本文關(guān)鍵詞： 毛竹 半纖維素提取 結(jié)構(gòu)分析 半纖維素利用 制備木糖　出處：《浙江農(nóng)林大學(xué)》2016年碩士論文　論文類型：學(xué)位論文

【摘要】：本論文以毛竹為原料,首先采用熱水抽提,60%乙醇沉淀,得到水提粗半纖維素。通過高效液相色譜技術(shù)(HPLC)研究發(fā)現(xiàn),其化學(xué)組成以葡萄糖為主,含有一定量的木糖和少量阿拉伯糖,且通過傅里葉變換紅外光譜技術(shù)(FT-IR)和核磁共振氫譜技術(shù)(1HNMR)的分析可知,水提粗半纖維素是一種含有葡聚糖和木聚糖等多糖的混合多糖。用DEAE-Cellulose-52柱層析純化,依次加入蒸餾水、梯度NaCl(0.1 M、0.3 M、0.5 M)和梯度NaOH(0.1 M、0.3 M、0.5 M)溶液對竹子水提粗半纖維素進行洗脫,得到5種半纖維素多糖組分,蒸餾水洗脫多糖再進一步經(jīng)Sephadex G-100柱層析純化,可得到兩種分離完全的半纖維素多糖。采用1%、3%、5%、10%和15%的NaOH溶液提取熱水抽提過的毛竹殘渣,再依次用15%、30%和60%的乙醇分級沉淀,得到15個半纖維素級分,采用HPLC、FT-IR和1HNMR技術(shù),對得到的半纖維素進行研究。結(jié)果顯示,半纖維素化學(xué)組成主要以木糖為主,還含有葡萄糖和少量阿拉伯糖。毛竹堿提半纖維素主要是以β-苷鍵連接木糖構(gòu)成主鏈,α-L-呋喃阿拉伯糖作為支鏈連接在主鏈木糖的C-3位上,并含有少量4-O-甲基-D-葡萄糖醛酸作為支鏈的木聚糖。以毛竹竹屑為原料,制備木糖。首先采用氨爆法預(yù)處理毛竹,氨爆后半纖維素保留了82.62%,得出氨爆預(yù)處理方法還是比較好的,可以作為一種保存半纖維素的預(yù)處理方法,但相同堿濃度提毛竹原料和氨爆后毛竹的半纖維素,氨爆后堿提半纖維素得率僅提高2.43%,從經(jīng)濟角度和設(shè)備安全方面考慮,直接用原料進行堿提半纖維素更好。在單因素的基礎(chǔ)上進行正交試驗得出堿提半纖維素的最優(yōu)條件是:溫度55℃,NaOH質(zhì)量分?jǐn)?shù)8%,固液比1:10,時間4h。NaOH質(zhì)量分?jǐn)?shù)是主要影響因素,其次為時間和溫度,固液比影響最小。進一步對半纖維素酸解制備木糖進行了正交試驗,得出半纖維素酸解的最佳條件為:溫度130℃,硫酸濃度0.25M,固液比2:100,時間1.5h,硫酸濃度是影響半纖維素酸解的主要因素,其次為時間和溫度,固液比影響最小。將酸解液進一步加工得純度較高的木糖晶體,得率達(dá)79.60%。
[Abstract]:In this paper, crude hemicellulose was obtained by extracting 60% ethanol from bamboo by hot water extraction. The chemical composition of crude hemicellulose was found to be mainly glucose by high performance liquid chromatography (HPLC). It contains a certain amount of xylose and a small amount of arabinose, and is analyzed by Fourier transform infrared spectroscopy (FTIR) and 1H NMR. Crude hemicellulose extracted by water is a mixed polysaccharide containing polysaccharides such as dextran and xylan. Purified by DEAE-Cellulose-52 column, distilled water was added successively, gradient NaCl(0.1 M0. 3 M0. 3 M0. 5 M) and gradient NaOH(0.1 M0. 3 M0. 3 M0. 5 M) solution were used to elucidate the crude hemicellulose extracted from bamboo water. Five kinds of hemicellulose polysaccharides were obtained, which were eluted by distilled water and further purified by Sephadex G-100 column chromatography. Two completely separated hemicellulose polysaccharides were obtained. 10% and 15% NaOH solutions were used to extract bamboo residue extracted by hot water. Fifteen hemicellulose fractions were obtained by fractionation of 15% and 60%% ethanol respectively. The hemicellulose components were studied by HPLC- FT-IR and 1H NMR techniques. The results showed that the chemical composition of hemicellulose was mainly xylose. It also contains glucose and a small amount of arabinose. The main chain of hemicellulose is composed of 尾 -glucoside bonds, and 偽 -L- furan arabinose is attached to the C-3 position of the main chain xylose as a branching chain. A small amount of 4-O- methyl-Dglucuronic acid was used as a branched xylan. Xylose was prepared from bamboo chips. Firstly, the pretreatment of bamboo by ammonia explosion was carried out. The hemicellulose retained 82.62% after ammonia explosion, and it was concluded that the method of ammonia-explosion pretreatment was better. It can be used as a pretreatment method to preserve hemicellulose. However, the yield of hemicellulose extracted from bamboo with the same alkali concentration and the hemicellulose of bamboo after ammonia explosion can only be increased by 2.43%, which is considered in terms of economic and equipment safety. It is better to directly use raw materials to extract hemicellulose by alkali. The optimum conditions for alkali extraction of hemicellulose are obtained by orthogonal experiment on the basis of single factor: temperature 55 鈩，

本文編號：1514347