Chemical characterization of wood and extractives of fast-growing Schizolobium parahyba and Pinus taeda

This study aims to evaluate the chemical composition of wood and extractives of Pinus taeda and Schizolobium parahyba (guapuruvu) as potential feedstock for new applications in the biorefinery industry. For this purpose, their content of α-cellulose, hemicellulose, insoluble lignin, hot water solubility, NaOH_1% solubility, inorganic materials (ash), and monomeric sugars by high-performance liquid chromatography was quantified. Attenuated total reflectance infrared spectroscopy and thermogravimetric analysis were also used to complete the physicochemical characterization of the studied woods. The extractives were obtained by soxhlet extraction with ethanol:toluene and dichloromethane and identified with pyrolysis-gas chromatography/mass spectroscopy technique. The results showed that guapuruvu wood has the higher amount of hemicellulose (16%) when compared to pine wood (10%), which resulted in higher solubility in alkali solution. Furthermore, in relation to other biomasses, the two woods presented more percentage of lignin and minor content of hemicelluloses. The P. taeda wood presented the highest percentage of extractives mainly composed of fatty acids and aromatic hydrocarbons, while guapuruvu wood had a higher percentage of phenolic compounds and also fatty acids. Both the materials have low content of extractives with dichloromethane and were mainly composed of lipophilic compounds.     

氧漂过程中脱木质素与木质素氧化之间定量关系的研究

对氧碱漂白过程中木质素氧化进行定量分析,分析方法是基于氧化前后高锰酸钾消耗量的变化。该方法对溶出残余木质素的氧化结果分析发现其呈明显3个阶段：第一段木质素氧化的当量电荷数约4～5／木质素单元;木质素总氧化电荷数大约为9／木质素单元。这些数据以及甲氧基的脱除（75％）均表明：木质素的氧化不仅发生在酚型木质素单元,同时也发生在非酚型结构单元上。只有第一阶段氧化反应是木质素与氧气直接反应,而在第二、三阶段主要是协同氧化作用,氧化反应过程中产生的活性氧基团扮演了一定角色。通过对低浓度针叶材硫酸盐浆的氧漂研究发现：当卡伯值下降一半（25．4至13．4）时平均每个木质素单元氧化3当量电子,氧漂后的纸浆中仍然有大量未被氧化的残余木质素。定量地证明了在氧漂过程中木质素氧化是脱木质素反应的实质。     

Discolouration of birch wood: analysis of extractives from discoloured surface of vacuum-dried European white birch (Betula pubescens) board

A discolouration that appeared on the surfaces of a European white birch (Betula pubescens) board during vacuum drying was studied by means of colour measurements (CIEL*a*b*), elemental analysis and the analysis of extractives. The discoloured surface layer of the dried board contained substantially more methanol-soluble extractives than did the light-coloured part (50.7 mg g⁻¹ vs. 26.7 mg g⁻¹ dry wood), and the colour difference (ΔE* _ab 20.0) between the two extracts was notable. Characterization by means of GC and ¹³C NMR spectroscopy showed that the extracts contain sugars (mainly glucose and fructose), low-molecular-weight phenolic compounds, proanthocyanidins, Brauns’ lignin and fatty acid esters. Concentrations of sugars, low-molecular-weight phenols, proanthocyanidins and Brauns’ lignin were higher in the discoloured surface layer than in the light-coloured part. The yellowness of the surface layer was associated with the accumulation of low-molecular-weight phenolic extractives, and the redness with Brauns’ lignin and possibly proanthocyanidins.     

Analysis on Chemical Composition of Guadua amplexifolia Planted in China

The objective of this study is to determine the properties of G. amplexifolia. In this paper; the chemical composition, including holocellulose, acid-insoluble lignin, 1% NaOH solubility, benzene-ethanol extractives and ash content, was considered for the variability with respect to positions along bamboo culm height （bottom, middle and top）, parts along radial direction （inner part and outer part）and ages （1-year and 2- year）. The test results were also compared to those of moso that is commonly planted and used in China. This study indicated that both the holocellulosecontent and the lignin content in inner part were lower than ; in outer part, but for extractives and ash content, the reverse was true. Bamboo age also had effect on chemical composition; both the holocellulose content and the ash content in the culm of 1- year were higher than those of 2-year; while the lignin content and the extractive content m the culm of 1- year were higher than those of 2-year. High holocellulose content, low lignin contentand extractive content were advantages of G. amplexifolia.     

