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Sample records for cellulose microfibril orientation

  1. Cellulose microfibril assembly and orientation in higher plant cells

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, S.C. (Syracuse Univ., NY); Maclachlan, G.A.; Brown, R.M. Jr.

    1983-01-01

    Freeze-fractured plasma membranes of seedlings of Zea mays L., Burpee's Snowcross, and Pisum sativum L., variety Alsaka, contain terminal complex structures and the impressions of microfibrils from the newest cell wall layer.Terminal complex subunits are on the exoplasmic fracture (EF) face, and rosette subunits are on the protoplasmic fracture (PF) face of the membrane. The association of terminal complexes and rosettes with microfibril tips and their association with newly deposited groups of microfibrils is indirect evidence for their role in microfibril assembly. Microtubules may be responsible for certain orientations of microfibrils, particularly the formation of bands of microfibrils in newly deposited wall layers. However, microfibril orienting mechanisms are more complex, involving factors still present during colchicine treatment. Since UDP-glucose is thought to be a precursor of cellulose microfibrils in higher plant cells, EM radioautography was used to determine the site of incorporation of glucose. However, under the conditions used, glucose was only incorporated from UDP-glucose at the surface of cut or damaged pea stem cells, i.e., in vitro. Thus, incorporation of glucose from UDP-glucose was not useful for probing the patterns of cellulose microfibril synthesis in vivo. 18 references, 8 figures.

  2. Non-invasive imaging of cellulose microfibril orientation within plant cell walls by polarized Raman microspectroscopy.

    Science.gov (United States)

    Sun, Lan; Singh, Seema; Joo, Michael; Vega-Sanchez, Miguel; Ronald, Pamela; Simmons, Blake A; Adams, Paul; Auer, Manfred

    2016-01-01

    Cellulose microfibrils represent the major scaffold of plant cell walls. Different packing and orientation of the microfibrils at the microscopic scale determines the macroscopic properties of cell walls and thus affect their functions with a profound effect on plant survival. We developed a polarized Raman microspectroscopic method to determine cellulose microfibril orientation within rice plant cell walls. Employing an array of point measurements as well as area imaging and subsequent Matlab-assisted data processing, we were able to characterize the distribution of cellulose microfibril orientation in terms of director angle and anisotropy magnitude. Using this approach we detected differences between wild type rice plants and the rice brittle culm mutant, which shows a more disordered cellulose microfibril arrangement, and differences between different tissues of a wild type rice plant. This novel non-invasive Raman imaging approach allows for quantitative assessment of cellulose fiber orientation in cell walls of herbaceous plants, an important advancement in cell wall characterization. PMID:26137889

  3. Microfibrillated cellulose: morphology and accessibility

    Energy Technology Data Exchange (ETDEWEB)

    Herrick, F.W.; Casebier, R.L.; Hamilton, J.K.; Sandberg, K.R.

    1983-01-01

    Microfibrillated cellulose (MFC) is prepared by subjecting dilute slurries of cellulose fibers to repeated high-pressure homogenizing action. A highly microfibrillated product will have a gel-like appearance at 2% concentration in water. Such gels have pseudoplastic viscosity properties and are very fluid when stirred at high shear rate. The relative viscosity of 2% MFC dispersions may be used as a measure of the degree of homogenization or microfibrillation of a given wood cellulose pulp. The water retention value of an MFC product can also be used as an indicator for degree of homogenization. Structurally, MFC appears to be a web of interconnected fibrils and microfibrils, the latter having diameters in the range 10-100 nm as observed in scanning and transmission electron micrographs. Chemical studies have revealed that MFC is only moderately degraded, while being greatly expanded in surface area. The accessibility of cellulose in MFC is only moderately degraded, while being greatly expanded in surface area. The accessibility of cellulose in MFC toward chemical reagents is greatly increased. Higher reactivity was demonstrated in dilute cupriethylenediamine solubility, triphenylmethylation, acetylation, periodate oxidation, and mineral acid and cellulase enzyme hydrolysis rates. 16 references, 8 figures, 7 tables.

  4. Isolation of cellulose microfibrils - An enzymatic approach

    Directory of Open Access Journals (Sweden)

    Sain, M.

    2006-11-01

    Full Text Available Isolation methods and applications of cellulose microfibrils are expanding rapidly due to environmental benefits and specific strength properties, especially in bio-composite science. In this research, we have success-fully developed and explored a novel bio-pretreatment for wood fibre that can substantially improve the microfibril yield, in comparison to current techniques used to isolate cellulose microfibrils. Microfibrils currently are isolated in the laboratory through a combination of high shear refining and cryocrushing. A high energy requirement of these procedures is hampering momentum in the direction of microfibril isolation on a sufficiently large scale to suit potential applications. Any attempt to loosen up the microfibrils by either complete or partial destruction of the hydrogen bonds before the mechanical process would be a step forward in the quest for economical isolation of cellulose microfibrils. Bleached kraft pulp was treated with OS1, a fungus isolated from Dutch Elm trees infected with Dutch elm disease, under different treatment conditions. The percentage yield of cellulose microfibrils, based on their diameter, showed a significant shift towards a lower diameter range after the high shear refining, compared to the yield of cellulose microfibrils from untreated fibres. The overall yield of cellulose microfibrils from the treated fibres did not show any sizeable decrease.

