Fungal Enzyme-Assisted Conversion of Water Hyacinth and Sugarcane Bagasse Hemicelluloses into Xylooligosaccharide-Rich Hydrolysates with Potential Prebiotic Applications

The valorization of lignocellulosic residues through xylooligosaccharides (XOS) production offers a promising route for obtaining value-added compounds from underutilized biomass. In this study, five biocatalysts were produced by solid-state fermentation using water hyacinth (WH) as the substrate and solid support for five fungal strains. Xylanases were extracted from each fermented solid, exhibiting maximum activity between 45–55 °C and pH 5–7. Additionally, the recovery of hemicellulosic fractions from WH and sugarcane bagasse (SCB) reached 14.3 ± 0.91% and 18.4 ± 0.22% of initial dry biomass, respectively. Commercial xylan and hemicellulosic fractions from WH (WHh) and SCB (SCBh), at an initial concentration of 25 g/L, were partially hydrolyzed, releasing 12–18, 9–12 and 2–4 g/L of reducing sugars, respectively, after 6 h of reaction, depending on the enzyme extract used. Xylobiose was detected in all hydrolysates, with the Trichoderma harzianum extract yielding the highest concentrations: 8.3, 4.4, and 2.4 g/L from xylan, WHh, and SCBh, respectively. Hydrolysates supplemented into MRS medium enhanced the growth of Bifidobacterium lactis and Lactococcus lactis compared to the control medium. These findings demonstrate the feasibility of using waste-derived biocatalysts and WH and SCB as inexpensive and abundant sources of hemicellulose to produce XOS-containing hydrolysates with potential prebiotic applications.