Multiscale multimodal analysis of brown rot fungal decay mechanisms for improved biomimetic lignocellulosic biorefinery processes
EMSL Project ID
60858
Abstract
An improved understanding of non-enzymatic brown-rot decay mechanisms in lignocellulosics, such as wood, could inspire improved biomimetic biorefinery processes to elevate lignocellulosic materials as important renewable resources for meeting a sustainable energy future. Lignocellulosic polymers in secondary cell walls are too tightly packed for direct enzymatic deconstruction. Like biorefineries, fungi can first “pretreat” the cell walls using non-enzymatic mechanisms before enzymatic access is possible. The main non-enzymatic mechanisms used by brown-rot are generally understood to include chelator-mediated Fenton (CMF) reactions that involve Fe(II)/Fe(III) redox reactions, a wide range of metabolites, such as oxalic acid and catecholate/hydroxyquinone chelators, and trace elements like Fe, Mn, Ca, Zn, and K. However, to mimic the full decay process details about the decay mechanisms are still needed. Nearly all previous work studying brown-rot decay mechanisms relied on bulk wood characterization techniques. A major shortcoming of these previous studies is that decay in wood is inhomogeneous across the wood cellular structure in decaying wood. Even neighboring cells may be at different stages of decay. Therefore, bulk wood characterization results are the agglomeration of various decay stages. Mechanistic study of different decay stages requires multiple characterization techniques that can probe across relevant cellular and cell wall length scales. The project scope will therefore be centered on multiscale (from molecular to cellular) compositional and structural characterization of wood at different stages of decay using a combination of techniques at EMSL, JGI, and the Advanced Photon Source (APS). Experiments at EMSL will include mass spectrometry imaging (MSI), atom probe tomography (APT), nano-FTIR, and AFM Raman. Experiments at JGI will include transcriptome experiments and liquid-chromatography tandem mass spectrometry (LC-MS/MS). Experiments at APS will include multiscale X-ray fluorescence microscopy (XFM), micro-X-ray absorption near edge spectroscopy (μXANES), wide angle X-ray scattering (WAXS), and ptychography. With regards to feasibility, Forest Products Laboratory (FPL) researchers have already developed unique sample preparation techniques and successfully performed experiments on wood for the proposed X-ray techniques and nano-FTIR. Application of APT to wood cell walls is novel and protocols will be guided by EMSL experience from previous projects. The remaining techniques have already been successfully applied to similar organisms and materials. Experiments will be designed such that multiple techniques can be performed on the same wood tissue. Combined JGI, EMSL, and APS results will include gene expression during different decay stages, multiscale maps of metabolites and trace elements, trace element oxidation states, changes in polymer chemistry in individual wood cell walls, and characterization of 0.1-100 nm structure in wood cell walls. Mechanical properties of the same cell walls will also be measured by nanoindentation at FPL. The accumulative transcriptomic, chemical, composition, structural, and mechanical data will be used to identify different decay stages with their associated decay mechanisms and cell wall modifications.
Project Details
Project type
FICUS Research
Start Date
2023-10-01
End Date
N/A
Status
Active
Released Data Link
Team
Principal Investigator
Co-Investigator(s)