Comparative study of alkaline extraction process of hemicelluloses from pear pomace
Comparative study of alkaline extraction process of hemicelluloses from pear pomace
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DOI：
10.1016/j.biombioe.2013.12.022
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发表时间：
2014-02
影响因子：
6
通讯作者：
H. Rabetafika;Brahim Bchir;C. Blecker;M. Paquot;B. Wathelet
中科院分区：
文献类型：
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作者：
H. Rabetafika;Brahim Bchir;C. Blecker;M. Paquot;B. Wathelet
以梨渣为原料，采用直接碱抽提(氢氧化钠和过氧化氢)和脱木素两步法(酸化亚氯酸钠/氢氧化钠)提取半纤维素。采用体积排阻色谱、傅里叶变换红外光谱和热重分析比较了分离半纤维素的萃取率、组成和理化性质。对固体残留物进行了分析，以评估工艺对副产品(木质素和纤维素)的影响。在直接碱性过氧化氢和两步酸化亚氯酸钠/氢氧化钠工艺中，原料脱木素(木质素高达995.4 mg/kg−1)可使半纤维素的得率提高到945.3 g/kg−1。半纤维素主要由木聚糖组成(木糖/葡萄糖比为4.6~16.2)，木质素含量低(53.5~61.0 g/kg−1干物质)。直接氢氧化钠提取的木聚糖和葡聚糖(木糖/葡萄糖比为1.5)含有较高的木素含量(149.3 g/kg−1干物质)。所有分离的馏分都是聚合物和低聚物的混合物，分子质量从1710g/−1到8/870000 mg/−1。两步法得到了最纯的纤维素残留物(799.2 mg/kg−1干物质)。结果表明，过氧化氢直接碱抽提法是从梨渣中提取纯富含木糖的半纤维素的一种有前途的工艺，可溶解802.2 mg/kg−1的原半纤维素，但会导致半纤维素的碎裂。
Hemicelluloses were produced from pear pomace using direct alkaline extraction (sodium hydroxide and hydrogen peroxide) and two-step extraction with delignification pre-treatment (acidified sodium chlorite/sodium hydroxide). The aim of the study was to compare the extraction yield, composition and physicochemical characteristics of isolated hemicelluloses by size exclusion chromatography, FTIR and thermogravimetric analyses. Solid residues were analysed in order to evaluate the effect of processes on co-products (lignins and cellulose). Delignification of material (up to 995.4 g kg−1of original lignins) during the direct alkaline hydrogen peroxide and two-step acidified sodium chlorite/sodium hydroxide processes improved the hemicellulose extraction yield attaining up to 945.3 g kg−1. Hemicelluloses were mainly composed of xylans (xylose/glucose ratio of 4.6–16.2) and had low lignin content (53.5–61.0 g kg−1dry matter). Those from direct sodium hydroxide extraction were composed of xylans and glucans (xylose/glucose ratio of 1.5) with high content of lignins (149.3 g kg−1dry matter). All isolated fractions were a mixture of polymers and oligomers with a molecular mass ranging from 1710 g mol−1to 8 870 000 g mol−1. The two-step process gave the most pure cellulose residue (799.2 g kg−1dry matter). According to results, the direct alkaline extraction with hydrogen peroxide was a promising process for the production of pure xylose-rich hemicelluloses from pear pomace solubilizing 802.2 g kg−1of the original hemicelluloses but induced fragmentation of hemicelluloses.