用木质素原料制乙醇

国内外专家对木质纤维素原料转化为乙醇燃料进行了大量的研究。木质纤维素转化为乙醇的步骤主要分为两步：纤维素水解成糖,糖发酵成醇。由于木质纤维素结构复杂,纤维素、半纤维素不但被木质素包裹,而且半纤维素部分共价和木质素结合,纤维素具有高度有序晶体结构．因此必须经过预处理,使得纤维素、半纤维素、木质素分离开,切断它们的氢键,破坏晶体结构,降低聚合度,以提高水解效率。     

造纸污泥中纤维素分离提取

造纸污泥中一般含有20%~70%的碳水化合物,主要成分中含有为纤维素、半纤维素和木质素。本文采用传统亚氯酸钠法分离脱除木质素,采用碱处理法分离纤维素和半纤维素。并对分离提取的纤维素和脱除的木质素分别进行红外表征。     

半纤维素含量对纸浆性能的影响

APMP浆是一种重要的高得率浆，除纤维素外，其中还保留了大量的木质素和半纤维素。人们已经较全面地研究了木质素对纸浆的影响，主要集中于卡伯值、白度和返黄值，而针对半纤维素对纸浆性能的研究甚少。     

汉麻和槿麻湿整理后的理化性能

研究了槿麻^＊和汉麻^＊＊两种纤维的物理化学性能。进行湿整理的方法有：碱处理、双氧水漂白及其两者的组合。在处理前后，测定木质素和半纤维素的成分、束纤维的强力、伸长率及阿潮率。用气相色谱仪对木质素的成分加以探讨；用分析法确定半纤维素的成分。经弱碱及双氧水处理后，两者都能从纤维上祛除部分木质素和半纤维素。经过处理的及未经处理的槿麻，其所含的木质素和半纤维素均分别高于经过处理的及未经处理的汉麻。漂白处理会破坏纤维的某砦内部结构，致使纤维的强力和伸长率减小。与之相反的是：碱处理纯清了原纤维结构，而且未见对纤维束强度产生显著影响。     

稻壳中纤维素、半纤维素和木质素的测定

阐述了几种不同的测定稻壳中纤维素、半纤维素和木质素含量的方法。最终选定测定稻壳中纤维素、半纤维素和木质素含量的方法分别为72％浓硫酸水解法、2mol／L盐酸水解法和浓硫酸法。结果测得纤维素、半纤维素、木质素含量分别为21．9％、19．0％、17．8％。     

苹果渣中纤维素、半纤维素的提取分离

苹果渣不溶性膳食纤维的主要成分为纤维素、半纤维素、木质素.分别采取甲酸、乙酸、硝酸、硫酸、传统次氯酸钠法及超声波辅助法去除木质素,采用碱处理法分离提取纤维素和半纤维素.     

木质纤维素的预处理及应用

木质纤维素主要包括纤维素、半纤维素、木质素3大类,本文对木质纤维素的各种组分结构作了系统综述。概述了纤维素类物质的预处理方法,主要包括物理法、化学法、生物法,并比较了几种方法的优劣点。介绍了木质纤维素实际生产运用的6个实例：木质素制备乙醇、乳酸、二甲醚,半纤维索类物质制备木糖醇,纤维素基重金属离子吸附材料,纳米纤维素晶须在纳米材料中的应用。     

低共熔溶剂选择性溶解木质纤维原料的研究进展

综述了近年来低共熔溶剂（DES）在木质纤维原料预处理过程中选择性溶解木质素、纤维素和半纤维素的相关研究进展,分析了DES类型、组成和处理条件对木质素、半纤维素及纤维素的选择性溶解差异,总结了DES溶解木质纤维原料过程的规律和机理,为高效预处理木质纤维原料的新型绿色DES的理论设计提供依据。     

利用纤维素作物生产乙醇预处理技术

纤维素作物中的纤维素、半纤维素、木质素紧密结合在一起,经预处理后可以水解半纤维素和纤维素,并破坏木质素,增大物质与酵母的接触面积,从而增大乙醇产量.总结了目前较有成效的预处理技术,并对其进行了比较,指出了未来发展的方向.     

甘肃大麻纤维组分的测定分析

大麻纤维的组分有纤维素、半纤维素、木质素、果胶、脂蜡及灰分等,其组分的定量分析采用GB 5889-86(质量法)比较繁琐,采用质量法(半纤维素、木质素、脂蜡、灰分)和容量法(纤维素、果胶)结合分析更简单、准确.     

白腐菌对稻草秸秆中木质纤维素降解规律的研究

通过对傅里叶变换红外光谱(FTIR)谱图的分析和木质纤维素组分含量变化的测定,研究了3株白腐菌在50天培养期内降解稻草中木质纤维素的规律。结果表明,3株白腐菌对稻草秸秆中木质纤维素的降解具有一定的顺序和选择性,先降解半纤维素和木质素,再同时降解半纤维素、纤维素和木质素。从降解比例来看,白腐菌对半纤维素和木质素具有很好的降解优势,对半纤维素有较好的降解选择性。     

嗜碱性木素降解菌降解能力的初步研究

通过比较不同嗜碱细菌对麦草中木素、纤维素和半纤维素的降解率, 并比较不同菌株的产酶及酶活情况, 筛选出了木素降解能力较强, 而纤维素和半纤维素降解能力相对较弱的嗜碱性木素降解菌。在ｐＨ≈１０－４的条件下培养８ｄ 后, 菌株６ 降解了３２－３７％ 的麦草木素, 而纤维素和半纤维素分别降解了２１－４８％ 和２２－６９％ 。这与其产酶情况基本一致, 该菌株的酶活最高, 分别为ＭｎＰ２７１－３０Ｕ／Ｌ和ＬｉＰ４１－９４Ｕ／Ｌ。     

