Symbiosis of bio- & chemo-catalysts for the sustainable conversion of hemicelluloses
Acronym: CrossCat

- Thomas Bley - Technische Universität Dresden - Germany
- Rüdiger Lange - Technische Universität Dresden - Germany
- Tapio Salmi - Abo Akademi University - Finland
- Patrick Sagmeister - EXPUTEC GmbH - Austria

In our day-to-day life, most of us need items and energy which still strongly depend on fossil resources. But the increasing scarcity and prices, as well as environmental aspects of these resources require a shift towards renewable raw materials such as plant biomass. During the last decades, as biorefinery technology started to grow out of its infant stage, the research community recognized that of the three main biomass components, hemicelluloses are still relatively under-represented. Therefore, hemicelluloses - the second most abundant component - recently started to receive nearly equal attention as cellulose and lignin.

A prominent example of hemicellulose-based chemical products is xylitol (E 967) which is in strong demand for applications in food, pharmaceuticals, cosmetics and dental care due to its insulin independence, high sweetening power and anti-cariogenic effect. However, the conventional production of xylitol via Raney-nickel catalysts is ineffective and expensive, compared to the potential of a future process based on industrial biotechnology.

Therefore, we propose to develop a hybrid process to convert lignocellulosic biomass into platform chemicals (e.g. sugars and polyols) for food, pharma and cosmetic industries. Key will be the combination of chemical catalysts, enzymes and extremophiles (whole cells) in a novel one-pot process. This innovative approach connects the advantages of chemical catalysis and white biotechnology and minimizes disadvantageous factors, such as high energy consumption and long residence time. Thus, both economic efficiency and environmental sustainability of a future
bio-economy will be increased significantly. The conversion of hemicelluloses into sugar monomers and alcohols will be investigated using xylan as example. The intermediate product xylose is an established platform chemical and the final product xylitol has high added-value for existing markets for chemicals, pharmaceuticals, paper and food industry.