The structural changes of lignin at different stages of growth of Napier grass

The aim of this study was to investigate the lignin composition and structure during Napier grass growth. Napier grass showed an increase in lignin, xylan, glucan content and a decrease in acetone extractives and ash content with its growth, while the content of cellulose and holocellulose reached the highest value after four months growth. In addition, milled-wood lignins (MWL) isolated from Napier grass were characterized with 2D-NMR and Py-GC-MS. The results obtained showed that GSH-type substructures were included in Napier grass lignin, whereas the S-G ratio decreased and the abundance of H-substructures increased during lignification. H-units were deposited at the earlier stages, whereas Napier grass was enriched in G-lignin during the late lignification, and S-units were reduced at the final stage. The differences in deposition of lignin units influenced the distribution of the different linkages of lignin units during Napier grass growth. All lignin samples showed the most abundant β-O-4', β-β' resinol linkages, whereas the data obtained by 2D-NMR indicated the similar development in GSH-type substructures with by Py-GC-MS during all stages of lignification.

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Opracowanie ze środków MNiSW w ramach umowy 812/P-DUN/2016 na działalność upowszechniającą naukę (zadania 2017).