白腐菌对甘蔗渣木质纤维的降解及其影响因子(Ⅰ)--木聚糖对木质纤维不同组分降解的影响

在培养的过程中,加入木聚糖的白腐菌的生长明显优于空白对照样,白色的菌丝较早地覆盖在处理样品的表面;加入木聚糖,促进了木素的生物降解,大量的木素降解发生在培养的前期,而后期木素的降解量明显减少.木聚糖对酸溶木素含量变化没有明显的影响.木聚糖的加入使纤维素降解有所下降,但由于半纤维素含量较少,可以认为木聚糖的加入对半纤维素降解的影响很小.     

白腐菌对甘蔗渣木质纤维的降解及其影响因子（I）——木聚糖对木质纤维不同组分降解的影响

在培养的过程中，加入木聚糖的白腐菌的生长明显优于空白对照样，白色的菌丝较早地覆盖在处理样品的表面；加入木聚糖，促进了木素的生物降解，大量的木素降解发生在培养的前期，而后期木素的降解量明显减少。木聚糖对酸溶木素含量变化没有明显的影响。木聚糖的加入使纤维素降解有所下降，但由于半纤维素含量较少，可以认为木聚糖的加入对半纤维素降解的影响很小。     

生物制浆的技术难度以及木素降解酶的应用前景

本就生物制浆存在的技术难度和木素降解酶的应用前景进行了讨论，木素是造纸原料的主要成分之一，因为它是自然界光合植物的进化产物，所以木素对生物降解呈现出极大的屏蔽作用，而且木素降解酶的活力较低，另一方面，白腐菌所分泌的木素降解酶不但在大规模扩大生产中存在着技术上的困难，而且在生物制浆过程中不可避免地存在着纤维素降解，在造纸工业中，木素降解酶应用的研究主要包括生物机械制浆、生物漂白和漂白废水的生物处理。     

白腐菌对甘蔗渣木质纤维的降解及其影响因子(Ⅱ)--黎芦醇对木质纤维不同组分降解的影响

添加黎芦醇处理的蔗渣在培养期间失重增加,这种作用随着黎芦醇加入量的增加而增加,同时黎芦醇的加入量和木素的降解总量成正比,黎芦醇加入量越多,木素降解总量也相对越多,而且木素的降解也提前启动了.黎芦醇的加入对纤维素的降解几乎没有影响,对半纤维素降解的影响也不明显.     

木素降解酶在制浆漂白中的应用

木素降解酶的生物漂白是通过木素降解酶的直接氧化和降解纸浆中的残余木素,以降低纸浆的卡伯值,提高纸浆白度或有利于后续化学漂白剂的漂白,提高可漂性.本文着重介绍了三种木素降解酶在漂白中的应用.     

桉木CTMP法制浆过程中化学成分的变化

针对桉木的化学特性,用化学分析和光谱分析相结合的手段,对ＣＴＭＰ（热磨化学机械浆）制浆过程中桉木的化学组分（木素、多酚类物质、纤维素等）的含量及结构的变化进行了系统分析,结果表明：我国华南地区出产的桉木含有较多的多酚类化合物（ｋｉｎｏ）,但是大部分的多酚类化合物可以通过碱处理和热磨的协同作用来除去,成为化机浆废水的成分而排出,只有极少部分残留在纸浆中,从而避免多酚类化合物在高温下发生缩合并沉积在纤维表面而发生树脂障碍。桉木ＣＴＭＰ法制浆对于半纤维素和纤维素的影响较小,对木素的作用也主要是磺化改变其化学结构。桉木ＣＴＭＰ法制浆废液中有多酚类物质、木素和碳水化合物的降解产物等。     

漆酶的特性及其在制浆造纸工业中的应用

漆酶是一种多酚氧化酶,参与木素的降解或聚合,具有氧化木素的能力,在制浆造纸中的应用广泛.本文综述了近年来漆酶在制浆造纸工业中的应用研究进展.     

乙酸木素-TDI-PEG聚氨酯化纸张物理性能和表面结构的研究

以纸张和乙酸木素为主要原料合成乙酸木素-TDI-PEG聚氨酯化纸张,分析了其物理特性、表面形态及其机理.研究结果表明,该复合材料的纸张耐折度、耐破度和湿强度等物理指标有明显改善.其原因是木素-TDI-PEG体系能够与纸张中纤维素的羟基反应,生成氨基甲酸酯结构,通过电子显微镜观察发现,其不仅可在纤维之间起到架桥作用,还可以把木素与纤维素联结起来,形成木素-TDI-PEG-纤维素四元体系型聚氯酯复合材料.     

