Browsing by Subject "CELLULOSE"

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  • Zhang, Rui; Eronen, Aleksi; Du, Xiangze; Ma, Enlu; Guo, Ming; Moslova, Karina; Repo, Timo (2021)
    The synthesis of new types of furan-based compounds other than 5-hydroxymethylfurfural from glucose is a very attractive yet underexploited strategy. We report here a catalytic conversion of glucose with acetylacetone (acac) to furan-centered chemicals, 2-methyl-3-acetylfuran (MAF) and 1-(5-(1,2-dihydroxyethyl)-2-methylfuran-3-yl)ethan-1-one (DMAF), which are potential building blocks for the synthesis of fine chemicals. The experimentally supported reaction mechanism is cascade-type, including glycolaldehyde (GA) formation by H2MoO4-catalysed retro-aldol condensation (C2 + C4) of glucose and immediate capture of transient C2 and C4 intermediates by acac to yield MAF and DMAF. To the best of our knowledge, this is the first report on the straightforward synthesis of MAF and DMAF from glucose, providing a new but generic synthesis strategy for GA-based C2 and erythrose-based C4 chemistry in biorefining.
  • Khakalo, Alexey; Tanaka, Atsushi; Korpela, Antti; Hauru, Lauri K. J.; Orelma, Hannes (2019)
    Synthetic structural materials of high mechanical performance are typically either of large weight (for example, steels, and alloys) or involve complex manufacturing processes and thus have high cost or cause adverse environmental impact (for example, polymer-based and biomimetic composites). In this perspective, low-cost, abundant and nature-based materials, such as wood, represent particular interest provided they fulfill the requirements for advanced engineering structures and applications, especially when manufactured totally additive-free. Here, we report on a novel all-wood material concept based on delignification, partial surface dissolution using ionic liquid (IL) followed by densification resulting in a high-performance material. A delignification process using sodium chlorite in acetate buffer solution was applied to controllably delignify the entire bulk wooden material while retaining the highly beneficial structural directionality of wood. In a subsequent step, obtained delignified porous wood template was infiltrated with an IL 1-ethyl-3-methylimidazolium acetate, [EMIM]OAc and heat activated at 95 degrees C to partially dissolve the fiber surface. Afterward, treated wood was washed with water to remove IL and hot-pressed to gain a very compact cellulosic material with fused fibers while retaining unidirectional fiber orientation. The obtained cellulose materials were structurally, chemically, and mechanically characterized revealing superior tensile properties compared to native wood. Furthermore, suggested approach allows almost 8-fold tensile strength improvement in the direction perpendicular to fiber orientation, which is otherwise very challenging to achieve.
  • Kanerva, M.; Puolakka, A.; Takala, T.M.; Elert, A.M.; Mylläri, V.; Jönkkäri, I.; Sarlin, E.; Seitsonen, J.; Ruokolainen, J.; Saris, P.; Vuorinen, J. (2019)
    The antibacterial features of natural pine/spruce rosin are well established, yet the functionality in various thermoplastics has not been surveyed. This work focuses on the processing of industrial grade purified rosin mixed with polyethylene (PE), polypropylene (PP), polylactic acid (PLA), polyamide (PA) and corn starch based biopolymer (CS). Homopolymer masterbatches were extrusion-compounded and melt-spun to form fibres for a wide range of products, such as filters, reinforcements, clothing and medical textiles. Due to the versatile chemical structure of rosin, it was observed compatible with all the selected polymers. In general, the rosin-blended systems were shear-thinning in a molten condition. The doped fibres spun of PE and PP indicated adequate melt-spinning capability and proper mechanical properties in terms of ultimate strength and Young's modulus. The antibacterial response was found dependent on the selected polymer. Especially PE with a 10 wt% rosin content showed significant antibacterial effects against Escherichia coli DH5α and Staphylococcus aureus ATCC 12598 when analysed in the Ringer's solution for 24 h.
