Fractionation of Eucalyptus grandis chips by dilute acid-catalysed steam explosion
Fractionation of Eucalyptus grandis chips by dilute acid-catalysed steam explosion
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DOI：
10.1016/s0960-8524(02)00165-7
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发表时间：
2003-01-01
影响因子：
11.4
通讯作者：
Ramos, LP
中科院分区：
文献类型：
--
作者：
Emmel, A;Mathias, AL;Ramos, LP
将木片用 0.087 和 0.175% (w/w) H2SO4 浸渍后，在各种预处理条件（200-210 ℃，2-5 分钟）下对巨桉进行蒸汽爆破。这项研究采用 21 因子设计，表明预处理温度是影响蒸汽处理馏分收率的最关键变量。在 210℃ 下预处理 0.175% (w/w) H2SO4 浸渍的木片 2 分钟是水溶性部分中半纤维素回收（主要为木糖）的最佳条件，几乎达到相应木糖理论产量的 70%。相比之下，200 摄氏度的较低预处理温度足以产生蒸汽处理的底物，使用低酶负载量的 Celluclast 1.5 1 加 Novozym 188 混合物（诺和诺德），在 48 小时内获得 90% 的纤维素转化率。通过紫外光谱监测水溶性发色团的释放，其浓度随着预处理强度的增加而增加。在较高水平的酸浸渍和预处理温度下，碱溶性木质素的产量增加。这些木质素级分的热分析表明木质素碎裂的模式朝向更高的预处理强度，但在最剧烈的预处理条件下木质素缩合占主导地位。 (C) 2002 Elsevier Science Ltd. 保留所有权利。
Steam explosion of Eucalyptus grandis has been carried out under various pretreatment conditions (200-210 degreesC, 2-5 min) after impregnation of the wood chips with 0.087 and 0.175% (w/w) H2SO4. This study, arranged as a 21 factorial design, indicated that pretreatment temperature is the most critical variable affecting the yield of steam-treated fractions. Pretreatment of 0.175% (w/w) H2SO4-impregnated chips at 210 degreesC for 2 min was the best condition for hemicellulose recovery (mostly as xylose) in the water soluble fraction, reaching almost 70% of the corresponding xylose theoretical yield. By contrast, lower pretreatment temperatures of 200 degreesC were enough to yield steam-treated substrates from which a 90% cellulose conversion was obtained in 48 h, using low enzyme loadings of a Celluclast 1.5 1 plus Novozym 188 mixture (Novo Nordisk). Release of water-soluble chromophores was monitored by U-v spectroscopy and their concentration increased with pretreatment severity. The yield of alkali-soluble lignin increased at higher levels of acid impregnation and pretreatment temperatures. Thermoanalysis of these lignin fractions indicated a pattern of lignin fragmentation towards greater pretreatment severities but lignin condensation prevailed at the most drastic pretreatment conditions. (C) 2002 Elsevier Science Ltd. All rights reserved.