Production of xylooligosaccharides, bioethanol, and lignin from structural components of barley straw pretreated with a steam explosion

Abstract

Barley straw (BS) serves as a potential source to obtain bioethanol and xylooligosaccharides (XOS). In this study, BS was submitted to steam explosion pretreatment to solubilise the hemicellulose (xylan mainly). Different combinations of endo-β-(1,4)-D-xylanase enzyme with accessories enzymes (α-L-arabinofuranosidase, feruloyl esterase and acetylxylan esterase) to produce XOS with a low degree of polymerization (DP2-DP6) have been studied. The application of all accessories enzymes combined with endo-β-(1,4)-D-xylanase enzymes turned out to be the more effective for the formation of XOS, achieving 13.0 g of XOS (DP2-DP6) per 100 g of untreated BS. A mass balance has been including for showing a process integration to produce XOS, bioethanol and lignin-rich residue from BS achieving to valorise this residue.