A group of young researchers from Canada, Finland, Sweden and USA attended the MWP Prize Event in Stockholm in October 2017. The young researchers contributed to the MWP Symposium by presenting their own research in a poster exhibition, see the below abstracts.
- FLOWERING LOCUS T genes control growth and development of forest tree species
Author(s): Domenique André, Ove Nilsson
Corresponding author: Domenique André
Affiliation: Swedish University of Agricultural Sciences, Umeå Plant Science Centre
Here we show that FLOWERING LOCUS T (FT) genes are involved in regulation of the annual growth cycle and control various aspects of tree growth, thus having a major impact on the fitness of the tree but also its value for forestry industry.
In this project we aim to elucidate the specific functions of FT1 and FT2, two FT paralogs found in the model species hybrid aspen (Populus tremula x tremuloides). Despite being very similar in sequence, both genes have highly diverged expression patterns and functions. We aim to determine which FT gene controls flowering and to further elucidate their roles in warm temperature-induced bud flush and short day-induced growth cessation, respectively. Besides temperature and light, nutrient availability also influences plant growth and new data suggest that growth responses are (at least in part) regulated through the modification of FT expression. In our experiments, the level of FT expression greatly influenced the trees’ ability to grow on nutrient scarce soil.
Prolonged growing season, improved nutrient usage and decreased flowering time are desired traits in breeding of many forest species. Our understanding of the biological processes behind these traits may lead to new applications and improved productivity of Swedish forests.
Key words: Populus, FLOWERING LOCUS T, phenology, nutrients, growth
- Accuracy of genomic selection in multi-environmental Scots pine trials in Sweden
Author(s): Ainhoa Calleja-Rodríguez 1, 2; Tomas Funda 2; Jin Pan 2; and Harry X. Wu 2
Corresponding author: Ainhoa Calleja-Rodriguez
Affiliation: 1 Skogforsk; 2 Swedish University of Agricultural Sciences
The genomic selection (GS) using dense markers has been successfully used in livestock breeding programs to accelerate the breeding cycle and increase the selection precision, resulting in an increased genetic gain per unit time.
Dealing with the large size of conifer genomes, low rates of linkage disequilibrium and the absence of genetic maps, among others, makes the integration of GS in conifer tree breeding a big challenge.
Several studies on GS have been recently published in trees, but without considering genotype x environmental (GxE) and age-age correlations.
It has been observed that incorporating GxE in crops could increase the accuracy of prediction by GS for progenies that were tested or progenies that were only tested in a subset of environments. In our Scots pine project, we are evaluating the accuracy of GS for growth and wood properties at different ages, in three genetically connected environments from the Swedish Scots pine breeding program (Skogforsk). Using genotyping by sequencing SNP markers, we will genotype 2000 offspring and 50 parents from 176 full-sib families for a critical evaluation of GS in Scots pine, including effect of GxE and age-age correlations, on the efficiency and accuracy of genomic selection. To our knowledge, this will be the first study on GS in a boreal species’ tree improvement program in Europe that will incorporate both GxE and age-age correlations.
Key words: Genomic selection, Scots pine, tree breeding, GxE interaction, age-age correlation
- Transformation of lignin into fibrous carbon materials forming 2D to 3D structure
Author(s): Mijung Cho and Scott Renneckar
Corresponding author: Mijung Cho
Affiliation: Department of Wood Science, University of British Columbia, Vancouver, CANADA
Lignin nanofibers produced by electospinning processing have great potential to become a high value fibrous material product for a new forest products industry. Although many studies focused on how to improve lignin derived carbon nanofiber properties by modifying lignin, controlling processing parameters or adding reinforcement. Very little number of studies shows the relationship their nanoscale structures and performance. Fore 20 years, nanocrystalline cellulose (NCC) has shown its effectiveness in polymer based nanocomposite systems as a reinforcing agent. In this study, technical softwood kraft lignin was turned into composite nanofiber mats with polyethylene oxide (PEO) and NCC as a potential reinforcement stage. Lignin based nanofiber mats with or without NCC loadings were transformed into carbon nanofiber mats and aerogels by different heat treatment. By loading NCC, lignin based composite nanofibers were rheologically stabilized and turned into composite carbon nanofibers without thermo-stabilization process (i.e. direct carbonization). The resulting carbon material maintained their fibrous structure and produced the partially interconnected fiber morphology with 3-5 wt% NCC loading. This surprising result was investigated to understand the relationship between performance of the carbon nanofibers and role of NCC in the lignin nanofibers. The morphology, thermo-rheological response and carbon structure of the composite nanofibers were studied and manipulated in order to create materials with shape recovery function.
Key words: Lignin, carbon nanofibers, Nanocrystalline cellulose (NCC)
- Investigating how to improve Populus tree biomass as a basis for bioproducts
Author(s): Sacha Escamez, Madhavi Latha Gandla, Marta Derba-Maceluch, Sven-Olof Lundqvist, Ewa J. Mellerowicz, Leif J. Jönsson and Hannele Tuominen
Corresponding author: Sacha Escamez & Hannele Tuominen
Affiliation: Department of Plant Physiology, Umeå University, Umeå Plant Science Centre (UPSC), SE-901 87 Umeå, Sweden
E-mail: firstname.lastname@example.org email@example.com
Moving towards a bio-based economy requires a variety of elaborate products to be refined from wood biomass. Populus species represent a promissing source of biomass thanks to their rapid growth, their well mastered cultivation techniques and their well studied physiologies and genomes, but their potential remains underexploited. One problem is that wood biomass is recalcitrant to bioprocessing, which is needed to separate its basic coumpounds such as its valuable glucose. To understand the basis for glucose yield we targeted 39 genes of interest in 40 genetically engineered Populus trees in which we measured 65 traits related to bioprocessing, growth, wood chemistry and structure. We analyzed the relationship between different biomass properties, tree growth and glucose yield through advanced multivariate analyses and mathematical modelling. A mathematical model could predict glucose yield from a subset of only seven traits, while a combination of improved glucose yield and improved growth was predicted from a subset of twenty-two traits (Escamez et al., under review; http://dx.doi.org/10.1101/124396). Hence, we identified diagnostic traits for guiding the engineering or the breeding of Populus lines with increased growth and superior bioprocessing properties. Our work provides information and tools for exploiting the full potential of Populus trees as bioproducts crops.
Key words: Wood, Biomass, Populus, Glucose, Lignin, Recalcitrance
- Towards flexible and cheap printed electronics using inks of exfoliated 2D materials stabilized by cellulose
Author(s): Viviane Forsberg, Magnus Hummelgård, Renyun Zhang, Håkan Olin
Corresponding author: Viviane Forsberg
Affiliation: Mid Sweden University
Flexible and cheap electronics are needed for simple applications such as sensors and solar cells. To achieve this, thin functional materials should be deposited efficiently to flexible substrates such as paper. A promising method for the deposition of such materials is through inkjet printing that said a stable and printable dispersion is necessary. We achieved this through liquid-based exfoliation of 2D materials in water using shear exfoliation and cellulose stabilizers. The resulted dispersion was then concentrated and inkjet printed on a flexible substrate. We used ethyl cellulose, cellulose nanofibers (CNF) and ultra-fine cellulose nanofibers (UF-CNF). All three stabilizers appear to work very well for MoS2 nanosheets even though the mechanisms of stabilization were different among them. For the MoS2-EC dispersions we achieved a broader PSD and higher dispersion stability. Thin nanosheets were observed from the SEM image of MoS2-EC dispersions deposited onto cellulose filters. The estimated concentration of the MoS2-EC dispersion after 20 days of sample preparation was 0.20 mg/mL. This dispersion was further processed to adjust the concentration and viscosity. Good coverage of the substrate was achieved after 50 printing passes. If the same technique is applied to other 2D materials such as
graphene (conductor) and boro nitride (insulator), a transistor can be fabricated.
