Paper Pulp Production Research Articles

Valorisation of Pulp and Paper Industry Wastes—Incorporation in Bituminous Mixtures for Road Construction

Some wastes from the paper pulp production process are still sent to a controlled waste landfill. These materials can constitute alternative resources for constructing road pavements. The study aimed to characterize and explore the sustainable application of two inorganic wastes resulting from the paper pulp process, the dregs (green liquor wastes) and the grits (slaker wastes), in the production of bituminous mixtures by the analysis of samples prepared with 5 and 10% of dregs and 5 and 10% of grits on the baseline reference bituminous mixture AC 14 surf 35/50. Some relevant mechanical properties of the blends were assessed based on Marshall compression, sensitivity to water and wheel-tracking tests. Additionally, water poured on the loose asphalt and compacted slabs’ surface was analysed to determine the portion of harmful chemical compounds leached from the asphalt material. The results show that using dregs presented some technical limitations related to mechanical performance and that the incorporation of grits has an acceptable mechanical behaviour. Moreover, the study shows that the measured leachate resulting from water flow in a reference asphalt mixture and the blends with grits are insignificant. It can be concluded that using grits in asphalt mixtures is a promising technique regarding mechanical behaviour and environmental impacts that need further studies.

Sustainable Solution Economically for The Production of Paper Pulp from Peanut Shell

The increasing demand for sustainable and eco- friendly materials has prompted researchers to explore alternative sources for paper pulp production. This research paper investigates the feasibility of utilizing peanut shells, an abundant agricultural waste, as a potential raw material for paper pulp production. The study focuses on the process of converting peanut shells into high-quality pulp through various methods such as chemical and mechanical pulping. The paper further discusses the potential benefits, challenges, and environmental implications of using peanut shell pulp as a sustainable alternative to conventional wood-based pulps. The findings of this research contribute to the growing body of knowledge on sustainable resource management and promote the utilization of agricultural waste for value- added applications.

Optimization of bioactive compounds by ultrasound extraction and gas chromatography - mass spectrometry in fast-growing leaves

Fast-growing crops are of great economic importance in the production of paper pulp and energy. The commercialization of the bioactive components from underutilized parts could provide additional value to these crops. In the present study, chromatography gas coupled to mass spectrometry triple quadrupole (GC–MS/MS) and ultrasound extraction technique was used in the bioactive compounds determination in fast-growing crops leaves. Twenty-one terpenes and eight polyphenolic bioactive compounds were studied. Prior to GC–MS/MS, polydimethylsiloxane (PDMS) - stir bars preconcentration and trimethylsilane (TMS) derivatization steps were used for terpenes and polyphenolic compounds, respectively. Several parameters (pH, temperature, ethanol–water mixtures, ultrasound power, and ultrasound time) of the extraction step were optimized by central composite experimental design. Ethanol content, ultrasound power, and ultrasound time were the parameters that most influence the extraction efficiency of terpenes in biomass residues, while for polyphenolic compounds it was temperature and ultrasound time.The optimal ultrasound extraction conditions for terpenes were 60% ethanol, pH 4, 80 W, 40 °C, and 15 min, whereas for polyphenolic compounds they were 60% ethanol, pH 4, 120 W, 50 °C, and 15 min. The detection limits (LOD) were in the range of 0.200–3.02 µg kg−1 and 7.9–540 µg kg−1 for terpenes and polyphenolic compounds, respectively.The developed analytical method was applied to twelve fast-growing leaves (Leucaene (diversifolia and leucocephala), Eucalyptus (globulus and urograndis), Populus (I214 and AF2), Prosopis (alba and juliflora), Robinia, Tagasaste, Ulmus pumila, and Paulownia). Eucalyptol was the mayor terpene present in all the plants studied, while chlorogenic and quinic acid were the mayor phenolic compounds.

