Scale-Up: Multi-Feed SSF with integrated propagation of flocculating xylose-fermenting yeast

Research Project, 2013 – 2015

In this project we will design an efficient process for production of bioethanol, Multi-Feed SSF, and validate it in demonstration scale. In Multi-Feed SSF, solids are separated from a slurry of steam preatreated, renewable wood and pentose-rich raw materials. Solids, fresh yeast and enzymes are gradually fed into a fermenter where ethanol is formed via high gravity Simultaneous Saccharification and Fermentation. The liquid part of the slurry is used to propagate yeast which therefore can adapt to inhibitors present in the pretreated material. The process has been very successful in our lab-scale experiments. Our goal is to reach 7% ethanol concentration with resource-efficient use of raw materials, enzymes, yeast, water and energy. We will further develop an already well-performing yeast, and use mathematical modelling for heat integration and optimisation of the process. The project may enable sustainable large-scale production of bioethanol and chemicals from Swedish raw materials.