Browsing by Subject "LIGNIN"

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  • Valoppi, Fabio; Lahtinen, Maarit; Bhattarai, Mamata; Kirjoranta, Satu; Juntti, Venla; Peltonen, Leena; Kilpeläinen, Petri O.; Mikkonen, Kirsi S. (2019)
    With the emerging bio-based technologies, the fractionation of complex biomass is essential to obtain value-added functional molecules for material, chemical, and energy production. The refining process of biomasses often requires the use of solvents and hazardous chemicals, whose removal after fractionation decreases the eco-compatibility of the process and increases the cost and time of the refinement. Softwood extracts obtained through the environmentally friendly pressurized hot water extraction are heterogeneous mixtures rich in hemicelluloses and lignin. Here we developed a simple, fast, organic solvent-free, and sustainable method to fractionate softwood extracts using centrifugal forces. The characteristics of each obtained fraction in terms of composition, macromolecular properties (particle size, molar mass, charge), interfacial activity, and stabilization capacity were highly dependent on the centrifugal force and time applied. The hemicellulose and lignin contents in the fractions were balanced by centrifugal forces to obtain functional emulsifiers that efficiently stabilized the oil/water interface. Through fractionation of softwood extracts, we also found that both the hemicelluloses and lignin particles are involved in emulsion interface formation and stabilization. Centrifugation is a scalable concept that can be feasibly and easily introduced into the biorefinery system and used to optimize the composition of biomass fractions for targeted purposes.
  • Bhattarai, Mamata; Sulaeva, Irina; Pitkänen, Leena; Kontro, Inkeri; Tenkanen, Maija; Potthast, Antje; Mikkonen, Kirsi S. (2020)
    Development of a sustainable bioeconomy requires valorization of renewable resources, such as wood hemicelluloses. The intra- and inter-molecular associations of hemicelluloses within themselves or with other wood components can result in complex macromolecular features. These features exhibit functionality as hydrocolloids, however macromolecular characterization of these heterogeneous materials are challenging using conventional techniques such as size-exclusion chromatography. We studied galactoglucomannans (GGM) -rich softwood extracts at two grades of purity—as crude extract and after ethanol-precipitation. Asymmetrical flow field-flow fractionation (AF4) was optimized and utilized to fractionate size classes in GGM extracts, and subsequent characterization was performed with light scattering and microscopy techniques. Both GGM extracts contained polysaccharides of around 10,000 g/mol molar mass, and colloidal assemblies and/or particles in sub-micron size range. The optimized AF4 method facilitates the characterization of complex biomass-derived carbohydrates without pre-fractionation, and provides valuable understanding of their unique macromolecular features for their future application in food, pharmaceuticals, and cosmetics.
  • Daly, Paul; Lopez, Sara Casado; Peng, Mao; Lancefield, Christopher S.; Purvine, Samuel O.; Kim, Young-Mo; Zink, Erika M.; Dohnalkova, Alice; Singan, Vasanth R.; Lipzen, Anna; Dilworth, David; Wang, Mei; Ng, Vivian; Robinson, Errol; Orr, Galya; Baker, Scott E.; Bruijnincx, Pieter C. A.; Hilden, Kristiina S.; Grigoriev, Igor V.; Mäkelä, Miia R.; de Vries, Ronald P. (2018)
    White-rot fungi, such as Dichomitus squalens, degrade all wood components and inhabit mixed-wood forests containing both soft- and hardwood species. In this study, we evaluated how D. squalens responded to the compositional differences in softwood [guaiacyl (G) lignin and higher mannan content] and hardwood [syringyl/guaiacyl (S/G) lignin and higher xylan content] using semi-natural solid cultures. Spruce (softwood) and birch (hardwood) sticks were degraded by D. squalens as measured by oxidation of the lignins using 2D-NMR. The fungal response as measured by transcriptomics, proteomics and enzyme activities showed a partial tailoring to wood composition. Mannanolytic transcripts and proteins were more abundant in spruce cultures, while a proportionally higher xylanolytic activity was detected in birch cultures. Both wood types induced manganese peroxidases to a much higher level than laccases, but higher transcript and protein levels of the manganese peroxidases were observed on the G-lignin rich spruce. Overall, the molecular responses demonstrated a stronger adaptation to the spruce rather than birch composition, possibly because D. squalens is mainly found degrading softwoods in nature, which supports the ability of the solid wood cultures to reflect the natural environment.