Valorization of Kraft Lignin from Black Liquor in the Production of Composite Materials with Poly(caprolactone) and Natural Stone Groundwood Fibers

The development of new materials is currently focused on replacing fossil-based plastics with sustainable materials. Obtaining new bioplastics that are biodegradable and of the greenest possible origin could be a great alternative for the future. However, there are some limitations-such as price, physical properties, and mechanical properties-of these bioplastics. In this sense, the present work aims to explore the potential of lignin present in black liquor from paper pulp production as the main component of a new plastic matrix. For this purpose, we have studied the simple recovery of this lignin using acid precipitation, its thermoplastification with glycerin as a plasticizing agent, the production of blends with poly(caprolactone) (PCL), and finally the development of biocomposite materials reinforcing the blend of thermoplastic lignin and PCL with stone groundwood fibers (SGW). The results obtained show that thermoplastic lignin alone cannot be used as a bioplastic. However, its combination with PCL provided a tensile strength of, e.g., 5.24 MPa in the case of a 50 wt.% blend. In addition, when studying the properties of the composite materials, it was found that the tensile strength of a blend with 20 wt.% PCL increased from 1.7 to 11.2 MPa with 40 wt.% SGW. Finally, it was proven that through these biocomposites it is possible to obtain a correct fiber-blend interface.

Dose-Response Effects of Bamboo Leaves on Rumen Methane Production, Fermentation Characteristics, and Microbial Abundance In Vitro.

Simple SummaryDue to economic, environmental, and nutritional considerations, mitigating enteric methane production from ruminants is an important issue. Nutritionists have recently shown that feeding livestock natural feed additives could ameliorate this problem, due to the antimicrobial activities of the biologically active components in the additives. Bamboo is widely distributed in Asia and is currently being used in construction and paper pulp production, which results in a significant amount of bamboo leaves as by-products. The present study investigated whether bamboo leaves feeding can decrease methane production in ruminants. Here we found that bamboo leaves supplementation in vitro caused a 12.7–34.2% reduction in methane production after 12 and 48 h. Further studies are needed to demonstrate the effect of bamboo leaves supplementation in vivo, to determine its potential for mitigating methane production from ruminants.Ruminants produce large amounts of methane as part of their normal digestive processes. Recently, feed additives were shown to inhibit the microorganisms that produce methane in the rumen, consequently reducing methane emissions. The objective of this study was to evaluate the dose–response effect of Phyllostachys nigra var. henonis (PHN) and Sasa borealis supplementation on in vitro rumen fermentation, methane, and carbon dioxide production, and the microbial population. An in vitro batch culture system was used, incubated without bamboo leaves (control) or with bamboo leaves (0.3, 0.6, and 0.9 g/L). After 48 h, total gas, methane, and carbon dioxide production decreased linearly with an increasing dose of bamboo leaves supplementation. The total volatile fatty acid, acetate, and acetate-to-propionate ratio were affected quadratically with increasing doses of bamboo leaves supplementation. In addition, propionate decreased linearly. Butyrate was increased linearly with increasing doses of PHN supplementation. The absolute values of total bacteria and methanogenic archaea decreased linearly and quadratically with an increasing dose of PHN treatment after 48 h. These results show that bamboo leaves supplementation can reduce methane production by directly affecting methanogenic archaea, depressing the metabolism of methanogenic microbes, or transforming the composition of the methanogenic community. These results need to be validated using in vivo feeding trials before implementation.

