With this new concept, the fermentation liquid is circulated between the hydrolysis vessel and the fermentation vessel and a filtration device prevents the solid fraction from reaching the fermentation vessel. This approach allows for repeated and/or continuous use of the fermenting culture.

The aim of this project, a co-operation between University of Borås and SEKAB E-Technology, is to optimize and evaluate this new concept on laboratory scale and to upscale and verify it in the Ethanol Pilot in Örnsköldsvik. Since the concept is flexible regarding the choice of raw material, Swedish spruce will be used as a reference. A second raw material intended for the international market will be selected.