Key words: Cellulose stabilizers, 2D ink, 2D materials, Flexible electronics, Cheap transistors
- Non-destructive wood quality assessment in Scots pine
Author(s): Irena Fundova 1, 2), Harry Wu 1), Tomas Funda 1)
Corresponding author: Irena Fundova
Affiliation: 1) Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences (SLU); 2) Forestry Research Institute of Sweden (Skogforsk)
Scots pine is the second most commercially significant tree species in Sweden. Its current national breeding program has targeted the improvement of stem volume, with genetic gain of more than 10% achieved. However, stem volume is negatively correlated with wood quality traits such as density or stiffness, which are crucial for timber utilization. It is therefore of vital importance to develop a suitable strategy for improving both volume and wood quality traits simultaneously. This brings a need 1) to find non-destructive methods that would provide reliable estimates of wood quality on standing trees and 2) to investigate inheritance of wood quality traits and their relationships with stem volume.
We tested three non-destructive methods: steel pin penetration (Pilodyn), drilling resistance (Resistograph) and acoustic velocity (Hitman) and compared their results with those from an x-ray analysis (SilviScan). X-ray analysis is a highly accurate, non-destructive method but, at the same time, it is enormously time and labor intensive, thus unsuitable for large-scale evaluation. Currently, we are conducting a sawmill study with the aim of linking wood quality assessment at different phases of wood processing – on standing trees, logs, and final sawn-boards. The data will be used to build a multiple selection index for a joint improvement of growth and wood quality traits in Scots pine.
Key words: Scots pine, genetic improvement, wood quality traits, Resistograph, Pilodyn, Hitman, sawmill
- Aligned biodegradable cellulose reinforced nanocomposites with high strength and toughness
Author(s): Shiyu Geng 1), Kun Yao 2), Maria Harila 1), Maxime Noël 1), Qi Zhou 2), Kristiina Oksman 1)
Corresponding author: Shiyu Geng
Affiliation: 1) Luleå University of Technology, Division of Materials Science, SE-971 87 Luleå, Sweden; 2) Royal Institute of Technology, School of Biotechnology, SE-100 44 Stockholm, Sweden
Cellulose, as the most abundant component in wood, has attracted a lot of attention for utilizing it in environmentally-friendly applications to replace the fossil-based materials. Nanocellulose materials with high stiffness and strength, large surface area and biodegradability, are promising reinforcement in polymers. However, the energy consumption of nano-scale isolation of cellulose and the dispersion of nanocellulose materials in the polymers are still challenging for obtaining low-cost and ultra-strong nanocomposites. To overcome these, we focus on investigating the aligned nanocomposites reinforced by a very low cellulose nanofibers (CNF) content (0.1 wt%), and grafting polyethylene glycol (PEG) on CNF was performed to improve the dispersion of them. We found that the alignment can improve mechanical properties of the polylactic acid (PLA)/CNF composites dramatically. With a draw ratio of 8, the strength of the aligned composite reached 320 MPa and the toughness was 30 times enhanced compared to the isotropic material. Much better dispersion of the CNF grafted with PEG in PLA matrix was confirmed by scanning electron microscopy (SEM) compared to the ungrafted CNF, and further supported by the mechanical testing results. Furthermore, the aligned nanocomposites exhibited light scattering behavior indicating they have the potential to be used in optical applications.
Key words: Nanocellulose; Alignment; Grafting; Mechanical property; Optical property
- Tunable materials from industrial lignin fractions
Author(s): Claudio Gioia; Martin Lawoko, Giada Lo Re; Lars Berglund
Corresponding author: Claudio Gioia
Lignin represents the most abundant source of renewable aromatic structures on the planet, readily available on industrial scale. Technically, it is a by-product in the production of cellulose-rich fibers. The huge potential of such macromolecule currently hosts the expectations of both academia and industries towards a key field such as renewable and sustainable material science.
Due to its biological synthesis and to the different extractive processes, lignin is constituted by a huge variety of chemical structures. Unfortunately, such heterogeneity deeply reduces the applicability of lignin producing materials presenting unpredictable and poorly reproducible behaviour.
The aim of my research is to demonstrate the possibility to refine industrial lignin in order to produce well characterized lignin fractions. Such controlled intermediates are employed for the production of materials presenting specific and reproducible properties. Furthermore, the different lignin structures involved are also directly responsible for the main thermo-mechanical properties of the materials.
In particular, we are currently able to choose a specific lignin fraction to tune the properties of the corresponding material in order to tailor a required application.
Key words: Industrial lignin refining; reproducible fractions; selective modification; tunable mechanical properties
- Furfural production from xylose in a bi-phasic set-up
Author(s): Gomez Millan, Gerardo; Hellsten, Sanna; Llorca, Jordi; Sixta, Herbert.
Corresponding author: Gomez Millan, Gerardo
Affiliation: Aalto University
In recent years we have witnessed much activity to upgrade sugars contained in side-streams from the pulp and paper industry into ethanol and other value-added chemicals. An interesting catalytic route, namely the dehydration of sugars to furans, is considered one of the most promising routes for the production of platform chemicals and fuels. Furans such as furfural are highlighted in the “Top 10 + 4” by the United States Department of Energy list as the most rewarding bio-based platform molecules1. The current furfural production uses mineral acids at approx. 200 °C, providing around 50 mol% yield. These mineral acids possess several drawbacks, e.g., high toxicity, corrosiveness, difficult recovery and large salt waste after work-up. The purpose of this study is to replace compare two organic solvents to improve the selectivity to furfural and avoid its decomposition. This approach may offer several advantages over current processes in the conversion of pentosan derivatives e.g. xylose into furfural: high yields and facile extraction.
In the present study, two organic solvents have been compared: 2-Methyltetrahydrofuran (2-MTHF) and Isophorone. 2-MTHF shows a better selectivity to furfural and the highest yield (82%) was obtained at 190 °C in 3 hours. Besides, this bi-phasic system performs better than aqueous systems and un-catalyzed reaction, as this study demonstrates.
The results of this work could be used to produce platform chemicals from sugar-based side-streams in the forestry industry, in particular from the pre-hydrolysate liquor generated during dissolving pulp production. These obtained value-added products have applications in a wide range of industrial branches (biofuel, pharmaceutical, agrochemical, petrochemical and chemical industry, among others).