  • Ma, Hao; Zhou, Bo; Li, Yiqun; Argyropoulos, Dimitris S. (2012)
  • Mäkelä, Miia R.; Bouzid, Ourdia; Robl, Diogo; Post, Harm; Peng, Mao; Heck, Albert; Altelaar, Maarten; de Vries, Ronald P. (2017)
    The coprophilic ascomycete fungus Podospora anserina was cultivated on three different plant biomasses, i.e. cotton seed hulls (CSH), soybean hulls (SBH) and acid-pretreated wheat straw (WS) for four days, and the potential of the produced enzyme mixtures was compared in the enzymatic saccharification of the corresponding lignocellulose feedstocks. The enzyme cocktail P. anserina produced after three days of growth on SBH showed superior capacity to release reducing sugars from all tested plant biomass feedstocks compared to the enzyme mixtures from CSH and WS cultures. Detailed proteomics analysis of the culture supernatants revealed that SBH contained the most diverse set of enzymes targeted on plant cell wall polymers and was particularly abundant in xylan, mannan and pectin acting enzymes. The importance of lytic polysaccharide monooxygenases (LPMOs) in plant biomass deconstruction was supported by identification of 20 out of 33 AA9 LPMOs in the SBH cultures. The results highlight the suitability of P. anserina as a source of plant cell wall degrading enzymes for biotechnological applications and the importance of selecting the most optimal substrate for the production of enzyme mixtures. (C) 2017 Elsevier B.V. All rights reserved.
  • Mali, Tuulia; Mäki, Mari; Hellén, Heidi; Heinonsalo, Jussi; Bäck, Jaana; Lundell, Taina (2019)
    Effect of three wood-decaying fungi on decomposition of spruce wood was studied in solid-state cultivation conditions for a period of three months. Two white rot species (Trichaptum abietinum and Phlebia radiata) were challenged by a brown rot species (Fomitopsis pinicola) in varying combinations. Wood decomposition patterns as determined by mass loss, carbon to nitrogen ratio, accumulation of dissolved sugars, and release of volatile organic compounds (VOCs) were observed to depend on both fungal combinations and growth time. Similar dependence of fungal species combination, either white or brown rot dominated, was observed for secreted enzyme activities on spruce wood. Fenton chemistry suggesting reduction of Fe3+ to Fe2+ was detected in the presence of F. pinicola, even in co-cultures, together with substantial degradation of wood carbohydrates and accumulation of oxalic acid. Significant correlation was perceived with two enzyme activity patterns (oxidoreductases produced by white rot fungi; hydrolytic enzymes produced by the brown rot fungus) and wood degradation efficiency. Moreover, emission of four signature VOCs clearly grouped the fungal combinations. Our results indicate that fungal decay type, either brown or white rot, determines the loss of wood mass and decomposition of polysaccharides as well as the pattern of VOCs released upon fungal growth on spruce wood.
  • Alonso Serra, Juan Antonio; Shi, Xueping; Peaucelle, Alexis; Rastas, Pasi; Bourdon, Matthieu; Immanen, Juha; Takahashi, Junko; Koivula, Hanna; Eswaran, Gugan; Muranen, Sampo Johannes; Help-Rinta-Rahko, Hanna; Smolander, Olli-Pekka; Su, Chang; Safronov, Omid; Gerber, Lorenz; Salojärvi, Jarkko; Hagqvist, Risto; Mähönen, Ari Pekka; Helariutta, Yrjö; Nieminen, Kaisa (2020)
    Tree architecture has evolved to support a top-heavy above-ground biomass, but this integral feature poses a weight-induced challenge to trunk stability. Maintaining an upright stem is expected to require vertical proprioception through feedback between sensing stem weight and responding with radial growth. Despite its apparent importance, the principle by which plant stems respond to vertical loading forces remains largely unknown. Here, by manipulating the stem weight of downy birch (Betula pubescens) trees, we show that cambial development is modulated systemically along the stem. We carried out a genetic study on the underlying regulation by combining an accelerated birch flowering program with a recessive mutation at the ELIMAKI locus (EKI), which causes a mechanically defective response to weight stimulus resulting in stem collapse after just 3 months. We observed delayed wood morphogenesis in eki compared with WT, along with a more mechanically elastic cambial zone and radial compression of xylem cell size, indicating that rapid tissue differentiation is critical for cambial growth under mechanical stress. Furthermore, the touch-induced mechanosensory pathway was transcriptionally misregulated in eki, indicating that the ELIMAKI locus is required to integrate the weight-growth feedback regulation. By studying this birch mutant, we were able to dissect vertical proprioception from the gravitropic response associated with reaction wood formation. Our study provides evidence for both local and systemic responses to mechanical stimuli during secondary plant development.