  5. Exploring the Nature of Cellulose Microfibrils

    Energy Technology Data Exchange (ETDEWEB)

    Su, Ying [Stony Brook Univ., NY (United States); Burger, Christian [Stony Brook Univ., NY (United States); Ma, Hongyang [Stony Brook Univ., NY (United States); Chu, Benjamin [Stony Brook Univ., NY (United States); Hsiao, Benjamin S. [Stony Brook Univ., NY (United States)

    2015-03-20

    Ultrathin cellulose microfibril fractions were extracted from spruce wood powder using combined delignification, TEMPO-catalyzed oxidation, and sonication processes. Small-angle X-ray scattering of these microfibril fractions in a “dilute” aqueous suspension (concentration 0.077 wt %) revealed that their shape was in the form of nanostrip with 4 nm width and only about 0.5 nm thicknesses. We found that these dimensions were further confirmed by TEM and AFM measurements. The 0.5 nm thickness implied that the nanostrip could contain only a single layer of cellulose chains. At a higher concentration (0.15 wt %), SAXS analysis indicated that these nanostrips aggregated into a layered structure. The X-ray diffraction of samples collected at different preparation stages suggested that microfibrils were delaminated along the (110) planes from the Iβ cellulose crystals. Moreover, the degree of oxidation and solid-state 13C NMR characterizations indicated that, in addition to the surface molecules, some inner molecules of microfibrils were also oxidized, facilitating the delamination into cellulose nanostrips.

  6. Cellulose Microfibril Formation by Surface-Tethered Cellulose Synthase Enzymes.

    Science.gov (United States)

    Basu, Snehasish; Omadjela, Okako; Gaddes, David; Tadigadapa, Srinivas; Zimmer, Jochen; Catchmark, Jeffrey M

    2016-02-23

    Cellulose microfibrils are pseudocrystalline arrays of cellulose chains that are synthesized by cellulose synthases. The enzymes are organized into large membrane-embedded complexes in which each enzyme likely synthesizes and secretes a β-(1→4) glucan. The relationship between the organization of the enzymes in these complexes and cellulose crystallization has not been explored. To better understand this relationship, we used atomic force microscopy to visualize cellulose microfibril formation from nickel-film-immobilized bacterial cellulose synthase enzymes (BcsA-Bs), which in standard solution only form amorphous cellulose from monomeric BcsA-B complexes. Fourier transform infrared spectroscopy and X-ray diffraction techniques show that surface-tethered BcsA-Bs synthesize highly crystalline cellulose II in the presence of UDP-Glc, the allosteric activator cyclic-di-GMP, as well as magnesium. The cellulose II cross section/diameter and the crystal size and crystallinity depend on the surface density of tethered enzymes as well as the overall concentration of substrates. Our results provide the correlation between cellulose microfibril formation and the spatial organization of cellulose synthases. PMID:26799780

  7. Characterization of Cellulose Microfibrils Obtained from Hemp

    OpenAIRE

    Šutka, Anna; Kukle, Silvija; Gravitis, Janis; Grave, Laima

    2013-01-01

    Microfibrillated cellulose was extracted from hemp fibres using steam explosion pretreatment and high-intensity ultrasonic treatment (HIUS). The acquired results after steam explosion treatment and water and alkali treatments are discussed and interpreted by Fourier transform infrared spectroscopy (FTIR). Scanning electron microscopy (SEM) was used to examine the microstructure of hemp fibres before and after each treatment. A fibre size analyser was used to analyse the dimensions of the untr...

  8. Interactions of microfibrillated cellulose and cellulosic fines with cationic polyelectrolytes

    OpenAIRE

    Taipale, Tero

    2010-01-01

    The overall aim of this work was to produce and characterize different types of cellulosic fines and microfibrillated cellulose; to study their interactions with high molar mass cationic polyelectrolytes; and to demonstrate novel examples of their utilization. The work was performed, and its results discussed mainly from papermaking point of view, but the results are also well applicable in other fields of industry. Cellulosic fines are an essential component of papermaking fiber suspens...