Key words: Furfural, xylose, CPME, MTHF, Isophorone
- Capturing the Uncatchable – Cellulose Nanofibrils for Clean Technology
Author(s): Minna Hakalahti 1, Marco Faustini 2, Cédric Boissière 2, Eero Kontturi 3, Tekla Tammelin 1
Corresponding author: Minna Hakalahti
Affiliation: 1 High Performance Fibre Products, VTT Technical Research Centre of Finland Ltd, 02150 Espoo, Finland; 2 Sorbonne Universités, UPMC Univ Paris 06, CNRS, Collège de France, UMR 7574, Chimie de la Matière Condensée de Paris, F-75005, Paris, France; 3 Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, 02150 Espoo, Finland
Capturing of small particles is immensely topical, as pollutants are accumulating in the environment at an alarming rate due to human activity. Cellulose nanoparticle films have been shown to function as an efficient membrane material for capturing heavy metal ions from water. Using the unique features of cellulose nanofibrils (CNF) – strong affinity for water, nanoscale structure and high density of hydroxyl groups – films made thereof could also be promising templates for capturing pollutants that escape existing filter systems. However, understanding of the bionanomaterial beyond simple characterization is needed in order to harness its innate features for use as pollutant-capturing membranes. We address this demand by systematically investigating the humidity-response of (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) oxidized cellulose nanofibril (CNF) films. We use the Quartz Crystal Microbalance with Dissipation monitoring and the Spectroscopic Ellipsometry coupled with quantitative modelling to build a comprehensive view of the water interactions of CNF, and to reveal underlying sorption mechanisms and water transport properties. The work provides new insights into the peculiar behaviour of CNF and paves the way for utilizing the nanoscaled biomaterial in unprecedented ways in future membrane materials and biofilters to catch pollutants beyond the capability of current systems.
Key words: Cellulose nanofibril films, pollutants, sorption, membranes
- QualityWBPs – Innovative treatments and adhesives for high quality, sustainable wood-based panels
Author(s): Reza Hosseinpourpia, Stergios Adamopoulos, Carsten Mai
Corresponding author: Reza Hosseinpourpia
Affiliation: Department of Forestry and Wood Technology, Linnaeus University
Forest product industry is an important industrial sector in Sweden by comprising of 15-20% of total industrial investments. One of the imminent challenges that this sector has faced is to meet the expected increasing demand and efficient use of raw materials resulting from the promotion of renewable energy sources. This target can be accomplished through interdisciplinary approaches for a more sustainable use of resources and development of environmentally-friendly products. A number of scientists and industries are struggling to decrease the usage of formaldehyde-based adhesives and to shift towards more eco-friendly adhesives in the production of wood panels, such as particleboards and fiberboards. This is not only due to their abundance and low cost, but also to the potential hazard to the environment and human health of the formaldehyde-based adhesives used in the wood panel industries. Starch, a potential eco-friendly adhesive, is an important and interesting biopolymer. However, due to some major drawbacks such as insufficient bonding strength, poor water resistance, and sensitivity to biological degradation, the application of starch polymer as a sole adhesive system in manufacturing of wood panels has been limited. This research project focuses at production of sustainable wood-based panel bonded with improved starch-based adhesives.
Key words: Biopolymer, eco-friendly adhesive, forest product industry, sustainable production, wood-based panel
- Novel lignin based thermoset resins
Author(s): Marcus Jawerth, Mats Johansson, Stefan Lundmark, Claudio Gioia, Martin Lawoko
Corresponding author: Marcus Jawerth, Claudio Gioia, Martin Lawoko
Affiliation: Wallenberg Wood Science Center, WWSC
Lignin has long been considered a waste stream of the pulp and paper industry and has to a large extent been burnt for energy recovery. In recent years, however, the interest to utilize lignin in more value added applications has increased dramatically. Its aromatic structure makes it a potential renewable and abundant resource to replace fossil based aromatics in e.g. material applications. Utilizing this raw material is not without hurdles to overcome; heterogeneity in molecular weight and functionalities are, e.g., two properties one must consider. The aim of this Ph.D. project is to provide tools for precise chemical tailoring of lignin for incorporation in new thermoset resin systems. This far, lignin model compounds and industrial Kraft lignin has been selectively modified by allylation of phenolic groups. The allyl ether is a versatile chemical handle that can be used in various resin systems and provide a platform for different reaction pathways. The aromatic structure of lignin provides molecular rigidity to the cured thermoset, resulting in a polymeric material with relatively high glass transition temperature. The chemically modified lignin has been cured using thermally induced thiol-ene chemistry to obtain thermosets. The material is transparent, homogeneous and has no residual smell of thiol.
Key words: Thermoset resin, Kraft lignin, selective allylation, thiol-ene
- Next-Generation sequencing technologies in tree improvement and conservation genetics of Dipteryx oleifera Benth
Author(s): Jose P. Jimenez 1,2; Olman Murillo2; Theodore H. Shear1; Ross W. Whetten1
Corresponding author: Jose P. Jimenez 1,2
Affiliations: 1North Carolina State University; 2 Instituto Tecnológico de Costa Rica
E-mail: firstname.lastname@example.org, email@example.com
Dipteryx oleifera is endemic to the Caribbean lowlands, ranging from Nicaragua to Colombia. This keystone tree species provides food and shelter for many mammals and birds, including the endangered great green macaw. In addition, its high-quality wood has significant economic value. However, illegal logging and habitat fragmentation have diminished natural populations to the point that trade of the wood is now controlled by international treaty (CITES). This research constitutes the first steps in reversing that trend. The goal is to develop genomic resources to aid tree improvement and conservation efforts in a D. oleifera breeding program. Next-generation sequencing technologies provide an ideal platform to accomplish this goal, because it allows for whole-genome study at relative low cost. Furthermore, it enables the identification of thousands of single nucleotide polymorphisms (SNPs) in multiple individuals simultaneously. SNPs are ubiquitous, codominant, and can be in functional parts of the genome, thus making them suitable markers for both tree improvement and conservation genetics. Our breeding program will pursue the selection and deployment of improved genotypes; this can alleviate logging pressure on natural populations by providing better seeds for plantation forestry and climate resilient trees for reforestation, a much-needed trait since extreme weather conditions – higher temperatures, drier summers, and wetter winters – are expected to become more frequent in the tropics.
Key words: Dipteryx oleifera, next-generation sequencing (NGS), genomics, genotyping by sequencing
- Controlling dispersion properties of cellulose nanofibrillar systems by surface modification for melt-processed bio-nanocomposites with enhanced performance
Author(s): Tahani Kaldéus, Eva Malmström, Lars Berglund and Giada Lo Re
Corresponding author: Tahani Kaldéus
Affiliation: KTH Royal Institute of Technology
With the environmental awareness towards a sustainable society, great efforts are nowadays invested to replace conventional plastics and hence decrease the dependency of materials generated from fossil fuel. Modern nanofibre reinforced bio-composites produced from renewable materials will in the future most probably be made exclusively from aqueous dispersions containing both the matrix polymer and nanofibres for reinforcement. In order to fully utilise the excellent inherent properties of the nanofibres it is essential to distribute them homogeneously throughout the formed nanocomposite and to avoid aggregation.
In our current work, we have focused on a one-step wet-feeding nanofibre reinforced bio-composite system consisting of poly(ε-caprolactone) (PCL), a biodegradable thermoplastic with unique process properties similar to low-density poly(ethylene) (LDPE), and reinforcing nanocellulose fibrils (CNF) which have been surface modified in water with an amphiphilic statistical copolymer (MX) in order to enhance the interfacial interactions between the polymer matrix (PCl) and the reinforcing part (CNF). The effect of the wet feeding and the surface modification on the composite morphology has been assessed as well as the wet feeding extrusion in comparison to traditional dry feeding melt-processes.