  • Hurmekoski, Elias; Jonsson, Ragnar; Korhonen, Jaana; Jänis, Janne; Mäkinen, Marko; Leskinen, Pekka; Hetemäki, Lauri (2018)
    This study identifies new wood-based products with considerable potential and attractive markets, including textiles, liquid biofuels, platform chemicals, plastics, and packaging. We apply a mixed-methods review to examine how the position of the forest industry in a given value chain determines the respective production value. An assessment is provided as to the degree to which these emerging wood-based products could compensate for the foreseen decline of graphic paper markets in four major forest industry countries: USA, Canada, Sweden, and Finland. A 1%-2% market share in selected global markets implies a potential increase in revenues of 18-75 billion euros per annum in the four selected countries by 2030. This corresponds to 10%-43% of the production value of forest industries in 2016 and compares with a projected decline of graphic paper industry revenue of 5.5 billion euros by 2030. The respective impacts on wood use are manifold, as many of the new products utilize by-products as feedstock. The increase in primary wood use, which is almost entirely attributed to construction and to some extent textiles markets, would be in the range of 15-133 million m(3), corresponding to 2%-21% of the current industrial roundwood use in the selected countries.
  • Miettinen, Jenni; Ollikainen, Markku (2022)
    We examine the emerging forest bioeconomy as an integrated, multi-product industrial ecosystem, where the traditional pulp mills allocate the use of side streams to independent biochemical companies manufacturing bioproducts in the vicinity of the pulp mills. Biochemical companies benefit from the proximity by receiving wood-based side streams at lower costs, and at the same time, pulp mills benefit from having a new source of revenue from selling side streams. We focus on the economic interaction between the pulp mill and the biochemical company, and we study the impacts on the use of wood and profits under perfect and imperfect competition. We demonstrate that the new industrial ecosystem uses more wood than traditional pulp mills, but depending on the side stream, it may promote cascading use of wood-based side streams.
  • Varnai, Aniko; Costa, Thales H. F.; Faulds, Craig B.; Milagres, Adriane M. F.; Siika-aho, Matti; Ferraz, Andre (2014)
    Background: Sugar cane internodes can be divided diagonally into four fractions, of which the two innermost ones are the least recalcitrant pith and the moderately accessible pith-rind interface. These fractions differ in enzymatic hydrolyzability due to structural differences. In general, cellulose hydrolysis in plants is hindered by its physical interaction with hemicellulose and lignin. Lignin is believed to be linked covalently to hemicellulose through hydroxycinnamic acids, forming a compact matrix around the polysaccharides. Acetyl xylan esterase and three feruloyl esterases were evaluated for their potential to fragment the lignocellulosic network in sugar cane and to indirectly increase the accessibility of cellulose. Results: The hydrolyzability of the pith and pith-rind interface fractions of a low-lignin-containing sugar cane clone (H58) was compared to that of a reference cultivar (RC). Acetyl xylan esterase enhanced the rate and overall yield of cellulose and xylan hydrolysis in all four substrates. Of the three feruloyl esterases tested, only TsFaeC was capable of releasing p-coumaric acid, while AnFaeA and NcFaeD released ferulic acid from both the pith and interface fractions. Ferulic acid release was higher from the less recalcitrant clone (H58)/fraction (pith), whereas more p-coumaric acid was released from the clone (RC)/fraction (interface) with a higher lignin content. In addition, a compositional analysis of the four fractions revealed that p-coumaroyl content correlated with lignin, while feruloyl content correlated with arabinose content, suggesting different esterification patterns of these two hydroxycinnamic acids. Despite the extensive release of phenolic acids, feruloyl esterases only moderately promoted enzyme access to cellulose or xylan. Conclusions: Acetyl xylan esterase TrAXE was more efficient in enhancing the overall saccharification of sugar cane, compared to the feruloyl esterases AnFaeA, TsFaeC, and NcFaeD. The hydroxycinnamic acid composition of sugar cane fractions and the hydrolysis data together suggest that feruloyl groups are more likely to decorate xylan, while p-coumaroyl groups are rather linked to lignin. The three different feruloyl esterases had distinct product profiles on non-pretreated sugar cane substrate, indicating that sugar cane pith could function as a possible natural substrate for feruloyl esterase activity measurements. Hydrolysis data suggest that TsFaeC was able to release p-coumaroyl groups esterifying lignin.
