A group of young researchers from Austria, Canada, Finland, France, Sweden, United Kingdom and United States are selected for the MWP Young Researchers’ Program 2022.

The Young Researchers’ abstracts are published below:

1: Cellulose nanomaterials for thermal insulation and packaging applications following the circular economy principles

Author(s): Varvara Apostolopoulou-Kalkavoura, Maria-Ximena Ruiz-Caldas, Lennart Bergström, Aji P. Mathew
Corresponding author: Varvara Apostolopoulou-Kalkavoura
Affiliation: Stockholm University
E-mail: varvara.apostolopoulou@mmk.su.se

To move from linear towards circular economy model fossil-based products need to be replaced by biobased materials. Cellulose nanomaterials (CNM) constitute excellent candidates to compete with fossil-derived materials in many sectors such as thermal insulation and packaging as they exhibit tunable surface chemistry, low thermal conductivity, abundancy, and renewability.
The intrinsic anisotropy of wood-derived CNM can turn moisture into a benefit even if cellulose is hygroscopic. Unexpectedly, those findings show that anisotropic CNM foams can be used in varying climatic conditions as moisture-induced swelling reduces the thermal conductivity below the one of air. Experiments combined with theoretical estimates on anisotropic CNM foams of varying densities indicated that that interfacial phonon scattering is the main mechanism to keep the thermal conductivity low.
To reduce the carbon footprint of biobased materials by creating an ‘industrial symbiosis’ approach, alternative cellulose sources have been identified in textile waste. Following the circular economy principles, combinations of chemical and mechanical treatment was used to isolate CNM from textile waste which exhibited similar properties as wood-derived CNM, making our waste a valuable raw material. Upcycling of textile waste cannot only result in materials with attractive properties but can also result in minimizing the waste that piles up in landfills or burn in incineration facilities.

Key words:
Cellulose nanomaterials, thermal conductivity, humidity, phonon scattering, recycling, textile waste, biobased materials

2: Microtemplating films of microfibrillated cellulose with tunable roughness and surface properties

Author(s): Gabriel Banvillet, Joice Jaqueline Kaschuk, Monireh Imani, Milad Kamkar, Xuetong Shi, Yi Lu, Samantha Pritchard, Ayako Takagi, Orlando J. Rojas
Corresponding author: Orlando J. Rojas
Affiliation: Bioproducts Institute, Departments of Chemical and Biological Engineering, Chemistry and Wood Science, The University of British Columbia, Vancouver, BC, Canada

E-mail: orlando.rojas@ubc.ca

Although cellulose possesses outstanding properties in its native form, many efforts have been made to broaden its range of properties and applications. Conventional strategies for tuning the surface features of cellulose-based papers or films include: (i) physical modification by coating with a (bio)polymer or by deposition of particles, and (ii) chemical modification by using techniques such as polymer grafting. However, such strategies can result in intensive and onerous chemical processes, and/or recycling challenges. In this study, we propose a new, green, facile and efficient method to micropattern the surface of cellulosic films, resulting in a significant modification of their physicochemical properties. The method, following microtemplating, is based on fluid flow through the network to confer three-dimensional designs on the surface of the film with precise control of spatial distribution. The films are shown for optical, haptic and surface effects that are achieved in the absence of any chemical modification or adsorption. This work follows a previous study on the large-scale production of cellulose nanofibrils films, for plastics replacement in packaging applications. The present approach replaces cost and time-consuming (nano)lithography and paves the way for new applications at nanometric scales, including those associated with microfluidic and biomedical systems.

Key words:
cellulose nanofibrils, films, microtemplating, surface properties

3: From Spun Cellulose Textile Fibres to Sustainability- and Performance- Driven Structural Composites

Author(s): Hiba Ben Kahla(1); Janis Varna(1) , Juha Salmela(2) , Kristiina Oksman(1)
Corresponding author: Hiba Ben Kahla
Affiliation: (1) Luleå University of Technology, Sweden, (2) Spinnova Oyj, Finland
E-mail: Hiba.ben.kahla@ltu.se

In the strive toward sustainable societies and industries, raw materials and production processes, need to be selected according to their assessment against the sustainability criteria. Therefore, sustainably processed cellulose fibre polymer composites are increasingly developed to be used in a wider range of applications where good structural performance is needed. The interest of this work is to study spun cellulose fibres, produced in an environmentally friendly spinning process of cellulose nanofibers in water dispersion without using harsh chemicals. Although these fibres are currently destined for the textile industry, they show high potential as a future composite reinforcement. The work is first focusing on understanding the fibres´ properties such as morphology and cellulose alignment within the fibre axis and then investigating the mechanical properties to theoretically model the fibres´ behaviour. Second, the macroscopic mechanical performance of prepared composites made of these fibres is studied experimentally and analytically, correlated to the microstructure’s different aspects, and compared to existent composite materials. The vision of this work is to contribute to achieving 2030 sustainability goals by developing more eco-friendly processed wood composites with more attractive mechanical properties.

Key words:
Man-made cellulose fibre, Composites, Mechanical properties, Sustainable processing

4: Underutilized wood hemicelluloses as biobased alternatives to surfactants- Case sustainable agriculture

Author(s): Mamata Bhattarai1, Kai Liu2, Hedar Al-Terke2, Petri Kilpeläinen3, Robin Ras2, Bruno D. Mattos1, Orlando J. Rojas1,4
Corresponding author: Mamata Bhattarai, Orlando J. Rojas
Affiliation: 1 Department of Bioproducts and Biosystems, Aalto University, Finland, 2 Department of Applied Physics, Aalto University, Finland, 3 Natural Resources Institute (LUKE), Finland , 4 BioProducts Institute, The University of British Columbia, Canada
E-mail: mamata.bhattarai@aalto.fi

