Production and characterization of xylooligosaccharides from sugarcane bagasse using response surface methodology and its prebiotic properties

Xylooligosaccharides (XOS) are non-digestible carbohydrates as they are not readily degraded by the stomach acids and enzymes, reaches the lower bowel, for utilization by the microbiota colonized in the small intestine. XOS are resistant to digestion and hence major proportion of XOS reaches small intestine as unhydrolyzed form and promote the growth of gut microflora. In this study, xylooligosaccharides were produced by enzymatic hydrolysis on alkali-extracted xylan from sugarcane bagasse and their production was optimized using response surface methodology. Xylooligosaccharides were investigated for their prebiotic potential through in vitro study. The maximum (relative yield of 86%) yield of 0.21 +/- 0.00 g of xylan was observed in 20% NaOH treatment. FTIR peaks were at 3762 cm-1, 3347 cm-1, and 2917 cm-1 and represented the OH and CH stretching vibrations of xylan. The main NMR signals at 4.26 ppm, 3.19 ppm, 3.59 ppm, 3.63 ppm, and 3.98 ppm determine the existence of xylan. The optimum condition for XOS production was observed in pH 4.75, temperature 45 degrees C, enzyme 4 U/ml, and for the time of 16 h. The spectrum of 5.00-5.40 ppm and 4.30-4.60 ppm represents the alpha anomeric and beta anomeric protons in XOS. The maximum prebiotic index for XOS from xylan was noted in L. plantarum (1.92) and L. fermentum (1.61). The highest prebiotic activity score was observed in L. plantarum (1.9) and L. fermentum (1.7). The maximum bacteriocin production by Enterococcus faecium was observed and it was active against E. faecalis (13 mm) and Streptococcus pyogenes (11 mm). Therefore, utilization of agricultural residues for a value-added product not only shows a great impact on environmental issues but also could double the farmer's economy.