  • Hyväkkö, Uula; King, Alistair W. T.; Kilpeläinen, Ilkka (2014)
  • Wang, Zhao; Pawar, Prashant Mohan-Anupama; Derba-Maceluch, Marta; Hedenström, Mattias; Chong, Sun-Li; Tenkanen, Maija; Jönsson, Leif J.; Mellerowicz, Ewa (2020)
    Fast-growing broad-leaf tree species can serve as feedstocks for production of bio-based chemicals and fuels through biochemical conversion of wood to monosaccharides. This conversion is hampered by the xylan acetylation pattern. To reduce xylan acetylation in the wood, the Hypocrea jecorina acetyl xylan esterase (HjAXE) from carbohydrate esterase (CE) family 5 was expressed in hybrid aspen under the control of the wood-specific PtGT43B promoter and targeted to the secretory pathway. The enzyme was predicted to deacetylate polymeric xylan in the vicinity of cellulose due to the presence of a cellulose-binding module. Cell-wall-bound protein fractions from developing wood of transgenic plants were capable of releasing acetyl from finely ground wood powder, indicative of active AXE present in cell walls of these plants, whereas no such activity was detected in wild-type plants. The transgenic lines grew in height and diameter as well as wild-type trees, whereas their internodes were slightly shorter, indicating higher leaf production. The average acetyl content in the wood of these lines was reduced by 13%, mainly due to reductions in di-acetylated xylose units, and in C-2 and C-3 mono-acetylated xylose units. Analysis of soluble cell wall polysaccharides revealed a 4% reduction in the fraction of xylose units and an 18% increase in the fraction of glucose units, whereas the contents of cellulose and lignin were not affected. Enzymatic saccharification of wood from transgenic plants resulted in 27% higher glucose yield than for wild-type plants. Brunauer-Emmett-Teller (BET) analysis and Simons' staining pointed toward larger surface area and improved cellulose accessibility for wood from transgenic plants compared to wood from wild-type plants, which could be achieved by HjAXE deacetylating xylan bound to cellulose. The results show that CE5 family can serve as a source of enzymes for in planta reduction of recalcitrance to saccharification.
  • Carvalho, Danila M.d.; Berglund, Jennie; Marchand, Célia; Lindström, Mikael E.; Vilaplana, Francisco; Sevastyanova, Olena (2019)
    The impact of various degrees of acetylation on improving the thermal stability of xylan isolated from different botanical source has been studied; methylglucuronoxylan from birch and eucalyptus, arabinoglucuronoxylan from spruce and glucuronoarabinoxylan from sugarcane bagasse and straw. The lower molecular weight of nonacetylated methylglucuronoxylan (17.7-23.7 kDa) and arabinoglucuronoxylan (16.8 kDa) meant that they were more soluble in water than glucuronoarabinoxylan (43.0-47.0 kDa). The temperature at the onset of degradation increased by 17-61 degrees C and by 75-145 degrees C for low and high acetylated xylans respectively, as a result of acetylation. A glass transition temperature in the range of 121-132 degrees C was observed for the samples non-acetylated and acetylated at low degree of acetylation (0.0-0.6). The acetylation to higher degrees (1.4-1.8) increased the glass transition temperature of the samples to 189-206 degrees C. Acetylation proved to be an efficient method for functionalization of the xylan to increase the thermal stability.
  • Driver, Gordon W.; Kilpelainen, Ilkka A. (2020)
    Knowledge of solution thermodynamics is fundamental for solution control and solvent selection processes. Herein, experimentally determined thermodynamic quantities for solutions of wood pulp (hardwood dissolving pulp, i.e. cellulose) in [m-TBDH][AcO] are presented. Model-free activities (a(i,j)) and associated mass fraction (w(i,j)) activity coefficients (omega(i,j)), are determined to quantify inherent solution non-ideality. Access to the Gibbs energy of mixing, G(mix), in combination with associated partial molar thermodynamic quantities, reveal strong enthalpically favourable (exothermic) interactions due to solvent-j and solute-i contact-encounters. Onset of an entropy driven phase instability appears at increased temperatures as excess entropic contributions dominate solvation character of the irregular solutions formed.