Production of Paper Pulp Using Sisal Fiber Waste from Sisal Spinning Processes

Disposal of large volumes of textile waste is an escalating problem for textile industries. Sisal spinning industry is the one of the textile industries releasing large volumes of textile waste in the landfills. The rising costs, and reduction of available space together with increasing stringent environmental measures are making burying and land filling of textile waste, a declining option. This study therefore explores recycling options where the potential of using sisal fiber waste produced during sisal spinning processes as raw materials for the production of paper pulp was investigated. Sampling was done at 21stCentury Holdings Limited allocated at Chang’ombe industrial street Dar es Salaam mainly dealer of sisal yarns production. Materials were prepared and cut into small pieces of about ½ inches to reduce the fiber into unit lengths so as to achieve pulping required performance. Pulping process was achieved through Soda pulping techniques with two different effective alkali charges (EA-20% and EA-24%) for 240 minutes under maximum temperature 140 C, and liquor to fiber ratio 4:1by using Mathis Labomat dyeing Machine. The kappa number obtained was (25.5, 34.5) for material treated under EA 24% and EA 20% respectively, Percentage pulp yield were (47.1, 54.4) for EA 24% and EA20% pulp respectively. Freeness (630CFS, 555CSF) after refining at 4500rpm. Finally, the resulting pulp was used for hand sheet making and the sheets were tested for their mechanical properties; Grammage (61.1, 61.1) g/m2, Tensile index (9.9, 22.3) Nm/g, Tear index (13.3, 17.4) Nm2/g, burst index (1.7, 3.7 and 1.6) k.pa.m2/g and Elongation at break (2.02, 2.22) % for EA24% pulp, EA20% pulp respectively. The findings shows that sisal fiber wastes have a promising potential for paper pulp production compared to other non-wood raw material.

Organosolv Fractionation of Birch Sawdust: Establishing a Lignin-First Biorefinery.

The use of residual biomass for bioconversions makes it possible to decrease the output of fossil-based chemicals and pursue a greener economy. While the use of lignocellulosic material as sustainable feedstock has been tried at pilot scale, industrial production is not yet economically feasible, requiring further technology and feedstock optimization. The aim of this study was to examine the feasibility of replacing woodchips with residual sawdust in biorefinery applications. Woodchips can be used in value-added processes such as paper pulp production, whereas sawdust is currently used mainly for combustion. The main advantages of sawdust are its large supply and a particle size sufficiently small for the pretreatment process. Whereas, the main challenge is the higher complexity of the lignocellulosic biomass, as it can contain small amounts of bark and cambium. Here, we studied the fractionation of birch sawdust by organosolv pretreatment at two different temperatures and for two different durations. We evaluated the efficiency of fractionation into the three main fractions: lignin, cellulose, and hemicellulose. The cellulose content in pretreated biomass was as high as 69.2%, which was nearly double the amount in untreated biomass. The obtained lignin was of high purity, with a maximum 4.5% of contaminating sugars. Subsequent evaluation of the susceptibility of pretreated solids to enzymatic saccharification revealed glucose yields ranging from 75% to 90% after 48 h but reaching 100.0% under the best conditions. In summary, birch sawdust can be successfully utilized as a feedstock for organosolv fractionation and replace woodchips to simplify and lower the costs of biorefinery processes.

Catalytic Liquefaction of Kraft Lignin with Solvothermal Approach

Lignin is a natural biopolymer present in lignocellulosic biomass. During paper pulp production with the Kraft process, it is solubilized and degraded in Kraft lignin and then burned to recover energy. In this paper, the solvolysis of Kraft lignin was studied in water and in water/alcohol mixtures to produce oligomers and monomers of interest, at mild temperatures (200–275 °C) under inert atmosphere. It was found that the presence of alcohol and the type of alcohol (methanol, ethanol, isopropanol) greatly influenced the amount of oligomers and monomers formed from lignin, reaching a maximum of 48 mg·glignin−1 of monomers with isopropanol as a co-solvent. The impact of the addition of various solid catalysts composed of a metal phase (Pd, Pt or Ru) supported on an oxide (Al2O3, TiO2, ZrO2) was investigated. In water, the yield in monomers was enhanced by the presence of a catalyst and particularly by Pd/ZrO2. However, with an alcoholic co-solvent, the catalyst only enhanced the formation of oligomers. Detailed characterizations of the products with FTIR, 31P-NMR, 1H-NMR and HSQC NMR were performed to elucidate the chemical transformations occurring during solvolysis. The nature of the active catalytic specie was also investigated by testing homogeneous palladium catalysts.

