芦苇乙二醇法分离木素制浆研究

以芦苇为原料，在常压条件下利用乙二醇的水溶液提取分离木素、纤维素，采用4因子二次正交旋转组合设计研究了乙二醇、催化剂1、催化剂2和液固比对木素、纤维素分离的影响，得到了相应单指标二次回归模型；并对分离出来的木素做了定性分析。研究结果表明：乙二醇（55％）、催化剂1（50％）、催化剂2（4％）、液固比（6：1），得浆纯度较高，所得木素仍是由苯及其衍生物构成的大分子，分布范围较窄。     

三倍体毛白杨原料木素结构分析

采用酶-弱酸解两段法从三倍体毛白杨原料木粉中分离出原料木素。通过凝胶渗透色谱分析（GPc），对原料木素试样分别进行了分子量的检测，得出原料木素的分子量分布，计算出原料木素质均和数均分子量。经过衍生化后的原料木素，可以通过磷谱核磁共振（51P--NMR）技术得出原料木素结构谱图，对原料木素结构中脂肪羟基、总酚羟基和羧基以及总酚羟基中各酚羟基等功能基团进行定量分析对比。对三倍体毛白杨原料木素结构有了更全面了解。     

芦苇乙醇法分离木素制浆研究(Ⅰ)

以芦苇为原料,在常压条件下利用乙醇的水溶液提取分离木素、纤维素,采用三因子二次正交旋转组合设计研究了乙醇、催化剂和液固比对木素、纤维素分离的影响,得到了相应单指标二次回归模型;并对分离出来的木素做了定性分析.研究结果表明:在乙醇50%、催化剂6%和液固比8:1条件下,得浆纯度较高,所得木素仍是由苯丙烷及其衍生物构成的大分子,其分子量远大于一般碱木素,分布范围较窄.     

微波辅助提取油茶果壳木质素工艺优化

采用微波碱液提取法对油茶果壳木质素进行提取分离,以探寻油茶果壳木质素最佳提取工艺。采用单因素试验和正交试验法研究碱浓度、料液比、微波射功率、微波时间对木质素提取效果的影响,并对所提取木质素进行红外和紫外光谱分析。确定最佳提取工艺条件为碱浓度0.7mol/L、料液比1:70(g/mL)、微波功率和时间分别为550W和60min,在此条件下油茶果壳木质素得率达到11.45%;紫外图谱和红外图谱显示该方法提取的木质素保持了木质素的原有结构。优化油茶果壳木质素的最佳提取工艺,对木质素的工业化生产以及油茶的综合开发利用具有重要意义。     

三倍体毛白杨KP法蒸煮中木素结构的变化

以三倍体毛白杨为研究对象,进行了常规硫酸盐法蒸煮。采用酶-弱酸解两段法分别从原料和KP纸浆中分离出原料木素和纸浆残余木素。采用酸析法从KP蒸煮黑液中分离出溶出木素样品,经过弱酸水解得到纯木素试样。通过凝胶渗透色谱分析(GPC),对所有试样分别进行了分子质量的检测,得出各种木素样品的分子质量及其分布,分析了木素溶出过程中的分子质量的变化。通过磷谱核磁共振31P-NMR技术得出木素结构谱图,对原料木素、纸浆残余木素和黑液溶出木素结构中各官能团进行了定量分析对比,研究了木素结构在KP蒸煮过程中的变化规律。     

乙醇法制浆木素吸附现象与卡伯值的关系

针对乙醇法制浆研究过程中发现的乙醇法纸浆卡伯值高却易于漂白及难以制取低卡伯值的乙醇法纸浆问题，研究了洗涤温度、洗涤段数及蒸煮操作对乙醇法制浆的影响，分析了乙醇法浆卡伯值高的原因，并采用纸浆筛分的方法初步证明了乙醇法制浆过程中存在显著的木素二次吸附现象。     

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.     