Degradation of lipophilic wood extractive constituents in Pinus sylvestris by the white-rot fungi Bjerkandera sp. and Trametes versicolor

The white-rot fungi Trametes versicolor and Bjerkandera spp. are among the most frequent decomposers of angiosperm wood in forest ecosystems and in wood products in service. Wood extractives have a major impact on wood properties and wood utilization. This work evaluated the ability of two white-rot fungal strains (Bjerkandera sp. strain BOS55 and T. versicolor strain LaVec94-6) to degrade the main lipophilic extractive constituents in Scots pine (Pinus sylvestris L.). The time course of wood decay and wood extractive degradation was monitored in stationary batch assays incubated for eight weeks. The strains tested eliminated high levels of total resin, 34 to 51% in two weeks. Wood triglycerides were the most readily degraded extractive components (over 93% elimination in only two weeks). Free fatty acids and resin acids, which are potential fungal inhibitors, were also rapidly decomposed by the fungal strains. Sterols were used more slowly, nonetheless, the fungal degradation of this extractive fraction ranged from 50 to 88% after four weeks. Received 19 March 1999     

芍药种子含油率与脂肪酸成分研究

[目的]本文对芍药种子含油率、脂肪酸成分及含量进行了探讨,为芍药开发成油料植物提供参考。[方法]选取芍药36个栽培品种和1个野生居群为样本,采用索氏提取法提取种子油脂并测定含油率,用气相色谱—质谱联用仪(GC-MS)对提取的籽油成分进行分析。[结果]表明:芍药36个栽培品种和1个野生居群种子平均含油率为20.20%。芍药籽油主要含有豆蔻酸、棕榈酸、棕榈一烯酸、硬脂酸、油酸、亚油酸、亚麻酸和花生酸8种脂肪酸,其中,亚麻酸含量最高,平均达34.14%,其次为油酸和亚油酸,这3种不饱和脂肪酸的含量占全部脂肪酸的93.37%。芍药籽油脂肪酸含量变化相对稳定,各脂肪酸成分的变异系数从大到小依次为亚油酸(13.90%)油酸(13.51%)亚麻酸(10.71%)棕榈酸(0.18%)硬脂酸(0.09%)花生酸(0.002%)、棕榈一烯酸(0.002%)豆蔻酸(0.00%)。[结论]芍药种子含油率高,富含亚麻酸、亚油酸和油酸,且含量相对稳定,变异很小,具有开发为高含量亚麻酸食用油潜力。     

A mathematical model of kraft pulping related to the alkali concentration in the cooking liquor

Summary A new mathematical model for checking and controlling the kraft pulping process has been derived. The model is based on the modified relationship between the lignin content and the alkali concentration of a cooking liquor expressed as the ratio of lignin/active alkali vs. concentration of the active alkali in a cooking liquor. The derived model characterizes the variation of the lignin content of the partially delignified wood or pulp with the concentration of the residual alkali in a cooking liquor during an entire pulping cycle, i.e. during the initial, transition, bulk and residual phases of the kraft delignification. The relationship between the lignin content of the partially delignified wood ships or pulp and the concentration of the residual alkali in a cooking liquor is expressed by the logarithmic straight line equation or its power form. The slope and intercept constants of the derived equation for the individual phase of delignification have different values. Received 5 June 1996     

人工林米老排木材化学成分及其在树干高度上的变异

采用我国木材化学成分分析国家标准,对人工林米老排木材化学成分进行了测定和研究分析.结果表明:人工林米老排木材冷水抽提物含量和热水抽提物含量分别为2.67%和3.12%,1%NaOH抽提物含量为17.08%,纤维素含量为47.49%,综纤维素含量为80.42%,木素含量为28.80%,pH值为5.44;木材冷水抽提物和综纤维素含量在树干的不同高度上略有差异,但方差分析检验,差异不显著,热水抽提物、1%NaOH抽提物、纤维素和木素含量在树干的不同高度上差异显著,达到1%显著性水平;由树基往上,热水抽提物含量略呈两端高、中间低的趋势,冷水抽提物、1%NaOH抽提物和木素的含量逐渐降低,综纤维素含量和木材pH值逐渐升高;纤维素含量在树干上的分布规律为中间高、两端低,而且从树干中部往上的降低幅度较大.     