Agricultural Residues as an Alternative Source of Fibre for the Production of Paper in Kenya-A Review

The pulp and paper industry is primarily dependent on fibrous wood for pulp and paper production. However, this over-dependence on fibrous wood poses serious environmental challenges such as the diminishing of the fibrous wood stocks, deforestation, emission of greenhouse gases, and global warming. Therefore, to mitigate these environmental challenges associated with its utilization for paper and pulp production, other sustainable raw material sources can also be considered for the production of paper and pulp. There are enormous benefits associated with the utilization of non-wood fibres as an alternative and sustainable raw materials source for the production of paper and pulp. These benefits have in the recent past prompted millers in China, India, Brazil, and the USA to consider the utilization of non-wood fibres in paper and pulp production.
 In Kenya, the pulp and paper industry is very much dependent on fibrous wood for production and the industry is yet to fully embrace the utilization of nonwood fibres for paper and pulp production. Further, the dependence on fibrous wood has contributed significantly to the decline of paper pulp and paper production, deforestation, and rise in paper importations due to insufficient raw material supplies. The importation of paper and pulp products has further led to the collapse of the paper industry in Kenya. The sector stands a chance of revival and vibrancy through the utilization of the abundant agricultural residues and feedstocks lying in the agricultural fields across the country. Similar experiences elsewhere have proved that the abundance of agricultural waste can be utilized for the production of paper and pulp due to their excellent fibre content for specialty papers, and easy pulpability. The agricultural residues are therefore considered a quintessential alternative and sustainable source of raw materials for the pulp and paper industry. Moreover, their utilization will mitigate environmental impacts such as deforestation, climate change, and pollution .

Benefits of Silvopastoral Systems for Keeping Beef Cattle.

Simple SummarySilvopastoral Systems (SPS) are agroforestry arrangements that combine forage grasses with shrubs and trees for animal nutrition and complementary uses. Their contribution to sustainable livestock production and animal welfare is well recognized, mainly with Zebu cattle in tropical regions. In order to obtain information in temperate climate zones, 130 beef cattle of European breeds were selected from four commercial herds and randomly allocated to two contiguous plots: SPS and Open Pastures Systems (OPS). The trees in the SPS were Eucalyptus globulus globulus for paper pulp production. They were planted with two meters between each tree over native, diverse grasses. Over the course of one year, individual body weights and animal welfare indicators were collected every 45 days. There were no differences observed in weight gain between the two systems. No sign of impaired welfare, such as lameness, integument alterations, coughing, nasal/ocular discharge, or hampered respiration, was observed in either system. Silvopastoral systems offer animals a sustainable and richer environment, which will improve their welfare. The additional income provided by the wood production allows the farmers to maintain their traditional cattle farming lifestyle.The potential benefits of keeping Zebu cattle in silvopastoral systems are well described in tropical regions. In order to obtain information on European breeds of beef cattle (Bos taurus taurus) in temperate climate zones, individual records of body weight and welfare indicators were obtained from 130 beef cattle. These belonged to four herds and were randomly allocated to two contiguous plots: Silvopastoral Systems (SPS) and Open Pastures Systems (OPS). The SPS in this study were areas with exotic trees of Eucalyptus globulus globulus for paper pulp production planted in a 2 × 2 design (two meters between each tree) over diverse, native grasses. The OPS were large open areas with a great diversity of native grasses, herbs, and small plots of trees where the animals could rest and shelter from extreme weather conditions. Over the course of one year, individual body weights and a number of specific animal welfare indicators were measured every 45 days. After a descriptive analysis, a generalized linear mixed model (GLMM) with a Gaussian distribution, with time and system (OPS or SPS) fitted as fixed effects and individuals nested by herd as random intercepts, was used. The results showed that weight gain did not differ between the two systems. None of the animals showed any sign of impaired welfare in either system over the study period. Silvopastoral systems offer animals a sustainable and richer environment that will improves their welfare. The additional income provided by the wood production allows the farmers to maintain their traditional cattle farming lifestyle.