Chemical composition of some forages and various residues from feeding value determinations

NDF, ADF, ‘cellulose’ and IVOMD residues, from feeding value determinations, were prepared from some forages, including straw, alkali-treated straw, grass and lucerne samples. The crude protein, cellulose, hemicellulose, uronic acid, Klason lignin, lignin and ash contents of these residues and the corresponding original forage samples were determined together with the relative composition of the neutral sugar constituents after acid hydrolysis. Cellulose, hemicellulose and Klason lignin were the main components in the NDF fractions but substantial amounts of crude protein (1–6%) also remained. Cellulose and Klason lignin were the main components in the ADF fractions, but 7–14% of the fractions was hemicellulose and 1–4% crude protein. Cellulose was the main component in the ‘cellulose’ fractions, but they also contained 8–13% hemicellulose, 2–7% Klason lignin and 2–11% ash. The composition of the IVOMD residues showed that cellulose and hemicellulose had been dissolved to about the same amounts (70–80%) and that most of the Klason lignin remained.     

纤维化学组分变化对纸张物理强度的影响研究

对半纤维素和木素在非木材纤维的纸张抄造过程中的作用进行了阐述,指出了脱除和保留一定量的半纤维素和木素对纸张物理强度和纸页性能的影响。     

Properties of lignin extracted from sugarcane bagasse and its efficacy in maintaining postharvest quality of limes during storage

Lignin extracts from sugarcane bagasse by alkaline extraction in the presence and absence of ethanol were investigated for their efficacy on maintaining fresh fruit shelf life. For lignin extraction, the highest lignin yield was obtained from 40% (w/w) NaOH extraction in water. Addition of ethanol gave relatively lower yield of lignin but less hemicellulose contamination. FT-IR intensity of lignin-to-carbohydrate transmittance ratios of extracted lignin from 40% (w/w) NaOH in distilled water were similar to the ratios of lignin standard from Kraft process. From gel permeation chromatography (GPC), lignin isolated from 40% (w/w) NaOH in distilled water yielded high amount of both large and small molecules of lignin. The weight loss ratio between lignin and hemicellulose was analyzed by thermogravimetric analysis (TGA). It was confirmed that isolated lignin from 40% (w/w) NaOH in distilled water contained highest amount of hemicellulose in lignin extract. The test of coating formulas on limes demonstrated that coating solutions of 0.8% (w/w) xanthan gum and 1.5% (w/w) extracted lignin from 40% (w/w) NaOH had potential to maintain weight loss and color change. This coating formula also exhibited higher antifungal activities. Limes coated with extracted lignin showed higher antifungal activity than limes coated with commercial lignin.     

Cellulose, Hemicellulose and Lignin Content of Raw and Cooked Processed Vegetables

The NDF, ADF, cellulose, hemicellulose and lignin contents of five frozen vegetables (raw and boiled) and five canned vegetables (two of them fried) have been studied. In general, it was observed that boiling resulted in an increase in the NDF, ADF and cellulose content. There was also a slight increase in hemicellulose values. The lignin contents of most vegetables did not change upon boiling. When the cooking process was frying, a drastic decrease of NDF, ADF, cellulose, and lignin contents occurred, while the amount of hemicellulose changed slightly in the vegetables analyzed.     

NaOH/尿素低温溶解法测定烟梗木质素含量的研究

建立了一种准确测定烟梗木质素含量的新方法。用低温NaOH/尿素水溶液抽提烟梗,采用优化的酸处理条件（硫酸浓度17.5 %、液固比80 mL?g-1、酸解温度100 ℃、酸解时间30 min）打断烟梗中木质素与纤维素等组份之间的化学键,残渣用低温NaOH/尿素水溶液进一步溶解纤维素、半纤维素等天然高分子物质,得到酸不溶木质素。酸溶木质素采用分光光度法在325 nm处测定,酸不溶木质素采用灼烧法测定。本方法RSD小于3%,准确度良好,且减少了有机溶剂预处理和浓硫酸处理,提高了测试的安全性。      

Extraction, Purification, and Applications of Hemicellulose

In addition to cellulose and lignin, hemicellulose is an important biomass material. Recently, hemicellulose and its derivatives and materials have attracted increasing attention owing to their unique structures, improved properties, and promising application potential, and many reports on the extraction, isolation, and modification of hemicellulose are currently available. We summarized the recent developments of hemicellulose and its derivatives and materials by focusing on the extraction, purification, and modification of hemicellulose. The synthesis of hemicellulose-based derivatives and materials was also reviewed. Various methods of extracting, isolating, and modifying hemicellulose were discussed. Remaining challenges related to hemicellulose extraction, purification, and application were mentioned, and directions for further research on hemicellulose were proposed.     

氢醌化合物对针叶木硫酸盐纸浆氧脱木素的影响

研究了具有氧化还原性的氢醌类化合物作为氧脱木素过程的添加物.结果表明,氢醌的加入可以降低纸浆的卡伯值,提高氧脱木素的选择性.其原因是氢醌的存在可以提高O2转化成为含氧的活性反应产物,加速木素中甲氧基的脱除,有利于破坏木素的结构和脱除木素.     

稳压时间对大麻韧皮纤维闪爆脱胶效果的影响

为提高大麻纤维的脱胶效果,采用先进的闪爆脱胶技术,对大麻韧皮纤维进行闪爆脱胶实验。针对大麻韧皮纤维在闪爆脱胶过程中,稳压时间对纤维分裂度的提高,对果胶、半纤维素、木质素的去除效果进行了研究与探讨。实验结果表明:适当延长稳压时间,对提高大麻纤维的分裂度,降低大麻纤维中果胶、半纤维素、木质素的含量等都有较为明显的效果。