  • Auvinen, Vili-Veli; Virtanen, Juhani; Merivaara, Arto; Virtanen, Valtteri; Laurén, Patrick; Tuukkanen, Sampo; Laaksonen, Timo (2020)
    Nanocellulose hydrogel has been shown to be an excellent platform for drug delivery and it has been lately studied as an injectable drug carrier. 3D printing is an effective method for fast prototyping of pharmaceutical devices with unique shape and cavities enabling new types of controlled release. In this study, we combined the versatility of 3D printing capsules with controlled geometry and the drug release properties of nanocellulose hydrogel to accurately modulate its drug release properties. We first manufactured non-active capsules via 3D printing from biocompatible poly(lactic acid) (PLA) that limit the direction of drug diffusion. As a novel method, the capsules were filled with a drug dispersion composed of model compounds and anionic cellulose nanofiber (CNF) hydrogel. The main benefit of this device is that the release of any CNF-compatible drug can be modulated simply by modulating the inner geometry of the PLA capsule. In the study we optimized the size and shape of the capsules inner cavity and performed drug release tests with common beta blockers metoprolol and nadolol as the model compounds. The results demonstrate that the sustained release profiles provided by the CNF matrix can be accurately modulated via adjusting the geometry of the 3D printed PLA capsule, resulting in adjustable sustained release for the model compounds.
  • Ajdary, Rubina; Zanjanizadeh Ezazi, Nazanin; Rebelo Correia, Alexandra Maria; Kemell, Marianna; Huan, Siqi; Ruskoaho, Heikki; Hirvonen, Jouni; Santos, Hélder A.; Rojas, Orlando J. (2020)
    A biomaterial system incorporating nanocellulose, poly(glycerol sebacate), and polypyrrole is introduced for the treatment of myocardial infarction. Direct ink writing of the multicomponent aqueous suspensions allows multifunctional lattice structures that not only feature elasticity and electrical conductivity but enable cell growth. They are proposed as cardiac patches given their biocompatibility with H9c2 cardiomyoblasts, which attach extensively at the microstructural level, and induce their proliferation for 28 days. Two model drugs (3i‐1000 and curcumin) are investigated for their integration in the patches, either by loading in the precursor suspension used for extrusion or by direct impregnation of the as‐obtained, dry lattice. In studies of drug release conducted for five months, a slow in vitro degradation of the cardiac patches is observed, which prevents drug burst release and indicates their suitability for long‐term therapy. The combination of biocompatibility, biodegradability, mechanical strength, flexibility, and electrical conductivity fulfills the requirement of the highly dynamic and functional electroresponsive cardiac tissue. Overall, the proposed cardiac patches are viable alternatives for the regeneration of myocardium after infarction through the effective integration of cardiac cells with the biomaterial.
  • Oleyaei, Seyed Amir; Razavi, Seyed Mohammad Ali; Mikkonen, Kirsi Susanna (2018)
    In this study, the physico-chemical and rheo-mechanical properties of sage seed gum hydrogel, reinforced by various ratios (0-25 wt.%) of Laponite, were investigated. Particles size measurements indicated the formation of large SSG-Laponite microstructures upon nanoparticle adding, due to the interactions generated between the anionic SSG and the charged surfaces of clay platelets. Laponite affected the surface tension and density of the SSG-based systems significantly, but only influenced the-potential above 20 wt.%. The dynamic rheological behavior of SSG-based nanocomposites reflected the reinforcing effect of secondary structures and percolated three-dimensional network, suggested a structural modification of the hydrogels with the Laponite loading. An improvement in texture profile analysis parameters was observed in Laponite content 5 wt.%, whereas for nanoparticles > 5 wt.%, a significant decrease was obtained. In conclusion, Laponite improved the rheological and physico-chemical properties of SSG-based hydrogel and extended its potential as promising future bio-products for industrial applications.