  • Dong, Yujiao; Paukkonen, Heli; Fang, Wenwen; Kontturi, Eero; Laaksonen, Timo; Laaksonen, Paivi (2018)
    Drug release from a new type of matrix material consisting of partially fibrillated microcrystalline cellulose was investigated. A mechanical treatment of novel AaltoCell T cellulose microcrystals caused partial opening of the nanofibrillary structure of the cellulose particles and entanglement of individual particles led into formation of an elastic network of microcrystalline cellulose. The rheological properties of the stable hydrogel-like materials were characterised by shear rheometry. Model compounds metronidazole and lysozyme were successfully employed in drug release experiments carried out by delignified (bleached) and lignin-containing matrices. The viscosity as well as the lignin-content played a role in the release dynamics of the drugs. Microcrystalline AaltoCell T was proven as high-performing material for diffusion controlled release of the chosen model compounds and can be seen as a safe and economical alternative for novel matrix materials such as nanocellulose or cellulose derivatives.
  • Veloz Villavicencio, Eliana Estefanía; Mali, Tuulia; Mattila, Hans; Lundell, Taina (2020)
    Four well-studied saprotrophic Basidiomycota Agaricomycetes species with different decay strategies were cultivated on solid lignocellulose substrates to compare their extracellular decomposing carbohydrate-active and lignin-attacking enzyme production profiles. Two Polyporales species, the white rot fungus Phlebia radiata and brown rot fungus Fomitopsis pinicola, as well as one Agaricales species, the intermediate “grey” rot fungus Schizophyllum commune, were cultivated on birch wood pieces for 12 weeks, whereas the second Agaricales species, the litter-decomposing fungus Coprinopsis cinerea was cultivated on barley straw for 6 weeks under laboratory conditions. During 3 months of growth on birch wood, only the white rot fungus P. radiata produced high laccase and MnP activities. The brown rot fungus F. pinicola demonstrated notable production of xylanase activity up to 43 nkat/mL on birch wood, together with moderate β-glucosidase and endoglucanase cellulolytic activities. The intermediate rot fungus S. commune was the strongest producer of β-glucosidase with activities up to 54 nkat/mL, and a notable producer of xylanase activity, even up to 620 nkat/mL, on birch wood. Low lignin-attacking but moderate activities against cellulose and hemicellulose were observed with the litter-decomposer C. cinerea on barley straw. Overall, our results imply that plant cell wall decomposition ability of taxonomically and ecologically divergent fungi is in line with their enzymatic decay strategy, which is fundamental in understanding their physiology and potential for biotechnological applications.
