Chemical conversion of various celluloses to glucose and its derivatives in supercritical water
Chemical conversion of various celluloses to glucose and its derivatives in supercritical water
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DOI：
10.1023/a:1009232508644
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发表时间：
1999-09-01
期刊：
影响因子：
5.7
通讯作者：
Ueno, T
中科院分区：
文献类型：
--
作者：
Saka, S;Ueno, T
本实验室自行设计开发了超临界水生物质转化系统。在锡槽温度为500℃、压力为35兆帕的条件下，用该体系在超临界水状态下(S 3~10~5)对装有纤维素样品的反应容器进行了指定时间的处理。对回收的水解物进行高效液相色谱分析。结果表明，经5-10 S超临界处理的纤维素I和纤维素II均能获得高含量的葡萄糖和左旋葡聚糖，而3-5 S超临界处理的纤维素I和纤维素II都能从淀粉中获得高含量的葡萄糖和左旋葡聚糖。尽管这种差异可能是由于纤维素和淀粉的分子结构不同造成的，但纤维素I和纤维素II之间的差异并不显著。相反，水对纤维素分子的可访问性似乎对它们的化学转化具有重要意义。随着处理时间的延长，观察到的这些化合物的数量由于分解而减少。因此，可以得出结论，与酸水解或酶糖化相比，超临界状态下，纤维素可以被或多或少地水解成葡萄糖及其衍生物，其程度与玉米淀粉中的相同。这一发现表明，超临界处理可以克服在酸解或酶糖化技术中将纤维素水解为葡萄糖的困难。
The supercritical water biomass conversion system was designed and developed in our laboratory. The reaction vessel with cellulose sample was treated with this system at supercritical state of water for a designated period (3-105 s) under the conditions of a tin bath temperature of 500 degrees C and pressure of 35 MPa. The recovered products of hydrolysates were then analyzed by high performance liquid chromatography. The obtained results indicated that a high amount of glucose and levoglucosan can be achieved from both celluloses I and II for 5-10 s supercritical treatment, while that from starch for 3-5 s treatment. Although this difference could be due to a difference in the molecular structure between cellulose and starch, a difference between celluloses I and II was not significant. Instead, an accessibility of the water towards cellulose molecules seemed to be significant for their chemical conversion. With the longer treatment, amounts of these compounds observed were decreased due to decomposition. Therefore, it may be concluded that, compared with acid hydrolysis or enzymatic saccharification, cellulose may be hydrolyzed to glucose and its derivatives more or less to the same degree as in corn starch under supercritical state. This finding suggests that the supercritical treatment can overcome the difficulties in hydrolyzing cellulose to glucose, found in the acid hydrolysis or enzymatic saccharification techniques.