Sub-micro and nano-lignin materials: Small size and rapid progress

Lignin is the second most abundant biopolymer and the main source of aromatic structures on the earth. As a by-product of cellulose in the paper pulp production, lignin has rather low added-value applications. Sub-micro and nano- lignin materials maybe open promising high added-value applications. These new fields have brought about renewed interest for lignin. In this paper, the current developments of sub-micro and nano-lignin materials were reviewed. The synthetic routes between sub-micro and nano- lignin materials were summarized. All the different shapes, microstructures, and properties of these sub-micro and nano- lignin materials were compared with that of conventional lignin. The future trend toward micro- and nanostructured lignin-based materials is also suggested. It is expected that the small size of sub-micro and nano-lignin materials displays great progress, which are promising applications of various fields in the near future.

Synthetic Process of Bio-Based Phenol Formaldehyde Adhesive Derived from Demethylated Wheat Straw Alkali Lignin and Its Curing Behavior

Lignin is a natural biopolymer with a complex three-dimensional network, commercially obtained from waste liquid of paper pulp and bioethanol production, and could be a candidate for preparation of environment-friendly bio-based polyphenol material. In the present work, the demethylated wheat straw alkali lignin (D-Lig), prepared by demethylation of wheat straw alkali lignin (Lig) using an <i>in-situ</i> generated Lewis acid, was used to synthesize bio-based phenol formaldehyde resin adhesive (D-LPF) applied in plywood. Effects of synthetic process’s factors, including lignin substitution for phenol, NaOH concentration and molar ratio of formaldehyde to phenol, on the bonding strength and free formaldehyde content of D-LPF were investigated in detail, and the optimum synthetic process of D-LPF was obtained as following: Lignin substitution for phenol 60%, NaOH concentration 5.0% and molar ratio of formaldehyde to phenol 2.0, and under the optimum reaction condition, the D-LPF presented lower free formaldehyde content (0.18%) and higher bonding strength (2.19 MPa), which was better than those of containing-lignin phenol formaldehyde resin adhesive(LPF). Additionally, the curing behavior of the adhesive was studied by differential scanning calorimetry (DSC) combined with gel time. It can be obtained that D-LPF resin adhesive had the shortest gel time, and fastest curing rate, compared with those of PF and L-PF resin adhesives. The curing kinetics data was fitted well by Kissinger model using non-isothermal DSC method, and the average activation energy value was 85.3 kJ/mol, slightly higher than that of commercial PF resin, while lower than that of LPF (90.2 kJ/mol). Finally, based on the analytical results of high temperature fourier transform infrared spectroscopy (FTIR), a possible curing mechanism of D-LPF was proposed.

Modelling Bioeconomy Scenario Pathways for the Forest Products Markets with Emerging Lignocellulosic Products

The forest-based sector plays diverse roles among the emerging bio-based industries. The goal of this study is to examine how forest product markets could develop in the face of a growing bioeconomy and which interdependencies occur between traditional and emerging forest-based sectors. Therefore, we analyze the development of dissolving pulp together with lignocellulose-based textile fibres and chemical derivatives in a partial equilibrium model. For this purpose, we extend the product structure of the Global Forest Products Model (GFPM) and analyze three different bioeconomy scenarios from 2015 to 2050. The simulation results show that, in a scenario where the world is changing toward a sustainable bio-economy, wood consumption patterns shift away from fuelwood (−30% by 2050) and classical paper products (−32% by 2050) towards emerging wood-based products. In this context, the dissolving pulp subsector could outpace the continuously shrinking paper pulp subsector by 2050. To develop in this way, the dissolving pulp subsector mainly uses released resources from the decreasing paper pulp production. Simultaneously, wood-based panels are finding increasing application (+196% by 2050) and thus are taking over potential markets for sawn wood, for which production growth remains limited. Our results also show that, until 2050, the production of many wood-based products will take place mainly in Asia instead of North America and Europe.

