Still largely underused, hemicelluloses could become a key resource for producing bio-based molecules. Coordinated by Grenoble INP – UGA, the HEMICELLULOSES project aims to change this.
Wood is about far more than cellulose. Hemicelluloses account for between 20% and 30% of plant biomass—a considerable proportion that is still poorly utilised. They were long treated as the poor relation of wood components, particularly because they are degraded by current industrial processes. “Cellulose is well understood and widely used, whereas hemicelluloses have long been overlooked,” says Christine Chirat, a professor at Grenoble INP – Pagora, UGA, and a researcher at LGP2*.
In the paper industry, these polysaccharides are dissolved and degraded along with lignin in black liquor before being burned to generate energy. Although effective, this approach prevents them from being converted into higher-value products.
The renewed interest in hemicelluloses stems from their composition. Unlike cellulose, which consists solely of glucose, they contain a wide variety of sugars, some of which are rare and difficult—or even impossible—to source. “They contain xylose, mannose, galactose, arabinose and more. These are known as rare sugars and are difficult to obtain from other sources,” Christine Chirat explains.
These molecules offer numerous potential applications. Xylose, for example, can be used to produce xylitol, a sweetener found in “sugar-free” chewing gum, toothpaste, diet foods. It can also be converted into furfural, which can be used as a bio-based solvent or to manufacture bio-based polymers. Oligomers derived from hemicelluloses also have prebiotic properties of interest to the health and cosmetics sectors. Another major advantage is that this resource does not compete with food production. Derived mainly from wood, it fits squarely within a sustainable, circular bioeconomy.
Harnessing the potential of these sugars is the central objective of the HEMICELLULOSES project. It has received €1.6 million in French government funding managed by the French National Research Agency under the France 2030 investment plan, through the B-BEST Priority Research Programme and Infrastructure (ANR-25-PEBB-0005).
Over four years, the teams will develop processes combining chemistry and biotechnology to extract and transform these compounds. “The aim is to integrate our processes into existing biorefineries, particularly in the paper industry, without disrupting their energy balance,” explains Christine Chirat, coordinator of the HEMICELLULOSES project. “We have identified two points in the process at which these hemicelluloses can be recovered."
The project adopts a multidisciplinary approach involving several French laboratories: LGP2*, G-SCOP** and CERMAV in Grenoble, Institut Pascal in Clermont-Ferrand and BioEcoAgro in Lille. It combines hemicellulose extraction, enzyme selection, pilot-scale production, advanced characterisation of these complex mixtures and assessment of the environmental footprint of the various processes under consideration.
Beyond its potential applications, the project opens up a field of research that remains largely unexplored. Owing to their complex structure, hemicelluloses have received less attention than the other components of wood and plant biomass more broadly. “When a field is still largely uncharted, the road ahead is wide open,” Christine Chirat observes.
By finding new uses for these currently underutilised co-products, the HEMICELLULOSES project directly supports the objectives of the French B-BEST programme, which aims to develop low-carbon processes and accelerate the transition towards a circular bioeconomy. Ultimately, it could profoundly transform the use of biomass by turning hemicelluloses into a new strategic resource for industry.
*CNRS / UGA / Grenoble INP – UGA
** CNRS / UGA / Grenoble INP – UGA
Photo credits: Adobe Stock, Christine Chirat