Surface wetting and adhesion play key roles in manufacturing and products’ performance in an array of applications. In agriculture, retention of sprayed agrochemicals (e.g., insecticides, herbicides) on plant leaves is challenging due to their water repelling surfaces. Current solution lies in using surfactants, mostly with petro-based origin, to assist adhesion of water-based droplets on hydrophobic surfaces. However, to achieve required efficiency, high concentrations (> 1 wt.%) and redundant usages of surfactants are required, potentially inviting phytoxicity and migration issues to environment and food chain.
We present a novel application of wood hemicelluloses to promote wetting and adhesion of hydrophobic surfaces. Wood hemicelluloses extracted from birch and spruce sawdust with hydrothermal treatment are effective to prevent droplet bounce, violent splashes and promote retention on hydrophobic surfaces like plant leaves at a reasonably lower concentration than surfactants require. A major issue of droplet roll-off from such surfaces is solved by hemicelluloses. This is due to their polymeric nature with surface activity imparted by lignin/phenolic groups.
Wood hemicelluloses, which are currently underutilized, represent one-third of the total lignocellulosic biomass. However, they can be extracted from forest side-streams e.g., sawdust, wood chips or non-wood biomass, with a green extraction approach using only water. This means, unprofitable streams convert to profitable revenue streams and minimal down streaming steps ensure cost-effectiveness of these extracts. Application of hemicelluloses as alternatives to surfactants offers green solutions in surface wetting and adhesion applications.

Key words:
wood hemicelluloses, sustainable agriculture, biomaterials

5: Assessing Structural Differences Among Genetically Improved Coastal Douglas-fir using High Density Airborne Laser Scanning

Author(s): Francois du Toit, Nicholas C. Coops
Corresponding author: Francois du Toit
Affiliation: University of British Columbia
E-mail: fdutoit2009@gmail.com

Tree improvement programs are critical to establishing high yield seed sources and developing sustainable plantation forests. Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) is commonly used in improvement programs due to its superior strength and stiffness properties. Trials in British Columbia, Canada aim to increase stem volume without sacrificing wood quality. Accurate and timely collection of phenotypic data is critical for estimating and validating these improvements with confidence. Branching traits are recognized as having a strong influence on strength and stiffness of Douglas-fir wood, however, they are rarely measured. High-density Airborne Laser Scanning (ALS), as well as Remotely Piloted Aerial Systems Laser Scanning Systems (RPAS-LS) produce three-dimensional point clouds which can be used to characterize individual tree structure. ALS-derived metrics were used to assess tree performance and predict genetic parameters in improvement trials, while new methods to estimate branch attributes of individual trees for inclusion as selection criteria in tree improvement programs were developed. Findings indicate that branch level metrics can be included as selection criteria in breeding programs, and that ALS-derived metrics are a suitable proxy for ground-based measurements. Given the cost efficiency of ALS, forest geneticists should explore this technology as tool to increase breeding programs’ overall efficiency. Findings from this research can be integrated into large-scale programs for monitoring trees, and identifying trees that display desirable attributes.

Key words:
Remotely piloted aerial systems (RPAS), airborne laser scanning, drone, internal geometric features, branching structure, tree phenotyping, Douglas-fir

6: Solid-state NMR reveals the importance of xylan chain length for a correct xylan-cellulose interaction and cellulose conformation

Alberto Echevarría-Poza1, Rosalie Cresswell2, Ray Dupree2, Henry Temple1, Steven P. Brown2, Paul Dupree1

Corresponding author: Paul Dupree
1Department of Biochemistry, University of Cambridge, Cambridge, UK.
2Department of Physics, University of Warwick, Coventry, UK.
E-mail: ae449@cam.ac.uk

Wood has always been widely used, from fuel to building materials, paper, cardboard, and even modern bioplastics and textiles. However, numerous applications are remarkably hindered by the recalcitrance of wood components: cellulose, hemicelluloses, and lignin. For instance, paper pulp production currently relies on strong alkalis and heat to separate these components. Among hemicelluloses, xylan predominates in angiosperms, and its function in gymnosperms continues to receive attention, being an essential polymer in all forests. As such, xylan is the most abundant polysaccharide on earth after cellulose and constitutes around 20% of all carbon in the biosphere. Although xylan is known to coat and crosslink cellulose, this phenomenon is poorly understood. Likewise, the biological significance of the length of xylan in binding cellulose is unexplored. To gain a better understanding, we conducted solid-state NMR studies on the model organism Arabidopsis thaliana. Mutants with short xylan showed notably disrupted xylan-cellulose interactions. Surprisingly, these mutants also had more disordered cellulose, as a likely consequence of less xylan coating it. This research could lead towards the engineering of trees for wood with specific properties for specialised applications. Furthermore, understanding the xylan-cellulose interaction will help develop sustainable ways to overcome wood recalcitrance during its processing.

Key words:
NMR, xylan, cellulose, conformation, interaction

7: Oxygen delignification – the promising future

Author(s): Cláudia Esteves, Olena Sevastyanova, Sören Östlund, Elisabet Brännvall
Corresponding author: Cláudia Esteves
Affiliation: RISE
E-mail: claudia.esteves@ri.se

Oxygen delignification is an important and well-known process in the industry however its potential has been disregarded. Normally, it is seen as an intermediate process between cooking and bleaching, rather than a strong oxidizing agent with powerful effects on pulp properties. The oxidation reactions occurring during the delignification can lead to outstanding properties on the pulp. Recent research showed promising outcomes for high kappa number pulps when part of the kraft cook is replaced by an extended oxygen delignification. Due to the oxidation of lignin and carbohydrates, fiber charges can be greatly increased leading to an increase in swelling up to 30%, and in strength up to 18%, together with 50% lower energy consumption, by reducing kraft cooking and reducing the refining energy needed. Sustainability is improved without compromising the fiber properties. This opens up a wide range of new products and applications for unbleached fibers subjected to an extended oxygen delignification, such as a great alternative to fully bleached fibers used in tissue and hygiene products, due to their high water absorption capacity. A new driving force to change paradigms in how the standard processes and products are used so far is coming to drive to a more sustainable world.

