Comparison of various pulping processes for producing pulp from vine shoots

The results of characterization for four different vine shoot varieties, grown using two different methods, revealed no significant differences in composition among vine varieties or between growing methods. The holocellulose content of vine shoots (67.14%) is lower than those of other non-wood raw materials (e.g. wheat straw, sunflower stalks, cotton stalks, etc.), but similar to those of pine and higher to those of olive trimmings. On the other hand, their lignin content (20.27%) is similar to those of eucalyptus and the non-wood raw materials. Also, their contents in cold-water, hot-water and 1% soda solubles, and ethanol–benzene extractables, are higher than for pine and eucalyptus.Soda, kraft, ethanol and ethylene–glycol pulping processes have low yields (29–47%) relative to the pulping processes applied to olive trimmings and wheat straw. Kraft pulp is that exhibiting the best properties, including a higher α-cellulose content (73.74%) than pulp from wheat straw or olive trimmings, but a higher lignin content (17.18%). Also, kraft pulp provides paper with the highest breaking length, burst index and tear index (viz. 1316 m, 1.63 kN/g and 1.59 mN m²/g, respectively); these values, which are intermediate among those for olive trimmings, wheat straw and sunflower seeds, are low and can be substantially improved by appropriate refining of the pulp.     

酶处理对芒果原浆性质的影响

在分析芒果原浆酶处理前后的理化性质的基础上,选用合适的配方,结合酶处理技术,改进芒果打浆工艺,生产出质量稳定的芒果原浆产品,提高了芒果打浆的得浆率。      

Environmentally friendly pulping and bleaching of bagasse

Depithed Sudanese bagasse was examined for its suitability for pulp production. Bagasse fibre dimensions, morphological and chemical characteristics are reported. The pulping trials were carried out with soda–AQ and alkaline sulphite–AQ (AS–AQ) methods and soda method as reference. The AS–AQ pulping gave the best results in yield, degree of delignification, mechanical and optical pulp properties. Blending of bagasse and bamboo alkaline sulphite–anthraquinone pulps in different ratios gave well-balanced pulp strength characteristics with good tensile and tear indices, widening the range of different end products from bagasse pulp. Totally chlorine free bleaching (Q₁O/PQ₂P) of the best unbleached bagasse pulps gave bleached pulps of 76.9% ISO brightness, suitable for use in writing and printing grades of paper.     

Upgrading of hemp core for papermaking purposes by means of organosolv process

Non-wood raw materials for paper production have been maintained constant during last decade. In Europe, fibres from non-wood resources proceed mainly from flax and hemp crops. Hemp core is considered a by-product of the process, mainly used in equestrian sector. The application of these fibres for papermaking process gives a significant added value to the sector.New technologies in cooking processes like organosolv pulping gives advantages compared with traditional Kraft cooking. Hemp fibres obtained by means of organosolv process have been compared with eucalyptus Kraft pulp to determine if physical and mechanical properties of final pulps are similar.Efficiency of the organosolv cooking experiments was evaluated by means of yield, percentage of uncooked sample, kappa number and viscosity.To analyze the suitability of pulp samples for papermaking applications, different evaluation of mechanical properties as morphological characterization were done. Controlling cooking conditions of hemp core, similar properties of eucalyptus Kraft fibres are obtained.     

Delignification of wheat straw using a mixture of carboxylic acids and peroxoacids

Wheat straw was pulping by an Organosolv process using a mixture of acetic acid/formic acid/water (AA/FA/water). In order to make easier the bleaching step, it was possible to improve the delignification in an efficient and selective manner by using peroxoacids in acidic organic medium. First a solution of peroxoacids was synthesized by adding hydrogen peroxide in a mixture of acetic acid/formic acid, without any inorganic acids as catalyst. Then this mixture was added to the unbleached pulp. Several parameters (temperature, extraction alkaline, reaction time …) were investigated.This simple and innovative way to use peroxoacids allows to overcome problem due to the control of their stability in aqueous medium and proves to be perfectly complementary to the cooking method in a carboxylic acid medium. Low kappa numbers and high viscosity were obtained. Strength properties of the pulp after the peroxoacids step were improved.     