  9. The solvation structures of cellulose microfibrils in ionic liquids.

    Science.gov (United States)

    Mostofian, Barmak; Smith, Jeremy C; Cheng, Xiaolin

    2011-12-01

    The use of ionic liquids for non-derivatized cellulose dissolution promises an alternative method for the thermochemical pretreatment of biomass that may be more efficient and environmentally acceptable than more conventional techniques in aqueous solution. Here, we performed equilibrium MD simulations of a cellulose microfibril in the ionic liquid 1-butyl-3-methylimidazolium chloride (BmimCl) and compared the solute structure and the solute-solvent interactions at the interface with those from corresponding simulations in water. The results indicate a higher occurrence of solvent-exposed orientations of cellulose surface hydroxymethyl groups in BmimCl than in water. Moreover, spatial and radial distribution functions indicate that hydrophilic surfaces are a preferred site of interaction between cellulose and the ionic liquid. In particular, hydroxymethyl groups on the hydrophilic fiber surface adopt a different conformation from their counterparts oriented towards the fiber's core. Furthermore, the glucose units with these solvent-oriented hydroxymethyls are surrounded by the heterocyclic organic cation in a preferred parallel orientation, suggesting a direct and distinct interaction scheme between cellulose and BmimCl. PMID:22179764

  10. Cellulose microfibril formation within a coarse grained molecular dynamics

    Science.gov (United States)

    Nili, Abdolmadjid; Shklyaev, Oleg; Crespi, Vincent; Zhao, Zhen; Zhong, Linghao; CLSF Collaboration

    2014-03-01

    Cellulose in biomass is mostly in the form of crystalline microfibrils composed of 18 to 36 parallel chains of polymerized glucose monomers. A single chain is produced by cellular machinery (CesA) located on the preliminary cell wall membrane. Information about the nucleation stage can address important questions about intermediate region between cell wall and the fully formed crystalline microfibrils. Very little is known about the transition from isolated chains to protofibrils up to a full microfibril, in contrast to a large body of studies on both CesA and the final crystalline microfibril. In addition to major experimental challenges in studying this transient regime, the length and time scales of microfibril nucleation are inaccessible to atomistic molecular dynamics. We have developed a novel coarse grained model for cellulose microfibrils which accounts for anisotropic interchain interactions. The model allows us to study nucleation, kinetics, and growth of cellulose chains/protofibrils/microfibrils. This work is supported by the US Department of Energy, Office of Basic Energy Sciences as part of The Center for LignoCellulose Structure and Formation, an Energy Frontier Research Center.

  11. Antibacterial paperboard packaging using microfibrillated cellulose.

    Science.gov (United States)

    Lavoine, Nathalie; Desloges, Isabelle; Manship, Brigitte; Bras, Julien

    2015-09-01

    The industry and consumers are focusing more and more on the development of biodegradable and lightweight food-packaging materials, which could better preserve the quality of the food and improve its shelf-life. In an attempt to meet these requirements, this study presents a novel bio-substrate able to contain active bio-molecules for future food-packaging applications. Based on a paperboard substrate, the development of an antibacterial bio-packaging material is, therein, achieved using a chlorhexidine digluconate (CHX) solution as a model of an antibacterial molecule, mixed with microfibrillated cellulose (MFC) and used as coating onto paperboard samples. AFM and FE-SEM analyses were performed to underline the nanoporous MFC network able to trap and to progressively release the CHX molecules. The release study of CHX was conducted in an aqueous medium and showed a lower proportion (20 %) of CHX released when using MFC. This led to the constant release of low amounts of CHX over 40 h. Antibacterial tests were carried out to assess the preservation of the antibacterial activity of the samples after the release studies. Samples remained active against Bacillus subtilis, with better results being obtained when MFC was used. The preservation of the quality of a model food was finally evaluated paving the way for future promising applications in the food packaging industry. PMID:26344972

  12. Cellulose microfibril deposition: coordinated activity at the plant plasma membrane

    NARCIS (Netherlands)

    Lindeboom, J.J.; Mulder, B.; Vos, J.W.; Ketelaar, M.J.; Emons, A.M.C.

    2008-01-01

    Plant cell wall production is a membrane-bound process. Cell walls are composed of cellulose microfibrils, embedded inside a matrix of other polysaccharides and glycoproteins. The cell wall matrix is extruded into the existing cell wall by exocytosis. This same process also inserts the cellulose syn

  13. EXPERIMENTAL STUDY OF MICRO-FIBRILLATED CELLULOSE REINFORCED EPOXY COMPOSITES

    OpenAIRE

    Huang, Chun-Heng

    2015-01-01

    Microfibrillated cellulose (MFC) is produced from naturally occurring, abundant and sustainable fibres of cellulose through mechanical treatments. It has been studied as a possible replacement for synthetic fibres in engineering composites, since it has many advantages that can enhance their mechanical properties.MFC and epoxy resin composites were prepared with varying weight fractions for three different sources of cellulose fibre (softwood Kraft pulp, hardwood Kraft pulp and recycled newsp...

