Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2019 Mar 9;20(5):1200.
doi: 10.3390/ijms20051200.

Miscanthus x giganteus Stem Versus Leaf-Derived Lignins Differing in Monolignol Ratio and Linkage

Michel Bergs  1   2 , Georg Völkering  3 , Thorsten Kraska  4 , Ralf Pude  5   6 , Xuan Tung Do  7 , Peter Kusch  8 , Yulia Monakhova  9   10 , Christopher Konow  11 , Margit Schulze  12
Affiliations

Miscanthus x giganteus Stem Versus Leaf-Derived Lignins Differing in Monolignol Ratio and Linkage

Michel Bergs et al. Int J Mol Sci. .

Abstract

As a renewable, Miscanthus offers numerous advantages such as high photosynthesis activity (as a C₄ plant) and an exceptional CO₂ fixation rate. These properties make Miscanthus very attractive for industrial exploitation, such as lignin generation. In this paper, we present a systematic study analyzing the correlation of the lignin structure with the Miscanthus genotype and plant portion (stem versus leaf). Specifically, the ratio of the three monolignols and corresponding building blocks as well as the linkages formed between the units have been studied. The lignin amount has been determined for M. x giganteus (Gig17, Gig34, Gig35), M. nagara (NagG10), M. sinensis (Sin2), and M. robustus (Rob4) harvested at different time points (September, December, and April). The influence of the Miscanthus genotype and plant component (leaf vs. stem) has been studied to develop corresponding structure-property relationships (i.e., correlations in molecular weight, polydispersity, and decomposition temperature). Lignin isolation was performed using non-catalyzed organosolv pulping and the structure analysis includes compositional analysis, Fourier transform infradred (FTIR), ultraviolet/visible (UV-Vis), hetero-nuclear single quantum correlation nuclear magnetic resonsnce (HSQC-NMR), thermogravimetric analysis (TGA), and pyrolysis gaschromatography/mass spectrometry (GC/MS). Structural differences were found for stem and leaf-derived lignins. Compared to beech wood lignins, Miscanthus lignins possess lower molecular weight and narrow polydispersities (<1.5 Miscanthus vs. >2.5 beech) corresponding to improved homogeneity. In addition to conventional univariate analysis of FTIR spectra, multivariate chemometrics revealed distinct differences for aromatic in-plane deformations of stem versus leaf-derived lignins. These results emphasize the potential of Miscanthus as a low-input resource and a Miscanthus-derived lignin as promising agricultural feedstock.

Keywords: HSQC NMR; Miscanthus x giganteus; biomass; chemometrics; genotype; lignin; monolignol ratio; principal component analysis.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Monolignol linkages. First line: Ether bonds (ß-O-4’, α-O-4’, 4-O-5’). Second line: C-C-bonds. (ß-ß’, ß-1’, 5-5’) and third line: more complex linkages (ß-5’/ α-O-4’, 5-5’/ ß-O-4’/ α-O-4’, ß-1’/ ß-O-4’).
Figure 2
Figure 2
Miscanthus crop analysis via NREL measurements. Leaf versus stem content of Miscanthus genotypes: M. x giganteus (Gig17, Gig34, Gig35), M. nagara (NagG10), M. sinensis (Sin2), and M. robustus (Rob4) harvested in September (09/15), December (12/14), and April (04/15), respectively (arranged to follow the seasonal order from autumn to spring).
Figure 3
Figure 3
FT-IR spectra of Gig17 (stem, leaf, and mixture) with numbered signals listed in Table 4.
Figure 4
Figure 4
FT-IR spectra of mixture (Gig17M), leaf (Gig17L), and stem-derived (Gig17S) lignins obtained from M. x giganteus (Gig17).
Figure 5
Figure 5
FT-IR spectra of mixture (Gig34M), leaf (Gig34L), and stem-derived (Gig34S) lignins obtained from M. x giganteus (Gig34).
Figure 6
Figure 6
Multivariate data analysis of FT-IR data using the principal component analysis (PCA). L: leaf-derived lignin. M: mixture-derived lignin. S: stem-derived lignin.
Figure 7
Figure 7
SEC curves of lignins obtained from Miscanthus x giganteus (Mixture: Gig17M. Leaf: Gig17L. Stem Gig17S).
Figure 8
Figure 8
UV/Vis curves for lignins obtained from Miscanthus x giganteus. (Mixture: Gig17M. Leaf: Gig17L. Stem Gig17S).
Figure 9
Figure 9
Pyrolysis-GC/MS pyrogram of a lignin obtained from Miscanthus x giganteus Gig17M. Stem/leaf mixture with numbers for all aromatic fragments listed and assigned in Table 6.
Figure 10
Figure 10
Detected Py-GC/MS fragments attributed to the H-unit.
Figure 11
Figure 11
Detected Py-GC/MS fragments attributed to the G-unit.
Figure 12
Figure 12
Detected Py-GC/MS fragments attributed to the S-unit.
Figure 13
Figure 13
Non-aromatic HSQC region of a lignin obtained from M. x giganteus stem/leaf mixture (Gig17M). Numbers are listed and assigned in Table 9.
Figure 14
Figure 14
Aromatic HSQC region of a lignin obtained from M. x giganteus stem/leaf mixture (Gig17M). Numbers are listed and assigned in Table 9.
Figure 15
Figure 15
Lignin structure elements for HSQC NMR signal assignment (A: β-O-4 linkage, B: phenylcoumaran, C: resinol, D: β-unsaturated ester).
See this image and copyright information in PMC

References

    1. Emmerling C., Pude R. Introducing Miscanthus to the greening measures of the EU Common Agricultural Policy. GCB Bioenergy. 2017;9:274–279. doi: 10.1111/gcbb.12409. - DOI
    1. Lewandowski I., Clifton-Brown J., Trindade L.M., van der Linden G.C., Schwarz K.-U., Müller-Sämann K., Anisimov A., Chen C.-L., Dolstra O., Donnison I.S., et al. Progress on optimizing miscanthus biomass production for the European bioeconomy: Results of the EU FP7 project OPTIMISC. Front. Plant Sci. 2016;7:1620. doi: 10.3389/fpls.2016.01620. - DOI - PMC - PubMed
    1. McCalmont J.P., Hastings A., McNamara N.P., Richter G.M., Robson P., Donnison I.S., Clifton-Brown J. Environmental costs and benefits of growing Miscanthus for bioenergy in the UK. GCB Bioenergy. 2017;9:489–507. doi: 10.1111/gcbb.12294. - DOI - PMC - PubMed
    1. Kellogg E.A. C4 photosynthesis. Curr. Biol. 2013;23:R594–R599. doi: 10.1016/j.cub.2013.04.066. - DOI - PubMed
    1. Villaverde J.J., Ligero P., Vega A. Miscanthus x giganteus as a Source Of Biobased Products Through Organosolv Fractionation: A Mini Review. TOAJ. 2010;4:102–110. doi: 10.2174/1874331501004010102. - DOI

MeSH terms