Pulping and papermaking properties of Tunisian Alfa stems (Stipa tenacissima)—Effects of refining process

The objective of this work is to study characteristics of chemical pulps (soda cooking process) and of paper obtained from Alfa, also known as Stipa tenacissima. For this purpose, Tunisian Alfa stems, and both unbleached and bleached pulps were characterized by determining their chemical composition as well as their morphological and physical properties. Through a detailed comparison with the other pulps obtained from various species, we show that the properties of Alfa stem fibres are intermediate between those of non-wood and wood plants, and most often close to those of Eucalyptus fibres. Refining process (PFI mill device) was then applied to the unbleached and bleached Alfa pulps. The modifications of the morphological properties of the fibres and the drainability and water retention values of the pulps were studied as a function of the refining degree. Here again, Alfa fibres exhibit a behaviour similar to that of Eucalyptus fibres, as the fibre shortening is very limited during the refining process. Finally, conventional handsheets with a basis weight of 65 g/m² were prepared from the unrefined and refined pulps. Their characterization showed that Alfa based papers present low density values and quite good mechanical properties, which are significantly enhanced by the refining treatment, particularly for the unbleached pulp. This study demonstrates the high potentiality of this non-wood species for papermaking applications.     

Pulp and paper from kenaf bast fibers

Samples of kenaf (Hibiscus cannabinus) grown in Malaysia were examined to determine the kraft pulp and papermaking properties of their bast (or bark) fibers. Using kraft pulping process showed that bast fibers were relatively easy to cook resulting good pulp yields in the range of 45–51%. The bast pulp produced sheets with great density, tear index and dry zero-span breaking length. Kenaf bast fiber is considered promising for production of high-grade printing, writing and specialty papers.     

藤茶的功能性及黄酮类化合物提取研究进展

藤茶系葡萄科蛇葡萄属,为显齿蛇葡萄科的嫩茎叶,内富含多种生物功效成分,是具有很大开发潜力的野生植物资源.本文对藤茶的营养成分、主要化学成分进行了简要介绍,综合国内外研究报道.对藤茶植物的生物活性及其功效成分的提取方法进行了总结.为从事藤茶生理、药理功能研究及产品开发的相关人员提供参考.     

Comparative field performance of potatoes from microculture

The growth and yield in the field of two cultivars of potatoes originating from three different propagation sources — tubers, microcultured shoots (microcuttings) and small tubers produced in culture (microtubers) — were analyzed. Plants originating from microculture produced only single stems emerging from the soil surface whereas tubers formed multistemmed plants. Due to vigorous branching on microcultured plants, however, vine growth appeared similar. Although the total tuber yields were the same for plants from all three propagation sources, in general microcultured plants produced smaller-sized but a greater number of tubers. Microculture is a promising method of producing high quality, certified propagules for potato production.     

Characterization of by-products of sunflower culture – commercial applications for stalks and heads

The by-products of sunflower production were characterized. The sunflower heads contain a strong smelling essential oil (EO) (0.2%) and pectins (22%). The galacturonic acid (GA.A.) content of the pectins depends on the extraction conditions (water-soluble pectins: 67%, soluble in ammonium oxalate/oxalic acid: 74%, in hydrochloric acid: 33%). They are all slightly methylated (degree of methylation (DM) <20%). The stalks may be readily separated into two parts: fiber (external part, 90%) and the pith (internal part, 10%). The mechanical properties of paper pulp obtained by thermomechanical treatment in a twin-screw extruder of the whole stalks or depithed stems were investigated. The pulps had high values of ring crush test (RCT) and concora medium test (CMT), which make them suitable for the manufacture of cardboard. Low-density materials can be also shaped with ground pith. The role of water-soluble substances in the cohesion of these materials is discussed. Its mechanical properties, which are comparable to those of polystyrene, were determined. They may find application in the packaging and packing industries.     

Multivariate chemometric analysis of the fluorescence spectra of eucalyptus wood

In this paper, multivariate chemometric analysis of fluorescence spectra of juvenile and mature eucalyptus wood samples is used in order to investigate the existence of any correlation between fluorescence data and, the physical/chemical properties, as well as the pulping data of eucalyptus wood. The results obtained demonstrated that the wood of juvenile and adult trees could be discriminated by fluorescence spectroscopy. Data analysis also has shown the existence of good statistical correlation between fluorescence data on the one hand, and ash content, sodium hydroxide solubility, and lignin monomeric composition of the wood samples on the other hand. Moreover, fluorescence spectral data were found to be well correlated with the pulping yield and the Kappa number of the kraft pulps issued from the adult and juvenile eucalyptus wood.     

