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白腐菌漆酶特性及异生芳香化合物的降解 总被引：13，自引：0，他引：13
漆酶是一种含铜多酚氧化酶，在白腐菌中普遍存在。漆酶可催化酚类化合物和芳香胺的氧化，在小分子介体物质存在下，漆酶氧化范围可进一步扩大。本文对漆酶降解纺织染料、多环芳香化合物、氯化芳香化合物的机理及最新研究进展作一介绍。在纺织染料中，蒽醌类染料为漆酶底物，可被漆酶直接氧化，而偶氮染料和靛青染料为非酶底物。当小分子的还原介体存在下，可介导酶与非酮底物染料之间的氧化；漆酶对多环芳烃的氧化也多属于酶与非酶底物之间的氧化，因此，选择合适的介体物质非常重要；漆酶可氧化氯酚类物质形成自由基，然后形成低溶性聚合物，可通过沉淀去除，介体物质的存在也有助于氯化芳香化合物的降解。 相似文献
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以松香酸、亚油酸、油酸、β-谷甾醇、甾醇油酸酯分别作为纸浆中单一树脂的模拟物,采用一种产自黄孢原毛平革菌的漆酶对树脂模拟物进行降解,通过对比漆酶/介体体系的降解效率,筛选了该漆酶合适的介体,探讨了漆酶/介体体系对单一树脂模拟物的降解效果,研究了漆酶/介体体系降解亚油酸和油酸的动力学,并对漆酶降解亚油酸的工艺条件进行了优化。研究结果表明:1-羟基苯并三唑(HBT)是较为合适的介体;漆酶/HBT体系对松香酸、亚油酸、油酸、β-谷甾醇、甾醇油酸酯单一树脂模拟物均有较好的降解效果;漆酶/HBT体系处理亚油酸、油酸的米氏常数分别为1.38和1.86mmol/L,表明亚油酸更易与漆酶/HBT体系结合;该漆酶处理亚油酸的最佳工艺条件为酶用量2.0U/mg、1-羟基苯并三唑介体用量7.6mol/g、时间60min、温度50℃、pH值4.0,此条件下亚油酸的降解率为88.9%,当酶用量增加到4.0U/mg或者处理时间延长至120min时,亚油酸的降解率可达到100%。 相似文献
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利用生物酶（如漆酶）预处理可以降低化学浆的残余木素量,减少制浆中的能源消耗,提高纸浆强度特性和光泽度等。在介体参与下,漆酶能够降解木素,使残余木素的摩尔质量减少、木素中的酚羟基减少、羰基和羧基增加,对后续的漂白过程起到活化木素的作用。漆酶等酶活系统能将漂白废水中的有机氯化物转变成无机氯和CO2,破坏发色基团组织和结构,降低漂白废水中的TOCl、BOD、COD和色度。漆酶在氧气和介体存在下能使木素产生自由基的缩合,提高纤维间的粘合性,改善高木素含量和纸浆的性能。漆酶作为一种非专一型聚酚酶,在一定程度上可与树脂反应,可以催化好氧污染物的酚羟基基固,生成苯氧自由基和水。 相似文献
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以2,2'-联氮-双(3-乙基苯并噻唑啉-6-磺酸)二铵盐(ABTS)为介体测定漆酶活性,在最适pH为4、温度为40℃下测得比酶活为2 096.3 U/g。在此基础上,以漆酶和天然介体香草醛构建漆酶/介体系统(LMS)处理木质素,探究粒径和官能团变化,优化反应条件(时间、温度、pH和酶量)。结果表明:经LMS处理的木质素粒径可比对照组降低49.17%;在本试验条件下确定的优化工艺条件为反应时间3 h、pH3.5、温度35℃、酶量3 U/g,时间和pH值为主导因素;处理前后木质素的官能团种类未发生改变,但—OH、—CH_3、—CH_2—、—OCH_3等基团数量出现变化。相较于仅介体处理,LMS可更好地减小木质素粒径,同时更多地保留—OH、—OCH_3等活性基团。 相似文献
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漆酶催化氧化反应研究进展 总被引：38，自引：2，他引：38
总结了漆酶底物的结构特点。漆酶催化氧化反应机理主要表现在底物自由基的产生和漆酶分子中四个铜离子的协同作用。选择适当的底物和反应条件，可以提高漆酶催化氧化反应的选择性，展望了漆酶催化反应的工业应用前景。 相似文献
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漆酶催化活性中心结构及其特性研究进展 总被引：22，自引：3，他引：22
漆酶是一种多酚氧化酶，参与木质素的降解或聚合，具有氧化木质素的能力，但不同来源的漆酶其氧化降解木质素的能力相差很大。漆酶的结构决定了漆酶的特性，因而也就决定了漆酶氧化降解木质素的能力。本文综述了近10年来漆酶分子催化活性中心的结构与功能及其特性的研究进展。 相似文献
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白腐菌糙皮侧尔漆酶性质及其对蒽醌染料脱色性能的研究 总被引：11，自引：0，他引：11
白腐菌糙皮侧尔(Pleurotus ostreatus strain 3.42)分泌胞外漆酶，但未发现分泌木质素过氧化物酶(LiP)和锰过氧化物酶(MnP)、每升反应液以0．5mmol 2，2′-连氮-二(3-乙基苯并噻唑-6-磺酸)(ABTS)和0．1mmol的Cu^2 为诱导剂可明显提高漆酶酶活，酶活分别可达1000和800U／mL。与其它真菌漆酶相比，该酶最适反应pH值为3．5，在pH值4．0～6．0之间酶活性稳定；最适反应温度为65℃，在醋酸缓冲液(pH值5．0)中，反应温度低于50℃时，漆酶非常稳定；该酶对对-甲氧基酚的氧化速度要快于邻-甲氧基酚。叠氮化钠对该漆酶有强烈的抑制作用。蒽醌染料活性艳蓝KN-R(RBBR)可被该漆酶(30U／mL)直接脱色，12h脱色率为70％；添加小分子的介体物质ABTS(5μmol／L)，可使染料完全脱色。 相似文献
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Six aromatic compounds were isolated from the endophytic fungus Colletotrichum sp. of Cephalotaxus hainanensis Li [Cephalotaxus mannii Hook. f.]. Their structures were determined on the basis of chemical and spectroscopic methods. The compound 2 was the enantiomer of compound 1. The compound 4 was the epimeride of the compound 3. The compounds 1, 2, 4 and 5 were evaluated for cytostatic activity against HL-60 and PC-3 cells. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(3):234-240
Proanthocyanidins (PAs), which are common phenolic compounds in plants, are considered to be mainly defensive compounds against different kinds of stress, e.g. herbivory. In addition to increasing after stress, they may condense and/or oxidize to form coloured compounds when cells die, which may affect both the resistance of xylem to rot and its colour. This is important in the mechanical wood industry. The effects of some biological factors (growing site, sampling date, wood location in the trunk) on the concentration of soluble PAs (sPAs) were studied in fresh and dried birch wood. Those factors that affected sPA concentration most were sampling date and radial location. Drying method also had a great effect on the sPA concentration, which in turn correlated with the colour of the wood. 相似文献