APMP法制浆过程中桉木的化学成分的变化

本文针对桉木的化学特性，用化学分析和光谱分析相结合的手段，对ＡＰＭＰ（碱性过氧化氢机械浆）制浆过程中桉木的化学组成（木素、多酚类物质、纤维素等）的含量及结构进行了系统性分析，结果表明：我国华南地区出产的桉木含有较多的多酚类化合物（Ｋｉｎｏ），但是大部分的多酚类化合物可以通过汽蒸—挤压预处理和碱性过氧化氢处理来除去，成为化机浆废水的成分而排出，只有极少部分残留在纸浆中，从而避免多酚类化合物在高温下发生缩合、沉积在纤维表面而发生树脂障碍。ＡＰＭＰ法制浆对于半纤维素和纤维素的影响比较小，对木素的作用也只是改变其化学结构。ＡＰＭＰ法制浆废液成分中有多酚类物质、木素和碳水化合物的降解产物等。     

工业木素应用中的挑战

现代生物质精炼的首要目标是将木质纤维素原料有效地转化为有价值的产品。目前木素的加工仍然面临挑战。大量木素被燃烧处理,只有极少部分木素用来生产高附加值产品。在木质纤维素精炼厂中,工业木素作为副产品被分离出来,如硫酸盐浆木素、烧碱法木素、有机溶剂木素、水解木素和木素磺酸盐。这些木素的结构有所改变,依据加工方法的不同而含有不同的杂质。工业木素的结构和组成对其应用造成了一定约束。文章探讨了工业木素在实际应用中的限制因素,分析了存在的主要问题,并提出了解决这些问题的方法。     

Lignin-based Hydrogels for Biological Application

Lignin is the most abundant aromatic compound found in nature. The rich functional groups of lignin are responsible for its antibacterial, antioxidant, anti-ultraviolet, and biocompatible properties. As modified lignin has a higher molecular weight, water solubility, and better surface activity, it is a good candidate for the construction of new biological materials. Lignin-based hydrogels are a type of functional materials with broad application prospects in the biomedical field. This review aimed to introduce the biological properties of lignin and the application of lignin-based hydrogels in the biological field.     

Lignin-derived phenols in Houston aerosols: implications for natural background sources

Solvent-extractable monomeric methoxyphenols in aerosol samples conventionally have been used to indicate the influence of biomass combustion. In addition, the presence of lignin oxidation products (LOP), derived from the CuO oxidation of vascular plant organic matter, can help trace the source and inputs of primary biological particles in aerosols. Ambient aerosols (coarse and fine) collected in Houston during summer 2010 were analyzed by gas chromatography-mass spectrometry to characterize monomeric and polymeric sources of LOPs. This is the first time polymeric forms of the LOPs have been characterized in ambient aerosols. The absence or small concentrations of solvent-extractable monomeric LOPs and levoglucosan isomers point to the limited influence of biomass burning during the sampling period. The trace levels of anhydrosugar concentrations most likely result from long-range transport. This observation is supported by the absence of co-occurring lignin monomers that undergo photochemical degradation during transport. The larger concentration (142 ng m(-3)) of lignin polymers in coarse aerosols shows the relative importance of primary biological aerosol particles, even in the urban atmosphere. The LOP parameters suggest a predominant influence from woody tissue of angiosperms, with minor influence from soft tissues, gymnosperms, and soil organic matter.     

木质素生物调控及其对制浆的影响

原料中木质素的种类、含量与组成不同,直接影响制浆的经济性和污染程度.若能利用生物技术(反义调控)的方法调控木质素在植物体内的合成过程及其合成量,制浆的第一道工序将移到林场、农田,会真正从源头上控制与减少污染物的产生.     

预水解液中木素去除方法的研究现状

去除预水解液中的木素符合生物质利用的要求,有利于木素和半纤维素的有效利用。本文简单阐述了预水解液中木素的结构与性质,重点介绍了预水解液中木素去除的不同方法,主要包括物理法(吸附法,冷冻法,树脂交换等),化学法(加入高分子、表面活性剂、PAC等),生物法(加入漆酶)及多种方法相结合(物理与化学法,物理与生物法,化学与生物法)的方法。通过对这些方法进行总结对比,提出多种方法相结合及生物法是今后研究的重点。     

Chemical and in vivo evaluation of a brown midrib mutant of Zea mays. I. Fibre, lignin and amino acid composition and digestibility for sheep

Two types of corn (maize) were used which were genetically identical except for a mutant gene (bm₁) in one which reduced the type and amount of lignin produced compared with the normal plant (Tr). The Tr plant appeared to have only slightly lower digestibilities of dry matter and fibre for sheep even though the protein contents of the cornstalks, normally less in the Tr, were equalised by supplementation with soya bean protein. Comparing the acid-detergent method of fibre and lignin determination with an acid-pepsin method revealed that the former method gave values considerably lower than the latter. The alkali—lignin contents of the bm₁ were higher than the acid—detergent lignins which must under-estimate the true lignin content. The acid—pepsin method gave fibre and lignin concentrations which were more closely correlated with rumen digestion of the diets as shown by dry matter loss of the diets suspended into the rumen in nylon bags. This technique also revealed there was a significant increase in the rate of rumen digestion after 69 to 74 h of incubation. Digestion of lignin on the Tr diet could be explained by loss of ferulic and p-coumaric acids. The reduced lignin and p-coumaric acid content of the bm corn was associated in young plants with a low phenylalanine content but normal tyrosine content suggesting that the genetic block in lignin synthesis in this plant may occur between prephenic acid and phenylalanine.     

