in Tables 1 and 2

Summary

Introduction

An abundant renewable biomass resource, consists of cellulose, hemicelluloses, and lignin, which are associated with one another through physical binding and chemical linkages to form complex structures [1,2]. Lignin and hemicelluloses are generally considered to be linked to one another through covalent bonds, which gives them high mechanical strength and makes the plant cell walls resistant to biodegradation. These bonds and interactions are thought to interfere with their separation from and the degradation of the plant [9]. This may be crucial to the rigidity of lignified plant cell walls

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