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Registro Completo |
Biblioteca(s): |
Embrapa Agroenergia. |
Data corrente: |
03/06/2019 |
Data da última atualização: |
18/11/2019 |
Tipo da produção científica: |
Artigo em Periódico Indexado |
Autoria: |
BREGADO, J. L.; SECCHI, A. R.; TAVARES, F. W.; RODRIGUES, D. de S.; GAMBETTA, R. |
Afiliação: |
Jurgen Lange Bregado, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil; Argimiro Resende Secchi, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil; Frederico Wanderley Tavares, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil; DASCIANA DE SOUSA RODRIGUES, CNPAE; ROSSANO GAMBETTA, CNPAE. |
Título: |
Amorphous paracrystalline structures from native crystalline cellulose: a molecular dynamics protocol. |
Ano de publicação: |
2019 |
Fonte/Imprenta: |
Fluid Phase Equilibria, v. 491, p.56-76, 2019. |
Idioma: |
Inglês |
Conteúdo: |
Cellulose amorphization is a suitable process that allows greater accessibility of cellulolytic enzymes to glycosidic bonds of cellulose, thus improving the yield of bioethanol obtained from lignocellulosic biomass. In a theoretical framework, we demonstrated the amorphization process of two cellulose allomorphs (Ia, Ib) using a new Molecular Dynamics (MD) protocol at high temperatures. At 700 K, in the high-temperature molten phase, these allomorphs showed the formation of structures with quite amorphous-shell and slightly paracrystalline-core (Am-Par structures) when the degree of polymerization is increased. Applying different characterization methods, we confirmed that Am-Par structures were similar at 700 K, as well as over a temperature ranging from 680 K to 380 K. This confirmation was based on low density of intra-chain hydrogen bonds (HBs), the absence of bands in the region of 3330 e3470 cm1 corresponding to such HBs in the simulated IR, low values of the lateral order index calculated from IR, Q4 and Q6 values close to zero, loss of long-range ordering observed in radial distribution functions, total destruction of crystal unit cell corroborated by X-ray diffraction, and similarity between probability density distribution of dihedral angle j with that computed for completely amorphous cellulose. Nonetheless, as revealed by X-ray diffraction results, this protocol seems to provide more crystalline structures starting from cellulose microfibrils having a polymerization degree higher than 10. MenosCellulose amorphization is a suitable process that allows greater accessibility of cellulolytic enzymes to glycosidic bonds of cellulose, thus improving the yield of bioethanol obtained from lignocellulosic biomass. In a theoretical framework, we demonstrated the amorphization process of two cellulose allomorphs (Ia, Ib) using a new Molecular Dynamics (MD) protocol at high temperatures. At 700 K, in the high-temperature molten phase, these allomorphs showed the formation of structures with quite amorphous-shell and slightly paracrystalline-core (Am-Par structures) when the degree of polymerization is increased. Applying different characterization methods, we confirmed that Am-Par structures were similar at 700 K, as well as over a temperature ranging from 680 K to 380 K. This confirmation was based on low density of intra-chain hydrogen bonds (HBs), the absence of bands in the region of 3330 e3470 cm1 corresponding to such HBs in the simulated IR, low values of the lateral order index calculated from IR, Q4 and Q6 values close to zero, loss of long-range ordering observed in radial distribution functions, total destruction of crystal unit cell corroborated by X-ray diffraction, and similarity between probability density distribution of dihedral angle j with that computed for completely amorphous cellulose. Nonetheless, as revealed by X-ray diffraction results, this protocol seems to provide more crystalline structures starting from cellulose microfibrils having a polymerizat... Mostrar Tudo |
Palavras-Chave: |
Amorphization; CHARMM force field; Crystallinity; Thermal treatment. |
Thesaurus Nal: |
Molecular dynamics. |
Categoria do assunto: |
-- |
Marc: |
LEADER 02211naa a2200229 a 4500 001 2109595 005 2019-11-18 008 2019 bl uuuu u00u1 u #d 100 1 $aBREGADO, J. L. 245 $aAmorphous paracrystalline structures from native crystalline cellulose$ba molecular dynamics protocol.$h[electronic resource] 260 $c2019 520 $aCellulose amorphization is a suitable process that allows greater accessibility of cellulolytic enzymes to glycosidic bonds of cellulose, thus improving the yield of bioethanol obtained from lignocellulosic biomass. In a theoretical framework, we demonstrated the amorphization process of two cellulose allomorphs (Ia, Ib) using a new Molecular Dynamics (MD) protocol at high temperatures. At 700 K, in the high-temperature molten phase, these allomorphs showed the formation of structures with quite amorphous-shell and slightly paracrystalline-core (Am-Par structures) when the degree of polymerization is increased. Applying different characterization methods, we confirmed that Am-Par structures were similar at 700 K, as well as over a temperature ranging from 680 K to 380 K. This confirmation was based on low density of intra-chain hydrogen bonds (HBs), the absence of bands in the region of 3330 e3470 cm1 corresponding to such HBs in the simulated IR, low values of the lateral order index calculated from IR, Q4 and Q6 values close to zero, loss of long-range ordering observed in radial distribution functions, total destruction of crystal unit cell corroborated by X-ray diffraction, and similarity between probability density distribution of dihedral angle j with that computed for completely amorphous cellulose. Nonetheless, as revealed by X-ray diffraction results, this protocol seems to provide more crystalline structures starting from cellulose microfibrils having a polymerization degree higher than 10. 650 $aMolecular dynamics 653 $aAmorphization 653 $aCHARMM force field 653 $aCrystallinity 653 $aThermal treatment 700 1 $aSECCHI, A. R. 700 1 $aTAVARES, F. W. 700 1 $aRODRIGUES, D. de S. 700 1 $aGAMBETTA, R. 773 $tFluid Phase Equilibria$gv. 491, p.56-76, 2019.
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