Fig. 1

Scheme of multi-feed SSCF and process optimization targets. Pre-treated wheat straw from SP Biorefinery Demo Plant (BDP) contained WIS about 15–20 % (w/w). Separating solid from liquid fraction of the slurry by centrifugation (in lab) or filter press (in the plant) gave a solid fraction with about 40 % (w/w) WIS content. The multi-feed SSCF used solid fraction as substrate and allowed operation above 20 % (w/w) WIS. The liquid fraction was used for yeast propagation