Modification of the nanostructure of lignocellulose cell walls via a non-enzymatic lignocellulose deconstruction system in brown rot wood-decay fungi

Journal Article · Tue Jul 11 00:00:00 EDT 2017 · Biotechnology for Biofuels

DOI:https://doi.org/10.1186/s13068-017-0865-2· OSTI ID:1618685

Goodell, Barry ; Zhu, Yuan; Kim, Seong; Kafle, Kabindra; Eastwood, Daniel; Daniel, Geoffrey; Jellison, Jody; Yoshida, Makoto; Groom, Leslie; Pingali, Sai Venkatesh; O’Neill, Hugh

Wood decayed by brown rot fungi and wood treated with the chelator-mediated Fenton (CMF) reaction, either alone or together with a cellulose enzyme cocktail, was analyzed by small angle neutron scattering (SANS), sum frequency generation (SFG) spectroscopy, Fourier transform infrared (FTIR) analysis, X-ray diffraction (XRD), atomic force microscopy (AFM), and transmission electron microscopy (TEM). Results showed that the CMF mechanism mimicked brown rot fungal attack for both holocellulose and lignin components of the wood. Crystalline cellulose and lignin were both depolymerized by the CMF reaction. Porosity of the softwood cell wall did not increase during CMF treatment, enzymes secreted by the fungi did not penetrate the decayed wood. The enzymes in the cellulose cocktail also did not appear to alter the effects of the CMF-treated wood relative to enhancing cell wall deconstruction. This suggests a rethinking of current brown rot decay models and supports a model where monomeric sugars and oligosaccharides diffuse from the softwood cell walls during non-enzymatic action. In this regard, the CMF mechanism should not be thought of as a “pretreatment” used to permit enzymatic penetration into softwood cell walls, but instead it enhances polysaccharide components diffusing to fungal enzymes located in wood cell lumen environments during decay. SANS and other data are consistent with a model for repolymerization and aggregation of at least some portion of the lignin within the cell wall, and this is supported by AFM and TEM data. The data suggest that new approaches for conversion of wood substrates to platform chemicals in biorefineries could be achieved using the CMF mechanism with >75% solubilization of lignocellulose, but that a more selective suite of enzymes and other downstream treatments may be required to work when using CMF deconstruction technology. Strategies to enhance polysaccharide release from lignocellulose substrates for enhanced enzymatic action and fermentation of the released fraction would also aid in the efficient recovery of the more uniform modified lignin fraction that the CMF reaction generates to enhance biorefinery profitability.

• Research Organization: Energy Frontier Research Centers (EFRC) (United States). Center for Lignocellulose Structure and Formation (CLSF)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: IPTS-12345/CG-3; SC0001090; FWP ERKP752; FWP ERKP291
• OSTI ID: 1618685
• Alternate ID(s): OSTI ID: 1389009
• Journal Information: Biotechnology for Biofuels, Journal Name: Biotechnology for Biofuels Vol. 10 Journal Issue: 1; ISSN 1754-6834
• Publisher: Springer Science + Business Media
• Country of Publication: Netherlands
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
09 BIOMASS FUELS
biofuels (including algae and biomass)
bio-inspired
membrane
carbon sequestration
materials and chemistry by design
synthesis (self-assembly)