Prebiotics are interesting compounds able to modulate the gut microbiota by inducing the growth or activity of beneficial bacteria in the gastrointestinal tract, while the pathogenic ones are inhibited. Several carbohydrates have been considered prebiotics including xylooligosaccarides (XOS). XOS are the only nutraceuticals that can be produced from lignocellulosic biomass. Indeed, XOS can be produced from agro-residues, which is encouraging to the food ingredient industries, as these raw materials are inexpensive, abundant and renewable in nature. In particular, the coffee agro-industry generates million tonnes of solid residues yearly worldwide, including coffee sliver skin (CSS). The use of coffee agro-industry residues for XOS production through a sustainable process is undoubtably aligned with the concept of circular economy.
In this work, the production potential of XOS was evaluated for CSS and CSS pellets (CP), using one-pot fermentation by recombinant Bacillus subtills. In previous work, this strain was genetically modified to express the xylanase gene (xyn2) from Trichoderma reesei.
CP presented the highest potential for XOS production. After process optimization, the highest reducing sugars yield (63 ± 3 mg.gCP-1) was achieved at 8 h, 45 °C, pH 7.0 and 10 g.L-1 of CP.
One-pot fermentation proved to be a promising strategy for XOS production from CP, presenting advantages over the use of commercial enzymes. This study provides important insights for novel bioprocess integration approaches using agro-residues towards production cost reduction.info:eu-repo/semantics/publishedVersio