Key words: nanofibre reinforced bio-nanocomposite, cellulose nanofibrils, surface modification, dispersion properties, interfacial interactions
- Super-extensible paper for 3D forming
Author(s): Alexey Khakalo, Jarmo Kouko, Ilari Filpponen, Elias Retulainen, Orlando J. Rojas
Corresponding author: Alexey Khakalo
Affiliation: VTT Technical Research Centre of Finland Ltd, P.O. Box 1000, FI-02044, Espoo, Finland
The typically poor ductility of cellulosic fibers and ensuing bonded networks and paper webs set a limit in any effort to produce associated three-dimensional structures without relying on chemical, often unsustainable, approaches. To address this challenge, we report on a facile and green method that combines mechanical and biopolymer treatment: In-plane compression and aqueous solution permeation via spraying. The first enabled network extensibility while the second, which relied on the use of protein, improved network strength and stiffness. As a result, an unprecedented elongation of ~30% was achieved after unrestrained drying of the paper. At the same time, the structures experienced a significant increase in tensile strength and stiffness (by ~306% and ~690%, respectively). Such simultaneous property improvement, otherwise very difficult to achieve, represent a substantial gain in material’s toughness, which results from the synergistic effects associated with the mechanical response of the network under load, fiber intrinsic strength and inter-fiber bonding. The level of plasticity developed in fiber webs allowed the synthesis of 3-D packaging materials via direct thermoforming. Overall, an inexpensive, green and scalable approach is introduced to expand the properties spaces for paper and related nonwovens that allows 2D and 3D formability of fiber networks.
Key words: paper toughness, extensibility, formability, 3D forming, chemical modification
- Introducing a new fast method to assess the chemical reactivity of cellulose under mild conditions
Author(s): Pegah Khanjani
Corresponding author: Pegah Khanjani
Affiliation: Aalto University
The reactivity of cellulosic materials has been a topic of continuous interest in their conversion into various products, such as cellulose derivatives, regenerated textile fibers and monosaccharides for biofuel production. The natural structure of cellulose, which is characterized by the assembly of elementary fibrils (EFs) and their highly ordered crystalline regions stabilized by intramolecular and intermolecular hydrogen bonds, limits its reactivity. Besides the crystal surfaces, amorphous regions of EFs are often considered to be accessible to solvents and chemical reagents. The definition of chemical reactivity of cellulose depends on its application. In textile fiber production the reactivity of dissolving pulps from different raw materials and with different processes has been assessed by a microscale viscose process. We recently introduced a new fast method to assess the chemical reactivity of cellulose under mild conditions (room temperature, pH 9) by using 4-acetamido-2,2,6,6-tetramethylpiperidine-1-oxo-piperidinium cation (4-AcNH-TEMPO+) as a stoichiometric oxidant of hydroxymethyl groups. The method provides an absolute amount (mmol/g) or fraction (percentage on theoretical maximum) of hydroxymethyl groups that react easily (in ca 15 min) with 4-AcNH-TEMPO+. Bleached softwood and hardwood pulps as well as bacterial cellulose (BC) were analyzed for their chemical reactivity and a number of indirect measures of reactivity. The method complements the more traditional, indirect methods, such as water retention value, fiber saturation point and specific surface area, in characterizing various pulps. Eventually, we observed differences in the reactivity of the pulps of different origin that result from the processes applied especially at elevated temperature.
Key words: Bacterial cellulose, accessibility, reactivity, oxidation, 4-acetamido-TEMPO+, iodometry, UV–vis spectrophotometry
- Water solubility of softwood hemicelluloses
Author(s): Saina Kishania b), Francisco Vilaplanab c), Wenyang Xu d), Chunlin Xu d), Lars Wågberg a), b)
Corresponding author: Saina Kishani, Lars Wågberg
Affiliation: a) School of Chemical Science and Engineering, Fibre and Polymer Technology, Royal Institute of Technology, Teknikringen 56-58, SE-10044 Stockholm, Sweden; b) Wallenberg Wood Science Centre (WWSC), Teknikringen 56-58, SE-10044 Stockholm, Sweden; c) School of Biotechnology, Division of Glycoscience, Royal Institute of Technology, Albanova University Centre, SE-10691 Stockholm, Sweden; d) Johan Gadolin Process Chemistry Centre, Laboratory of Wood and Paper Chemistry, Åbo Akademi University, FI-20500, Turku/Åbo Finland.
E-mail: firstname.lastname@example.org email@example.com
A fundamental understanding of the solubility/dispersibility of wood biopolymers is crucial to develop new materials from wood; such as films and barriers from hemicelluloses. We have performed careful study where the molecular solubility and solution properties of softwood hemicelluloses have been determined applying light scattering, microscopy, and chromatography techniques. Softwood hemicelluloses have been isolated using different preparation and separation methods. A comparison between the Molar mass (Mw) data and the dimensions from Dynamic Light Scattering (DLS) measurements, indeed show that the hemicelluloses are aggregated even though they produce clear dispersions. The morphology characterizations are also in agreement with the size measurements and indicate the extracted hemicelluloses are not molecularly dissolved in aqueous media. However, the molecular solubility differs for the differently extracted samples.
This work provides a well-defined isolation, and fundamental characterization of molecular solubility of softwood polysaccharides obtained from bio-based resources. These new findings, regarding the molecular solubility, will be used to determine how films from these materials are formed upon drying and how this will affect the barrier and mechanical properties of the films.
Key words: Thermomechanical pulp, Hemicellulose, Galactoglucomannans, Isolation, Solubility
- Zero-valent iron modified carbon sorbents from biomass wastes for water treatment
Author(s): Ivan Kozyatnyk
Corresponding author: Ivan Kozyatnyk
Affiliation: Umeå University, Department of Chemistry
My current post-doc project is focusing on after-treatment of end-of-life biochar adsorbents and comparative evaluation with regard to both environmental and economical sustainability. The task is to examine how biochar from low-value biobased residues, used as adsorbents in water treatment applications, should be treated in the most sustainable way. Three alternative management strategies will be compared: 1) incineration with energy recovery, 2) landfilling, and 3) regeneration. The sustainability assessment will mainly be based on life cycle analysis where the environmental impact of biochar adsorbent is evaluated throughout its complete lifecycle, from production to the end-of-life-treatment of the material.
The main idea of project I am applying for will focus on the production of carbon sorbents from different types of biomass wastes (wood cheeps, sawdust, bark etc.) and modification of these with nano zero-valent iron. This research will potentially create a possibility for economic growth by introducing more effective method for treatment of wastewater. Strengthening the competitiveness and growth of companies by developing innovations meeting the needs of European and global markets, by delivering such innovations to the public and private markets. For the industry, this will reduce costs, decrease environmental impact and increase energy efficiency compared to current practices.