  14. Structural characterization of a mixed-linkage glucan deficient mutant reveals alteration in cellulose microfibril orientation in rice coleoptile mesophyll cell walls

    Directory of Open Access Journals (Sweden)

    Andreia Michelle Smith-Moritz

    2015-08-01

    Full Text Available The CELLULOSE SYNTHASE-LIKE F6 (CslF6 gene was previously shown to mediate the biosynthesis of mixed-linkage glucan (MLG, a cell wall polysaccharide that is hypothesized to be a tightly associated with cellulose and also have a role in cell expansion in the primary cell wall of young seedlings in grass species. We have recently shown that loss-of-function cslf6 rice mutants do not accumulate MLG in most vegetative tissues. Despite the absence of a structurally important polymer, MLG, these mutants are unexpectedly viable and only show a moderate growth compromise compared to wild type. Therefore these mutants are ideal biological systems to test the current grass cell wall model. In order to gain a better understanding of the role of MLG in the primary wall, we performed in-depth compositional and structural analyses of the cell walls of three day-old rice seedlings using various biochemical and novel microspectroscopic approaches. We found that cellulose content as well as matrix polysaccharide composition was not significantly altered in the MLG deficient mutant. However, we observed a significant change in cellulose microfibril bundle organization in mesophyll cell walls of the cslf6 mutant. Using synchrotron source Fourier Transform Mid-Infrared Spectromicroscopy for high-resolution imaging, we determined that the bonds associated with cellulose and arabinoxylan, another major component of the primary cell was of grasses, were in a lower energy configuration compared to wild type, suggesting a slightly weaker primary wall in MLG deficient mesophyll cells. Taken together, these results suggest that MLG may influence cellulose deposition in mesophyll cell walls without significantly affecting anisotropic growth thus challenging MLG importance in cell wall expansion.

  15. Pattern formation of cortical microtubules and cellulose microfibrils

    NARCIS (Netherlands)

    Lindeboom, J.J.

    2012-01-01

    In this thesis we study the roles of microtubules at the plasma membrane and the cellulose microfibrils in the cell wall and how they are organized. This topic is introduces in chapter 1. In chapter 2 we study the formation of the transverse cortical microtubule array that is characteristic for elon

  16. Structure of cellulose microfibrils in primary cell walls from Collenchyma

    Czech Academy of Sciences Publication Activity Database

    Thomas, L. H.; Forsyth, V. T.; Šturcová, Adriana; Kennedy, C. J.; May, R. P.; Altaner, C. M.; Apperley, D. C.; Wess, T. J.; Jarvis, M. C.

    2013-01-01

    Roč. 161, č. 1 (2013), s. 465-476. ISSN 0032-0889 R&D Projects: GA ČR GAP108/12/0703 Institutional support: RVO:61389013 Keywords : primary cell wall * cellulose microfibril structure * chain packing disorder Subject RIV: CD - Macromolecular Chemistry Impact factor: 7.394, year: 2013

  17. Investigation of mass transport properties of microfibrillated cellulose (MFC) films

    DEFF Research Database (Denmark)

    Minelli, Matteo; Baschetti, Marco Giacinti; Doghieri, Ferruccio;

    2010-01-01

    The structure and transport properties of a four different films based on two different generations of microfibrillated cellulose (MFC), alone or in combination with glycerol as plasticizer, were investigated through FE-SEM analysis and sorption or permeation experiments. FE-SEM revealed the exis......The structure and transport properties of a four different films based on two different generations of microfibrillated cellulose (MFC), alone or in combination with glycerol as plasticizer, were investigated through FE-SEM analysis and sorption or permeation experiments. FE-SEM revealed...... sorption experiments confirmed the hydrophilic character of these cellulosic materials and showed a dual effect of glycerol which reduced the water uptake at low water activity while enhancing it at high relative humidity. The water diffusion in dry samples was remarkably slow for a porous material...

  18. Visualization of Cellulose Microfibrils of Phyllostachys pubescens Fibers with Atomic Force Microscope

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Atomic force microscope(AFM) was used to investigate the arrangement of cellulose microfibrils (CMF) in Moso bamboo (Phyllostachys pubescens) fibers. Two methods of sample preparation were used here for different purposes. The first method was chemical maceration with a mixture of hydrogen peroxide and glacial acetic acid, through which the obtained fibers were suitable for observing the orientation of CMF in the primary wal1. The other method was to prepare tangential microtomed sections with a thickness o...

  19. Microfibrillated cellulose from bamboo pulp and its properties

    International Nuclear Information System (INIS)

    Microfibrillated cellulose (MFC) was obtained by disintegrating bleached kraft bamboo (Phyllostachys pubescens) pulp with a procedure of chemical pretreatment and high-pressure homogenization. The influences of sodium hydroxide dosage and homogenization times were evaluated by water retention value (WRV) of MFC. The properties, such as the surface morphology, rheological property and carboxyl acid content of MFC were also characterized using scanning electron microscope (SEM), rheometer and headspace gas chromatography (HS-GC) separately.

  20. Rheology and flocculation of polymer-modified microfibrillated cellulose suspensions

    OpenAIRE

    Karppinen, Anni

    2014-01-01

    In this thesis, the rheology and flocculation of microfibrillated cellulose (MFC) suspensionswas modified using different cationic and anionic polymers and surface modification. For this purpose, MFC suspensions were studied simultaneously with a dynamic rotational rheometer and two imaging methods. The flocculation tendency of the suspensions was mainly evaluated using photographing through a transparent rheometer cup, and for some suspensions, optical coherence tomography (OCT), which gives...