  • Han, Liuyang; Tian, Xingling; Keplinger, Tobias; Zhou, Haibin; Li, Ren; Svedström, Kirsi; Burgert, Ingo; Yin, Yafang; Guo, Juan (2020)
    Structural and chemical deterioration and its impact on cell wall mechanics were investigated for visually intact cell walls (VICWs) in waterlogged archaeological wood (WAW). Cell wall mechanical properties were examined by nanoindentation without prior embedding. WAW showed more than 25% decrease of both hardness and elastic modulus. Changes of cell wall composition, cellulose crystallite structure and porosity were investigated by ATR-FTIR imaging, Raman imaging, wet chemistry, C-13-solid state NMR, pyrolysis-GC/MS, wide angle X-ray scattering, and N-2 nitrogen adsorption. VICWs in WAW possessed a cleavage of carboxyl in side chains of xylan, a serious loss of polysaccharides, and a partial breakage of beta -O-4 interlinks in lignin. This was accompanied by a higher amount of mesopores in cell walls. Even VICWs in WAW were severely deteriorated at the nanoscale with impact on mechanics, which has strong implications for the conservation of archaeological shipwrecks.
  • Lopez, Sara Casado; Peng, Mao; Issak, Tedros Yonatan; Daly, Paul; de Vries, Ronald P.; Mäkelä, Miia R. (2018)
    Fungi can decompose plant biomass into small oligo-and monosaccharides to be used as carbon sources. Some of these small molecules may induce metabolic pathways and the production of extracellular enzymes targeted for degradation of plant cell wall polymers. Despite extensive studies in ascomycete fungi, little is known about the nature of inducers for the lignocellulolytic systems of basidiomycetes. In this study, we analyzed six sugars known to induce the expression of lignocellulolytic genes in ascomycetes for their role as inducers in the basidiomycete white-rot fungus Dichomitus squalens using a transcriptomic approach. This identified cellobiose and L-rhamnose as the main inducers of cellulolytic and pectinolytic genes, respectively, of D. squalens. Our results also identified differences in gene expression patterns between dikaryotic and monokaryotic strains of D. squalens cultivated on plant biomass-derived monosaccharides and the disaccharide cellobiose. This suggests that despite conservation of the induction between these two genetic forms of D. squalens, the fine-tuning in the gene regulation of lignocellulose conversion is differently organized in these strains. IMPORTANCE Wood-decomposing basidiomycete fungi have a major role in the global carbon cycle and are promising candidates for lignocellulosic biorefinery applications. However, information on which components trigger enzyme production is currently lacking, which is crucial for the efficient use of these fungi in biotechnology. In this study, transcriptomes of the white-rot fungus Dichomitus squalens from plant biomass-derived monosaccharide and cellobiose cultures were studied to identify compounds that induce the expression of genes involved in plant biomass degradation.
  • Mansikkala, Tuomas; Patanen, Minna; Karkonen, Anna; Korpinen, Risto; Pranovich, Andrey; Ohigashi, Takuji; Swaraj, Sufal; Seitsonen, Jani; Ruokolainen, Janne; Huttula, Marko; Saranpaa, Pekka; Piispanen, Riikka (2020)
    Lignans are bioactive compounds that are especially abundant in the Norway spruce (Picea abiesL. Karst.) knotwood. By combining a variety of chromatographic, spectroscopic and imaging techniques, we were able to quantify, qualify and localise the easily extractable lignans in the xylem tissue. The knotwood samples contained 15 different lignans according to the gas chromatography-mass spectrometry analysis. They comprised 16% of the knotwood dry weight and 82% of the acetone extract. The main lignans were found to be hydroxymatairesinols HMR1 and HMR2. Cryosectioned and resin-embedded ultrathin sections of the knotwood were analysed with scanning transmission X-ray microscopy (STXM). Cryosectioning was found to retain only lignan residues inside the cell lumina. In the resin-embedded samples, lignan was interpreted to be unevenly distributed inside the cell lumina, and partially confined in deposits which were either readily present in the lumina or formed when OsO(4)used in staining reacted with the lignans. Furthermore, the multi-technique characterisation enabled us to obtain information on the chemical composition of the structural components of knotwood. A simple spectral analysis of the STXM data gave consistent results with the gas chromatographic methods about the relative amounts of cell wall components (lignin and polysaccharides). The STXM analysis also indicated that a torus of a bordered pit contained aromatic compounds, possibly lignin.