In silico screening and experimental analysis of family GH11 xylanases for applications under conditions of alkaline pH and high temperature

BackgroundXylanases are one of the most extensively used enzymes for biomass digestion. However, in many instances, their use is limited by poor performance under the conditions of pH and temperature required by the industry. Therefore, the search for xylanases able to function efficiently at alkaline pH and high temperature is an important objective for different processes that use lignocellulosic substrates, such as the production of paper pulp and biofuels.ResultsA comprehensive in silico analysis of family GH11 sequences from the CAZY database allowed their phylogenetic classification in a radial cladogram in which sequences of known or presumptive thermophilic and alkalophilic xylanases appeared in three clusters. Eight sequences from these clusters were selected for experimental analysis. The coding DNA was synthesized, cloned and the enzymes were produced in E. coli. Some of these showed high xylanolytic activity at pH values > 8.0 and temperature > 80 °C. The best enzymes corresponding to sequences from Dictyoglomus thermophilum (Xyn5) and Thermobifida fusca (Xyn8). The addition of a carbohydrate-binding module (CBM9) to Xyn5 increased 4 times its activity at 90 °C and pH > 9.0. The combination of Xyn5 and Xyn8 was proved to be efficient for the saccharification of alkali pretreated rice straw, yielding xylose and xylooligosaccharides.ConclusionsThis study provides a fruitful approach for the selection of enzymes with suitable properties from the information contained in extensive databases. We have characterized two xylanases able to hydrolyze xylan with high efficiency at pH > 8.0 and temperature > 80 °C.

Valorization, extraction optimization and technology advancements of artichoke biowastes: Food and non-food applications

Large quantities of non-edible parts of the artichoke plant (Cynara cardunculus L.) comprising leaves, stems, roots, bracts, and seeds are discarded annually during industrial processing. These biowastes also contain high moisture making them susceptible to microbial growth and consequently may cause environmental contamination. However, these by-products are high in many phytochemicals similar to those of its edible flower heads including dietary fibers, phenolic acids, sesquiterpene lactones, enzymes, and flavonoids. Based on worldwide interest in renewable resources of energy, pharmaceutically-active biomolecules, and foods, many recent investigations have been conducted on recycling and the optimization the downstream processes for maximal exploitation of agri-food biowastes. Valorization of C. cardunculus L. biowastes presents opportunities for applications in the food (such as natural preservatives and milk coagulant) and non-food (such as therapeutics, biofuels, and paper pulp production) industries. This review focuses on the state-of-the-art for valorization practices of C. cardunculus L. biowastes and suggests potential novel uses in food and non-food industries. Different optimization techniques combining downstream and white biotechnology processes to develop better utilization of artichoke biowastes are presented.

Electiveness of agro-pulping process in the sustainable production of black liquor-based activated carbons.

During the production of paper pulp, the waste water loaded with organic materials from pulping process is discharged. Therefore, water treatment should be performed before disposing of such effluent. The use of such effluent for production of activated carbon will be effective in omitting the wastewater treatment and in obtaining the product required in many industries. In this respect, this paper deals with evaluating the performance of activated carbons (ACs) produced from black liquors (BLs) as by-products from three pulping processes of rice straw (RS) and sugar-cane bagasse (SCB), namely: alkaline, sulfite and neutral sulfite, which are coded SP, SSP and NSP, respectively. Elemental analysis and thermal analysis (TGA and DTGA) are carried out on the BLs, while the surface area (SBET), micro-/mesoporous distribution, adsorption capacity of methylene blue (MB) and iodine (I2-value), as well as Fourier transform infrared spectra (FT-IR) and scanning electron micrograph (SEM) are studied on synthesizing ACs. The optimal pulping approach for achieving BL-based AC, with the following characteristics: specific surface area (SBET) ∼ 921 and 545 m2 g−1, MB adsorption capacity 238 and 370 mg g−1, and I2-value 928 and 1255 mg g−1 of BL-based ACs, are from neutral sulfite pulping of SCB (B-NSP) and RS (RS-NSP), respectively. These finding data are ascribed to the carbon content of BL, as well as greatest total volume (VT 0.786 and 0.701 cm3 g−1) together with decreasing the volume of micropores/total (38 and 48%) of BL-NSP-ACs. It is interesting to note that the AC provided from RS-NSP has greater adsorption capacity for I2 and MB than the AC produced from RS-pulp fibres.

