快速测定黑荆树栲胶单宁含量方法的研究

本文研究了用甲醛缩合法分析黑荆树栲胶单宁含量的可行性，讨论了栲胶中不溶物、非单宁酚类物质对测定结果的影响，并研究缩合产物的过滤方式与方法，从而确定一种简单、快速、分析结果准确、重现性好的黑荆树栲胶单宁分析方法。     

快速测定黑荆树栲胶单宁含量方法的研究

本文研究了用甲醛缩合法分析黑荆树栲胶单宁含量的可行性，讨论了栲胶中不溶物、非单宁酚类物质对测定结果的影响，并研究缩合产物的过滤方式与方法，从而确定一种简单，快速分析结果准确、重现性好的黑荆树栲胶单宁分析方法。     

新品种黑荆树栲胶在四川问世

被誉为世界王牌的黑荆树栲胶已在四川达县地区栲胶厂投入批量生产。原产澳大利亚的黑荆树速生树种,为常绿乔木,其树皮食单宁量高,列为当今世界优良的栲胶原料。八十年代初,四川达县地区的开江、达县等县的林业部门积极推广引种黑荆树的栽培技术,通过科学管理,现保存一定面积。近两年开始间伐采剥树皮,仅该地区开江县1992年剥皮交售量约70t。为开发栲胶新品     

芽孢杆菌应用于聚乳酸的降解及其降解条件的研究

采用液体培养法,将巨大芽孢杆菌、枯草芽孢杆菌和解淀粉芽孢杆菌应用于聚乳酸生物降解,探究降解过程中培养条件的改变,对蛋白酶活性以及薄膜降解过程的影响。结果表明：不同种类的诱导物能够提高芽孢杆菌的蛋白酶活性,巨大芽孢杆菌的最高蛋白酶活性约为23.79 U/mL,枯草芽孢杆菌的最高蛋白酶活性约为11.61 U/mL,解淀粉芽孢杆菌的最高蛋白酶活性约为21.23 U/mL。三种芽孢杆菌中,巨大芽孢杆菌对聚乳酸的生物降解影响最大。初始pH值为8.0,接种2%(V/V)种子液,1%酵母浸粉作为降解诱导物,可以有效加快巨大芽孢杆菌对聚乳酸的降解速率,5 d后降解率可达20.96%。薄膜表面存在菌生长,生物降解后出现轻微裂痕。     

江西黑荆树单宁胶粘剂压制胶合板的研究

用江西黑荆树栲胶进行了胶粘剂的制备和胶合工艺研究。试验证明，用８０％黑荆树栲胶和２０％苯酚制成的黑荆树胶粘剂，用于压制胶合板，其质量符合Ⅰ类胶合板国家标准。     

栲胶科技近期规划与长远设想

一、必须加速优质高产栲胶原料基地的规划和建设,开创我国栲胶工业新局面党的十二大提出要全面开创社会主义现代化建设的新局面,到2000年实现工农业总产直翻两番。栲胶战线怎么办?我们认为:应该依靠科学技术,在充分利用现有栲胶资源的同时,在南方一部分地区,积极建设以黑荆树为主的栲胶原料生产基地。使栲胶质量有个根本的改善。为了满足制革的需要外,栲胶产量应由现在的4万吨到1990年达到6万吨(其中黑荆树栲胶2万吨),2000年黑荆树栲胶增至4万吨。为此建议:在充分利     

江西黑荆树单宁胶粘剂压制胶合板的研究

用江西黑荆树栲胶进行了胶粘剂的制备和胶合工艺研究。试验证明，用８０％黑荆树栲胶和２０％苯酚制成的黑荆树胶粘剂，用于压制胶合板，其质量符合Ｉ类胶合板国家标准。     

人参内生多粘类芽孢杆菌对5种农药降解的影响

[目的]研究人参内生多粘类芽孢杆菌对5种农药氟啶胺、六六六、五氯硝基苯、毒死蜱、滴滴涕的降解作用。[方法]通过气相色谱法测定人参内生多粘类芽孢杆菌对5种农药的降解率,研究其对农药降解作用,并以田间试验方法验证其实际降解效果。[结果]人参内生多粘类芽孢杆菌接种7 d后对培养基中氟啶胺、六六六、五氯硝基苯、毒死蜱、滴滴涕降解率分别为94.77%、70.34%、77.92%、78.30%、66.70%;人参内生多粘类芽孢杆菌对田间栽培人参根中5种农药的降解率为66.07%、46.24%、21.05%、72.40%、54.21%;对田间栽培人参茎叶中5种农药的降解率分别为降解率为74.18%、55.61%、73.65%、58.13%、46.91%。[结论]人参内生多粘类芽孢杆菌具有同时降解人参中5种农药的作用。     