Key words:
Oxygen delignification, fiber charges, tensile index, energy savings

8: SmartRecovery to boost lignin commercialization

Author(s): Olesya Fearon, Anna Kalliola
Corresponding author: Olesya Fearon
Affiliation: VTT Technical Research Centre of Finland
E-mail: Olesya.fearon@vtt.fi

The global movement towards a circular bioeconomy entails a switch from fossil-based to bio-based products across all industries. One of the keys to success is converting wood and other lignocellulosic biomass, into different materials. Traditional biorefineries, such as pulp mills, fractionate biomass into a carbohydrate fraction/fiber, and lignin. Lignin is the only biomass constituent based on aromatic compounds, making it an important feedstock for the chemical industry.

A comprehensive understanding of the structure-property-performance of lignins is essential to its successful utilization. Lignin, recovered by conventional methods (CO2 precipitation and acid washing) results in a heterogeneous material with a relatively low reactivity thus limiting its applications. Recently, we have demonstrated a promising novel method to recover lignin by membrane technologies in a feasible and cost-effective manner. The recovered lignin has high purity, a consistent size and morphology as well as high reactivity, therefore it is suitable for high-value applications. This research aims at further developing the recovery technology and scaling up the recovery to enable product testing in selected applications based on the lignin properties. Boosting lignin commercialization, reducing the carbon footprint, and bringing biobased products to the market at reasonable price could all be achieved through this research.

Key words:
lignin, bio-based materials, membranes, black liquor, lignin recovery

9: Synthesis of guanidine – derived ionic liquids for cellulose processing

Author(s): Eva Gazagnaire, Ilkka Kilpeläinen
Corresponding author: Eva Gazagnaire
Affiliation: University of Helsinki
E-mail: eva.gazagnaire@helsinki.fi

The forest-based industry aims to lighten the ecological burden of textile manufacturing by creating textile fibres derived from sustainable feedstock: wood. Traditional man-made cellulose textile fibre manufacturing requires toxic chemicals (CS2 in viscose process) or unstable solvents (NMMO) to dissolve cellulose, which is unwanted in an eco-responsible world. Superbase ionic liquids (SILs) represent a suitable alternative, as their water stability and their high cellulose dissolution capacity make them environmentally and economically feasible for industrial use. [mTBDH][OAc], which is one of the core SILs, demonstrated its potential for cellulose spinning process at pilot scale and validated this approach. However, its hydrolytic stability is somewhat limited and its high melting point are possible challenges at industrial scale. Knowing this issue, novel SILs structures were developed and some are currently being tested in a pilot scale spinning processes. Our ultimate goal is to recognize the most promising new SILs for industrial production of wood-based man-made textile fibres. The list for required properties include full recyclability without efficiency or material loss, low cost, non-toxicity, high quality of produced fibres, and feasible handling/equipment requirements (low m.p.), among many other properties. While this ‘demand-list’ is challenging, most of the criteria are already met and even exceeded.

Key words:
Cellulose dissolution, ionic liquids, hydrolytic stability, pilot scale

10: Development of cellulose films by means of the Ioncell® technology, as an alternative to synthetic films

Author(s): Eva González, Inge Schlapp-Hackl, Michael Hummel, Herbert Sixta
Corresponding author: Michael Hummel
Affiliation: Aalto University
E-mail: eva.gonzalezcarmona@aalto.fi

Nowadays, synthetic films (and other products made of plastic) are immensely consumed worldwide, which drive to massive amounts of waste that end up in a great portion in water resources, creating a huge hazard for biodiversity and, not least, for human health. As an alternative to them, a dry-jet wet spinning technique to produce films, based on the Ioncell® technology, has been established. Regenerated films are produced by the extrusion of an ionic liquid-cellulose solution in a semi-continuous mode. The obtained films are thin (12 to 21 µm), completely transparent (90 to 91% transmittance) and show high-performance mechanical properties (stress values up to 200 MPa in machine direction (MD) and 50 to 100 in transversal direction (TD)). These properties clearly outperform those of commercial cellophane (stress values of 120 MPa in MD and 70 MPa in TD). Our cellulose-based films, produced in a sustainable process from renewable raw materials, and with outstanding properties bear great potential to become green and biodegradable alternatives to widespread PP and PET films.

Key words:
Cellulose films, Ioncell®, dry-jet wet spinning, ionic liquid, wood, sustainability, mechanical properties, transparent films

11: Peeling and sawing of large-diameter logs of Norway Spruce

Author(s): Michael Gstettner, Gerhard Schickhofer
Corresponding author: Michael Gstettner
Affiliation: Institute of Timber Engineering and Wood Technology, Graz University of Technology
E-mail: m.gstettner@tugraz.at

Referring to an increasing number of 178 million growing solid cubic metre of large logs with d = 0.5+m of softwood and hardwood species in Austria, predominately Norway Spruce (Picea Abies; Pinaceae), and even more than one billion solid cubic metre within the “DACH”-region {Germany│Austria│Switzerland}, new and efficient opportunities in further timber-processing are needed. Due to a specific limitation in the standard sawing-technologies caused by the maximum log-diameter, an innovative symbiosis between peeling- and sawing-technology was found. Therefore, the outer ranges of these large-scaled logs, including high stiffness and strength-properties, are used for peeling with high thicknesses of tv = 10 ÷ 20 mm and the remaining inner peeling core is afterwards sawn with standard-technologies. First peeling- and drying-tests with layer thicknesses of tv = {10│12│15} mm were successfully finished. In order to possibly substitute the standard GLT- or CLT-lamella, a test program, run at the Institute of Timber Engineering and Wood Technology with an experience of almost 10 years in veneers, form-pressed profiles, and so-called peeled-boards for load-bearing purpose, was carried out. Results of (i) a possible homogenizationeffect with an increase of the number of glued “peeled-boards”, (ii) the tensional strength ft,0,k and (iii) the rolling shear strength fr,k of CLT are part of this contribution.