Key words: nano zero-valent iron, biomass, wastewater, adsorption, carbon sorbents, emerging pollutants
- Roll-to-roll processing of nanocellulose into barrier and functional coatings
Author(s): Vinay Kumar, Douglas Bousfield, Martti Toivakka
Corresponding author: Vinay Kumar
Affiliation: Åbo Akademi University
Paper products with barrier and functional coatings have attracted interest in recent years to counter the stagnating demand for traditional graphic paper grades. Nanocellulose with its exceptional properties and wide-ranging applications seems promising as a coating material. Excellent oil and gas barrier properties along with functionalization ability of nanocellulose films and coatings are particularly interesting. It is crucial to produce nanocellulose films and coatings on a large scale to reap these benefits. However, nanocellulose suspensions cannot be easily coated or formed into films with traditional coating and metering constructions due to either clogging caused by the aggregation of fibers or due to excessively high viscosity, which cause coating and film defects, poor coating/film quality or otherwise poor process runnability.
Coating of nanocellulose suspensions herein is enabled by utilizing their apparent shear thinning behavior, which allows working with low effective process viscosity material. A slot die is used in an unconventional manner where it acts as both a shearing and a metering element. The process developed in this work successfully demonstrates the possibility to coat nanocellulose on paper in a continuous roll-to-roll manner, which is an effective potential solution to replace oil-based materials with their “green” alternatives. Continuously processable nanocellulose films and coatings on industrial scale could very well be the future of day-to-day packaging applications in a sustainable society, which may help restore forest-based industry profitability and contribute to curbing the menace of climate change and achieving a sustainable planet.
Key words: Roll-to-roll coating, slot die, nanocellulose, high shear rheology, barrier properties
- Genetic parameter estimates for fusiform rust disease from a multi-environment trial of loblolly pine (Pinus taeda)
Author(s): Eddie Lauer, Fikret Isik
Corresponding author: Eddie Lauer
Affiliation: North Carolina State University Tree Improvement Program
Fusiform rust, caused by the fungal pathogen Cronartium quercuum (Berk) Miyabe ex. Shirai f. sp. fusiforme, is a serious disease of loblolly pine plantations, causing multimillion-dollar losses to landowners. When Fr loci in host trees are challenged with single genotype lines of the fungal pathogen, the inheritance of fusiform rust disease behaves like a traditional Mendelian inheritance. However, at the population level, rust resistance appears more quantitative in nature, due to the presence of multiple Fr genes segregating among different families, which confer resistance to different races of the pathogen. In this study, a dataset of 11987 trees from 68 half-sib families of loblolly pine tested across 10 environments was analysed to understand the heritability and patterns of GxE interactions for fusiform rust resistance. Heritability of family means was 0.91, indicating that a substantial amount of phenotypic variation in the field can be explained by among-family differences. GxE interactions for fusiform rust resistance were minimal, as indicated by the high additive genetic correlation between pairs of sites (0.77). The results of this study indicate that mapping efforts targeting these large effect Fr genes could provide useful markers to improve the accuracy of genomic selection models, and accelerate marker-assisted breeding of southern pines in the US.
Key words: Fr gene-pathogen interactions, Fr resistance genes, tree breeding, genotype by environment interactions
- Distinct cell wall properties contribute to plant cell polarity
Author(s): Mateusz Majda & Stephanie Robert
Corresponding author: Mateusz Majda (PhD student), Stephanie Robert (Prof., supervisor)
Affiliation: Umeå Plant Science Centre (UPSC), Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences (SLU)
E-mail: Mateusz.Majda@slu.se ; Stephanie.Robert@slu.se
Developmental changes in plants are mediated by cell elongation, which is a very complex process due to the presence of cell wall outside the cell membrane. Cell wall is a composite material consisting of a network of different polysaccharides, which are fairly rigid and provide protection to the cell. However, this compartment also needs to be flexible to allow cell elongation and general growth. The aim of our research was to understand the implication of cell wall mechano-chemical properties in triggering cell shape and overall organ development. We studied multipolar epidermal pavement cells, a powerful model to investigate the cellular and subcellular processes underlying shape determination in plant tissues. Combining genetics, atomic force microscopy, electron microscopy and immunolabeling, we demonstrated that contiguous cell walls exhibit indeed hybrid mechano-chemical properties. We determined heterogeneous mechanical properties along and across sinuous pavement cell walls. Furthermore, we related the local softening of the cell wall to specific distribution of some cell wall components. Such cell wall heterogeneities precede morphological changes in the cell shape. Overall, our results support a scenario in which multipolar cell shape relies on finely tuned modifications of cell wall composition and mechanical properties. Altogether, this provides a novel and more realistic mechanism for the generation of complex plant cell shapes.
Key words: Cell, polarity, elongation, cell wall, heterogeneity, biomechanics
- How Genomics is shaping the future of Christmas trees
Author(s): Lilian Matallana 1), Jill L. Wegrzyn 2), Kathryn Coats 3), Gary Chastagner 3), John Frampton 1) and Ross Whetten 1)
Corresponding author: Lilian Matallana
Affiliation: 1) Department of Forestry & Environmental Resources, College of Natural Resources, North Carolina State University, Raleigh, NC. USA; 2) Department of Ecology and Evolutionary Biology, University 10 of Connecticut, 75 North Eagleville Road, Storrs, CT 06269-3043 USA; 3) Department of Plant Pathology, Washington State University Research and Extension Center, Puyallup, WA, USA.
In spite of ongoing progress in plant genomics, a thorough and practical understanding of forest genomics is still in its infancy, especially for conifer genomes. The real Christmas tree industry (RCTI) is an important component of American and European economies. One of the main challenges for RCTI is the identification and prediction of trees that show high needle retention after harvesting. This is because consumers are more likely to buy artificial trees to avoid the messiness associated with needle shedding. Abscission of different organs is a universal process in the plant kingdom. While there is evidence that this process depends on shared groups of master gene regulators, little is known about the diversification of the process during plant evolution and the relation with environmental adaptation. Abies fraseri is the most sold Christmas tree in North America and the only Abies species endemic to the southern Appalachian Mountains. Eastern North American Abies provide an excellent opportunity to study the effects of species distributions and genetic variation of important traits such as needle retention. We have developed and validated a high-throughput system for conifer RNA extraction and constructed the first reference transcriptome for A. freaseri. We are also validating a computational Abies RNA-seq data analysis pipeline using a combination of computational tools and laboratory techniques. The ultimate goals of these efforts are to better understand conifer genomes and needle abscission, and to develop genetic marker systems to predict needle retention variation and other important traits that support farmers and RCTI market competitiveness.
Key words: Genome, conifer, abscission, RNA-seq, Christmas tree industry
- Mechanical Properties of Cellulose Nanofibers-Graphene Oxide Biocomposite
Author(s): Hanieh Mianehrow, Lars Berglund
Corresponding author: Lars Berglund
Affiliation: Wallenberg wood science center, Kth Royal Intitule of Technology, Stockholm, Sweden
With respect to the importance of high performance bio-based composites, an attempt was made to prepare biocomposites based on cellulose nanofibers (CNF) and Graphene oxide (GO) to study the synergistic effect of their superior properties on the resultant biocomposite. Different samples containing 0.1 – 4 wt% of GO were prepared by vacuum filtration and characterized using Scanning electron microscopy (SEM), Atomic Force Microscopy (AFM), X-ray diffraction spectrophotometry. Then, the mechanical properties of the resultant composites with different mass ratios of GO were measured using tensile test. Results showed that the addition of only 0.1 wt% of GO to CNF, increases the modulus of the nanocomposite from 13.5 GPa for pure CNF to 17.3 GPa. This effective reinforcement only by adding a small amount of GO, which is more than what rule of mixture predicts, apparently shows the efficient stress transfer between CNF and GO that is the result of utilizing large GO sheets with high aspect ratio, effective dispersion of GO in the nanocomposite and the layered structure of the resultant nanocomposite.