  • Kohl, Lukas; Myers-Pigg, Allison; Edwards, Kate A.; Billings, Sharon A.; Warren, Jamie; Podrebarac, Frances; Ziegler, Susan E. (2021)
    Plant litter chemistry is altered during decomposition but it remains unknown if these alterations, and thus the composition of residual litter, will change in response to climate. Selective microbial mineralization of litter components and the accumulation of microbial necromass can drive litter compositional change, but the extent to which these mechanisms respond to climate remains poorly understood. We addressed this knowledge gap by studying needle litter decomposition along a boreal forest climate transect. Specifically, we investigated how the composition and/or metabolism of the decomposer community varies with climate, and if that variation is associated with distinct modifications of litter chemistry during decomposition. We analyzed the composition of microbial phospholipid fatty acids (PLFA) in the litter layer and measured natural abundance δ13C-PLFA values as an integrated measure of microbial metabolisms. Changes in litter chemistry and δ13C values were measured in litterbag experiments conducted at each transect site. A warmer climate was associated with higher litter nitrogen concentrations as well as altered microbial community structure (lower fungi:bacteria ratios) and microbial metabolism (higher δ13C-PLFA). Litter in warmer transect regions accumulated less aliphatic-C (lipids, waxes) and retained more O-alkyl-C (carbohydrates), consistent with enhanced 13C-enrichment in residual litter, than in colder regions. These results suggest that chemical changes during litter decomposition will change with climate, driven primarily by indirect climate effects (e.g. greater nitrogen availability and decreased fungi:bacteria ratios) rather than direct temperature effects. A positive correlation between microbial biomass δ13C values and 13C-enrichment during decomposition suggests that change in litter chemistry is driven more by distinct microbial necromass inputs than differences in the selective removal of litter components. Our study highlights the role that microbial inputs during early litter decomposition can play in shaping surface litter contribution to soil organic matter as it responds to climate warming effects such as greater nitrogen availability.
  • Hyväkkö, Uula; Maltari, Riku; Kakko, Tia; Kontro, Jussi; Mikkilä, Joona; Kilpeläinen, Petri; Enqvist, Eric; Tikka, Panu; Hilden, Kristiina; Nousiainen, Paula; Sipilä, Jussi (2020)
    In modern biorefineries, low value lignin and hemicellulose fractions are produced as side streams. New extraction methods for their purification are needed in order to utilize the whole biomass more efficiently and to produce special target products. In several new applications using plant based biomaterials, the native-type chemical and polymeric properties are desired. Especially, production of high-quality native-type lignin enables valorization of biomass entirely, thus making novel processes sustainable and economically viable. To investigate sulfur-free possibilities for so-called "lignin first" technologies, we compared alkaline organosolv, formic acid organosolv, and ionic liquid processes to simple soda "cooking" using wheat straw and aspen as raw materials. All experiments were carried out using microwave-assisted pulping approach toy enable rapid heat transfer and convenient control of temperature and pressure. The main target was to evaluate the advantage of a brief hot water extraction as a pretreatment for the pulping process. Most of these novel pulping methods resulted in high-quality lignin, which may be valorized more diversely than kraft lignin. Lignin fractions were thoroughly analyzed with NMR (C-13 and HSQC) and gel permeation chromatography to study the quality of the collected lignin. The cellulose fractions were analyzed by determining their lignin contents and carbohydrate profiles for further utilization in cellulose-based products or biofuels.
