Efficient production of nutraceuticals and lactic acid from lignocellulosic biomass by combining organosolv fractionation with enzymatic/fermentative routes

[Display omitted] •OxiOrganosolv with isobutanol as solvent was used for beechwood pretreatment.•High delignification rates, up to 97%, were achieved.•Around 50 wt% of initial hemicellulose was recovered as XOS in the liquid fraction.•Enzymatic hydrolysate supported C. cohnii growth and lipid accumulation (~52 wt%)•Up to 51.6 g /L (0.57 g/gbiomass) D-lactic acid was produced through SSF. The aim of this work was to investigate the use of isobutanol as organic solvent for the efficient delignification and fractionation of beechwood through the OxiOrganosolv process in the absence of any catalyst. The results demonstrate that cellulose-rich solid pulp produced after pretreatment is a source of fermentable sugars that can be easily hydrolyzed and serve as a carbon source in microbial fermentations for the production of omega-3 fatty acids and D-lactic acid. The C5 sugars are recovered in the aqueous liquid fractions and comprise a fraction rich in xylo-oligosaccharides with prebiotic potential. The maximum production of optically pure D-lactic from Lactobacillus delbrueckii sp. bulgaricus reached 51.6 g/L (0.57 g/gbiomass), following a simultaneous saccharification and fermentation strategy. Crypthecodenium cohnii accumulated up to 52.1 wt% lipids with a DHA content of 54.1 %, while up to 43.3 % hemicellulose recovery in form of oligosaccharides was achieved in the liquid fraction.