  • Rico del Cerro, Daniel; Mera-Adasme, Raúl; King, Alistair W. T.; Perea-Buceta, Jesus E.; Heikkinen, Sami; Hase, Tapio; Sundholm, Dage; Wähälä, Kristiina (2018)
    Comprehensive spectroscopic kinetic studies illustrate an alternative mechanism for the traditional free-carbene intermediated H/D exchange reaction of 1,3-dialkylimidazolium salts under neutral (D2O) and acidic conditions (DCl/D2O 35wt% solution). The deuteration of high purity [bmim]Cl in D2O is studied at different temperatures, in absence of catalyst or impurities, to yield an activation energy. DFT transition-state modelling, of a small water cluster and [bmim] cation, also yields an activation energy which strongly supports the proposed mechanism. The presence of basic impurities are shown to significantly enhance the exchange reaction, which brings into question the need for further analysis of technical purities of ionic liquids and the implications for a wide range of chemical reactions in such media.
  • Kyllönen, Lasse; Parviainen, Arno; Deb, Somdatta; Lawoko, Martin; Gorlov, Mikhail; Kilpeläinen, Ilkka; King, Alistair W. T. (2013)
  • Oleyaei, Seyed Amir; Razavi, Seyed Mohammad Ali; Mikkonen, Kirsi S. (2018)
    Sage seed gum (SSG) is a promising biopolymer candidate for utilization and substitution prevalent galactomannan gels of interest in soft biomaterial applications. Herein, physicochemical and rheo-mechanical properties of SSG matrix reinforced by various titanium dioxide (TiO2) nanoparticles loading (0-25wt%) were monitored. Particle size and density of the nanocomposite increased with raising TiO2 content, due to the creation of more compact agglomerated and aggregated microstructure. Increasing the particle size resulted in lower electrophoretic mobility of SSG-TiO2 systems upon nanoparticles addition, confirmed the adsorption of TiO2 on the SSG macromolecule. Mechanical spectra of the SSG-based nanocomposites demonstrated a more solid-like behavior by lower frequency-dependent viscoelastic moduli, suggested a structural decoration of the nanohybrid gels discussed in terms of polymer bridging effect and formation of percolated matrix-particle superstructure. Crucial textural parameters improved with increasing TiO2 until a critical level (15 wt%), after which further increments in filler resulted in a reduction of hardness, adhesiveness and apparent modulus of elasticity. Deformation of rod-like junction zones acting as physical crosslinks in the system and fracture theory were used to explain the strain-stiffening and adhesive behavior of SSG-based gels, respectively. The nanocomposite gels with tunable functional properties might be ideal candidates for biomaterial industry. (C) 2018 Elsevier B.V. All rights reserved.
  • Shah, Firoz Hussain; Mali, Tuulia Leena Elina; Lundell, Taina Kristina (2018)
    Basidiomycota fungi in the order Polyporales are specified to decomposition of dead wood and woody debris and thereby are crucial players in the degradation of organic matter and cycling of carbon in the forest ecosystems. Polyporales wood-decaying species comprise both white rot and brown rot fungi, based on their mode of wood decay. While the white rot fungi are able to attack and decompose all the lignocellulose biopolymers, the brown rot species mainly cause the destruction of wood polysaccharides, with minor modification of the lignin units. The biochemical mechanism of brown rot decay of wood is still unclear and has been proposed to include a combination of nonenzymatic oxidation reactions and carbohydrate-active enzymes. Therefore, a linking approach is needed to dissect the fungal brown rot processes. We studied the brown rot Polyporales species Fomitopsis pinicola by following mycelial growth and enzyme activity patterns and generating metabolites together with Fenton-promoting Fe3+-reducing activity for 3 months in submerged cultures supplemented with spruce wood. Enzyme activities to degrade hemicellulose, cellulose, proteins, and chitin were produced by three Finnish isolates of F. pinicola. Substantial secretion of oxalic acid and a decrease in pH were notable. Aromatic compounds and metabolites were observed to accumulate in the fungal cultures, with some metabolites having Fe3+-reducing activity. Thus, F. pinicola demonstrates a pattern of strong mycelial growth leading to the active production of carbohydrate-and protein-active enzymes, together with the promotion of Fenton biochemistry. Our findings point to fungal species-level "fine-tuning" and variations in the biochemical reactions leading to the brown rot type of wood decay. IMPORTANCE Fomitopsis pinicola is a common fungal species in boreal and temperate forests in the Northern Hemisphere encountered as a wood-colonizing sapro-troph and tree pathogen, causing a severe brown rot type of wood degradation. However, its lignocellulose-decomposing mechanisms have remained undiscovered. Our approach was to explore both the enzymatic activities and nonenzymatic Fenton reaction-promoting activities (Fe3+ reduction and metabolite production) by cultivating three isolates of F. pinicola in wood-supplemented cultures. Our findings on the simultaneous production of versatile enzyme activities, including those of endoglucanase, xylanase, beta-glucosidase, chitinase, and acid peptidase, together with generation of low pH, accumulation of oxalic acid, and Fe3+-reducing metabolites, increase the variations of fungal brown rot decay mechanisms. Furthermore, these findings will aid us in revealing the wood decay proteomic, transcriptomic, and metabolic activities of this ecologically important forest fungal species.