Key words: Biocomposite, Cellulose Nanofibers, Graphene Oxide, Mechanical properties
- Expandable cellulose capsules
Author(s): Katarzyna Mystek, Anna Svagan, Per Larsson and Lars Wågberg
Corresponding author: Katarzyna Mystek
Affiliation: KTH Royal Institute of Technology, Department of Fiber and Polymer Technology, School of Chemical Science and Engineering, Stockholm, Sweden.
In recent years, there has been an increasing interest in application of new, innovative materials and technologies based on natural polymers. One of the most abundant biopolymers is cellulose, which due to its unique structure possesses unique properties including mechanical strength and chemical stability. The aim of my research is to create a fundamental understanding of the formation of cellulose based capsules, as well as modification of cellulose, to allow for a significant expansion of the capsules without breaking the capsule wall. As a first step to achieve this purpose, we propose a unique solution precipitation method in order to obtain capsules made with regenerated and ductile cellulosic material, created by heterogeneous periodate oxidation followed by borohydride reduction of the native cellulose. Such prepared capsules can find different end-use applications, for example in packaging, insulation and cosmetics. Moreover, they can successfully replace already commercial thermoplastic microspheres.
The initial focus of our work will be on the application of novel methods to obtain homogeneous and different sized cellulose capsules and to tailor a controlled release of materials from the interior of the capsules. An effective encapsulation of biologically active substances and their controlled diffusion through the capsule wall would allow the capsules to be used as a drug delivery system.
Key words: Capsules, cellulose, ductility, expansion
- Genetic architecture of gene expression in Populus tremula
Author(s): Niklas Mähler, Jing Wang, Barbara K Terebieniec, Kathryn M Robinson, Pär K Ingvarsson, Torgeir R Hvidsten, Nathaniel R Street
Corresponding author: Niklas Mähler
Affiliation: Umeå Plant Science Centre, Department of Plant Physiology, Umeå University
Natural variation is widespread in Swedish aspen (Populus tremula), and much of this variation is highly heritable, suggesting that the phenotypic variation we observe cannot be attributed to environmental factors and that it originates from the genome. DNA is transcribed and consequently translated into proteins that act as the building blocks and the machinery of the cell. This process is immensely complex, which is why some of the phenotypic variation cannot be explained by genetic variation using conventional approaches. To improve our understanding of what type of genetic variation controls gene expression we used the Swedish Aspen collection (SwAsp) to associate gene expression, i.e. transcript abundance, with genetic variation. We associated the expression of 22,306 genes with 3.2 million Single Nucleotide Polymorphisms (SNPs) and identified 164,290 significant expression Quantitative Trait Loci (eQTLs). The advances in quantification of individual gene transcripts in recent years have also made it possible to identify transcript eQTLs. We find genes that on the gene level are not significantly associated with genetic variation, but have significant associations on the transcript level. We took these associations and compared them with results from genome wide associations with metabolites and saw that SNPs associated with the abundance of some metabolites were also associated with the expression of some genes. These results can help to build an understanding of what components are involved in synthesising these metabolites, which is currently unknown. We are now developing a public, interactive tool that can be used to explore these types of data.
Key words: systems genetics, association mapping, GWAS, eQTL mapping
- Large area electrodes for supercapacitors by carbonization of electrospun lignin nanofibers
Author(s): Maxime Noël a), Peter Oléhn a), Shiyu Geng a), Olli Pitkänen b), Krisztian Kordas b), Mehdi Jonoobi c), and, Kristiina Oksman a), d)
Corresponding authors: Maxime Noël, Kristiina Oksman
Affiliation: a) Department of Engineering Sciences and Mathematics, Luleå University of Technology, SE-97187 Luleå, Sweden; b) Microelectronics, University of Oulu, Finland; c) Department of Wood and Paper Science and Technology, Faculty of Natural Resources, University of Tehran, Karaj, Iran; d) Fibre and Particle Engineering, University of Oulu, Finland
E-mail: Maxime.Noel@ltu.se ; Kristiina.Oksman@ltu.se
The continuous increase in energetic demand has led to the search for new solutions of energy storage applications. In this regard, supercapacitors have emerged as promising alternatives to replace or to be combined with batteries. A supercapacitor relies on the electrical adsorption of ions at the interface between electrodes and an electrolyte. Usually nanosized carbon materials, such as carbon nanotubes are used because of their high specific surface area as well as good electrical conductivity. Nonetheless, the need of reducing impact on environment as well as the high price of these materials calls for new ways of production of carbon nanomaterials. This study explores the possibility of development of large area carbon electrodes from lignin, the second most abundant natural polymer on the Earth. Electrospinning of lignin based nanofibers results in a mesoporous fiber network that can be kept intact after the carbonization process and will lead to attractive electrochemical properties suitable for supercapacitors. In this study optimization of the carbonization processes in order to tune the assets of the resulting electrodes were investigated. The carbon structure of the mats was studied using Raman Spectroscopy, the morphology of the fibers was studied using X-high resolution electron microscopy and their electrochemical properties were evaluated.
Key words: Lignin, electrospinning, carbon nanofibers, supercapacitors
- Novel synthetic expression system (SES) provides a universal genetic engineering platform for forest biotechnology
Author(s): Anssi Rantasalo, Heiko Rischer, Kirsi-Marja Oksman-Caldentey, Jussi Jäntti & Dominik Mojzita
Corresponding author: Anssi Rantasalo
Recent advancements in genomics and gene editing technologies are providing enabling technologies for forest biotechnology. The new methods are expected to significantly speed up gene discovery in tree development studies and in establishing efficient breeding technologies for improved properties. In order to enable the full benefit of the current methods there is a high demand for molecular tools for predictable and adjustable gene expression. The existing tools for plant engineering with well characterized and robust performance are largely lacking. We have developed a novel technology, the synthetic expression system (SES), which provides a universal genetic engineering platform for a broad range of organisms from eukaryotic micro-organisms to plants (Patent application PC6118-015234FI). The system is based on DNA parts that enable efficient and predictable functionality. In Agrobacterium infiltrated tobacco leaves precise tuning of mCherry reporter gene expression levels from very low to several fold over the most commonly used CaMV 35S plant promoter levels was achieved. We are convinced that the SES technology will have a high impact to understand gene function for the structural and physiological studies of trees, and it offers unprecedented opportunities in forest biotechnology.
