SUPERVISOR: Thomas ROSENAU 

PROJECT ASSIGNED TO: Julian SAUER

The goal of the sustainability revolution is the complete replacement of unsustainable fossil fuel-based chemicals, materials and products with sustainable bio-based ones in all industries from packaging to pharmaceuticals. For this reason, biorefineries strive for a complete utilization of the biomass and reduction of unused waste by-products. To achieve this the variety of unknown and complex molecules and materials which constitute biomass or result out of biorefinery processes need to be identified and characterized. This applies also to byproducts and other unwanted compounds, such as chromophores and degradation products, mostly having  unknown structures and being present in trace amounts only. 

While most of these compounds can be identified via a combination of chromatography, IR, UV-vis, MS and NMR methods, especially solid-state structure of biopolymer and bio-oligomers and absolute chirality of degradation products and byproducts often cannot be determined reliably by using these methods. These analytic challenges are aggravated by the mentioned fact that often these analytes can only be isolated in minute quantities, making many of the usual methods completely unviable. Single crystal diffraction techniques are the only way to directly determine absolute molecule and solid-state structures, but unfortunately the classic SC-XRD method needs crystallite sizes in the µm-range, which are only achievable in rare cases by slow crystallization protocols, if at all. Fortunately, recent advances in microcrystal electron diffraction (MicroED) and derived techniques offer the capability to refine single crystal structures out of much more accessible microcrystalline samples.

This project aims at developing general methodology for the structural determination of analytes from biomass and biorefineries (oligosaccharides, chromophores, lignin fragments) using MicroED and related techniques, and at studies into the solid-state structures of common biomaterials, such as cellulose, hemicelluloses and lignin along their lifecycles.