Physicochemical and morphological evaluation of sago ( Metroxylon sagu ) pith hydrolyzed by xylanase for xylooligosaccharide production

Abstract

Sago pith waste is a lignocellulosic byproduct of sago strach processing characterized by a high complex carbohydrates content, particularly hemicellulose with a dominant xylan fraction. Converting xylan into xylooligosaccharides (XOs), a high-value prebiotic, is the main focus for optimizing the use of this waste. This study aimed to determine the effects of sago pith waste substrate concentration (5%, 10%, 15%, and 20%, w/v) during endo-β-1,4-D-xylanase hydrolysis on reducing sugar production, hemicellulose and cellulose fractions, XOS profiles, and surface morphology. The methodology involved enzymatic hydrolysis and analysis of reducing sugar and fiber composition. The hydrolysis products were visualized using Thin Layer Chromatography (TLC) and Scanning Electron Microscopy (SEM). The results demonstrated that increased substrate concentration correlated positively with the release of reducing sugars; the 20% substrate yielded the highest concentration. Compositional analysis revealed hemicellulose degradation after enzymatic hydrolysis; levels decreased from 28.50% in the control to 19.79% in the 20% treatment, while cellulose content remained stable. TLC analysis revealed that the enzymatic hydrolysis yielded XOs, specifically xylotetrose (X4), xylopentose (X5), and xylohexose (X6). SEM analysis showed that post-hydrolysis, sago pith waste appeared coarse, degraded, and irregularly layered, with significantly diminished cavity sizes compared to the pristine, spherical morphology of untreated samples. These findings demonstrate that endo-β-1,4-D-xylanase effectively depolymerizes sago xylan into XOs, which has potential for industrial prebiotic production.