采用LignoBoost技术从制浆黑液中高效萃取木素

木素是自然界重要的天然有机物，是制浆黑液中的重要组分，不断开发黑液中木素的应用，充分实现其价值最大化是造纸业界研发的重要内容之一。采用LignoBoost技术将制浆黑液中的木素萃取出来，转化为固体生物质，提高了黑液的回收效率和对木素的综合利用。本文主要介绍了LignoBoost技术的发展历程、工艺流程和商业化案例等。     

Characterization of asparagus lignin by HPLC

Lignin is the cell wall component most frequently associated with hardening. Its characterization and quantification are very important to understand the biochemical modifications related to the changes in texture of vegetables such as asparagus (Asparagus officinalis), in which this organoleptic attribute is a very important quality factor. In this study, asparagus lignin from the basal sections of fresh and stored spears was analyzed using 2 methods, the traditional (Klason lignin) and the recently developed derivatization, followed by reductive cleavage (DFRC) method. The latter is a simple and reproducible technique for lignin characterization based on a degradation procedure that produces analyzable monomers and dimers by cleaving alpha- and beta-aryl ethers in lignins. The primary monomers derived from DFRC degradation of lignins are essentially p-coumaryl peracetate, coniferyl peracetate, and sinapyl peracetate. To evaluate the efficiency of the DFRC method, our investigations have been carried on distinct sample types, including wood (data not shown), straw, and asparagus samples. The results have confirmed that lignin composition is affected by plant nature. It has been found that whereas wood samples mostly contain coniferyl units, plant foods, such as straw and asparagus, contain both coniferyl and guaiacyl units.     

Lignin Effect on Calcium Absorption in Rats

The effect of lignin on calcium absorption was studied in a rat model. Lignin preparations were isolated directly from wheat bran and from kale by two treatments, enzymatic and acidic. Calcium absorption in the presence or absence of isolated wheat bran lignin, isolated kale lignin, commercially available pine lignin, and wheat bran was determined by femur uptake of 45Ca. The fractional calcium absorption of wheat bran was significantly lower than for the control. However, there were no differences in calcium absorption between the various lignin sources and the control without lignin. Thus, lignin is probably not inhibitory to calcium absorption in plant foods.     

Determination of lignin in herbaceous plants by an improved acetyl bromide procedure

A modified acetyl bromide procedure is proposed for the spectrophotometric determination of lignin in herbaceous plants. The digestion with 25 % acetyl bromide (AcBr) in acetic acid at 70°C is improved by including 4 % perchloric acid in the digesting solutions. This allows for more rapid, complete digestion and the use of coarser samples. On the basis of infrared spectra and nitrobenzene oxidation data for milled sample lignins, the value of 20.0 g^?1 litre cm^?1 for the specific absorption coeficient of AcBr-treated lignins of herbaceous plant samples gave lignin values which were consistent with nitrobenzene oxidation data, but were higher than those obtained by the acid detergent lignin method and the earlier AcBr method proposed for grasses. The lower lignin values obtained in the latter methods are considered to be due to partial lignin solubilisation in the sulphuric acid digestion.     

Yield and composition of cell wall residues isolated from various feedstuffs used for non-ruminant farm animals

The contents of cell wall residue were measured in 14 common feedstuffs used for non-ruminant farm animals by utilising a technique involving pronase and α-amylase treatments. Comparison with the contents of neutral detergent fibre (NDF) revealed that the NDF procedure underestimated cell wall contents in the dicotyledonous plant materials. The losses of cell wall material due to the neutral detergent solution were correlated (r=0.931, P<0.01) with the amount of pectic substances present in the cell wall residues of the dicotyledonous plant materials. Cell wall residues were analysed for starch, crude protein, polysaccharides, condensed tannins, sulphuric acid lignin, acetyl bromide lignin, and ash. Condensed tannins in the cell wall residues of sorghum, rapeseed meal and field bean resulted in a large protein contamination (11.3–26.6%) of these residues and to an overestimation of their lignin content. Compositions of polysaccharides are discussed from chemical and nutritonal viewpoints.