麦草NaOH-AQ法蒸煮中溶出木素结构的变化

采用酸析-弱酸解两段法对麦草NaOH-AQ蒸煮中溶出木素进行分离和提纯,得到木素试样,通过凝胶渗透色谱分析(GPC),得出木素样品的平均分子质量及分布,分析了木素在溶出过程中分子质量的变化。采用红外光谱(FT-IR)对蒸煮各个阶段中溶出木素的结构进行了分析。经过乙酰化后的木素试样,可以通过磷谱核磁共振(31P-NMR)技术得出木素结构谱图,对木素结构中脂肪羟基、羧基和总酚羟基以及总酚羟基中各酚羟基等功能基团进行定量分析对比,得出了溶出木素在NaOH-AQ法蒸煮过程中的变化规律。     

三倍体毛白杨KP纸浆TCF漂白中木素结构的变化

对三倍体毛白杨KP纸浆进行了OQP全无氯漂白,漂白后纸浆白度达到82%ISO。采用酶-弱酸解两段法分别从KP纸浆、氧脱木素后KP纸浆和过氧化氢漂白后KP纸浆中分离纸浆残余木素。通过凝胶渗透色谱（GPC）对以上木素试样分别进行检测,得出各木素样品的平均相对分子质量及其分布,总结了OQP漂白中相对分子质量的变化规律。通过磷谱核磁共振31P-NMR技术分别得出木素谱图,对所有木素样品中各官能团进行了定量分析及对比,分析了木素结构在KP纸浆TCF漂白过程中的变化规律。     

乙醇胺循环法芦苇高纯木素分离研究

以浓度为60％乙醇胺的水溶液为溶剂循环蒸煮芦苇以分离木素，木素得率最高可达71．44％；利用凝胶色谱、红外光谱、紫外光谱研究了乙醇胺循环法对高纯木素分离的影响。结果表明：乙醇胺循环法分离木素重均分子量最高达6234．14，多分散系数在2～2．7之间，分子量范围分布较窄，且受循环次数的影响不显著。     

Pd/C催化下碱木质素与环己烯的还原反应

以钯/炭(Pd/C)为催化剂,以环己烯为氢给予体与麦秆碱木质素进行还原反应,分析了不同因素对反应过程的影响,通过正交实验优化了反应参数,用化学法对反应前后碱木质素官能团进行了定量测定,实验结果表明,最佳的Pd/C催化、环己烯还原法活化碱木质素的反应条件为:pH值10,催化剂质量分数7%,反应时间1.5h,碱木质素与环己烯质量比1:4.1,反应后碱木质素的总羟基含量为13.45%,增加了104.72%;羧基含量为1.60%,降低了39.39%;羰基2.96%,降低了50.99%.凝胶渗透色谱(GPC)分析表明,对于反应前后的碱木质素,其相对分子质量主要在1000～10000之间,所占比例分别为63.23%、84.66%,经Pd/C催化还原后碱木质素的多分散系数变小.     

A comparative study of hard and softwood lignins alterations during treatment in dioxane-water-HCl agent

The objective of the presented contribution was a study of the lignin alterations occurring in the process of the acidolytic delignification of chosen representatives of soft and hard wood species (maple and spruce) in dioxane-water-HCl mixture. All lignin samples were characterised by yield or recovery, molecular weights, as well as by GLC data of corresponding nitrobenzene oxidation products. In order to obtain more information about condensation and degradative reactions of lignin under conditions of acidolytic treatment a simulation of the process of lignin isolation was performed, too. Samples of dioxane lignins obtained after 90 min. of isolation at 82.5 and 98 °C were therefore recooked during 360 min. under identical conditions as applied in the lignin isolations. Concentrations of lignin in the reaction mixture were 1 and 10% thus approximately corresponding the lignin concentration inside and outside of the wood meal during the lignin isolation. The obtained experimental data point out the course of both degradative and condensation reactions. Maple wood lignin undergo deeper degradation than those of spruce under the same reaction conditions. The decreased yields of lignin oxidation products with the time of acidolytic treatment and after recooking hint at the formation of new linkages among building units of lignin thus modifying its macromolecules. The intensity of occurring alterations of examined lignins is not only dependent of time and temperature, but also of the concentration of lignin.     