Key words:
Peeled boards; peeling; veneer; sawing; boards; Norway Spruce; strength properties

12: Lignin’s Role in a Forest-Based Society

Author(s): K. Alexander Henn
Corresponding author: K. Alexander Henn
Affiliation: Aalto University
E-mail: karl.henn@aalto.fi

Pulp mills and biorefineries in the Nordics could be much more than they are today. Biorefineries could become consortium production-centers for a variety of wood-based products. Lignin arguably remains an untapped resource, but recent findings could change the situation. Water-dispersible colloidal lignin particles (CLPs) have unique properties that allow them to be used in e.g. easy-to-use adhesives and beautiful surface coatings that laymen can apply themselves. Lignin can also be epoxidized and used together with CLPs for competitive industrial plywood adhesive resins and anti-flame coatings for modern wooden cities, or even composites for electronics, and automotive and aerospace transport. Through recent advances in interfacial catalysis, the epoxidation procedure could be made quickly and cheaply with reagents mainly from trees and plants. The forest industry uses significant resources on transportation, which is an obstacle for price-competitive valorization. Therefore, biorefineries should be designed to be versatile, and allow for a variety of highly advanced procedures on-site. For example, a biorefinery could isolate lignin, turn it into particles and adhesive resins, and assemble it into wood panels using almost only materials available in the surrounding forests. The forests can be much more than paper, with new views, resourcefulness and effort.

Key words:
Lignin, biorefinery, adhesives, coatings, plywood, wooden cities

13: Toward new process design: Preserving the lignin structure by using a physical protection strategy

Author(s): Maria Karlsson, Martin Lawoko
Corresponding author: Maria Karlsson
Affiliation: Wallenberg Wood Science Center, KTH Royal Institute of Technology, Stockholm, Sweden
E-mail: maria11@kth.se

The smart utilization of biomass can contribute to a sustainable future. Following this line, we need to evaluate the potential of new process concepts to produce suitable precursors for future bio-based materials and chemicals. The lignin obtained from the technical processes appears in heterogenic complex mixtures, and there is a need for less heterogenic lignin, where a larger part of the structure and functionalities are known. One way to get there is by increasing the fundamental knowledge about the lignin structure and how it can be preserved and tailored toward desired properties by changing the design of the process. The knowledge about the chemical and physical properties of lignin is valuable for the use of lignin in future biobased products, which will contribute to the transformation into a bioeconomy. In this context, a biorefinery process has been developed based on a green solvent system, where physical protection is used to preserve the native lignin structure, indicated by a high amount of aryl ether (β-O-4´) inter-unit linkages and only low content of inter-units formed through condensations. The lignin has been characterized in detail by several NMR techniques, among others. For future applications, it is desirable to have less reacted lignin with a well-characterized structure and functionalities. The lignin obtained in this work meets this pre-requisite using a simple process.

Key words:
Biorefinery process, lignin, protection strategy, preserved structure

14: Smart assembly of wood polymers for advanced materials

Author(s): Erfan Kimiaei, Muhammad Farooq, Monika Österberg
Corresponding author: Monika Österberg
Affiliation: Aalto University
E-mail: Erfan.kimiaei@aalto.fi

Free-standing nanocellulosic films (nanopapers) have emerged as attractive sustainable materials to replace traditional plastics. However, the moisture sensitivity of cellulose and its incompatibility with nonpolar polymers are challenges to its widespread application. We offer an innovative solution based on efficient use of bio-based components and green processing concepts that alleviates the prior art problems. To achieve this goal, we introduce a Pickering emulsion approach to fabricate biobased, biodegradable, and waterproof multifunctional composite that enable combing polar cellulose fibers, micro and nano fibrils, or crystals with nonpolar polymers, using colloidal lignin nanoparticles (CLPs) as the emulsion stabilizer or interfacial mediator. The active surface sites of CLPs, along with their well-defined morphology facilitate the effective interactions with polymers and cellulosic materials. To the best of our knowledge, our results show the highest obtained wet strength for cellulosic composites developed without any direct covalent surface modifications or synthetic additives. Our solution provides a generic foundation for a variety of polymers-cellulose composites via engineering the interfacial interactions among the composite’s components, harnessing the maximum benefits of each constituent’s inherent functionality by economically-viable symbiotic and sustainable processes without using excessive chemicals and solvents. Thus, our approach promotes the sustainable use of Finland’s natural resources.

Key words:
Cellulosic composites, Wet strength, Pickering emulsion, Interfacial mediator

15: Cellulose interactions with CO2(g) in NaOH(aq): the (un)expected coagulation as a key to the future of more sustainable cellulose technology

Author(s): Aleksandra M. Kozlowski and Merima Hasani
Corresponding author: Aleksandra M. Kozlowski
Affiliation: Chalmers University of Technology
E-mail: aleksandra.kozlowski@chalmers.se

Rapidly increasing demand for textile fibres has put wood-based cellulose in focus; especially since cotton cultivation has reached the limit and production of synthetic fibres is not sustainable. Celluloses applied in textiles need to meet structural and chain length requirements to enable dissolution and spinning into textile-applicable material. Therefore, the reshaping of cellulose through dissolution is a crucial processing tool. However, the ‘green’ solvent like NaOH(aq) is currently unattractive from an industrial point, as limited in terms of concentration, temperature, and amount of dissolving polymer. Moreover, cellulose re-established from alkali would not necessarily match the industrial appointment.
In my research, I present the method of recovery of NaOH(aq) dissolved cellulose via CO2(g) catalysed coagulation. The initial results of structural studies showed that such material is competitive with other quenching methods. The application of CO2(g) in the process makes it attractive not only from an economical (availability and price of gas), but importantly, an ecological perspective as enables the utilization of air-captured CO2(g). Furthermore, the minimum alkalinity loss observed during the coagulation opens for easier recycling of the coagulation bath. From here, the doors to wood-based cellulose materials with the perspective in textile applications are being opened.