Key words: synthetic biology, gene expression, plant expression system, forest biotechnology
- Forest trafficability prediction by fusion of open data, hydrologic forecasts and harvester-measured rolling resistance and rut depth
Author(s): Salmivaara, Aura; Launiainen, Samuli; Ala-Ilomäki, Jari; Laurén, Ari; Tuominen, Sakari; Finér, Leena
Corresponding author: Salmivaara, Aura
Affiliation: Natural Resources Institute Finland
Forest operations can harm forest growth and water quality through soil rutting and compaction, particularly when bearing capacity of soil is low. Bearing capacity is influenced by soil type, moisture, stoniness and amount of roots, and is highly variable in space and time. Smart tools are needed to predict trafficability conditions and plan forest operations to minimize negative environmental impacts. We aim to develop a model framework that will combine soil moisture forecasts, open spatial data and field measurements of rolling resistance and rut depth collected by forest machines. We develop methods for measuring trafficability as part of forest operations, and explore the potential for dynamic trafficability predictions nation-wide in Finland.
Work flow and related results:
Three field tests in southern and central Finland during 2016-2017.
On-site measurements: Rut-depths measured by forest machine-mounted LiDAR sensor and
rolling resistance measured by harvester CAN-BUS channel.
A spatially distributed hydrologic model is used to predict dynamics of soil moisture at 16x16m spatial and daily temporal resolution using weather observations and forecasts.
Geographically weighted regression (GWR) models are developed based on predicted soil moisture and open spatial data, such as soil maps, derivatives of digital elevation model and multi-source national forest inventory, to explain: (1) the rut depths and (2) the rolling resistance.
The dynamic trafficability prediction framework is demonstrated both at the field sites and on regional scale.
Key words: forest trafficability, bearing capacity of soil, soil moisture, forest machine instrumentation, rut depth, rolling resistance, CAN-BUS channel, data fusion, distributed hydrological model, GWR
- In vitro Biocatalytic Pathway and Process Design for Sustainable Terpene-based Materials
Author(s): Björn Schmidt†, Arne Stamm, Linda Fogelström, Mattias Tengdelius, Jörg Brücher, Eva Malmström Jonsson, Uwe Bornscheuer, Per-Olof Syrén*
Corresponding author: Per-Olof Syrén
Affiliation: KTH Chemistry
E-mail: firstname.lastname@example.org †, email@example.com *
The extensive use of fossil resources to produce petroleum-based materials at levels surmounting 300 Megaton/year is associated with severe impacts on our climate and environment. Still, the proportion of bio-based polymers only correspond to 1% of all man-made materials today. This has evoked an urgent need to find alternative bio-based resources as feed-stock for polymer synthesis. Our interdisciplinary research project aims at developing novel and renewable biomaterials from underutilized molecules from forestry waste using green technologies. To achieve this, we capitalize on a systems biocatalysis approach that combines artificial pathway design in concert with in vitro synthetic biology, enzyme design and polymer chemistry. Using this unique concept, we have developed a synthetic route towards a new polymer starting from α-pinene, an abundant terpene in pine wood extractives. For the purpose of generating monomers for renewable terpene-based polyesters, the enzyme cyclohexanone monooxygenase from Acinetobacter sp. (Ac-CHMO) has been engineered for the production of bio-based lactones. Thus, herein we demonstrate how currently overlooked terpene side-streams from paper mills and wood industries offer highly versatile molecular building blocks for developing novel bio-based materials enabled by innovative biotechnologies.
Key words: Systems biocatalysis, enzyme, terpenes, polymers, enzyme cascades, enzyme engineering , oxidoreductases
- Improving Wood Properties for Wood Utilization Through Multi-Omic Integration in Lignin Biosynthesis
Author(s): Jack P. Wang, Megan L. Matthews, Cranos M. Williams, Rui Shi, Chenmin Yang, Sermsawat Tunlaya-Anukit, Hsi-Chuan Chen, Quanzi Li, Jie Liu, Chien-Yuan Lin, Punith Naik, Ying-Hsuan Sun, Philip L. Loziuk, Ting-Feng Yeh, Hoon Kim, Erica Gjersing, Todd Shollenberger, Christopher M. Shuford, Jina Song, Zachary Miller, Yung-Yun Huang, Charles W. Edmunds, Bao-Guang Liu, Yi Sun, Ying-Chung Lin, Wei Li, Hao Chen, Ilona Peszlen, Joel J. Ducoste, John Ralph, Hou-Min Chang, David C. Muddiman, Mark Davis, Chris Smith, Fikret Isik, Ronald R. Sederoff, Vincent L. Chiang
Corresponding author: Vincent L. Chiang
Affiliation: NC State University
We present an unprecedented multi-omic quantitative integrative analysis of lignin biosynthesis with important immediate implications for bioenergy and biomaterials as well as tree growth and adaptation. Lignin is polymerized from three monomers (monolignols) produced by a grid-like pathway. The pathway in wood formation has 21 core genes, encoding enzymes that mediate 37 reactions on 24 metabolites, leading to lignin and affecting wood properties. We perturbed the 21 pathway genes in Populus trichocarpa and integrated transcriptomic, proteomic, fluxomic and phenomic data from 221 lines selected from ~2,000 transgenics. The integrative analysis quantifies how changing expression of any pathway gene or gene combination affects protein abundance, metabolic-flux, metabolite concentrations, and 25 wood traits, including lignin, tree-growth, density, strength, and saccharification. The analysis then allows improvements in any of these 25 traits individually or in combinations, through engineering the expression of specific monolignol genes. Our multi-omic integrative approach provides a general strategy for rigorous definitions of other biological pathways that could lead to a more comprehensive understanding and description of plant metabolism, growth, and adaptation.
Key words: Lignin biosynthesis; multi-omic integration, bioenergy, wood formation, strategic engineering, transgenic tree; poplar
- Nanocellulose, Pectin and Lignin Biomimetic Composite Filaments by Wet Spinning
Author(s): Ling Wang, Meri Lundahl, Gisela Cunha, Orlando Rojas
Corresponding author: Orlando Rojas
Affiliation: Aalto University
An effort within the field of biomimetics of wood fibres, is the use of TEMPO-oxidized
nanocellulose (TOCNF), pectin and alkaline lignin to synthesize composite filaments. Such
effort is aimed to the development of high performance products with low environmental
impact. In order to spin composite water-based dope, pectin gelation was necessary, wherein
CaCO3 was applied. It turned out that the obtained filaments showed similar mechanical
properties as those from TOCNF. Specifically, lignin even improved the mechanical
properties of TOCNF-based filament, especially in the wet state. Finally, quartz crystal
microgravimetry was applied to better understand the interaction mechanism between
TOCNF, pectin and lignin, which showing that Ca cations increased the amount of lignin
absorbed on TOCNF surface. Figure 1 (A) shows the stress and strain curves of dry TOCNF
based filaments, inside which (a) illustrates the wet mechanical properties of respective
Key words: nanocellulose, pectin, lignin, composites, wet spinning
- Value of root traits in trees – Searching for the link between root architecture, ectomycorrhizal community and growth rate in Norway spruce
Author(s): Sannakajsa Velmala, Matti Salmela, Leena Hamberg, Risto Sievänen, Taina Pennanen
Corresponding author: Sannakajsa Velmala
Affiliation: Natural Resources Institute Finland (Luke), Latokartanonkaari 9, FI-00790 Helsinki, Finland
The relationship between aboveground growth rate and fine root development of trees is poorly known. In recent years our research group has conducted a series of studies on the tripartite relationship between fine root architecture, symbiotic ectomycorrhizal fungi (EMF) associated with roots and growth rate in Norway spruce. In a field study we observed higher EMF species richness in fast-growing spruce genets than in even aged slowly growing genets. Further, we showed that EMF richness increases the nutrient acquisition potential of spruce by diversifying the production of fungal derived exoenzymes. We also investigated early root development of spruce seedlings belonging to families with contrasting aboveground adult phenotypes. Root characteristics varied systematically between seedlings of fast- and slow-growing groups when grown in an even substrate. Fast-growing families had 30% higher number of root branches and tips, and they allocated biomass further away from the base of the seedling than slow-growing families. Larger root extension of fast-growing families may provide an advantage in nutrient limited and heterogeneous forest soil by enhancing exploration and contact with soil microbiota. Moreover, based on preliminary data, the nutrient foraging strategy of these seedlings of does not differ. Small differences in root growth may create positive self-reinforcing mechanisms affecting long-term growth performance.