薄壁型巨龙竹秆材化学成分分析

巨龙竹是至目前为止所发现最粗的竹子,单株竹材生物量居同类竹材之首。对3-5年生薄壁型巨龙竹秆材不同部位的主要化学成分进行了测定,包括灰分、木素、综纤维素、多戊糖、冷水抽出物、热水抽出物、1%Na OH抽出物、乙醚抽出物、苯-醇抽出物。结果表明：薄壁型巨龙竹的木素、综纤维素、多戊糖的含量与常用纸浆造纸原料木材接近,灰分含量介于木材和草类原料之间;除冷水抽出物外,薄壁型巨龙竹其它抽出物含量在秆高方向上均表现出递增的分布规律。     

安徽地区华东野核桃果实特征和坚果品质的初步评价

[目的]探究华东野核桃果实性状、核仁成分及其相关性,为其资源的开发和综合利用提供依据。[方法]本研究以皖南华东野核桃资源为对象,测定其鲜果单果质量、果皮厚度与坚果单果质量、壳厚度、出仁率等果实性状及坚果核仁成分,分析其相关性。[结果]华东野核桃果实性状具有丰富的变异,大部分变异系数大于10%,其中,坚果壳厚度变异系数最大为43.92%。对坚果核仁成分的测定表明:核仁中脂肪含量最高,蛋白质次之,总糖含量较低;对脂肪组分的进一步分析可知,其不饱和脂肪酸含量较高,达92.68%。利用相关性分析,发现坚果单果质量与核仁脂肪含量呈显著正相关。利用主成分分析对华东野核桃果实性状及核仁成分的综合分析及评价发现,单株编号10和8的鲜果大小及不饱和脂肪酸含量在所受试单株中综合表现最好,可作为进一步育种的遗传资源。[结论]本研究首次报道华东野核桃果实核仁成分,发现其核仁脂肪酸含量高于薄壳山核桃、山核桃,且不饱和脂肪酸含量也高,表明其核仁是值得开发的一种新食品资源。该研究结果为华东野核桃资源的综合开发与利用提供了数据支持。     

Biodegradation of sugarcane bagasse with marine fungusPhlebia sp. MG-60

A marine fungus,Phlebia sp. MG-60, and three white-rot fungi were incubated with whole sugarcane bagasse (WSB). The residual lignin content and holocellulose content in the decayed WSB were determined, and based on their content delignification selection factors of the fungi were calculated. More than 50% of lignin in the WSB was degraded byPhlebia sp. MG-60, and less than 10% of the holocellulose was lost. The WSB was fractioned by sieving to separate long-fiber bagasse, shortfiber bagasse, and bagasse pith. WhenPhlebia sp. MG-60 was incubated with the three fractions, more efficient delignification activity on the bagasse pith was observed. As the most efficient utilization of bagasse, we predict that bagasse fiber might be employed as the raw material in the pulp and paper industry after biopulping withPhlebia sp. MG-60 and bagasse pith, or WSB might be used to produce animal feed after fermentation with the strain.     

A mid-IR multivariate analysis study on the gross calorific value in longleaf pine: impact on correlations with lignin and extractive contents

Twenty 70-year-old longleaf pine trees from a spacing, thinning, and pruning study were harvested, from which samples were analyzed for gross calorific value (GCV). A strong correlation was found between GCV and extractive contents for the unextracted wood samples. Although lignin content should impact GCV, no correlation was found between the variation in GCV with lignin content for the extractive-free wood samples. Mid-IR spectroscopy coupled with multivariate analysis provided strong correlations between the mid-IR-predicted and calorimetry-determined values for the unextracted wood samples. Plotting the regression coefficients for GCV and extractive contents showed that the same mid-IR bands were responsible for the strength of these models. Spectral differences were observed between the different extract samples, and relative peak intensities appeared to be dependent upon the extractive contents from the wood samples. Thus, models were also built based on the corresponding wood extractive contents using the actual extracts. These provided good correlations, suggesting a proportional change in extractive compositions coinciding with the total amount of extractives present in the unextracted wood samples.     