Key words:
Cellulose, NaOH(aq) dissolution, CO2(g) coagulation

16: Sustainable forest battery technology

Author(s): Divyaratan Kumar, Ziyauddin Khan. Ujwala Ail, Jaywant Phopase, Magnus Berggren, Viktor Gueskine, Xavier Crispin
Corresponding author: Xavier Crispin
Affiliation: Linköping University
E-mail: xavier.crispin@liu.se

Organic electrolytes, an essential component in today’s energy storage technologies, inherently suffers from safety, cost, and non-ecofriendly issues. Water-based electrolytes have proven out to be better alternative to organic electrolytes because of their much superior ionic conductivities. Ionic transport constitutes part of the bottleneck for the total resistance of the devices which limit the power. Moreover, aqueous electrolytes are cost effective and non-flammable. The major challenge of aqueous electrolytes in organic batteries is that they lead to drastic self-discharge.
Herein, we have utilized the concept of “water-in-salt electrolyte” with polymer electrolytes, called potassium polyacrylate (PAAK). This is a new class of electrolyte that we called “water-in-polymer salt electrolyte”. It is non-flammable and displays a high ionic conductivity (70-90 mS/cm).
The sustainable organic lignin battery displayed a high specific power of 6.8 kW/kg owing to the high ionic conductivity of PAAK electrolyte and the fast redox quinone redox chemistry. The organic redox polymers were also stable in this electrolyte as the specific capacity degrades to only 35% in 2500 cycles. Moreover, we achieved extremely low self-discharge rate as open circuit potential (OCP) drops from 1V (faradic peak) to 0.75V in >100 h. This is the world record for self-discharge of organic electrodes in aqueous electrolyte. We believe this study opens a new avenue for efficient lignin- based truly safe, non-flammable and large-scale high-power energy storage solutions.

Key words:
Lignin, Organic batteries self-discharge, water-in polymer salt electrolytes (WIPSE)

17: Characterization of Poplar BAHD Acyltransferase Enzymes Involved in Suberin Biosynthesis

Author(s): Leta Landucci, Rebecca A. Smith, Debayan Chaudhury, Steve D. Karlan, Craig A. Bingman, Justin F, Acheson, Kirk Vander Meulen, Alexis Eugene
Corresponding author: John Ralph
Affiliation: University of Wisconsin
E-mail: leta.landucci@icloud.com

Suberin is a complex polymer deposited within the boundary layers of plant tissues to establish a protective barrier impermeable to water, solutes, and pathogens. Suberin is present within the cork layer of bark, in seed coats, and in the cell wall of root endodermal cells. BAHD family acyltransferase enzymes are directly involved in the biosynthesis of suberin precursors; they transfer acyl moieties to acceptor groups forming esters integral to the suberin polymer, linking the major phenolic and aliphatic domains. We identified and assessed over 100 uncharacterized poplar BAHD acyltransferases for similar activity to the single published poplar enzyme implicated in suberin biosynthesis. Extensive screening revealed two candidate acyltransferases putatively involved in suberin biosynthesis. These were characterized through enzymatic activity and kinetic assays, and are now being transformed into plants to assess their biological roles. With an improved understanding of acyltransferases involved in suberin biosynthesis, the suberin polyester may be engineered to introduce traits for sustainable biomass production or for imbuing plants with greater tolerance to harsh environmental conditions such as high salt concentrations and stresses including those from pathogenic invaders. Such qualities could be advantageous for, and enhance the sustainability of, the poplar bioenergy/forestry industry and beyond.

Key words:
acyltransferase, suberin, biosynthesis, characterization, sustainability

18: Unveiling local structural information of nanocelluloses using transmission electron microscopy (TEM)

Author(s): Jia Hui Lim, Muriel Véron, Yoshiharu Nishiyama, Edgar Rauch, Yu Ogawa
Corresponding author: Jia Hui Lim
Affiliation: Univ. Grenoble Alpes, CNRS, CERMAV
E-mail: jia-hui.lim@cermav.cnrs.fr

Transmission electron microscopy (TEM) has played a central role in nano- to microscale characterization of cellulosic materials from paper and fibers to cellulose nanoparticles, or nanocelluloses. It provides valuable information on their morphology and internal structures as well as structural heterogeneity such as defects.
Kinks are one of the most common defects of nanocelluloses. They can occur during the extraction, processing, and use of these nanoparticles. Despite its frequent occurrence, little is known about the structural aspect of the kink due to the lack of an appropriate analytical method. Electron diffraction (ED) provides local structural information by using a nanosized electron probe, allowing us to elucidate the nanoscale structural heterogeneity.
We used scanning ED and found that the cellulose nanocrystals maintained their crystallinity at the kink point, indicating that the amorphization is minimal even in the largely deformed area. Further studies are currently underway to correlate the kink structure and the anisotropic mechanical properties of cellulose. These findings could lead to a better understanding of this common defect of nanocelluloses and its consequence on their material properties.

Key words:
transmission electron microscopy, electron diffraction, nanocellulose, kink defects

19: Biocolorants – sustainable coloration for cellulosics with added functionality

Author(s): Tia Lohtander-Piispa, Nikita Durandin, Rafael Grande, Timo Laaksonen, Monika Österberg, Päivi Laaksonen, and Suvi Arola
Corresponding author: Suvi Arola
Affiliation: VTT
E-mail: tia.lohtander-piispa@vtt.fi

Cellulose-based biomaterials have obtained increasing attention for a variety of applications. Especially in the textile industry, different processes to produce sustainable man-made cellulosic fibers have been invented. However, even though fiber material would be sustainably manufactured the dyeing is still mainly carried out with synthetic colorants in processes that cause textile dye pollution.
Compared to the state-of-the-art synthetic colorants, the bio-based colorants have a more complex composition, which is usually considered a drawback. However, in addition to the color, the biocolorants possess often additional functionalities, such as antioxidant, antimicrobial, and UV protective properties. Side streams of forest and agricultural industries and fast-growing crops, such as willows, can be utilized as a source of biocolorants. The compounds extracted from willows strongly absorb the harmful UV radiation and show radical scavenging activity, which we have harnessed to cellulosic textile fibers and films, which could be utilized as active packaging material in the future.
Additionally, we have shown that by combining nanocellulose and natural indigo, the reducing agent consumption can be lowered in the dyeing process as the nanocellulose hinders the oxidation of the readily oxidizing form of indigo. In conclusion, the characteristic complex composition of biocolorants can be turned from a drawback to an asset and the bioactive properties of biocolorants can be utilized to create materials with added value.