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Lignin pyrolysis reactions 总被引：2，自引：0，他引：2
Haruo Kawamoto 《Journal of Wood Science》2017,63(2):117-132
Lignin, an aromatic constituent of woody biomass, is a potential renewable aromatic feedstock for a sustainable future carbon economy. Pyrolysis-based technologies, such as fast pyrolysis and gasification, are promising methods for converting lignin into biochemicals, biomaterials, and biofuels. A better understanding of the molecular mechanisms involved in lignin pyrolysis/gasification would guide the development of the controlled pyrolysis and gasification systems to overcome issues with low product selectivity, an intrinsic drawback of current pyrolysis-based technologies. This review article summaries the state-of-the-art research into molecular mechanisms of lignin pyrolysis and gasification. This information should also be useful for understanding the influence of high temperature heat treatments on the properties of wood. 相似文献
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Summary In this study a quantitative analysis of the low molecular carbohydrates (predominantly sucrose, fructose and glucose) in a series of lumber samples of Pinus sylvestris and Picea abies taken at various distances from the surface has been made. The increase of nitrogenous compounds towards the surface had been shown in a previous study. Several of the lumber samples showed a marked sugar accumulation at the surface, which correlated quite well with a corresponding nitrogen accumulation. In one case, the total amount of the three sugars was as high as 4.9% of the dry matter content in the 0–1 mm layer. It was of special interest to note that samples with high nitrogen and sugar contents also had a yellow surface colour, which probably formed during the drying process by the well-known Maillard reaction — a complex of reactions occurring when sugars and amino acids, peptides and proteins are heat-treated together. Growth of the mould fungus Penicillium brevicompactum was well correlated with the content of nitrogen and low molecular carbohydrates in adjacent samples. The initial colonization was somewhat delayed in material from the outermost sapwood zone despite high nutrient contents indicating effects of antifungal compounds from the bark or toxic Maillard reaction products effective against germination. Growth of Aspergillus versicolor was likewise most elaborate on samples with the highest nitrogen and soluble carbohydrate content but the results also indicate a sensitivity to antifungal compounds present.The authors thank Mrs. Gunnel Fransson for skillful technical assistence 相似文献
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研究阔叶树上的6种木材白腐菌火木层孔菌、粗毛盖菌、偏肿拟栓菌、三色革裥菌、冬拟多孔菌和血红密孔菌对山杨材腐朽前后木材中游离酚酸种类和含量的变化情况.结果表明:受6种白腐菌腐朽后的山杨木材中酚酸的种类和含量各不相同,在山杨材被分解120 d后,偏肿拟栓菌、三色革裥菌、血红密孔菌和冬拟多孔菌的9种游离酚酸总含量远大于粗毛盖菌和火木层孔菌的9种游离酚酸总含量,表明前4种对木质素分解能力较强的菌种获得了较高含量的酚酸;但从9种游离酚酸总的含量上看,与各菌种对木材和木质素的分解百分率不尽相同,初步分析的原因表明在木质素被分解的过程中除了有这9种游离酚酸产生以外,可能还会产生其他的游离酚酸以及苯环二聚体、三聚体和各种寡聚体以及杂环的形式,所有这些苯环结构总体造成了对木质素分解百分率的差异. 对9种酚酸进行分析测试,只构成对木质素分解的一部分,不足以用来解释对木质素的全部分解能力,其他的酚酸和游离酚酸以外的苯环结构还有待进一步研究分析测试;从各种游离酚酸单个含量上看,各种白腐菌的种类和含量都各不相同,表明不同白腐菌对同一木质纤维基质的分解途径、中间降解产物各不相同.另外,未腐朽的木材中本身就含有一些微量的酚酸成分,这些酚酸在生物分解过程中会降解和转化成其他成分, 是否有可能转化成其他种类的酚酸还有待进一步证明. 相似文献