Pulp from oil palm fronds by chemical processes

To enhance the use of the abundant biomass generated by the palm oil industry in Malaysia a study was conducted in view of exploring the papermaking potential of this industrial byproduct. Fiber strands from the frond of oil palm trees were examined relative to their physical and chemical characteristics and their response to chemical pulping such as sulfite, soda-sulfite and soda processes. Morphologically, the frond fibers are comparable to those of hardwood. They contain high content of holocellulose but low in lignin. Chemical pulps of 45–50% yield produced either by soda-sulfite or soda process exhibit acceptable papermaking properties comparable to those of hardwood kraft pulps. The study showed that frond pulp might be used as a reinforcement component in newsprint production using softwood thermomechanical fibers.     

Variations in chemical characteristics and pulpability within jute plant (Chorcorus capsularis)

The differences in morphological and chemical characteristics and pulpability of core and bark fiber of jute at different position, top, middle and bottom were studied. The fiber length at the middle part of both bark and core was longer than the top and bottom part. With increasing height from bottom to top lignin content is decreased and α-cellulose content increased. The bark had higher α-cellulose and lower lignin than core. The bark produced nitrobenzene oxidation products with larger syringaldehyde/vanillin (S/V) ratios than the core. The yields of nitrobenzene oxidation products in bark were higher than core. The analysis of neutral sugars suggested that xylose is the predominant sugar of hemicellulose in both bark and core. The bark had higher glucose and lower xylose as compared to core. Under identical conditions of pulping, bark gave higher pulp yield and lower kappa number than core. The bark pulp showed better bleachability than core pulp. The higher tensile index in core pulp and higher tear index in bark pulp were observed.     

Lignin modification improves the biofuel production potential in transgenic Populus tomentosa

Lignin has been recognized for its negative impact on forage digestibility, tree pulping properties, and cellulosic biofuel production, although it is the major structural component of the secondarily thickened cell walls of vascular plants. Earlier studies have demonstrated that lignin modification improves forage digestibility and poplar pulping properties. To determine whether lignin modification has beneficial effect on saccharification of lignocellulosic biomass, we pretreated and then enzymatically hydrolyzed the mature wood from transgenic poplar plants that expressed the antisense transgenes of monolignol biosynthesis genes 4-coumarate: CoA ligase (4CL) or caffeoyl CoA 3-O-methyltransferase (CCoAOMT). Firstly, a long-term field trial was set up for the transgenic plants. Over five years, the reduced trend of lignin content remained stable in all transgenic lines. And a total lignin reduction of up to 10% did not alter the growth rate or biomass yield of the transgenic poplars. In the mature wood, suppression of CCoAOMT increased saccharification potential, but 4CL down-regulation had no significantly positive effect on saccharification. Sugar yield were negatively correlated with soluble lignin content of dried, extractive-free stem biomass. These results imply that lignin modification can facilitate the process of saccharification for biofuel production in tree crops.     

Vine pulling as a means of top killing potatoes

Vine pulling as a means of top killing potatoes was evaluated by measuring tuber discolouration, desiccation of stems and leaves, stems missed and rerooted, and tubers exposed during pulling. Tuber discolouration ratings determined for potatoes that had been top killed in mid-August by chemical desiccant, rotobeating or vine pulling, remained low during the four-year study except in 1978 with the chemical desiccant. Machine pulling evaluations indicated effective vine kill to be rated at 89–99% for leaves and 79–98% for stems with several cultivars of potatoes. A number of stems rerooted which reduced the vine kill ratings.     

Cynara cardunculus L. — a new fibre crop for pulp and paper production

The pulping potential of the thistle Cynara cardunculus L. was evaluated by studying anatomy and chemical composition of the stalks and Kraft pulp yields and properties. C. cardunculus is a perennial plant, with annual harvests, that can be grown in hot and dry climates with high productivities. The stalk of the plant has a central pith, ca. 45% in volume and 10% in weight, of small parenchyma cells, surrounded by a cortex where numerous fibre vascular bundles are imbedded. The fibres are on average 1.3 mm long, 18.8 μm wide and have a 4.8 μm wall thickness. The whole stalks have 7.7% ash, 14.6% extractives, 17.0% lignin and 53.0% polysaccharides, mainly cellulose and xylans. The pith has more lignin than the depithed stalk (20.3 vs. 13.6%). The Cynara stalks could be cooked by standard Kraft pulping to produce well delignified pulps with high yields (44–47% with Kappa 11–15), low rejects and very good strength properties, especially in relation to tensile strength. Depithing of the stalks has a positive impact on pulp yield, chemical consumption and on the pulp strength properties.     