Key words:
Cellulose nanofibrils, biocolorants, wood-bark extracts, indigo, bioactive polyphenols

20: From branch to beam – towards a resource efficient material concept for low-value hardwood assortments

Author(s): Tobias Nenninga, Johannes Konnertha, Michael Grabnera, Christian Hansmannb, Wolfgang Gindl-Altmuttera and Maximilian Pramreitera
Corresponding author: Tobias Nenning
Affiliation: aUniversity of Natural Resources and Life Sciences, Vienna, bWood K plus – Competence Centre for Wood Composites and Wood Chemistry
E-mail: tobias.nenning@boku.ac.at

Climate change adaptation requires a shift in vegetation away from softwood forests to potentially more resilient hardwood and mixed forest stands. Since hardwoods differ fundamentally in their habitus and mechanical-technological properties from the softwoods currently dominant in Europe, new approaches to boost hardwood utilization are urgently needed. Therefore, my research is addressing a new pathway to producing high-value wood products for structural building components from low-value non-sawmill grade hardwood tree branches and stem tops.
The route towards this aim consists of the following steps: firstly, fundamental characterization of physical-, and mechanical properties of wooden branches from Fagus sylvatica, Quercus petraea and Populus alba. Subsequently, mapping of material properties into a digital-tree including its branches by means of personal laser scanning. Secondly, splitting of branches along the grain to produce elongated macro-strands with minimised fibre deviation and thirdly, straightening with the aid of thermally assisted plasticisation in steam and densification to form straight fibre elements capable of serving as structural beam elements e.g. in construction.
This highly material-efficient utilisation concept for low-value hardwood is expected to enable a high proportion of bio-based material utilisation also in future, supporting the continuous competitiveness of the forest-based sector in times of climate change.

Key words:
Hardwood, branches, macro-strands, plasticisation, densification, structural building components, material efficiency

21: In-situ dyeing of man-made cellulosic fibres

Author(s): Nicole Nygren, Marike Langhans, Marja Rissanen, Michael Hummel
Corresponding author: Michael Hummel
Affiliation: Aalto University
E-mail: nicole.nygren@aalto.fi

The textile industry is a major polluter in the world, with the dyeing process being one of the steps with the highest environmental impact. Currently, the textile dyeing industry is mostly located in developing countries, often burdening the environment and population. A rise of awareness among consumers has driven the demand for more environmentally friendly fibres. A holistic approach is needed to tackle the problems connected to the growth of the fast fashion phenomena. Using spin dyeing, which is a technique already in use for dyed synthetic fibres, in combination with the Ioncell® process we can produce in-situ dyed man-made cellulosic fibres with high mechanical properties. We have used various Vat dyes and pigments dyes to produce coloured Ioncell® staple fibres. The fibres were converted into yarn. The resulting knitted fabrics were tested for wash fastness, light fastness and rubbing etc. Further it was possible to re-dissolve and re-spin spun-dyed fibres. This opens up new ways towards circular textiles.

Key words:
Ioncell, man-made cellulose fibres, spin dyeing, vat dyes, pigments

22: Organic nitrogen – a novel player in the field of sustainable forestry

Author(s): Barbora Parizkova, Ioanna Antoniadi, Karin Ljung
Corresponding author: Karin Ljung
Affiliation: Umeå Plant Science Centre (UPSC), Swedish University of Agricultural Sciences (SLU)
E-mail: barbora.parizkova@slu.se

Nitrogen is a principal macroelement embedded in vital structures such as proteins, nucleic acids or vitamins and represents a growth-limiting factor for plants. Inorganic forms of nitrogen, such as nitrate or ammonium, have therefore been intensively used in traditional synthetic fertilizers. However, overuse of inorganic N-based fertilizers results in severe environmental consequences contributing to groundwater pollution, acid rains or greenhouse gas emissions. Interestingly, Organic N (ON) was shown to exhibit a great impact on plant growth, while the regulation of plant responses to ON remains unexplored. We will use an interdisciplinary approach employing forward and reverse genetics, cutting-edge analytical methods together with confocal microscopy to identify candidate genes and associated proteins that can represent entirely new molecular players in ON growth-promoting potential. Moreover, highly targeted substance delivery by organic electronics together with state-of-art cell sorting technology will help to decipher the expression dynamics of candidate genes on tissue, cellular and single-cell levels. In collaboration with experts in plant physiology and bioelectronics, the gained knowledge can help to more efficiently facilitate processes of plant adaptability and rooting potential during reforestation and to develop sustainable organic fertilizers as well as bioengineered agriculture and forest plants with rich, stable, and uptake-efficient root systems.

Key words:
Organic nitrogen, root, root architecture, genetics, sustainability

23: Reusing textiles for composites processing: a step for a circular economy

Author(s): Luísa Rosenstock Völtz 1,2 and Kristiina Oksman 1,2
Corresponding author: Luísa Rosenstock Völtz
Affiliation: 1Luleå University of Technology, 2Wallenberg Wood Science Center
E-mail: luisa.voltz@ltu.se

This work contributes to circular economy and sustainability, as a new processing method for combining used textiles with polymers to make biocomposites was developed. Composites of used textiles or industrial textile residues have been used in composites before, but these textiles have been cleaned and pre-processed into fibers before use in composites. The cleaning and fibrillation processes are both time- and energy-consuming. The approach used in this study is a one-step process where the used fabric was cut into strips and fed directly into the extruder, using the method of the long-fiber thermoplastic process. The cut fabric was fibrillated and mixed simultaneously with the polymer matrix to form composite materials that can be used to replace engineering polymers, fiber composites, or even as an additional fiber for short fiber composites. The fiber length, dispersion, microstructure, and mechanical properties of the composites were studied. The results showed that recycling textile as fabric direct into the extrusion process is an excellent and energy-efficient way to manufacture composite materials, the cut fabric can be fibrillated and dispersed in this process and textile fibers improved the mechanical properties.

