聚木糖酶处理桉木预水解液制备低聚木糖的研究

Preparation of Xylo-oligosaccharides from Eucalyptus Pre-hydrolysis Liquor with Xylanase Treatment

以桉木预水解液为原料,首先采用Ca(OH)2和活性炭处理制备二级处理预水解液,然后采用聚木糖酶酶解制备低聚木糖。探讨了处理过程中聚木糖酶用量、处理时间、处理温度和pH值对二级处理预水解液中聚合度为2~4的低聚木糖(低聚木糖DP2~4)含量的影响,并对所制备的低聚木糖产品进行分析与表征。结果表明,聚木糖酶处理桉木预水解液制备低聚木糖的较优工艺条件为:聚木糖酶用量2U/g、处理时间3h、处理温度55℃和处理液pH值5.5,在此条件下,经酶处理后所得三级处理预水解液中低聚木糖DP2~4含量为12.22 g/L,与未经过酶处理的二级处理预水解液相比,低聚木糖DP2~4含量提高了67.2%;经过酶处理后三级处理预水解液中低聚木糖DP2~4含量占桉木预水解液中总木糖含量的56.1%。红外光谱(FT-IR)和热重分析(TGA)表明,经过聚木糖酶处理预水解液所制备的低聚木糖中含有部分糖醛酸侧链,且具有较高的热稳定性。

In this paper,xylanase treatment was used to prepare xylo-oligosaccharides(XOS)from the secondary eucalyptus pre-hydrolysis liquor(PHL)which had been treated with Ca(OH)2 and activated carbon successively.The effects of xylanase dosage,treatment time,treatment temperature and pH value on XOSDP2~4 contents were investigated and the prepared XOS were characterized.The results showed that the optimal treatment conditions were xylanase dosage of 2 U/g(based on the weight of secondary eucalyptus PHL),treatment time of 3 h,treatment temperature of 55℃and pH value of 5.5,The content of XOSDP2~4 of the third PHL was 12.22 g/L,increased by 67.2%com?pared to the secondary PHL,and the content of XOSDP2~4 of third PHL accounted for 56.1%of the total xylose in the eucalyptus PHL.Analy?sis of Fourier Transform infrared spectroscopy(FT-IR)and Thermo gravimetric(TGA)showed that XOS obtained with xylanase treatment process contained part of side-chains of uronic acid and showed a high thermal stability.