One-step process for producing prebiotic arabino-xylooligosaccharides from Brewer's spent grain employing Trichoderma species

Supplementary data associated with this article can be found, in the online version, at https://doi.org/10.1016/j.foodchem.2018.07.080.Xylooligosaccharides (XOS) are prebiotic nutraceuticals that can be sourced from lignocellulosic biomass, such as agro-residues. This study reports for the first time an optimization study of XOS production from agro-residues by direct fermentation using two Trichoderma species. A total of 13 residues were evaluated as potential substrates for single-step production. The best results were found for Trichoderma reesei using brewers spent grain (BSG) as substrate. Under optimal conditions (3 days, pH 7.0, 30°C and 20 g/L of BSG), a production yield of 38.3 ± 1.8 mg/g (xylose equivalents/g of BSG) was achieved. The obtained oligosaccharides were identified as arabino-xylooligosacharides (AXOS) with degree of polymerization from 2 to 5. One-step fermentation proved to be a promising strategy for AXOS production from BSG, presenting a performance comparable with the use of commercial enzymes. This study provides new insights towards the bioprocess integration, enabling further developments of low-cost bioprocesses for the production of these valuable compounds.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER006684) and under the scope of the Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and the Project MultiBiorefinery – Multi purpose strategies for broadband agro forest and fisheries by products valorisation: a step forward for a truly integrated biorefinery (POCI-01-0145-FEDER-016403) the Project Lignozymes (POCI-010145-FEDER-029773) and the Project FoSynBio (POCI-01-0145FEDER-029549). The authors also acknowledge financial support from BioTecNorte (NORTE-01-0145-FEDER-000004) Project BioInd – Biotechnology and Bioengineering for improved Industrial and AgroFood processes(NORTE-07–0124-FEDER-000028) funded by the European Regional Development Fund under the scope of Norte2020 Programa Operacional Regional do Norte. CA and SCS acknowledge their grants (PD/BD/105870/2014 SFRH/BPD/88584/2012) from FCT.