棉杆水解制备木糖的研究

Preparing D-xylose from Cotton Stalk

[目的]为了从廉价、丰富的棉杆中制备高纯度木糖。[方法]通过单因素多水平试验和正交试验,考察了影响半纤维素水解的因素。[结果]各因素的影响大小依次为:水解温度>硫酸浓度>水解时间≈固液比例;水解的最佳条件为:140℃下水解2.5h,硫酸浓度为5%,固液比为1∶6。还原糖的产率达到了最大值19.79%。通过中和、脱色、离子交换和结晶等过程,得到纯度为98.5%的木糖晶体。分离过程中,木糖的产率为58.72%。木糖的最终产率为11.62%,即1000g棉杆可制到116.2g木糖。[结论]通过稀硫酸水解棉杆中的半纤维素,制备出纯度达到食品级的结晶D-木糖,为棉杆的转化利用找到一条途径。

[Objective] The research aimed to prepare high purity D-xylose with cheap and abundant cotton stalk. [Method] The variables influencing the hydrolysis of hemicelluloses were discussed by signal factor test and orthogonal test. [Result] The sequence of the variable＇s importance was temperature concentration of H2SO4 solution time ≈ ratio of raw materials to solution. The optical conditions were hydrdysis temperature of 140 ℃,sulfuric acid solution concentration of 5%,time of 2.5 hours and solid-liquid ratio of 1：6. The highest yield of reducing sugar was 19.79%. The high purity of 98.5% D-xylose was obtained through neutrality,decoloring,ion estranges and crystal processes,with the purity yield of 58.72%. The final yield of D-xylose was 11.62%,which meant 116.2 g D-xylose could be prepared from 1 000 g cotton stalk. [Conclusion] A method was proposed to utilize the hemicelluloses of cotton stalk via preparing high purity D-xylose.