Key words:
Sustainability, recycling, textiles, composites, extrusion

24: Refining cellulose-based waste textiles: development of value-adding alternatives to waste textile management

Author(s): Edvin Ruuth, Miguel Sanchis-Sebastiá, Ola Wallberg
Corresponding author: Edvin Ruuth
Affiliation: Lund University
E-mail: edvin.ruuth@chemeng.lth.se

Cellulose-based waste textiles are an abundant and underutilized waste material and constitutes the largest fraction of waste textiles worldwide that are bio-renewable. Still, cellulosic fibers have been recognized as the most promising solution for a sustainable textile industry in the future. Hence, strategies for recycling and valorizing cellulose-based waste textiles are of great importance and highly sought after. We propose a concept of technologies providing fiber-to-fiber as well as end-of-life recycling of cellulose-based waste textiles. Through our concept, cellulosic textiles with a high degree of polymerization (DP), such as cotton, are converted into dissolving pulp by utilizing the dissolving capabilities of aqueous zinc chloride. The dissolving pulp can then be further processed into regenerated cellulosic fibers. Alternatively, cellulosic textiles with a low DP and thus unsuitable for fiber regeneration, such as viscose or previously recycled fibers, are hydrolyzed into monomeric glucose – a platform chemical for production of high-value products. By tailoring the processes to fit the conditions of the raw material and the intended product, we maximize the recovered value of the waste textiles. Through this approach, cellulosic fibers of all qualities could be optimally recycled, in order to properly close the fashion loop.

Key words:
Textile recycling; cellulose; cotton; viscose; circular economy; fiber regeneration; hydrolysis

25: Multifunctional wood pulp fibers for the simultaneous removal of cations and anions metals from wastewater – An innovative approach to production and recycling

Author(s): Sabrine Sayadi1,2, François Brouillette1,2, Sylvain Canesi2
Corresponding author: Sabrine Sayadi
Affiliation: 1) Innovations Institute in Ecomaterials, Ecoproducts and Ecoenergies (I2E3) -Université du Québec à Trois-Rivières (UQTR), 2) Université du Québec à Montréal (UQAM)
E-mail: sabrine.sayadi@uqtr.ca

The effective removal of heavy metals from wastewater is one of the most pressing environmental issues. The challenge is to develop an economical, green, and multifunctional adsorbent to extract a wide range of toxic cations and anions from different types of effluents.
We have developed a new low-cost bio-adsorbent based on wood pulp fibers. Kraft pulp fibers were functionalized in two steps. First, a new green approach to phosphorylate cellulose using phosphate ester and urea followed by an amino-silane functionalization. Finally, we have obtained bifunctional fibers with the potential to simultaneously remove metallic cations and anions from wastewaters.
According to the concept of sustainability, functionalized fibers loaded with heavy metals were recycled by using them as precursors for the synthesis of porous catalysts for hydrogen production. These multifunctional fibers have shown other interesting properties like a hydrophobicity and flame retardancy, thus allowing their integration in other industrial applications. Our phosphorylation method can also be applied to other substrates such as bark, leaves or even forest litter to make them fire retardant and stop the spread forest fires. Thanks to these new approaches, innovative materials can be developed from wood pulp fiber products.

Key words:
Wood pulp fibers, Phosphorylation, Amino-silane, Adsorption, Heavy metals, Flame retardant, Multifunctional materials

26: Native chemically-labile lignin bonds have implications for cell wall digestibility

Author(s): Rebecca A. Smith, Lisanne de Vries, Heather A. MacKay, Nuoendagula, Yaseen Mottiar, Steven D. Karlen, Faride Unda, Emilia Muirragui, Craig Bingman, Kirk Vander Meulen, Emily T. Beebe, Brian G. Fox, Shawn D. Mansfield, John Ralph
Corresponding author: Rebecca A. Smith
Affiliation: University of Wisconsin
E-mail: rasmith29@wisc.edu

In addition to the three traditional monolignols from which the lignin polymer derives, our lab has uncovered other phenolic compounds that decorate and are integrated into the polymer. One type of alternate monomer, monolignol conjugates, are the product esters derived from linking a CoA thioester donor to a monolignol alcohol acceptor through the activity of a BAHD acyltransferase enzyme. The ester-linked compound (the monolignol conjugate) is then integrated into the lignin. Ester bonds are more chemically labile than other bonds in the polymer, making the incorporation of ester bonds into lignin valuable for cell wall deconstruction. We have recently identified the acyltransferase enzymes responsible for the production of monolignol conjugates that are incorporated into poplar lignin, including a p-hydroxybenzoyl-CoA monolignol transferase (pHBMT), and a putative feruloyl-CoA monolignol transferase (FMT) / p-coumaroyl-CoA monolignol transferase (PMT). Manipulating the level of these monolignol conjugates in the lignin can impact the digestibility of the plant cell wall, without negatively impacting plant growth or development, an important trait for lignocellulosic biofuel production, the pulp and paper industry, and beyond.

