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

Amorim, Cláudia, Silvério, Sara C., Rodrigues, Lígia R.
Food chemistry 2019 v.270 pp. 86-94
Trichoderma reesei, biomass, bioprocessing, enzymes, fermentation, functional foods, lignocellulose, pH, polymerization, prebiotics, spent grains, xylooligosaccharides, xylose
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.