UNRAVEL – UNique Refinery Approach to Valorise European Lignocellulosics

The UNRAVEL project aims to develop advanced pre-treatment, separation and conversion technologies for complex lignocellulosic biomass. The technology relies on pre-extraction, fractionation using low-temperature acetone and subsequent downstream processing to isolate and convert the lignocellulosic constituents into high-value applications. This will produce usable lignin fragments and monomeric sugars from the cellulose along with a hemicellulose fraction suitable for biochemical conversions.

It will bring together specialists with expertise of the entire value chain from feedstock composition, chemical pulping and pre-treatment, enzymes production, polymer chemistry, separation and reactor engineering, techno-economic and sustainability assessments and knowledge dissemination, exploitation and communication.

fractionation of lignocellulose
© Fraunhofer IGB
Equipment for the scale up of lignocellulose fractionation processes at Fraunhofer CBP
Fractionation of renewable raw materials
© Fraunhofer IGB
Fractionation of renewable raw materials at Fraunhofer CBP.


The UNRAVEL project aims to develop an innovative lignocellulosic value chain and has the following specific objectives:

  • Develop a pre-extraction process optimised for mixed lignocellulosic biomass streams;
  • Achieve at least 80 percent delignification, 90 percent glucan recovery, 80 percent yield of monomeric hemicellulose sugars and less than 1 percent solvent loss;
  • Achieve at least 95 percent lignin recovery and 99 percent (non-condensed) solvent recovery from the liquor;
  • Develop an economically viable process for purifying the hemicellulose hydrolysate to ferment the hemicellulose sugars effectively into chemical building blocks;
  • Achieve over 90 percent sugar conversion, over 20 percent reduction of hydrolysis time and 20 percent reduction of enzyme dosage compared to cellulose alone;
  • Demonstrate the low inhibitory effect of the C5 and C6 hydrolysate in fermentation;
  • Activate and depolymerise lignin from the FABIOLATM process
  • Establish a series of high-value lignin applications;
  • Show a 30 percent reduction in operating expenses through lower overall energy consumption and costs as compared with a benchmark pre-treatment process;
  • Demonstrate an overall reduction of at least 15 percent in the carbon footprint compared with the state-of-the-art bio-based operation.

Expected impacts

As well as its contribution to the overall BBI-JU goals and key performance indicators, the UNRAVEL project aims to have the following impacts:

  • Creating a new cross-sector interconnection between the forestry, pulp and paper industries, the biotechnology industry and the building and construction material industry;
  • Establishing a new value chain using a mixture of hardwood wood chips, forest residues and bark, as well as straw and nut shells, to produce extractives, lignin-based polyols and chemical building blocks for the sugar fractions;
  • Reducing operational expenditure by at least 30 percent through a series of process improvements, principally by reducing operating temperatures. This reduction will also reduce the carbon footprint of the operation;
  • Lowering the overall environmental impact of biorefineries by reducing emissions and increasing the efficiency resource and chemical use;
  • Stimulate innovation through international and cross-sector collaboration.

Project information

Project title

UNRAVEL – UNique Refinery Approach to Valorise European Lignocellulosics


Project duration

June 2018 – May 2022


Project partners

  • Netherlands Organisation for Applied Scientific Research TNO, Petten, The Netherlands (Coordination)
  • Fraunhofer Center for Chemical-Biotechnological Processes CBP, Leuna, Germany
  • Celignis Ltd, Limerick, Ireland
  • Metgen OY, Kaarina, Finland
  • Soprema, Strasbourg, France
  • Institut für Energie- und Umweltforschung Heidelberg GmbH, Heidelberg, Germany
  • Rita Clancy (EURIDA), Berlin, Germany
  • Centre national de la recherche scientifique CNRS, Paris, France
  • Sappi, Lanaken, Belgium
  • Max-Planck-Gesellschaft zur Förderung der Wissenschaften e.V., Germany


This project has received funding from the Bio Based Industries Joint Undertaking (JU) under grant agreement no 792004. The JU receives support from the European Union’s Horizon 2020 research and innovation programme and the Bio Based Industries Consortium.

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