U.S.-China Collaboration: Exploring Assessment of 3D nanostructure and topochemical distributions of lignocellulosic biomass and their impact on biomass pretreatment

Biomass is an important resource for the manufacture of renewable energy, sustainable chemicals and biodegradable materials. However, the recalcitrance of biomass is a fundamental barrier to the widespread application for biofuels. Pretreatments serve to solubilize some of the components and although they significantly enhance biomass reactivity, the causes or mechanisms by which this occurs are not known. The principal objective of this work is to examine the topochemical and nano-structural aspects of cell walls and their impact on subsequent enzymolysis or pretreatment reactions, by applying a variety of leading edge topographic and chemical resolution techniques. This will show the fundamental mechanisms of cell wall deconstruction and lead to effective biomass conversions. The understanding of the topochemistry of the chemical reactions will enable enhancements of these methods and recommendations of novel, more efficient pretreatment methods. This is a collaborative work and will help educate scientists and engineers for the bioresource industry. The application of novel microscopic techniques in concert with biomass pretreatment will cover a wide range of engineering and scientific disciplines and academic institutions and help foster interdisciplinary research leading to broader impacts in education and dissemination of knowledge internationally.

Wood chips will be used as models for this preliminary study on account of their wide prevalence and use in pulp and paper. Explorations of the 3D nanostructure and topochemical distributions will be performed using TEM imaging, advanced computed tomography, Raman spectroscopy, and immunoassays as follows: 1) Recently developed immunochemical labels with nanoparticle tags and TEM to determine pore structure (SUNY), 2) 3D nanostructure digitally visualized and characterized using TEM and advanced computational tools (UMN), 3) AFM with functionalized probes coupled with the TEM for correlative imaging of the spatial chemical distributions within cell walls (UMN), 4) Raman spectroscopy will be applied to obtain lignin distributions inside the cell walls (in collaboration with Beijing Forestry University, China). The changes in the three dimensional nanoporous structure of the cell wall, porosity and pore size distributions and their impact on biomass pretreatment and the spatial distribution of the cell wall components will be obtained for two samples. This award will support three U.S. investigators and two U.S. students to travel to China to initiate this collaboration.