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449 results on '"Nishiyama, Yoshiharu"'

17. Tracking of enzymatic biomass deconstruction by fungal secretomes highlights markers of lignocellulose recalcitrance

Author

Paës, Gabriel, Navarro, David, Benoit, Yves, Blanquet, Senta, Chabbert, Brigitte, Chaussepied, Bernard, Coutinho, Pedro M, Durand, Sylvie, Grigoriev, Igor V, Haon, Mireille, Heux, Laurent, Launay, Charlène, Margeot, Antoine, Nishiyama, Yoshiharu, Raouche, Sana, Rosso, Marie-Noëlle, Bonnin, Estelle, and Berrin, Jean-Guy

Subjects
Biological Sciences, Industrial Biotechnology, Generic health relevance, Biomass, Filamentous fungi, Enzymatic degradation, Saccharification, Hydrolysis, Water sorption, Glucose release
Abstract

BackgroundLignocellulose biomass is known as a recalcitrant material towards enzymatic hydrolysis, increasing the process cost in biorefinery. In nature, filamentous fungi naturally degrade lignocellulose, using an arsenal of hydrolytic and oxidative enzymes. Assessment of enzyme hydrolysis efficiency generally relies on the yield of glucose for a given biomass. To better understand the markers governing recalcitrance to enzymatic degradation, there is a need to enlarge the set of parameters followed during deconstruction.ResultsIndustrially-pretreated biomass feedstocks from wheat straw, miscanthus and poplar were sequentially hydrolysed following two steps. First, standard secretome from Trichoderma reesei was used to maximize cellulose hydrolysis, producing three recalcitrant lignin-enriched solid substrates. Then fungal secretomes from three basidiomycete saprotrophs (Laetisaria arvalis, Artolenzites elegans and Trametes ljubarskyi) displaying various hydrolytic and oxidative enzymatic profiles were applied to these recalcitrant substrates, and compared to the T. reesei secretome. As a result, most of the glucose was released after the first hydrolysis step. After the second hydrolysis step, half of the remaining glucose amount was released. Overall, glucose yield after the two sequential hydrolyses was more dependent on the biomass source than on the fungal secretomes enzymatic profile. Solid residues obtained after the two hydrolysis steps were characterized using complementary methodologies. Correlation analysis of several physico-chemical parameters showed that released glucose yield was negatively correlated with lignin content and cellulose crystallinity while positively correlated with xylose content and water sorption. Water sorption appears as a pivotal marker of the recalcitrance as it reflects chemical and structural properties of lignocellulosic biomass.ConclusionsFungal secretomes applied to highly recalcitrant biomass samples can further extend the release of the remaining glucose. The glucose yield can be correlated to chemical and physical markers, which appear to be independent from the biomass type and secretome. Overall, correlations between these markers reveal how nano-scale properties (polymer content and organization) influence macro-scale properties (particle size and water sorption). Further systematic assessment of these markers during enzymatic degradation will foster the development of novel cocktails to unlock the degradation of lignocellulose biomass.

Published
2019

40. Residual Strain and Nanostructural Effects during Drying of Nanocellulose/Clay Nanosheet Hybrids : Synchrotron X-ray Scattering Results

Author

Li, Lengwan, Chen, Pan, Medina, Lilian, Yang, Lin, Nishiyama, Yoshiharu, Berglund, Lars, Li, Lengwan, Chen, Pan, Medina, Lilian, Yang, Lin, Nishiyama, Yoshiharu, and Berglund, Lars

Abstract

Cellulose nanofibrils (CNF) with 2D silicate nanoplatelet reinforcement readily form multifunctional composites by vacuum-assisted self-assembly from hydrocolloidal mixtures. The final nanostructure is formed during drying. The crystalline nature of CNF and montmorillonite (MTM) made it possible to use synchrotron X-ray scattering (WAXS, SAXS) to monitor structural development during drying from water and from ethanol. Nanostructural changes in the CNF and MTM crystals were investigated. Changes in the out-of-plane orientation of CNF and MTM were determined. Residual drying strains previously predicted from theory were confirmed in both cellulose and MTM platelets due to capillary forces. The formation of tactoid platelet stacks could be followed. We propose that after filtration, the constituent nanoparticles in the swollen, solid gel already have a “fixed” location, although self-assembly and ordering processes take place during drying., QC 20231115

Published
2023
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46. Quantifying the Contribution of the Dispersion Interaction and Hydrogen Bonding to the Anisotropic Elastic Properties of Chitin and Chitosan

Author

Chen, Pan, Zhao, Changjun, Wang, Huanyu, Li, Yiwei, Tan, Guoqiang, Shao, Ziqiang, Nishiyama, Yoshiharu, Hu, Tao, Wohlert, Jakob, Chen, Pan, Zhao, Changjun, Wang, Huanyu, Li, Yiwei, Tan, Guoqiang, Shao, Ziqiang, Nishiyama, Yoshiharu, Hu, Tao, and Wohlert, Jakob

Abstract

The elastic tensors of chitin and chitosan allomorphs were calculated using density functional theory (DFT) with and without the dispersion correction and compared with experimental values. The longitudinal Young's moduli were 114.9 or 126.9 GPa for alpha-chitin depending on the hydrogen bond pattern: 129.0 GPa for beta-chitin and 191.5 GPa for chitosan. Furthermore, the moduli were found to vary between 17.0 and 52.8 GPa in the transverse directions and between 2.2 and 15.2 GPa in shear. Switching off the dispersion correction led to a decrease in modulus by up to 63%, depending on the direction. The transverse Young's moduli of a-chitin strongly depended on the hydroxylmethyl group conformation coupled with the dispersion correction, suggesting a synergy between hydrogen bonding and dispersion interactions. The calculated longitudinal Young's moduli were, in general, higher than experimental values obtained in static conditions, and the Poisson's ratios were lower than experimental values obtained in static conditions., QC 20220516

Published
2022
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