  1. Microfibrillated cellulose : Energy-efficient preparation techniques and key properties

    OpenAIRE

    Ankerfors, Mikael

    2012-01-01

    This work describes three alternative processes for producing microfibrillated cellulose (MFC) in which pulp fibres are first pre-treated and then homogenized using a high-pressure homogenizer. In one process, fibre cell wall delamination was facilitated with a combined enzymatic and mechanical pre-treatment. In the two other processes, cell wall delamination was facilitated by pre-treatments that introduced anionically charged groups into the fibre wall, by means of either a carboxymethylati...

  2. Microfibrillated cellulose and new nanocomposite materials: a review

    DEFF Research Database (Denmark)

    Siró, Istvan; Plackett, David

    2010-01-01

    continuing research and are commercially interesting in terms of new products from the pulp and paper industry and the agricultural sector. Cellulose nanofibers can be extracted from various plant sources and, although the mechanical separation of plant fibers into smaller elementary constituents has......Due to their abundance, high strength and stiffness, low weight and biodegradability, nano-scale cellulose fiber materials (e.g., microfibrillated cellulose and bacterial cellulose) serve as promising candidates for bio-nanocomposite production. Such new high-value materials are the subject of...... typically required high energy input, chemical and/or enzymatic fiber pre-treatments have been developed to overcome this problem. A challenge associated with using nanocellulose in composites is the lack of compatibility with hydrophobic polymers and various chemical modification methods have been explored...

  3. Compatibility between cellulose and hydrophobic polymer provided by microfibrillated lignocellulose.

    Science.gov (United States)

    Gindl-Altmutter, Wolfgang; Obersriebnig, Michael; Veigel, Stefan; Liebner, Falk

    2015-01-01

    Microfibrillated lignocellulose (MFLC) was produced from wood subjected to partial lignin extraction using an ethanol/water mixture. After homogenization, the average fibril diameter of MFLC was in the same range as conventional microfibrillated cellulose (MFC). Although MFLC exhibited higher wettability with water compared to MFC, AFM adhesion force measurements revealed high variability in surface polarity of MFLC compared to MFC. Specifically, domains of higher polarity than in MFC but also domains of lower polarity than in MFC were observed in MFLC. This tendency towards amphiphilic behavior of MFLC was used to provide enhanced compatibility with polycaprolactone and polystyrene matrices. With both polymers, a significantly more homogeneous distribution of fibrils was achieved using MFLC compared to MFC. In line with better dispersion of the fibrils, significantly more efficient mechanical reinforcement of polymers was obtained using MFLC compared to MFC. PMID:25348210

  4. Extensional viscosity of microfibrillated cellulose suspensions.

    Science.gov (United States)

    Moberg, Tobias; Rigdahl, Mikael; Stading, Mats; Levenstam Bragd, Emma

    2014-02-15

    The extensional properties of micro fibrillated cellulose (MFC)-suspensions at different fibril concentrations and with different amounts of added sodium chloride were evaluated. The MFC-suspensions were obtained by diluting a stock solution consisting of 0.95 wt.% cellulose with either deionized water or sodium chloride solution, giving a series of different concentrations and sodium chloride contents. The extensional viscosities of the suspensions were measured utilizing contraction flow geometry. Here the specimens were forced through a hyperbolic nozzle and the required pressure drop over the nozzle was measured. The extensional viscosity exhibited an extensional-thinning behaviour over the extensional strain rates used. Furthermore the extensional viscosity decreased with decreasing concentration of the suspensions, in similarities with the shear properties of the specimens. For the suspensions containing sodium chloride, the extensional viscosity appeared to increase when the concentration of sodium chloride was increased. But excessive amounts of added sodium chloride promoted an agglomeration of the suspensions. PMID:24507298

  5. LUFFA CYLINDRICA AS A LIGNOCELLULOSIC SOURCE OF FIBER, MICROFIBRILLATED CELLULOSE, AND CELLULOSE NANOCRYSTALS

    OpenAIRE

    Gilberto Siqueira; Julien Bras; Alain Dufresne

    2010-01-01

    In this work the annual plant called Luffa cylindrica (LC) has been characterized and used to prepare macroscopic lignocellulosic fibers and cellulosic nanoparticles, viz. microfibrillated cellulose (MFC) and whiskers, each of which can be used as a reinforcing phase in bionanocomposites. The morphological, chemical, and physical properties of LC fibers were first characterized. The contents of lignin, hemicellulose, and other constituents were determined, and scanning electron microscopy (SE...

