Abstract:It was found based on results from alkaline nitrobenzene oxidation of natural and isolated dioxane lignins from several plants of the family Gramineae such as rice husks, rice straw, and corn and sorghum stems that the studied lignins consisted of three types of structural units with the predominance of guaiacyl structures.Grasses (Gramineae Juss.) are distributed in nature on all continents, represent a significant part of the biomass of many biocommunities, and are considered one of the most widespread and u… Show more
“…The GC-MS analysis of the nitrobenzene oxidation products showed that lignin in each organ consisted of guaiacyl, syringyl, and p-hydroxyphenyl units (Table 2), consistent with the result of thioacidolysis. The ratios of syringaldehyde to vanillin (S/V), which indicate the ratios of syringyl to guaiacyl lignins, were 0.61 in the inner part and 0.79 in the outer part (Table 2); the higher S/V ratio in the outer than the inner part was consistent with the results of the Mäule reaction (Figure 1D (Jung and Vogel 1992), and 0.37-0.59 in Miscanthus (Sarkanen and Hergert 1971)], and similar to those in small gramineous plants [e.g., 0.48-0.89 in rice straw (Dalimova and Abduazimov 1994;Dzhumanova and Dalimova 2011), and 0.72-0.93 in wheat straw (Dalimova and Abduazimov 1994)]. …”
Section: Lignin Structures Of E Arundinaceussupporting
Lignin is a major component of the secondary cell walls of vascular plants, and an obstacle in the conversion of plant cell wall polysaccharides into biofuels. Erianthus spp. are large gramineous plants of interest as potential energy sources. However, lignocelluloses of Erianthus spp. have not been chemically characterized. In this study, we analysed lignins, related compounds, enzymatic saccharification efficiencies, and minerals in the ash of the inner and outer parts of the internode, leaf blade and leaf sheath of Erianthus arundinaceus. Lignins in four organs consisted of guaiacyl, syringyl, and p-hydroxyphenyl units. The ratios of syringyl to guaiacyl lignins and lignin contents ranged from 0.43 to 0.79 and 20 to 28%, respectively, with values highest in the outer part of the internode. The amounts of ferulic acid were similar (7.3-11.8 mg g −1 dry weight of cell-wall material) in all four organs, while there was more p-coumaric acid in the inner part of the internode (44.7 mg g −1 dry weight of cell-wall material) than in other organs (25.7-28.8 mg g −1 dry weight of cell-wall material). The enzymatic saccharification efficiency (24 h reaction time) of the leaf blade was 21.6%, while those of the other organs ranged from 10.0 to 15.2%. The leaf blade had the highest ash content (17.1%); the main inorganic element was silicon. This paper provides the first fundamental knowledge of E. arundinaceus lignins.
“…The GC-MS analysis of the nitrobenzene oxidation products showed that lignin in each organ consisted of guaiacyl, syringyl, and p-hydroxyphenyl units (Table 2), consistent with the result of thioacidolysis. The ratios of syringaldehyde to vanillin (S/V), which indicate the ratios of syringyl to guaiacyl lignins, were 0.61 in the inner part and 0.79 in the outer part (Table 2); the higher S/V ratio in the outer than the inner part was consistent with the results of the Mäule reaction (Figure 1D (Jung and Vogel 1992), and 0.37-0.59 in Miscanthus (Sarkanen and Hergert 1971)], and similar to those in small gramineous plants [e.g., 0.48-0.89 in rice straw (Dalimova and Abduazimov 1994;Dzhumanova and Dalimova 2011), and 0.72-0.93 in wheat straw (Dalimova and Abduazimov 1994)]. …”
Section: Lignin Structures Of E Arundinaceussupporting
Lignin is a major component of the secondary cell walls of vascular plants, and an obstacle in the conversion of plant cell wall polysaccharides into biofuels. Erianthus spp. are large gramineous plants of interest as potential energy sources. However, lignocelluloses of Erianthus spp. have not been chemically characterized. In this study, we analysed lignins, related compounds, enzymatic saccharification efficiencies, and minerals in the ash of the inner and outer parts of the internode, leaf blade and leaf sheath of Erianthus arundinaceus. Lignins in four organs consisted of guaiacyl, syringyl, and p-hydroxyphenyl units. The ratios of syringyl to guaiacyl lignins and lignin contents ranged from 0.43 to 0.79 and 20 to 28%, respectively, with values highest in the outer part of the internode. The amounts of ferulic acid were similar (7.3-11.8 mg g −1 dry weight of cell-wall material) in all four organs, while there was more p-coumaric acid in the inner part of the internode (44.7 mg g −1 dry weight of cell-wall material) than in other organs (25.7-28.8 mg g −1 dry weight of cell-wall material). The enzymatic saccharification efficiency (24 h reaction time) of the leaf blade was 21.6%, while those of the other organs ranged from 10.0 to 15.2%. The leaf blade had the highest ash content (17.1%); the main inorganic element was silicon. This paper provides the first fundamental knowledge of E. arundinaceus lignins.
“…The GC-MS analysis of the nitrobenzene oxidation products showed that lignin in each organ consisted of guaiacyl, syringyl, and p-hydroxyphenyl units (Table 2), consistent with the result of thioacidolysis. e ratios of syringaldehyde to vanillin (S/V), which indicate the ratios of syringyl to guaiacyl lignins, were 0.61 in the inner part and 0.79 in the outer part (Table 2); the higher S/V ratio in the outer than the inner part was consistent with the results of the Mäule reaction (Figure 1D, E; Abduazimov 1994, Dzhumanova andDalimova 2011), and 0.72-0.93 in wheat straw (Dalimova and Abduazimov 1994)]. …”
Section: Lignin Structures Of E Ravennaesupporting
“…Alternatively, cellulolytic enzyme lignin (CEL) has commonly been used for the structural analysis of cell wall lignin, which utilizes cellulolytic enzyme hydrolysis prior to dioxane/water extraction of ball-milled wood meal to remove carbohydrates and achieve lignin with high yield and purity. , For decades, a lot of work was devoted to understanding the structural features of lignin from a plant cell wall; for example, the monomeric content of lignin polymer and some other structural features were analyzed with different chemical degradation methods such as alkaline nitrobenzene oxidation, ozonation, thioacidolysis, and derivatization followed by reductive cleavage that uses acetyl bromide for derivatization and zinc for reductive cleavage . These wet chemical methods can be very precise for specific functional groups and structural moieties.…”
Lignin structure has been considered to be an important factor that significantly influences the biorefinery processes. In this work, the effect of ball milling on the structural components and extractable lignin in enzymatic residues was evaluated, and the structural characteristics of the cellulolytic enzyme lignin preparations isolated from wheat straw stem (SCEL) and leaf (LCEL) were comparatively investigated by a combination of nitrobenzene oxidation (NBO), ozonation, infrared spectroscopy, and 1 H− 13 C heteronuclear single quantum coherence nuclear magnetic resonance (2D HSQC NMR). The results showed that 4 h ball-milled samples were good enough for structural analysis with high lignin yield. Both CELs are typical p-hydroxyphenylguaiacyl-syringyl lignins which are associated with pcoumarates and ferulates. However, the structure of lignin in wheat straw stem is rather different from that in leaf. Compared to stem lignin, leaf lignin has lower product yields of NBO and ozonation, lower erythro/threo ratio, and higher condensation degree. The analysis of 2D HSQC NMR indicated that the S/G ratio of SCEL was 0.8, which is about twice as much as that of LCEL. The flavone tricin is incorporated into both stem and leaf lignins. The content of tricin in LCEL is higher than that in SCEL.
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