Application of brown-rot basidiomycete Fomitopsis sp. IMER2 for biological treatment of black liquor

Acid-producing fungi can be used for the treatment of black liquor by biological acidification for the precipitation of alkali lignin. The effects of alkali lignin obtained from black liquor on the growth, acid-producing capacity and glucose consumption of a brown-rot fungus Fomitopsis sp. IMER2 were investigated and the changes in the functional group in the resulting alkali lignin were analyzed by Fourier transform infrared (FTIR) spectroscopy. Although the presence of alkali lignin inhibited fungal growth and acid production, it enhanced glucose consumption. This suggests that the physiological response of this fungus to stress induced by alkali lignin is unique. Furthermore, the analysis of the effects of the resulting alkali lignin on the growth rate showed that several functional groups were evidently improved for the use of available resources.     

经胆碱氨基酸水溶液预处理的水稻秸秆中残余木质素对多糖酶水解抑制作用的研究

本文通过考察牛血清蛋白(BSA)的添加量和不同纤维素酶用量下其添加与否对水稻秸秆残渣中多糖酶水解效率的影响,以及比较不同木质素含量的底物对纤维素酶催化行为的影响来探讨[胆碱][氨基酸]处理水稻秸秆残渣后其残留木质素对纤维素酶活性的抑制作用大小。结果发现,低酶量下,BSA的添加对纤维素和半纤维素的酶水解降解度有轻微的促进作用,分别最多提高5%及7%;而高纤维素酶用量时,其促进作用甚微。且经该类离子液体处理后的不同木质素含量的水稻秸秆基本上对酶蛋白皆无显著吸附和抑制作用。可见,该类离子液体可去除部分木质素以提高酶分子对多糖底物的可及性,此为多糖酶水解效率提高的关键因素,而该法所形成的残余木质素对酶蛋白的非特异吸附或抑制作用相对较弱。     

Study on Reuse of Coconut Fiber Chemical Retting Bath. Part II---Recovery and Characterization of Lignin

Study aimed at recovery of lignin from the reused residual liquor of chemical retting bath of coconut fiber caused by partial delignification to make it soft. The lignin of 8.9% was obtained after recovery (maintaining pH 2.0 for 1 h at ambient temperature) and further purification. Extracted lignin is characterized through FTIR, TGA and particle size analysis. FTIR showed absence of polysaccharides in purified lignin. TGA indicates presence of higher methyl-aryl ether groups than aromatic groups in lignin of coconut fibre. Analysis reveals about 91% of particles in the rage of 1–500 µm, which shows its good dispersiblity in fluid. Recovery of lignin associated with two benefits i.e., diversified use of extracted pure lignin and reduction of organic load of the waste liquor to make it suitable for discharge.     

In vivo determination of the caloric value of gum arabic in the male rat--biological data

Sprague-Dawley male rats were given normal diets (UAR A 03) containing various amounts of gum arabic, sucrose and lignin for eight consecutive weeks. The caloric values of the diets were derived by utilizing the indirect method comparing the slopes from food consumption and weight gain curves. While the data obtained from sucrose diets showed that these diets caused a clear incremental effect on energy production with respect to both test animals and controls, and data from lignin diets were found to produce a negative effect on energy yields, gum arabic diets produced results indicating that at certain levels of intake, gum arabic may contribute energy values slightly superior to those of lignin (0 cal-g), possibly between zero and 1 cal/g. However, it was not found possible to attribute a clear-cut quantitative caloric value to this additive from data obtained in this study.     