  6. Effect of rheological properties of dissolved cellulose/microfibrillated cellulose blend suspensions on film forming.

    Science.gov (United States)

    Saarikoski, Eve; Rissanen, Marja; Seppälä, Jukka

    2015-03-30

    Enzymatically treated cellulose was dissolved in a NaOH/ZnO solvent system and mixed together with microfibrillated cellulose (MFC) in order to find the threshold in which MFC fibers form a percolation network within the dissolved cellulose solution and in order to improve the properties of regenerated cellulose films. In the aqueous state, correlations between the rheological properties of dissolved cellulose/MFC blend suspensions and MFC fiber concentrations were investigated and rationalized. In addition, rheological properties of diluted MFC suspensions were characterized and a correlation with NaOH concentration was found, thus partly explaining the flow properties of dissolved cellulose/MFC blend suspensions. Finally, based on results from Dynamic Mechanical Analysis (DMA), MFC addition had strengthening/plasticizing effect on regenerated cellulose films if low concentrations of MFC, below the percolation threshold (5.5-6 wt%, corresponding to 0.16-0.18 wt% of MFC in the blend suspensions), were used. PMID:25563945

  7. Analysis of Enzymatic Degradation of Cellulose Microfibrils using Quantitative Surface Plasmon Resonance Imaging

    Science.gov (United States)

    Reiter, Kyle; Raegen, Adam; Allen, Scott; Quirk, Amanda; Clarke, Anthony; Lipkowski, Jacek; Dutcher, John

    2013-03-01

    Cellulose is the largest component of biomass on Earth and, as a result, is a significant potential energy source. The production of cellulosic ethanol as a fuel source requires conversion of cellulose fibers into fermentable sugars. Increasing our understanding of the action of cellulose enzymes (cellulases) on cellulose microfibrils is an important step in developing more efficient industrial processes for the production of cellulosic ethanol. We have used a custom designed Surface Plasmon Resonance imaging (SPRi) device to study the action of cellulases from the Hypocrea jecorinasecretome on bacterial cellulose microfibrils. This has allowed us to determine the rates of action and extent of degradation of cellulose microfibrils on exposure to both individual cellulases and combinations of different classes of cellulases, which has allowed us to investigate synergistic interactions between the cellulases.

  8. Extraction and characterization of cellulose microfibrils from agricultural residue –Cocos nucifera L

    International Nuclear Information System (INIS)

    The aim of this study was to extract cellulose microfibrils from the agricultural residue of coconut palm leaf sheath using chlorination and alkaline extraction process. Chemical characterization of the cellulose microfibrils confirmed that the α-cellulose mass fraction increased from 0.373 kg kg−1 to 0.896 kg kg−1 after application of several treatments including dewaxing, chlorite delignification and alkaline extraction of hemicelluloses. Similarly, the crystallinity index obtained from X-ray diffraction for leaf sheath and extracted cellulose microfibrils was found to be 42.3 and 47.7 respectively. The morphology of the cellulose microfibrils was investigated by scanning electron microscopy. The cellulose microfibrils had diameters in the range of 10–15 μm. Fourier transform infrared and Nuclear magnetic resonance spectroscopy showed that the chemical treatments removed most of the hemicellulose and lignin from the leaf sheath fibers. The thermal stability of the fibers was analyzed using thermogravimetric analysis, which demonstrated that this thermal stability was enhanced noticeably for cellulose microfibrils. This work provides a new approach for more effective utilization of coconut palm leaf sheaths to examine their potential use as pulp and paper and reinforcement fibers in biocomposite applications. -- Highlights: ► Utilization of Coconut palm leaf sheath as an alternate material for cellulose extraction. ► Using an abundant natural waste for paper pulp, biofilms and composite applications. ► Cellulose microfibrils have higher cellulose content than the leaf sheath. ► FTIR and NMR were used to study fiber structural changes during several treatments. ► Thermal stability of microfibrils is higher than their respective leaf sheath.

  9. Nonleaching antimicrobial films prepared from surface-modified microfibrillated cellulose.

    Science.gov (United States)

    Andresen, Martin; Stenstad, Per; Møretrø, Trond; Langsrud, Solveig; Syverud, Kristin; Johansson, Leena-Sisko; Stenius, Per

    2007-07-01

    We have prepared potentially permanent antimicrobial films based on surface-modified microfibrillated cellulose (MFC). MFC, obtained by disintegration of bleached softwood sulfite pulp in a homogenizer, was grafted with the quaternary ammonium compound octadecyldimethyl(3-trimethoxysilylpropyl)ammonium chloride (ODDMAC) by a simple adsorption-curing process. Films prepared from the ODDMAC-modified MFC were characterized by Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) and tested for antibacterial activity against the Gram-positive bacterium Staphylococcus aureus and the Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa. The films showed substantial antibacterial capacity even at very low concentrations of antimicrobial agent immobilized on the surface. A zone of inhibition test demonstrated that no ODDMAC diffused into the surroundings, verifying that the films were indeed of the nonleaching type. PMID:17542633

  10. A novel method for preparing microfibrillated cellulose from bamboo fibers

    Science.gov (United States)

    Dat Nguyen, Huu; Thanh Thuy Mai, Thi; Bich Nguyen, Ngoc; Duy Dang, Thanh; Loan Phung Le, My; Dang, Tan Tai; Tran, Van Man

    2013-03-01

    The bamboo fiber is a potential candidate for biomass and power source application. In this study, microfibrillated cellulose (MFC) is prepared from raw fibers of bamboo tree (Bambusa Blumeana J A & J H Schultes) by an alkali treatment at room temperature in association with a bleaching treatment followed by a sulfuric acid hydrolysis. Field-emission scanning electron microscopy (FESEM) images indicated that final products ranged from 20 to 40 nm in diameter. The chemical composition measurement and Fourier transform infrared (FTIR) spectroscopy showed that both hemicellulose and lignin are mostly removed in the MFC. The x-ray diffraction (XRD) results also show that MFC has crystallinity of more than 70%. The thermogravimetric analysis (TGA) curves revealed that cellulose microfibers have a two-step thermal decomposition behavior owing to the attachment of sulfated groups onto the cellulose surface in the hydrolysis process with sulfuric acid. The obtained MFCs may have potential applications in alternative power sources as biomass, in pharmaceutical and optical industries as additives, as well as in composite fields as a reinforcement phase.

