Decay of softwood in archaeological wooden artifacts

Hardwoods and softwoods were used side by side throughout Egyptian history, and importing softwoods that had an attractive color and texture was common. Over the decades, artifacts based on hardwoods and softwoods underwent deterioration phenomena, sometimes reaching either a level of brittleness or turning into a wood powder that may easily crumble. These levels of decay/degradation are often difficult to handle in terms of conservation treatments. To study or identify the reasons for decay has always been a point of interest for conservation purposes, but to assess decay and choose an appropriate treatment according to the state of preservation for the sake of keeping an artifact intact has become a subject of major importance. It is difficult at times to understand the deterioration process, because hardwoods and softwoods are different in structure, properties, and chemical composition. For this preliminary study, decayed samples from three commonly used softwood types, cypress (Cupressus sp.), cedar (Cedrus sp.), and pine (Pinus sp.), were identified and chosen. Scanning electron microscopy (SEM) of the samples indicated the degree of decay. Decayed and non-aged samples of the same wood type were analyzed using Fourier transform infrared spectroscopy (FTIR), and all the major carbohydrate and lignin bands were recorded. The strong hydrogen bonded (O–H) stretching absorption associated with water linked by hydrogen bonds to the –OH groups of cellulose and hemicelluloses in all decayed samples increased with decay. The brown powdery, fragile samples that had been evidently affected by microbial decay had a higher amount of lignin. The lignin/carbohydrate ratio was calculated and results compared. The increase of either lignin percentage or extractives in some of the samples had caused a darkening of color in both cypress and cedar samples, but the pine sample did not have the same texture and appearance. In cases where the lignin percentage decreased the samples had changed to a slightly lighter color. FTIR results explained the decay phenomena observed in SEM micrographs and helped assess wood decay and also confirmed results that had been previously obtained while applying traditional chemical analysis on wood.     

黄孢原毛平革菌胞外过氧化物酶系的固定化及性质研究

通过共价结合法将木素过氧化物酶(Lip)与锰过氧化物酶(Mnp)固定于聚氨酯泡沫上.固定化酶的Lip与Mnp活力分别为1.45 U/g(泡沫干重)和0.49 U/g(泡沫干重),酶活回收率分别达到34.79%和27.78%.固定化酶Lip和Mnp热稳定性提高,在温度达到50℃时酶活损失均少于20%.与游离酶相比,固定化酶稳定的pH范围前后都扩大了0.5个单位.固定化酶重复利用性好,连续使用6次,酶活力损失少于3%.     

Mapping of quantitative trait loci for fiber and lignin contents from an interspecific cross Oryza sativa×Oryza rufipogon

Rice straw is always regarded as a by-product of rice production, but it could be a significant energy source for ruminant animals. Knowledge of the genetic variation and genetic architecture of cell wall traits will facilitate rice breeders by improving relevant traits through selective breeding and genetic engineering. The common wild rice, Oryza rufipogon Griff., which is considered to be the progenitor of Oryza sativa, has been widely utilized for the identification of genes of agronomic importance for rice genetic improvement. In the present study, the mapping of quantitative trait loci (QTLs) for acid detergent fiber (ADF), neutral detergent fiber (NDF), acid detergent lignin (ADL), and ADL/NDF ratio was carried out in two environments using a backcrossed inbred line (BIL) population derived from a cross between the recurrent parent Xieqingzao B (XB) and an accession of Dongxiang wild rice (DWR). The results indicated that all four traits tested were continuously distributed among the BILs, but many BILs showed transgressive segregation. A total of 16 QTLs were identified for the four traits, but no QTLs were in common in two environments, suggesting that environment has dramatic effects on fiber and lignin syntheses. Compared to the QTL positions for grain yield-related traits, there were no unfavorable correlations between grain yield components and cell wall traits in this population. The QTLs identified in this study are useful for the development of dual-purpose rice varieties that are high in grain yield and are also high in straw quality.     

硫酸法测定花生壳中木质素的含量

利用硫酸法(即KLASON法)分析花生壳中木质素的含量.并探讨了酸的浓度、酸作用时间及温度、酸作用后的处理条件等测定因素对结果的影响.     

Hydrothermal production of formic and acetic acids from syringol

The production of formic and acetic acids （or salts） by hydrothermal oxidation of syringol, a model compound for lignin, was investigated using a batch reactor. Results show that the highest yields of formic and acetic acids were, respectively, 59.6% and 11.3% at the reaction condition of 0.5 mol/L NaOH, 120% H2O2 supply and 280 ℃. These results will inform studies aiming to develop more enviromnental friendly lignin conversion processes by obtaining products beyond a CO2 end product.     

生物质资源综合利用的方案(一)

用稻壳中可提取物提取黄酮类化合物、稻壳中含半纤维素水解制取木糖、稻壳中含纤维素水解发酵制取乙醇、用乙醇提取稻壳中木质素、剩余残渣制取纳米二氧化硅。所得产品质量符合标准,工业化生产可行,经济效益相当好。     

In vitro simulation studies of silica deposition induced by lignin from rice

To reveal the possible mechanism of silica deposition in higher plants, lignin was isolated from rice straw following a modified method to conduct a simulation experiment in vitro. UV and infrared absorption spectra showed that the substance had the unique characteristics of pure lignin. The presence of silicon in the precipitation was revealed by TEM （transmission electron microscopy） with EDXA （energy dispersive X-ray analysis） device. It was found that in the borax solution where lignin precipitation occurred silica-lignin co-precipitation was produced but not in the DMSO solution where lignin was broken into its composition compounds and did not precipitate. This means that it is macromolecular lignin itself but not its compounds that could induce silica deposition in higher plants.     

高沸醇木质素残留糖分的分析

采用DNS(3，5-二硝基水杨酸)比色法与直接滴定法测定高沸醇木质素中残留糖分的含量。这两种分析方法的可靠性通过测试已知残留糖含量的木质素磺酸钙试样得到证实。实验结果表明，上述两种方法所测得的同类高沸醇木质素中的含糖量基本相同。不同高沸醇木质素的含糖量分别为：松木木质素5．47％、杉木木质素4．10％、稻草木质素5．12％、芒秆木质素6．68％、花生壳木质素6．81％、麦秆木质素4．78％、毛竹木质素4．73％。     

木质素灰分测定

利用木质素灰分测定的方法,对高沸溶剂(HBS)法提取的木质素灰分与吉林独山子公司提供的木质素磺酸盐进行测定,结果表明本方法制备HBS木质素质量更好.     

高沸醇法(HBS法)制备稻草纸浆和木质素

采用1，4—丁二醇水溶液为溶剂的高沸醇溶剂法，从稻草中制备纤维素与木质素。在1，4—丁二醇水溶液中添加少量助剂、并在190℃—220℃条件下蒸煮1—3小时的方法制得纸浆和木质素。制得的纸浆可用于造纸。不溶于水的高沸醇(HBS)木质素则可以通过加水沉淀的方法，从反应后的液体混合物中分离。HBS木质素具有较高的反应活性，通过进一步改性，还有更多潜在的应用价值。回收的高沸醇溶剂，可作为制浆溶剂循环使用。