Giant leucaena (Leucaena leucocephala subsp. glabrata): a versatile tree-legume for sustainable agroforestry

Leucaena leucocephala (leucaena) is one of the 22 Leucaena species that originated in Central America. There are two major subspecies of leucaena, L. leucocephala subsp. glabrata (giant leucaena) and L. leucocephala subsp. leucocephala (common leucaena). Giant leucaena is a medium size fast-growing tree important for agroforestry while common leucaena is a small bushy shrub that is considered to be an invasive weed. Giant leucaena can be grown as a woody tree of up to ~ 20 m in height or maintained as a bushy fodder legume by repeated harvest of its foliage several times a year. Giant leucaena grown for fodder can produce forage dry mater yield of up to 34 Mg ha−1 year−1. High forage yield together with high protein content makes leucaena an ideal fodder legume for the tropical and subtropical regions of the world. Although mimosine present in the leucaena foliage has toxicity, it should not be a big concern because ruminants can be successfully inoculated with the mimosine-metabolizing rumen bacterium Synergistis jonesii. Alternatively, mimosine present in the leucaena foliage can be removed easily and inexpensively through simple processing. Giant leucaena cultivars are generally free from diseases and are highly tolerant to drought. Although infestation by psyllids may be a problem, a number of psyllid-resistant cultivars of giant leucaena have been developed through interspecies hybridization. The wood of giant leucaena can be used for timber, paper pulp, or biofuel production. Leucaena foliage and wood may serve as raw materials for development of new industry for production of phytochemicals such as mimosine, tannins and anthocyanins, wood products, and high-protein animal feed for farm animals in the future.

Characterization of crop residues from false banana /Ensete ventricosum/ in Ethiopia in view of a full-resource valorization

False banana /Ensete ventricosum [Welw.] Cheesman/ is exploited as a food crop in Ethiopia where it represents an important staple food. The plant is harvested and large amounts of biomass residues are originated, mainly from the pseudo stem (i.e., fiber bundles obtained from the leaf sheaths after being scrapped to produce starchy food) and the inflorescence stalk. These materials were studied in relation to their summative chemical composition, composition of lignin, lipophilic and polar extracts. Moreover, their structural characteristics, in view of their valorization, were scrutinized. The analytical studies were performed with the aid of FTIR, GC/MS, Py-GC/MS and SEM. The fiber bundles are aggregates of mainly long and slender fibers with low ash, extractives and lignin contents (3.8%. 4.4% and 10.5% respectively) and high holocellulose and α-cellulose contents (87.5% and 59.6% respectively). The hemicelluloses in the fibers are mostly highly acetylated xylans and the lignin is of the H-type (H:G:S, 1:0.7:0.8). This lignin composition is in line with the FTIR peaks at 1670 cm-1 and 1250 cm-1.The inflorescence stalk has high ash content (12.3% in the main stalk and 24.6% in fines) with a major proportion of potassium, high extractives (25.9%), and low lignin and α-cellulose contents (5.8% and 17.9% respectively). The stalk includes numerous starch granules in the cellular structure with the predominant presence of parenchyma. The potential valorization routes for these materials are clearly different. The fiber bundles could be used as a fiber source for paper pulp production with the possibility of a prior hemicelluloses removal while the inflorescence stalk has nutritional value for food and fodder. Furthermore, it can also be used for sugar fermentation products.