  11. A novel method for preparing microfibrillated cellulose from bamboo fibers

    International Nuclear Information System (INIS)

    The bamboo fiber is a potential candidate for biomass and power source application. In this study, microfibrillated cellulose (MFC) is prepared from raw fibers of bamboo tree (Bambusa Blumeana J A and J H Schultes) by an alkali treatment at room temperature in association with a bleaching treatment followed by a sulfuric acid hydrolysis. Field-emission scanning electron microscopy (FESEM) images indicated that final products ranged from 20 to 40 nm in diameter. The chemical composition measurement and Fourier transform infrared (FTIR) spectroscopy showed that both hemicellulose and lignin are mostly removed in the MFC. The x-ray diffraction (XRD) results also show that MFC has crystallinity of more than 70%. The thermogravimetric analysis (TGA) curves revealed that cellulose microfibers have a two-step thermal decomposition behavior owing to the attachment of sulfated groups onto the cellulose surface in the hydrolysis process with sulfuric acid. The obtained MFCs may have potential applications in alternative power sources as biomass, in pharmaceutical and optical industries as additives, as well as in composite fields as a reinforcement phase. (paper)

  12. Brittle Culm1, a COBRA-like protein, functions in cellulose assembly through binding cellulose microfibrils.

    Directory of Open Access Journals (Sweden)

    Lifeng Liu

    Full Text Available Cellulose represents the most abundant biopolymer in nature and has great economic importance. Cellulose chains pack laterally into crystalline forms, stacking into a complicated crystallographic structure. However, the mechanism of cellulose crystallization is poorly understood. Here, via functional characterization, we report that Brittle Culm1 (BC1, a COBRA-like protein in rice, modifies cellulose crystallinity. BC1 was demonstrated to be a glycosylphosphatidylinositol (GPI anchored protein and can be released into cell walls by removal of the GPI anchor. BC1 possesses a carbohydrate-binding module (CBM at its N-terminus. In vitro binding assays showed that this CBM interacts specifically with crystalline cellulose, and several aromatic residues in this domain are essential for binding. It was further demonstrated that cell wall-localized BC1 via the CBM and GPI anchor is one functional form of BC1. X-ray diffraction (XRD assays revealed that mutations in BC1 and knockdown of BC1 expression decrease the crystallite width of cellulose; overexpression of BC1 and the CBM-mutated BC1s caused varied crystallinity with results that were consistent with the in vitro binding assay. Moreover, interaction between the CBM and cellulose microfibrils was largely repressed when the cell wall residues were pre-stained with two cellulose dyes. Treating wild-type and bc1 seedlings with the dyes resulted in insensitive root growth responses in bc1 plants. Combined with the evidence that BC1 and three secondary wall cellulose synthases (CESAs function in different steps of cellulose production as revealed by genetic analysis, we conclude that BC1 modulates cellulose assembly by interacting with cellulose and affecting microfibril crystallinity.

  13. Physical properties and morphology of films prepared from microfibrillated cellulose and microfibrillated cellulose in combination with amylopectin

    DEFF Research Database (Denmark)

    Plackett, David; Anturi, Harvey; Hedenqvist, Mikael; Ankerfors, Mikael; Gallstedt, Mikael; Lindström, Tom; Siró, Istvan

    2010-01-01

    . Tensile testing revealed that MFC 2-reinforced films exhibited a more ductile behavior and that MFC 1-reinforced films had higher modulus of elasticity (E-modulus) at MFC loadings of 50 wt % or higher. Pure MFC films had relatively low oxygen permeability values when data were compared with those for a......Two types of microfibrillated cellulose (MFC) were prepared using either a sulfite pulp containing a high amount of hemicellulose (MFC 1) or a carboxymethylated dissolving pulp (MFC 2). MFC gels were then combined with amylopectin solutions to produce solvent-cast MFC-reinforced amylopectin films...... variety of other polymer films. MFC 1 and MFC 2 films had similar opacity but differences in appearance which were attributed to the presence of some larger fibers and nanofiber agglomerates in MFC 2. Field emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM) were used to...

  14. Cellulose microfibril-water interaction as characterized by isothermal thermogravimetric analysis and scanning electron microscopy

    OpenAIRE

    Suman K. Sen; Vinit K. Baheti; Richard A. Venditti; Joel J. Pawlak; Sunkyu Park; Mukesh C. Bansal

    2012-01-01

    Microfibrillated celluloses, liberated from macroscopic lignocellulosic fibers by mechanical means, are sub-fiber elements with lengths in the micron scale and diameters ranging from 10 to a few hundred nanometers. These materials have shown strong water interactions. This article describes an investigation and quantification of the ‘hard-to-remove (HR) water content’ in cellulose fibers and microfibrillated structures prepared from fully bleached softwood pulp (BSW). The fiber/fibril struct...

