ObjectiveThe condition of preparation of xylo-oligosaccharide (XOS) from sugarcane bagasse with enzymatic hydrolysis was investigated. In this study, the preparation efficiency of xylo-oligosaccharide was improved by NaOH-ethanol pretreatment.

MethodFirstly, the chemical composition of the sugarcane bagasse before and after pretreatment was characterized, and the effect of pretreatment on the components of the raw material was determined. Secondly, the wettability and physical structure of substrates were characterized by contact angle analysis and X-ray diffraction (XRD). Finally, in order to compare the effects of different pretreatments on the mass concentration of XOS with enzymatic hydrolysis, the enzymatic hydrolysate was harvested and analyzed by high performance liquid chromatography (HPLC).

ResultCharacterization results confirmed that optimal pretreatment condition was 10 g/L NaOH-ethanol (50% v/v ethanol) pretreatment. Under this pretreatment condition, a large amount of lignin was removed and the removal rate of lignin could reach 78.10%. Moreover, the pretreatment could effectively improve the hydrophilicity of raw materials, decreased the contact angle from 61.5° to 55.4°, and also increased the crystallinity of lignocellulose from 28.6% to 32.3%.The results showed that the highest XOS mass concentration was 1.85 g/L after 10 g/L NaOH-ethanol pretreatment, which was 122.89% higher than that of untreated sugarcane bagasse (0.83 g/L).

ConclusionIn the process of XOS preparation from sugarcane bagasse, enzymatic hydrolysis was an efficient way to achieve the conversion from hemicellulose to XOS. NaOH-ethanol pretreatment can effectively increase the efficiency of enzymatic hydrolysis and promote the preparation of XOS.