Impact of steam explosion on the wheat straw lignin structure studied by solution-state nuclear magnetic resonance and density functional methods
| Autor: | Stella Rovio, Harri Heikkinen, Jenni Rahikainen, Tarja Tamminen, Hannu Maaheimo, Thomas Elder, Kristiina Kruus |
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| Jazyk: | angličtina |
| Rok vydání: | 2014 |
| Předmět: |
density-functional methods
Hot Temperature Magnetic Resonance Spectroscopy Molecular Structure Plant Stems tricin lignin General Chemistry Homolysis steam explosion Steam chemistry.chemical_compound Nuclear magnetic resonance chemistry Heteronuclear molecule wheat straws Lignin Tricin General Agricultural and Biological Sciences Two-dimensional nuclear magnetic resonance spectroscopy Triticum Bond cleavage Heteronuclear single quantum coherence spectroscopy Steam explosion |
| Zdroj: | Heikkinen, H, Elder, T, Maaheimo, H, Rovio, S, Rahikainen, J, Kruus, K & Tamminen, T 2014, ' Impact of steam explosion on the wheat straw lignin structure studied by solution-state nuclear magnetic resonance and density functional methods ', Journal of Agricultural and Food Chemistry, vol. 62, no. 43, pp. 10437-10444 . https://doi.org/10.1021/jf504622j |
| ISSN: | 1520-5118 0021-8561 |
| DOI: | 10.1021/jf504622j |
| Popis: | Chemical changes of lignin induced by the steam explosion (SE) process were elucidated. Wheat straw was studied as the raw material, and lignins were isolated by the enzymatic mild acidolysis lignin (EMAL) procedure before and after the SE treatment for analyses mainly by two-dimensional (2D) [heteronuclear single-quantum coherence (HSQC) and heteronuclear multiple-bond correlation (HMBC)] and 31P nuclear magnetic resonance (NMR). The β-O-4 structures were found to be homolytically cleaved, followed by recoupling to β-5 linkages. The homolytic cleavage/recoupling reactions were also studied by computational methods, which verified their thermodynamic feasibility. The presence of the tricin bound to wheat straw lignin was confirmed, and it was shown to participate in lignin reactions during the SE treatment. The preferred homolytic β-O-4 cleavage reaction was calculated to follow bond dissociation energies: G–O–G (guaiacyl) (69.7 kcal/mol) > G–O–S (syringyl) (68.4 kcal/mol) > G–O–T (tricin) (67.0 kcal/mol). |
| Databáze: | OpenAIRE |
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