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We investigated the reaction behavior of cellulose in an ionic liquid, 1-ethyl-3-methylimidazolium chloride ([C2mim][Cl]), which can dissolve cellulose. The cellulose samples were treated with [C2mim][Cl] at 100, 120 and 140 °C. At the beginning of the treatment, the solubilized cellulose in [C2mim][Cl] is depolymerized into various low molecular weight compounds such as cellobiose, cellobiosan, glucose, levoglucosan and 5-hydroxymethylfurfural. As the treatment continued, some of the low molecular weight compounds reacted with the ionic liquid to form new polymers, which were black and contained nitrogen. [C2mim][Cl] is, therefore, not only a solvent for cellulose, but also a reagent for both depolymerization to produce various low molecular weight compounds, and subsequent polymerization of those compounds. 相似文献
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天然木质素一般是由愈创木基、紫丁香基和对羟苯基3种基本结构单元通过不同的碳氧键、碳碳键等连接形成的复杂大分子聚合物。作为自然界中含量丰富的天然芳香类聚合物,木质素及其衍生物具有广阔的应用潜力。木质素中含有芳基、酚羟基、酮基以及羧基等官能团,赋予了木质素一定的抗氧化性与抗紫外辐射性能。研究证明,木质素无论在植物的生长发育还是后续利用中都展示出良好的抗紫外辐射能力。木质素作为一种天然的紫外线防护剂,其抗紫外辐射功能的开发与利用逐渐引起了研究者们的关注。笔者重点介绍了木质素抗紫外辐射性能在防晒产品中的研究进展及其应用现状,探讨了木质素的抗氧化性能对其抗紫外辐射性能的影响,并对当前研究中存在的问题进行了分析。最后,结合木质素结构特点,对其抗紫外辐射性能在防晒应用中的发展方向和前景进行了展望,为木质素高值化利用提供一定的参考。 相似文献
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Ultrastructural observations showed that the European race of Gremmeniella abietina var. abietina can secrete several cell wall–degrading enzymes that help the invasion of Pinus banksiana and P. contorta shoot tip tissues. Alterations in the content or distribution of cellulose were obvious, indicating that colonization might be achieved primarily through the action of glucanases. Polygalacturonases seemed more abundant in the cortex and the phloem of the stem, suggesting they are among the first enzymes secreted by the pathogen during infection. Production of laccases and peroxidases was also revealed but always close to fungal cells or in areas where host wall degradation was obvious. In places where there was an accumulation of phenolic compounds in the infected zones of the shoot, particularly in or near the transition zone, immunolocalization of both enzymes was limited or absent. Laccases and polygalacturonases were regularly detected over the extracellular sheath of G. abietina, and this indicates that the sheath could play a significant role during host wall degradation. Finally, examination of G. abietina wall constituents, such as chitin and β‐1,3‐glucans, suggests that the composition of the pathogen wall changes during the infection process. This change may be associated with the secretion of fungal enzymes but could also be linked to host reactions altering the integrity of pathogen cell walls. 相似文献
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A Sphaceloma species causing greyish‐white leaf spots of several Salix species is described and illustrated. This is the first record for Europe of the mitosporic fungus identified as Sphaceloma murrayae, which was formerly known to occur only in New Zealand, Argentina and the US. In addition to information on symptoms and hosts, similar fungi occurring on willow, which can be confused with the new fungus are also discussed. 相似文献