石油降解菌的筛选、鉴定及降解石油的初步研究

从被石油污染的土壤中分离得到一株石油降解菌O-D-1,通过形态、生理生化实验和16S rDNA序列分析对其进行了鉴定.结果表明,该菌的形态及生理特征与芽孢杆菌相似,芽孢杆菌的代表菌株B.anthracis、B.cereus、B.thuringienssi与该菌的同源性达99%.从系统发育树也可以看出,该菌与苏云金芽孢杆菌B.thuringiensis的距离最近,归属于芽孢杆菌属(Bacillus).通过对降解条件的研究,确定了降解菌O-D-1的最适生长条件为:初始pH值5、温度37℃、渗透压1%NaCl、辅助营养物质蛋白胨浓度4 g·L-1.     

树皮新鲜程度对黑荆树栲胶颜色的影响

利用新鲜树皮能够改善黑荆树栲胶的颜色 ,树皮越新鲜 ,生产出来的栲胶颜色越浅。通过脱色处理 ,能达到国外脱色栲胶颜色的要求     

Adsorption of Cu(II) from aqueous solutions by tannins immobilized on collagen

Novel adsorbents were prepared by immobilizing tannins on collagen fibre matrices. Their adsorption properties, including adsorption equilibrium, adsorption kinetics, and column adsorption kinetics to Cu(II) were investigated. Immobilized Myrica rubra tannin and black wattle tannin exhibited significantly higher adsorption capacity than larch tannin and the adsorption isotherms of these three immobilized tannins can be described by the Freundlich model. Detailed adsorption studies of immobilized black wattle tannin to Cu(II) indicated that temperature had little effect on the adsorption isotherms whereas the effect of pH was significant. Adsorption rate data fitted well to a pseudo‐second‐order rate model, and the adsorption capacity calculated by this model was consistent with the result of actual measurement at relatively higher adsorption temperatures. Immobilized black wattle tannin also had excellent column adsorption kinetic properties and high binding capacity. The adsorptivity of the column was stable even after repeated adsorption–desorption cycles. Copyright © 2004 Society of Chemical Industry     

黑荆树皮单宁不同级分的抑菌性能

通过对黑荆树皮单宁进行醇沉纯化 ,可以使单宁质量分数提高 1 0 %。在此基础上进行萃取分级 ,可得到相对分子质量分布范围不同的单宁级分。各级分的抑菌性能与其浓度和pH有关。根据最低抑菌浓度 (MIC)测试结果 ,黑荆树皮单宁各级分在适宜pH条件下的抑菌性能依次为 :乙酸乙酯级分 >乙醚级分 >纯化后单宁 >水级分 >未纯化单宁。各级分在 1 0g dL质量浓度下对所选霉菌和酵母菌无抑制作用。     

单宁紫外吸收特性及其在PVA薄膜中的应用

采用紫外可见分光光度计对单宁酸、橡梳单宁和黑荆树单宁等进行定性扫描,探讨了不同种类单宁的紫外吸收特性,并考察了不同种类单宁的混和物的紫外吸收特性。将单宁添加到聚乙烯醇树脂中制成薄膜,探讨了单宁的种类和添加量对聚乙烯醇薄膜的紫外吸收特性的影响。结果表明：聚乙烯醇薄膜的紫外吸收特性不仅与单宁的种类有关,还与单宁的添加量有关。随着聚乙烯醇薄膜中单宁含量的增加,其对紫外吸收的效果越好。     

Laminating wood adhesives by generation of resorcinol from tannin extracts

Resorcinol has been generated in situ by high levels of sulfitation of the tannin extract of the black wattle tree (Acacia mearnsii, formely mollissima). Consequently, weather and boil-proof tannin-based cold-setting adhesives for wood, satisfying the requirements of international standards, have been prepared and optimized by halving the amount of resorcinol chemical added to the tannin. Sulfitation afforded also considerable improvement of the “drying out” time characteristics of these adhesives.     

Stabilization of collagen by the plant polyphenolics Acacia mollissima and Terminalia chebula

The central role of collagen as the major structural fibrous protein in the mammalian extracellular matrix has motivated a significant effort toward the determination of its mechanical properties at all levels, ranging from single monomers and long‐chain polymers to a structural element within a biological tissue. However, the stabilization of collagen against collagenolytic degradation finds significance in biomedical and industrial applications. Tannins are plant‐derived polyphenols that have the ability to inhibit the collagenase activity at minimum concentration. The inhibitory effect of wattle (Acacia mollissima) and myrobalan (Terminalia chebula) on the action of collagenase against collagen was probed in this study. The kinetics of the inhibition of collagenase by wattle and myrobalan was deduced from the extent of hydrolysis of 2‐furanacryloyl–L ‐leucyl–glycyl–L ‐prolyl–L ‐alanine. Both wattle and myrobalan tannin exhibited competitive modes of inhibition against collagenase. Circular dichroism studies of collagenase on treatment with wattle and myrobalan revealed changes in the secondary structure of collagenase. These results suggest that the tannins of A. mollissima and T. chebula extracts facilitated collagen stabilization through collagenase inhibition. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Physico-mechanical properties of particleboards bonded with pine and wattle tannin-based adhesives