Key words:
Acyltransferases, poplar, pHBMT, FMT, PMT

27: The use of forest residues to produce lower carbon intensity (CI) transportation fuels by co-processing “biocrudes” in (bio)refineries

Author(s): Jianping Su, Susan van Dyk, and Jack Saddler
Corresponding author: Jianping Su
Affiliation: University of British Columbia
E-mail: jianping.su@ubc.ca

Low carbon intensity (CI) drop-in biofuels are “functionally identical to petroleum fuels and fully compatible with existing infrastructure” and will be needed by the hard-to-electrify long-distance transport sectors such as aviation, marine and long-distance trucking. Currently, and in the short-term, “conventional” drop-in biofuels will be produced via the oleochemical/lipid pathway to make renewable diesel and biojet fuels using the catalytic processes typically carried out in an oil refinery. As well as producing “neat” drop-in biofuels, (as exemplified by companies such as Neste) refineries can also co-process low CI feedstocks to lower the CI of their operations and the fuels they produce. In the mid-to-longer-term, “advanced” drop-in biofuels using “biocrudes” derived from lignocellulosic feedstocks will be required with the expectation that biomass-derived-biocrudes will be cheaper, more available and more sustainable than lipid feedstocks. However, once available in commercial quantities, co-processing of biocrudes is likely to be carried out at the Fluid Catalytic Cracker (FCC) within the refinery, primarily due to the operational robustness of this unit. However, as will be described in more detail, tracking the “green molecules” has proven challenging with a combination of C14 and indirect methods likely to be needed if “enabling” policies such as BC’s/California the low carbon fuels standard (LCFS) are to be met.

Key words:
Co-processing; decarbonization; FCC; LCFS; Lower carbon intensity; drop-in biofuels

28: Bioluminescent imaging for the detection of antibacterial agents from natural-product-extract impregnated solid samples

Author(s): Jenni Tienaho
Corresponding author: Jenni Tienaho
Affiliation: Natural Resources Institute Finland
E-mail: jenni.tienaho@luke.fi

Antibiotic resistance was acknowledged as a life-threatening consequence of antibiotics-abuse even before the COVID-19 pandemic. Due to the excessive sterilization during the pandemic, we will likely witness the rise of previously treatable diseases and need novel antibacterial agents to replace ineffective ones.

The screening of antibacterials requires efficient tools, such as the simultaneous measurement of bioavailability, which can be achieved by using living bacterial cells and real-time monitoring of changes in their metabolism. Biosensor strains, producing an effortlessly monitorable luminescent light signal, offer a solution.

The phenomenon of living organisms emitting light is called ‘bioluminescence’. The responsible genes can be transferred via genetic modification to the leading pathogens of healthcare-associated infections: Escherichia coli and Staphylococcus aureus. In the method, this bioluminescent gene construct is used to detect antibacterial activity from solid samples impregnated with natural-product-extracts.
In the method, samples are placed in a Petri dish or 6-well plate onto a thin layer of solid-agar medium. The solution with bacteria infused with bioluminescent lux-genes and soft-agar medium is then cast over the sample. The samples are cultivated overnight and measured using an in vivo luminescence imaging device.
Method has been successfully utilized for paperboard infused with polyphenol-rich extracts from softwood bark.

Key words:
Antibacterial activity, bioluminescence imaging, natural products, solid sample testing

29: Norway spruce SE-pipeline in Finland

Author(s): Mikko Tikkinen, Saila Varis, Sakari Välimäki, Jaanika Edesi & Tuija Aronen
Corresponding author: Mikko Tikkinen
Affiliation: Natural Resources Institute Finland (Luke)
E-mail: mikko.tikkinen@luke.fi

Somatic embryogenesis (SE) has been recognized to have vast potential to produce improved reforestation material. Yet only few commercial applications have been achieved in conifers. Recent developments in Norway spruce (Picea abies (L.) H. Karst.) SE in Finland e.g. high initiations rates, high recovery from cryopreservation, short in vitro germination have developed into a SE pipeline, which can be applied to genetically wide materials. Current cryostorage at Luke exceeds 4000 genotypes from elite crossings of tree breeding program. This development has led to construction of Vegetative propagation technology platform (Kasvu1) and research greenhouse spaces (Kasvu2) located in Savonlinna.
Luke registered the first SE based basic material for forestry in 2017. The basic material (Laukansaari) includes 12 full-sib families of progeny tested plus trees. Propagation pilots have been carried out since 2018 (nearly 170 000 germinants sold). To decrease production cost of somatic plants, we have developed a pilot robot for in vitro germination (selects, classifies, orients and plates good embryos to germination, stacks and changes full plates to empty ones).
Currently a Public Private Partnership project is ongoing with commercial partners, aiming to register two more Basic materials, transfer SE knowhow to partners and apply marker-based selection in SE.

Key words:
Forest regeneration material, automation, vegetative propagation

30: Fundamental study of paper dry-strength additives

Author(s): Mengxiao Zhao1,2, Leif Robertsén1, Lars Wågberg2, Torbjörn Pettersson2
Corresponding author: Mengxiao Zhao1,2, Torbjörn Pettersson2
Affiliation: 1Kemira R&D Center, 2KTH Royal Institute of Technology
E-mail: mengx@kth.se

Light-weight paper products that contain less fibres, but with a maintained bulk and improved strength properties, are highly desired due to the low cost of raw materials and improved logistics of packaged goods. In this respect, this research topic is about understanding the fundamentals of how the commonly used strength additives interact with forest-based cellulose fibres based on the perspectives from both industrial and academia. Currently, strength chemicals are developed within industry with traditional tools. Launching to the market and profitability as the target of the strength chemicals limit the effort that should be put into understanding how they interact with fibres and how to promote the next generation development. We have studied how the surface charges of fibres affect the adsorption capacity of different strength chemicals on wood-based fibre, and the strength performance of the final paper was evaluated. More precise characterization techniques from academia are adopted to understand how the strength chemicals adsorb onto cellulose, and how they influence the strength of single fibre joints and the elasticity of single filament. In conclusion, we believe that the gained fundamental understanding of these strength additives is of significant importance to facilitate the industrial development of sustainable low-cost high-end packaging products.

Key words:
Surface charge, birch fibres, polyelectrolytes complexes, paper dry strength, anionic polyacrylamide, cationic starch