Lipophilic extractives in different tree fractions and forestry assortments of Pinus sylvestris due for thinning or final cutting

The objectives were to determine the content and composition of lipophilic extractives, particularly fatty and resin acids, in three Scots pine trees from each of two stands in northern Sweden, one that was due for thinning and one due for final cutting. Extractives content of branches, needles, barks, stem discs from branch whorls, and sapwood and heartwood samples from various heights was measured. Fractions had very different concentrations and distributions of extractives due to differences in the composition of tissues. The needles had the highest total extractive concentration (around 150?kg/ton d.w.), followed by the branches, bark, timber from the final cut stand, and then the pulpwood and timber from the thinning stand. The final cut stand generally provided higher yields of extractives in assortments per hectare than the thinning stand; the difference was five-fold for timber, three-fold for whole trees, two-fold for branches, needles and bark and similar for pulpwood. This information on the content and composition of extractives in different tissues, and the dependence of these quantities on tree age could be used together with information on conventional stand data such as tree numbers and dimensions to guide the selection and management of feedstocks for biorefineries.     

Chemical characterization of Pinus halepensis sapwood and heartwood

ABSTRACT

This paper describes the chemical composition of sapwood (SW) and heartwood (HW) of Pinus halepensis Mill stem. Extractives were first isolated by accelerated solvent extraction and then analysed by gas chromatography-mass spectrometry (GC-MS). The cellulosic polysaccharide content present in the pre-extracted wood samples was determined with acid hydrolysis and GC. The hemicelluloses content was determined with acid methanolysis and GC. Free monomers were additionally analysed by GC. The amount of lignin was determined gravimetrically by the Klason lignin method and the acid-soluble lignin was determined by a UV method. Formic and acetic acids in wood were determined after alkaline hydrolysis and analysed by HP-SEC. It was found that lipophilic and hydrophilic extractives were more abundant in heartwood (1.6% and 2.5%) than in sapwood (1.1% and 1.8%). Celluloses content was higher in sapwood (42.5%) than in heartwood (39.7%), whereas lignin, hemicelluloses and sugar monomer contents were more abundant in heartwood (28.9%, 26.8% and 0.3%) than in sapwood (28.0%, 24.5% and 0.2%). The variation in acetic and formic acids and ash contents between sapwood (0.7%, 0.2% and 0.5%) and heartwood (0.6%, 0.1% and 0.4%) was small. The acetylation degrees were found to be slightly similar in sapwood (0.4) and heartwood (0.3).     

The effect of lignin on the bending properties and fixation by cooling of wood

To clarify the effects of lignin on the fixation of bending deformation by cooling, cooling set for delignified woods with various lignin residues were investigated to compare with mechanical and dynamic viscoelastic properties. Bending tests showed that steep reductions occurred in the modulus of elasticity and modulus of rupture with delignification during the initial stage of delignification. The dynamic viscoelastic measurements revealed that the peak temperature of tan δ due to micro-Brownian motion of lignin was reduced with delignification, and the peak disappeared in the temperature range of 5°–100°C for the specimens that had lost more than 21% of their weight. On the other hand, no clear change in residual set was found in the range of 0%–15% of weight loss in spite of a marked reduction in lignin content. Subsequently, set decreased steeply for the specimens delignified beyond 15% of weight loss. It was suggested that cooling set is not determined solely by lignin content but is influenced by changes in the quality of lignin due to delignification. Lignin quality affects the balance of the elastic potential to recover from deformation and its viscosity, which is an indication of resistance against flow. Part of this report was presented at the 57th Annual Meeting of the Japan Wood Research Society, Hiroshima, August 2007     

Effects of heartwood extractive fractions of Thuja plicata and Chamaecyparis nootkatensis on wood degradation by termites or fungi

The effect of selective removal of extractives on termite or decay resistance was assessed with matched samples of Thuja plicata Donn ex D. Don and Chamaecyparis nootkatensis (D.Don) Spach heartwood. Samples were extracted using a variety of solvents and then exposed to the subterranean termite Coptotermes formosanus Shiraki in a no-choice feeding test or to the brown-rot fungus Postia placenta (Fr.) M. Larsen & Lombard in a soil bottle test. At the same time, the effect of naturally occurring variations in heartwood extractives on termite or decay resistance was evaluated by testing samples from the inner and outer heartwood of five trees of each species against C. formosanus and P. placenta and analyzing matched wood samples for their extractive content. The results suggest that the methanol-soluble extractives in T. plicata and C. nootkatensis play an important role in heartwood resistance to attack by C. formosanus and P. placenta. Total methanol-soluble extractive content of the heartwood was positively correlated with both termite and decay resistance; however, there was much unexplained variation and levels of individual extractive components were only weakly correlated with one another. Further studies are under way to develop a better understanding of the relationships between individual extractive levels and performance.     

Lignin characterization of triploid clones of Populus tomentosa Carr.