This study investigated the physical and mechanical properties of particleboards made using two types of tannin-based adhesives, wattle and pine, with three hardeners, paraformaldehyde, hexamethylenetetramine (hexamine) and TN (tris(hydroxyl)nitromethane), by measuring the physical (thickness swelling, linear expansion and water absorption) and mechanical properties (bending strength and internal bond strength). The performance of the particleboards made using tannin-based adhesives was influenced by physical conditions such as press time and temperature as well as by chemical conditions, such as the chemical structure of the tannin and the hardener. Wattle tannin-based adhesive being a thermoset, the wattle tannin-based particleboards were more influenced by physical conditions, while the pine tannin-based particleboards were influenced by the chemical structure of the pine tannin nuclei, which include phloroglucinolic A-rings. The reactivity of the hardener toward the tannin was in the order: paraformaldehyde > hexamine > TN for wattle tannin, while for pine tannin the order was hexamine > paraformaldehyde > TN.     

A new class of tannin adhesives for exterior particleboard

A new class of exterior and semi-exterior grade wattle tannin adhesives for particleboard is presented. Commercial formaldehyde concentrates containing uncondensed methylol ureas are used as hardeners-fortifiers of tannin-based adhesives. Moderate sulphitation of wattle extracts is also used to produce low cost tannin-based adhesives for exterior and semi-exterior particleboard.     

Recyclable plant tannin‐chelated Rh(III) complex catalysts for aqueous–organic biphasic hydrogenation of quinoline

BACKGROUND: Synthetic ligands have conventionally been used for the preparation of homogenous Rh complex catalyst but biomass has rarely been utilized for this purpose. In the present investigation, plant tannins (natural polyphenols) were used as water‐soluble ligands for the preparation of homogenous Rh³⁺ complex catalysts. RESULTS: Based on X‐ray photoelectron spectroscopy (XPS) and proton nuclear magnetic resonance (HNMR) analyses, the preparation mechanism of these complex catalysts was proven to involve chelating interactions between Rh³⁺ and the adjacent phenolic hydroxyls of plant tannins. As a result, the use of plant tannin promoted aqueous‐organic biphasic interactions and the plant tannin‐chelated Rh³⁺ complex catalysts exhibited much higher catalytic activity than commercial Rh complex catalysts in the biphasic hydrogenation of quinoline. Furthermore, the plant tannin‐chelated Rh³⁺ complex can be reused three times without significant loss of catalytic activity CONCLUSION: Our experimental results suggested that black wattle tannin (BWT) can be used as water‐soluble ligands for the preparation of highly active and recyclable Rh³⁺ complex catalysts. Copyright © 2012 Society of Chemical Industry     

Mechanism of viscosity variations during treatment of wattle tannins with hot NaOH

The mechanism causing viscosity decrease and subsequent viscosity increase of wattle tannin extract solutions under hot caustic soda treatment during the preparation of tannin-based adhesives for particleboard has been investigated. While the decrease of viscosity appears to be due, according to accepted theory, to hydrolysis of the hydrocolloid gums present in the extract, experiments with (+)-catechin as a tannin model compound indicate that the subsequent slow increase of viscosity of the solution, slow as related to the relatively small amount of alkali used, appears to be due to a tannin autocondensation reaction caused by cleavage of the etherocyclic rings of a certain of the tannins' flavonoid units.     

Inhibition of Cyanogenesis by tannins

During isolation of two biosynthetic types of cyanogenic glycosides fromCarica papaya, weak cyanide tests were obtained from initial fractions. Upon final purification, strongly positive cyanide tests were obtained. Pretreatment of extracts to remove polyphenolics alleviated inhibition of cyanogenesis, which led us to suspect that tannins were inhibitory agents. Qualitative and quantitative measures of inhibition were made using standard cyanogenic glycosides and polyphenolics. Cyanogenesis was inhibited quantitatively when condensed tannins (quebracho, wattle, and chestnut), or hydrolyzable tannin (tannic acid) were added. When tannins were precipitated from the reaction mixture, cyanide tests proceeded optimally. These results stress the need to interpret negative cyanide tests with care and indicate possible ecological synergisms between plant defensive chemicals.