  • Kyllönen, Lasse; Parviainen, Arno; Deb, Somdatta; Lawoko, Martin; Gorlov, Mikhail; Kilpeläinen, Ilkka; King, Alistair W. T. (2013)
  • Wang, Qing-Wei; Pieriste, Marta; Liu, Chenggang; Kenta, Tanaka; Robson, Thomas Matthew; Kurokawa, Hiroko (2021)
    Litter decomposition determines carbon (C) backflow to the atmosphere and ecosystem nutrient cycling. Although sunlight provides the indispensable energy for terrestrial biogeochemical processes, the role of photodegradation in decomposition has been relatively neglected in productive mesic ecosystems. To quantify the effects of this variation, we conducted a factorial experiment in the understorey of a temperate deciduous forest and an adjacent gap, using spectral-attenuation-filter treatments. Exposure to the full spectrum of sunlight increased decay rates by nearly 120% and the effect of blue light contributed 75% of this increase. Scaled-up to the whole forest ecosystem, this translates to 13% loss of leaf-litter C through photodegradation over the year of our study for a scenario of 20% gap. Irrespective of the spectral composition, herbaceous and shrub litter lost mass faster than tree litter, with photodegradation contributing the most to surface litter decomposition in forest canopy gaps. Across species, the initial litter lignin and polyphenolic contents predicted photodegradation by blue light and ultraviolet B (UV-B) radiation, respectively. We concluded that photodegradation, modulated by litter quality, is an important driver of decomposition, not just in arid areas, but also in mesic ecosystems such as temperate deciduous forests following gap opening.
  • Bhattarai, Mamata; Valoppi, Fabio; Hirvonen, Sami-Pekka; Hietala, Sami; Kilpelainen, Petri; Aseyev, Vladimir; Mikkonen, Kirsi S. (2020)
    The demand for naturally derived, functional and cost-effective raw materials for various food applications is escalating. Spruce wood is a sustainable and abundant, but underutilized source of novel hydrocolloids-galactoglucomannans (GGM). Pressurized-hot water extracted GGM with an intermediate molar mass are hypothesized to form colloidal solutions. To design superior quality products from GGM, an understanding of their colloidal stability and their potential effect in multiphasic systems is required. The present study addresses the functionality of GGM by characterizing their properties in a bi-phasic system, and for the first time, their time-dependent colloidal stability at different extrinsic conditions- pH, ionic strength and after the application of high-intensity mechanical shearing. Amongst the conditions studied, the colloidal stability of aqueous GGM solution was highly pH dependent. The results showed that an intermediate molar mass polysaccharide like GGM formed inter-/intra molecular assemblies, which grew over time, depending on the composition and processing of the aqueous medium. The molecular dispersion of GGM and their dynamic behavior was also compared to solutions of known food hydrocolloids-gum Arabic and hydroxypropylmethyl cellulose. The observed solution properties explain the hydmcolloid functionality of GGM and contribute to design of colloidal polysaccharide systems in food application.
  • Hänninen, Tuomas; Tukiainen, Pekka; Svedström, Kirsi; Serimaa, Ritva; Saranpää, Pekka; Kontturi, Eero; Hughes, Mark; Vuorinen, Tapani (2012)
  • Hagel, Sebastian; Kirjoranta, Satu; Mikkonen, Kirsi S.; Tenkanen, Maija; Körner, Ina; Saake, Bodo (2021)
    Street tree pruning residues are a widely available and currently undervalorized bioresource. Their utilization could help alleviate an increasing biomass shortage and offset costs of the pruning process for the municipalities. In this work, a holistic valorization pathway of pruning residues leading to fibers, oligosaccharides, biogas, and compost is presented. For this, representative mixtures of tree pruning materials from the most prevalent street tree genera (oak, linden, maple) found in Hamburg (Germany) were prepared by shredding and cleaning procedures. Collection of sample material was performed in summer and winter to account for seasonality. A steam-based fractionation was conducted using treatment severities ranging from log R-0 = 2.5 to 4.0. At the highest severity, a fiber yield of around 66%, and liquor yield of 26-30% was determined. The fibers were evaluated with respect to their properties for paper product applications, with higher treatment severities leading to higher paper strengths. From the oligosaccharide-rich liquor, emulsions were created, which showed promising stability properties over 8 weeks of storage. The liquors and the rejects from the material preparation also displayed good potential for biomethane production. Overall, the differences between material collected in summer and winter were found to be small, indicating the possibility for a year-round utilization of pruning residues. For the presented utilization pathway, high severity treatments were the most promising, featuring a high liquor yield, good biomethane potential, and the highest paper strengths.