In order to understand the structural characteristics of lignin in triploid clones of Populus tomentosa and its changes in the processes of pulping and bleaching, milled wood lignin (MWL), lignin carbohydrate complex (LCC) and the residual lignin from kraft pulp (KP) and sulfite pulp (SP) were isolated and analyzed by Fourier transform infrared (FTIR) spectrum and ¹³C nuclear magnetic resonance (NMR). The most diagnostic peaks were assigned and the differences were discussed. The spectral patterns reveal that triploid P. tomentosa shows the specific features of hardwood from temperate areas, but in the spectrum of FTIR, the strength ratio of A 1270 cm⁻¹ to A1226 cm⁻¹ is 0.88, higher than the average of hardwood from temperate areas, which will make the lignin delignification more difficult during pulping and bleaching. The LCC from triploid P. tomentosa is mainly composed of xyloglucan and glucuronic acid, and other glucides have much lower ratio. In LCC FTIR, there are three peaks at 1 427, 1 329 and 1 046 cm⁻¹, indicating that both semi-cellulose and cellulose could exist in LCC, and that there might be relationships between cellulose and lignin. Compared with the residual lignin from KP and SP, the condensed structure in KP is more than that in SP.     

A chemical and ultrastructural study of the Bamboo species Phyllostachys makinoi Hay

Summary A culm sample of Phyllostachys makinoi was investigated by analysis of its chemical composition, and by electron microscopic observations of the cell wall structure before and after extraction and degradation procedures. Quantitative determination of the components resulted in 2.6% extractives, 25.5% lignin, 45.3% alpha-cellulose, and 24.3% polyoses. The main polyose is an arabinoxylan with a Xyl: Ara ratio of about 17:1. The electron micrographs show a lamellar deposition of lignin and polyoses within the secondary walls. Lignin is obviously soluble by parts in alkaline as well as in acidic reagents. Sodium hydroxide solution removes cell wall substance mainly from the secondary walls, whereas trifluoroacetic acid removes substance from compound middle lamellae.     

Modeling of sapwood and heartwood delignification kinetics of <Emphasis Type="Italic">Eucalyptus globulus</Emphasis> using consecutive and simultaneous approaches

Eucalyptus globulus sapwood and heartwood were delignified at 130°, 150°, or 170°C by kraft pulping. Pulp yields of heartwood were lower than those of sapwood (46.5% vs. 50.4% at 170°C). Delignification was modeled using consecutive and simultaneous kinetic models. The modeling was similar for heartwood and sapwood, and either approach could be used, with both yielding good correlations between experimental and model data. The consecutive model identified two delignification phases with similar reaction rates and activation energies for heartwood and sapwood at 150° and 170°C. At 130°C only one phase was identified. Three reactive types of lignin fractions were identified using the simultaneous model, without differences between heartwood and sapwood. Their reaction rates were 0.152, 0.138, and 0.003 min⁻¹ at 170°C, and the activation energies were 132, 119, and 102 kJ.mol⁻¹. The presence of heartwood did not influence the kinetic development of delignification. The negative impact of heartwood in pulping is related to the higher content of extractives (9.8% vs. 3.9% in heartwood and sapwood) and to their influence on the process, namely in the heating-totemperature phase when a substantial mass loss occurs (30% vs. 20% for heartwood and sapwood).     

麦草碱性亚硫酸盐制浆生物炼制的研究(I) ——深度脱木质素及木质素磺化特性

提出了非木材木质纤维生物质碱性亚硫酸盐制浆(ASP)生物炼制的理念,研究了总用碱量、亚硫酸化度、温度和时间对麦草碱性亚硫酸盐法蒸煮深度脱木质素特性和木质素磺化的影响。结果表明:麦草ASP法具有高的深度脱木质素选择性;深度脱木质素延伸与木质素磺化度提高具有一致性;总用碱量、亚硫酸化度、最高温度和保温时间对深度脱木质素选择性和木质素磺化度都有重要的影响;在总碱用量18.0%,亚硫酸化度85.0%,液比值3.5,最高温度168℃,保温150 min的条件下,可制得卡伯值8.8,得率56.8%,黏度为33.3 mPa.s的优良纸浆,此时黑液中磺化木质素磺酸基含量达2.16 mmol/g(以固形物计)。从深度脱木质素选择性、木质素磺化和纸浆基本特性考虑,麦草ASP法具有制浆生物炼制的前景。