Development of efficient xylose fermenting and acid-tolerant yeast strains - a crucial step towards commercial (scale) cellulose-based fuel production!

The aim of this project is to develop new yeast strains suitable for a feasible large-scale lignocellulose based bioethanol production process. The project is part of a interdisciplinary project cluster, involving LTH and SEKAB. Xylose fermentation will be improved through a blend of metabolic engineering and randomized techniques, while acetic acid tolerance will be increased with the combination of two entirely novel strategies involving cell membrane modification and direct conversion of acetic acid to added value products. Finally, efficient xylose fermenting and acid-tolerant yeast strains will be developed by combining the results in an industrial strain background. Their fermentation capacity will be mapped. The strength of the project is a unique combination of state-of –the-art facilities, competences and experience in the field, within a interdisciplinary project cluster, which will lead towards strains directly applicable to commercial scale cellulose based fuel production.

Start date 01/01/2012
End date The project is closed: 30/09/2015

​The conversion of the lignocellulosic biomass into ethanol fuel is an interesting alternative to the present bioethanol production industry based on food-related feedstocks. Fermentation of lignocellulosic hydrolysates however, is very challenging to yeast because besides fermentable sugars, inhibitory compounds derived from cellulose, hemicellulose and lignin degradation during pretreatment of the biomass are also found in the broth. Acetic acid is among these compounds and it can be released from hemicellulose to such an extent that yeast fermentation is completely compromised. Furthermore, the yeast most commonly used for this purpose, S. cerevisiae, is not able to ferment xylose, which could constitute up to 40% of the lignocellulosic material. In this project we target the development of robust xylose fermenting S. cerevisiae strains.

Our project aims at increasing the tolerance of yeast to acetic acid and other acids. Furthermore, the expression of key genes associated to higher robustness and the related effect on xylose fermentation is also studied.

Funded by

  • Swedish Energy Agency (Public, Sweden)
  • Taurus energy (Private, Sweden)

Published: Thu 19 Jul 2018.