  • Seyfferth, Carolin; Wessels, Bernard A.; Vahala, Jorma; Kangasjarvi, Jaakko; Delhomme, Nicolas; Hvidsten, Torgeir R.; Tuominen, Hannele; Lundberg-Felten, Judith (2021)
    Secondary growth relies on precise and specialized transcriptional networks that determine cell division, differentiation, and maturation of xylem cells. We identified a novel role for the ethylene-induced Populus Ethylene Response Factor PtERF85 (Potri.015G023200) in balancing xylem cell expansion and secondary cell wall (SCW) formation in hybrid aspen (Populus tremula x tremuloides). Expression of PtERF85 is high in phloem and cambium cells and during the expansion of xylem cells, while it is low in maturing xylem tissue. Extending PtERF85 expression into SCW forming zones of woody tissues through ectopic expression reduced wood density and SCW thickness of xylem fibers but increased fiber diameter. Xylem transcriptomes from the transgenic trees revealed transcriptional induction of genes involved in cell expansion, translation, and growth. The expression of genes associated with plant vascular development and the biosynthesis of SCW chemical components such as xylan and lignin, was down-regulated in the transgenic trees. Our results suggest that PtERF85 activates genes related to xylem cell expansion, while preventing transcriptional activation of genes related to SCW formation. The importance of precise spatial expression of PtERF85 during wood development together with the observed phenotypes in response to ectopic PtERF85 expression suggests that PtERF85 contributes to the transition of fiber cells from elongation to secondary cell wall deposition.
  • Casteleijn, Marco G.; Richardson, Dominique; Parkkila, Petteri Kalervo; Granqvist, Niko Markus; Urtti, Arto Olavi; Viitala, Tapani Juhani Samuel (2018)
    Chitin, abundant in nature, is a renewable resource with many possible applications in bioengineering. Biosensors, capable of label-free and in-line evaluation, play an important role in the investigation of chitin synthesis, degradation and interaction with other materials. This work presents a comparative study of the usefulness of a chitin surface preparation, either on gold (Au) or on polystyrene (PS). In both cases the most common method to dissolve chitin was used, followed by a simple spin-coating procedure. Multi-parametric surface plasmon resonance (MP-SPR), modeling of the optical properties of the chitin layers, scanning electron microscopy, and contact angle goniometry were used to confirm: the thickness of the layers in air and buffer, the refractive indices of the chitin layers in air and buffer, the hydrophobicity, the binding properties of the chitin binding domain (CBD) of Bacillus circulans, and the split-intein capture process. Binding of the CBD differed between chitin on Au versus chitin on PS in terms of binding strength and binding specificity due to a less homogenous structured chitin-surface on Au in comparison to chitin on PS, despite a similar thickness of both chitin layers in air and after running buffer over the surfaces. The use of the simple method to reproduce chitin films on a thin polystyrene layer to study chitin as a biosensor and for chitin binding studies was obvious from the SPR studies and the binding studies of CBD as moiety of chitinases or as protein fusion partner. In conclusion, stable chitin layers for SPR studies can be made from chitin in a solution of dimethylacetamide (DMA) and lithium chloride (LiCl) followed by spin-coating if the gold surface is protected with PS.