竹材及其磺化化机浆木素结构与发色基团特性研究

研究了白夹竹及其磺化化机浆ＭＷＬ的结构与发色基团的特性，并把两者进行了对比。从而了解了木素特性及其磺化预处理后的变化。由１３Ｃ－ＮＭＲ谱和硝基苯氧化证明，竹料木素是ＧＳＨ型木素。竹料制成浆后，木素的分子量有很大降低，对香豆酸酯含量下降。醌式结构是木素中最主要的发色基团，制成浆后醌式结构有很大的增加。     

麦草组分水热-乙醇两步法处理过程中木素在纤维表面的沉积形态

本课题通过研究水热-乙醇两步法对麦草组分分离效果的影响，采用场发射扫描电子显微镜、原子力显微镜和X光电子能谱研究了木素沉积形态的变化。结果表明，水热-乙醇两步法对半纤维素脱除率高达94.2%，但是其木素的脱除率仅为41.5%；这与木素在纤维表面发生了沉积这一现象有着密不可分的关系，水热处理后部分木素以颗粒状形式沉积在固相残余物表面，而这一部分沉积的木素并不能在乙醇法处理后溶解，第二步的乙醇法处理改变了沉积木素的形态，将颗粒状木素转变为包覆层吸附在纤维表面，导致了水热-乙醇两步法对木素的脱除率较低。     

Chemical and in vivo evaluation of a brown midrib mutant of Zea mays. II. Nuclear magnetic resonance spectra of digested and undigested alkali lignins and undigested dimethyformamide lignins

Nuclear magnetic resonance (n.m.r.) spectra were obtained on the alkali lignins extracted from Tr and bm₁ cornstalks, before and after digestion by sheep, and on the dimethylformamide lignins (DMFL) from undigested cornstalks. Differences due to solvent extraction, plant genotype and digestion were apparent. The bm¹ corn lignin has a higher degree of cross linking of the propane side chain of the lignin molecule than Tr corn lignin, a factor which may be significant in determining the effect of lignin on digestibility. The main effect of digestion was to increase the degree of cross-linking of the propane side chain, especially with the Tr lignin. Alkali lignin n.m.r. spectra were considerably different from DMFL n.m.r. spectra. For example over 40% of the total bm DMFL protons were highly shielded protons but these were virtually absent in the alkali lignins. These highly shielded protons cannot be explained by the presence of ferulic and p-coumaric acids in DMFL.     

Lignin accumulation and biosynthetic enzyme activities in relation to postharvest firmness of fresh waxy corn

Lignification and changes in the enzymes involved in lignin biosynthesis were investigated in relation to the reduced tenderness occurring during the postharvest storage of fresh waxy corn at 20 °C. The firmness of the corn and its lignin and polyphenol contents increased as storage time increased. The lignin content was significantly correlated (p < .05) with the polyphenol content and firmness. Phenylalanine ammonia‐lyase was not the rate‐limiting enzyme in polyphenol biosynthesis, whereas the cinnamate 4‐hydroxylase activity was significantly correlated (p < .05) with the polyphenol content. The activity of coenzyme A ligase (4CL) had a limited effect on the polyphenol content. Peroxidase was significantly correlated (p < .05) with the lignin content, while no significant (p > .05) effect of polyphenol oxidase or cinnamyl alcohol dehydrogenase (CAD) on the lignin content was observed.

Practical applications

Tenderness is a main factor in sensory quality of fresh waxy corn. Secondary cell wall lignifications induced by phenylpropanoid pathway is the main reason of tenderness decline for postharvest fresh waxy corn. But little information of lignin accumulation of fresh waxy corn is obtained from the present studies. Analyzing the changes of lignin and related precursor materials, enzyme activities will help to comprehensively understand the regulatory mechanism of postharvest lignification of fresh waxy corn, which can provide suitable methods to delay postharvest lignin accumulation, and maintain the eating quality of fresh waxy corn.