Key words: Picea abies, root architecture, WinRhizo, nutrient foraging
- Electro-assisted dewatering of cellulose nanocrystals
Author(s): Jonas Wetterling, Karin Sahlin, Tuve Mattsson, Hans Theliander
Corresponding author: Hans Theliander
Affiliation: Chalmers University of Technology
Production of cellulosic materials with high specific surface areas, such as microfibrillated cellulose and cellulose nanocrystals, is an area that has gathered significant research interest as these materials combines a high mechanical strength and toughness with biodegradability and a low density. The potential applications of nanoscale cellulosic particles are therefore plentiful and includes films, hydrogels, foams, aerogels or as a component in composite materials. However, scaling up from laboratory scale to production on a commercial level requires process development in order to obtain production methods that are industrially viable. One of the main challenges of scaling up the production of cellulose nanocrystals is to obtain an energy-efficient solid-liquid separation as cellulose nanocrystals are produced at a low solid content.
In order to achieve an energy-efficient solid-liquid separation, thermal drying is often preceded by a mechanical dewatering technique such as filtration. The application of conventional pressure filtration may however pose a challenge due to high filtration resistances resulting in the need for prohibitively large equipment sizes and/or long operation times. This work shows how electro-assisted dewatering may be used as an energy-efficient alternative to thermal drying in order to increase the dry content of suspensions of cellulose nanocrystals.
Key words: Cellulose nanocrystals, solid-liquid separation, electro-assisted filtration, electroosmosis
- “Forest”-based Foams for a Sustainable World
Author(s): Wenchao Xiang, Shuai Li, Ilari Filpponen, Blaise Tardy, Erkki Saharinen, Timo Lappalainen, Kristian Salminen, Natalie Preisig, Cosima Stubenrauch, Orlando J. Rojas
Corresponding author: Wenchao Xiang
Affiliation: Aalto University
Foams are ubiquitously applied from household products to industrial applications. For a sustainable life cycle, producing natural components based foams are critical. Forest derived substances, including cellulose, hemicellulose and lignin, etc., are promising natural alternatives to achieve the target.
The research is based on foam generation in the presence of macro-/nano- (ligno)cellulosic fibers. The work involves efforts for a fundamental understanding of relevant foam chemistry and dynamics, and the efforts toward the application in conventional papermaking industry by using foam forming technology to replace the normal water laying process.
By exploring different fibers (wood fiber and nanocellulose; lignin-free and lignin containing), the resulted foam structures and properties are characterized. The relevant foam generation and stabilization mechanisms are proposed. These results are expected to benefit the design of functional foams.
By applying foams as suspending media to process (ligno)cellulosic fibers, up to 65% of water can be replaced by air in paper laying process. The subsequently decreased consumption in water and energy enables papermaking industry to achieve sustainability in the aspects of both production and environment. Importantly, foam-laden paper has evidently improved homogeneity of fiber network, especially for long fibers, indicating the applicability of extending the current knowledge to textile industry.
Key words: (ligno-) Cellulosic fiber, liquid foams, foam chemistry, foam dynamics
- The Regulation of GAs Biosynthesis During the Photoperiodic Response in Aspen.
Author(s): José Alfredo Zambrano 1, Shashank Sane 1 and Ove Nilsson 1
Corresponding author: José Alfredo Zambrano 1
Affiliation: Swedish University of Agricultural Sciences, Umeå, Sweden (SLU)
Gibberellins (GAs) are one of the major hormones regulating different aspects of plant growth, such as stem elongation, germination, dormancy, flowering or fruit development. In trees, GAs are key regulators of shoot growth and have been suggested as important factors controlling short day (SD)-induced growth cessation. In fact, Gibberellin 20-oxidase (GA20ox) overexpressing hybrid aspens (Populus tremula x tremuloides) do not set buds when grown in SD conditions. By contrast, GA20ox antisense transgenic aspen trees exhibited earlier bud set compared to wild type plants.
The aim of our work is to investigate how GA biosynthesis is affected by the photoperiodic signaling pathway in the regulation of growth cessation, bud set and bud break. In order to elucidate the relation between the GAs and the photoperiod pathway we analyzed the expression levels of the GA-metabolism genes (GA2ox, GA3ox and GA20ox) in Populus FLOWERING LOCUS T1 (PtFT1), PtFT2 and PtGIGANTEA (PtGI) RNAi transgenic plants grown in Long day (LD) and SD conditions, respectively. We also assessed the effect of exogenous application of gibberellins to this transgenic lines compared to the wild type.
Our results show low expression levels of the GA biosynthesis genes in PtGI RNAi and PtFT RNAi compared to WT. This may be related to the early bud set phenotype in both lines. It is known that growth cessation in hybrid aspen ultimately depends on concentrations of bioactive GA. Our data suggests that this occurs through the regulation of FT.
Besides these approaches, we have undertaken the absolute quantification of the different GA metabolites in FT and GI RNAi lines. This study, technically challenging, offers complementary information that suggests that the photoperiod pathway contributes to the regulation of GA metabolism during growth cessation in aspen trees.
Key words: Hybrid aspens, Flowering, Dormancy
- Nanocellulose and Its Biohybrid System for Water Purification Fundamentals to Applications
Author(s): Chuantao Zhu
Corresponding author: Aji P. Mathew
Affiliation: Stockholm University
The objective of the project is to develop scientific understanding on the fundamentals of knowing why and how the adsorption mechanisms between nanocellulose and water contaminants like heavy metal ions, dyes and virus etc. and finally tailor nanocellulose based membranes/ filters for water cleaning, at research scale as well as at industrial scale. The surface properties due to adsorption and the specific interactions of nanocellulose with water contaminants at nanoscale could be achieved by morphology imaging and force study using Atomic Force Microscopy (AFM) which could be employed both in air and aqueous medium. State-of-the-art modeling method like DFT calculation will be used to simulate the structure and interaction in molecular scale. The nanocellulose and/or its biohybrid membrane with higher adsorption capacity, flexibility, improved stability and mechanical robustness could be manufactured by adding graphene oxide nanocolloids system forming a unique open porous network structure. It could be easily scaled up and commercial utilized in industry, which is great significance to pioneer the development of green and clean technologies for water purification.
Key words: Nanocellulose, Water purification, Atomic Force Microscopy, Graphene Oxide, Bio-hybrid membrane