大豆E3连接酶基因GmPLR-2 的克隆及抗旱功能鉴定

PEG模拟干旱胁迫条件下E3连接酶GmPLR-2 基因在大豆根茎叶中呈上调表达，推测其可能参与大豆抗 旱调节。本研究克隆GmPLR-2 基因，构建植物过表达载体pCAMBIA3301-GmPLR-2、RNA干扰表达载体pCAM⁃ BIA3301-GmPLR-2-RNAi并转化到吉农38中，对T2转基因植株进行分子检测，连续7 d不浇水后测定转基因叶片 中相关生理生化指标。结果表明：共获得T2过表达阳性植株12株，RNA干扰阳性植株11株。干旱胁迫7 d后过表 达植株中相对含水率、POD活性、SOD活性、Pro含量均高于未转化植株，而RNA干扰植株中则低于未转化植株；另 一方面过表达植株中相对电导率、MDA含量均低于未转化植株而RNA干扰植株中含量则高于未转化植株，且差异 极显著，说明GmPLR-2 基因的表达与大豆中相关抗旱指标的变化有关。     

Improving the use of kenaf for kraft pulping by using mixtures of bast and core fibers

Kenaf (Hibiscus cannabinus L.) is a herbaceous annual plant amenable to use as a papermaking raw material. Kraft and soda pulping of kenaf have so far been done exclusively on the bark fraction (about 34–38% of the stem) or whole stem of the plant. Using kenaf bark exploits the higher quality of its bast fibers but reduces the typically high crop yields of this plant. In any case, core kraft pulp has acceptable properties some of which (e.g. tensile index, burst index) can even surpass those of bark pulp. Pulp made from both fractions has been found to exhibit better bonding properties than bark pulp. However, too high a proportion of core fibers can result in difficult drainage, a low tear strength or poor air permeability. These problems restrict the proportion of core that can be mixed with bast fibers, hinders separation of the two fractions and raises operational costs.The primary purpose of this study was to examine the influence of the core–bark ratio on the properties of mixed kenaf pulp. We used unrefined core pulp and refined bark pulp. Based on the results for kraft sacks, obtaining kenaf paper from both fractions has some advantages. Because Gurley air porosity changed dramatically with the proportion of core pulp used, it was used to determine the maximum amount of core fibers to be added to bast fibers. A proportion of up to 34% was found to have no adverse effect on air permeability. Such a proportion allowed paper strength to be preserved with an acceptable tear index (19.8 mN m²/g) and excellent tensile index (72 N m/g). Also, energy consumption was reduced if only the bark fraction was refined. The proposed strategy thus provides increased fiber yields of kenaf per hectare per year and valorizes the core fraction.     

影响成龄胡椒节间离体培养再生植株的几种因素

以成龄胡椒主蔓节间切段为外植体，通过愈伤组织诱导和芽的分化途径获得了再生植株。结果表明：外植体的污染率与采集材料后离接种时间的长短有关；以主蔓节间切段为外植体，愈伤组织诱导率高，愈伤组织生长快，并具有分化芽的潜力。     

Low Mw-lignin fractions together with vegetable oils as available oligomers for novel paper-coating applications as hydrophobic barrier

Lignin residues are available in large amounts as kraft lignin from chemical pulping processes. This lignin is mainly incinerated in recovery boilers. The recovery boilers are often the bottle-necks in the overall pulping process when pulp production increases are desired. Through cross-flow nano-filtration of the black liquor from kraft pulping, a low-molecular weight lignin fraction can be removed thus decreasing the organic load on the recovery boilers. The low-molecular weight lignin fraction furthermore exhibit different characteristics compared to other commercial kraft lignins and represents a new raw material source in novel applications.The low-molecular weight lignin was used together with a vegetable oil to produce a new hydrophobic lignin derivative similar to suberin. The lignin and the lignin derivative was analysed with FT-IR, UV–vis and SEC. The ability of the product to make paper surfaces hydrophobic was also evaluated.The results demonstrate the possibility to make a suberin-like lignin derivative that is potentially of interest in paper-coating applications due to its capability to interact well with wood fibres and make paper hydrophobic.