Mapping the genomic regions encoding biomass-related traits in Cynara cardunculus L

Cynara cardunculus, a member of the Asteraceae family, comprises the three taxa var. scolymus (globe artichoke), var. altilis (cultivated cardoon) and the ancestral var. sylvestris (wild cardoon). The substantial quantities of lignocellulosic biomass produced by these plants (up to 30.0 t/ha year−1 dry matter by the cultivated cardoon) can be used either as a source of bioenergy and/or as raw material for paper pulp production. Here, genotyping-by-sequencing to an F1 population derived from a cross between a globe artichoke (C3) and a cultivated cardoon (ALT) genotypes has been used to perform a genome-wide linkage analysis, leading to the elaboration of a pair of highly dense genetic maps, each derived from one of the two highly heterozygous parental genotypes. In both maps, the number of linkage groups (17) matched the species’ haploid chromosome number. The F1 population was phenotyped over two seasons with respect to plant height, stem number, capitulum number, leaf and stem fresh weight, and the dry weight of the whole plant, the leaves, the stems, the capitula and the achenes. The phenotypic data were combined with the linkage maps to identify 81 quantitative trait loci, of which 50 were placed on the C3 map and 31 on the ALT map. The loci were scattered over 13 linkage groups, and were clustered within 27 genomic regions, 22 of which harboured two or more QTL. Ten of these regions were specific to the C3 map and six to the ALT map, while the other 11 were represented on both maps. The 27 regions harboured in all 1960 genes, 83% of which could be functionally annotated. An enrichment for certain gene ontology terms was noted for the gene content of the genomic regions harbouring loci influencing seed yield and the number/weight of stems.

Identification of drought-induced genes in giant leucaena (Leucaena leucocephala subsp. glabrata)

A number of drought-induced genes have been identified from giant leucaena. Leucaena leucocephala subspecies glabrata (leucaena), which is also known as ‘giant leucaena’, is a multipurpose tree legume that can be grown and maintained as a woody tree for wood and paper pulp production, or as a shrubby legume through repeated harvest of foliage for use as a fodder. Leucaena is naturally resistant to most biotic and abiotic stresses including drought. The objective of this research was to identify drought-responsive genes in leucaena seedlings through microarray and qRT-PCR analyses. Ten thousand cDNA sequences selected from a leucaena transcriptome were screened for higher expression in a 4 × 180 k microarray using RNA isolated from drought-treated and untreated leucaena seedlings. Microarray analysis identified 73 and 39 drought-responsive genes sequences that were upregulated in the root and shoot, respectively. qRT-PCR analyses confirmed the root- and shoot-specific upregulation of some of the most highly expressed gene sequences identified in the microarray analysis. The proteins encoded by these genes could be grouped into four classes: (1) receptors that sense osmotic and oxidative stresses, (2) transcription factors, (3) degradation pathway enzymes, and (4) biosynthetic enzymes and structural proteins. The functions of these four classes of proteins can be used to explain the drought response in leucaena. The NB-LRR class of disease-resistance proteins may serve as receptors for detecting osmotic and oxidative stresses induced by drought, leading to induction of transcription factors such as zinc finger CCCH domain-containing protein and TCP14. As result, the genes for some degradative pathway enzymes, such as GDSL esterase/lipase, lipid acyl hydrolase patatin, and serine carboxypeptidase, were induced. Similarly, the expression of certain biosynthetic enzymes and structural proteins such as flavonoid 3-O-galactosyl transferase, caffeoyl-CoA O-methyltransferase, 9-cis-epoxy carotenoid dioxygenase, β-amyrin synthase, pentatricopeptide-containing protein, GPI-anchored protein COBRA, and peroxin, were also induced. High expression of some of these drought-inducible genes in leucaena seedlings may be used as a selection criterion in future breeding programs for drought resistance in leucaena and other legumes.