  15. Biocomposites based on poly(lactic acid) and kenaf fibers: effect of microfibrillated cellulose

    OpenAIRE

    Bogoeva-Gaceva, Gordana; Dimeski, Dimko; Srebrenkoska, Vineta

    2013-01-01

    In this work, the influence of microfibrillated cellulose (MFC) on the basic mechanical properties of PLA/kenaf fiber biocomposites has been studied. The addition of 5–15 % microfibrillated cellulose to a biocomposite premix has resulted in an increased glass transition temperature of the final product, produced by compression molding of previously melt-mixed composite components. The presence of MFC has influenced the interface-sensitive properties of the PLA/kenaf composite: at ...

  16. Dissecting the molecular mechanism underlying the intimate relationship between cellulose microfibrils and cortical microtubules

    Directory of Open Access Journals (Sweden)

    Lei eLei

    2014-03-01

    Full Text Available A central question in plant cell development is how the cell wall determines directional cell expansion and therefore the final shape of the cell. As the major load-bearing component of the cell wall, cellulose microfibrils are laid down transversely to the axis of elongation, thus forming a spring-like structure that reinforces the cell laterally and while favoring longitudinal expansion in most growing cells. Mounting evidence suggests that cortical microtubules organize the deposition of cellulose microfibrils, but the precise molecular mechanisms linking microtubules to cellulose organization have remained unclear until the recent discovery of CSI1, a linker protein between the cortical microtubules and the cellulose biosynthesizing machinery. In this review, we will focus on the intimate relationship between cellulose microfibrils and cortical microtubules, in particular, we will discuss microtubule arrangement and cell wall architecture, the linkage between cellulose synthase complexes and microtubules, and the feedback mechanisms between cell wall and microtubules.

  17. Effective Young's modulus of bacterial and microfibrillated cellulose fibrils in fibrous networks.

    Science.gov (United States)

    Tanpichai, Supachok; Quero, Franck; Nogi, Masaya; Yano, Hiroyuki; Young, Robert J; Lindström, Tom; Sampson, William W; Eichhorn, Stephen J

    2012-05-14

    The deformation micromechanics of bacterial cellulose (BC) and microfibrillated cellulose (MFC) networks have been investigated using Raman spectroscopy. The Raman spectra of both BC and MFC networks exhibit a band initially located at ≈ 1095 cm(-1). We have used the intensity of this band as a function of rotation angle of the specimens to study the cellulose fibril orientation in BC and MFC networks. We have also used the change in this peak's wavenumber position with applied tensile deformation to probe the stress-transfer behavior of these cellulosic materials. The intensity of this Raman band did not change significantly with rotation angle, indicating an in-plane 2D network of fibrils with uniform random orientation; conversely, a highly oriented flax fiber exhibited a marked change in intensity with rotation angle. Experimental data and theoretical analysis shows that the Raman band shift rate arising from deformation of networks under tension is dependent on the angles between the axis of fibrils, the strain axis, the incident laser polarization direction, and the back scattered polarization configurations. From this analysis, the effective moduli of single fibrils of BC and MFC in the networks were estimated to be in the ranges of 79-88 and 29-36 GPa, respectively. It is shown also that for the model to fit the data it is necessary to use a negative Poisson's ratio for MFC networks and BC networks. Discussion of this in-plane "auxetic" behavior is given. PMID:22423896

  18. Blends of dissolved cellulose with acrylic acid copolymers or microfibrillated cellulose

    OpenAIRE

    Saarikoski, Eve

    2015-01-01

    The aim of the thesis was to develop dissolved cellulose (dissolved in NaOH/ZnO) based blends with acrylic acid copolymers (poly(ethylene-co-acrylic acid) (PE-co-AA) or poly(acrylamide-co-acrylic acid) (PAA-co-AA)) or microfibrillated cellulose (MFC) in the way they could be used in injection molding or for film/coating applications. This thesis summarizes the research reported in five publications supported by some unpublished results. Rheological studies done in the contexts of this work...

  19. Microfibrillated cellulose, a new cellulose product: properties, uses, and commercial potential

    Energy Technology Data Exchange (ETDEWEB)

    Turbak, A.F.; Snyder, F.W.; Sandberg, K.R.

    1983-01-01

    A new form of cellulose, which is expanded to a smooth gel when dispersed in polar liquids, is produced by a unique, rapid, physical treatment of wood cellulose pulps. A 2% suspension of microfibrillated cellulose (MFC) in water has thixotropic viscosity properties and is a stable gel on storage, or when subjected to freeze-thaw cycles. At this concentration, MFC is an excellent suspending medium for other solids and an emulsifying base for organic liquids. In laboratory tests, microfibrillated cellulose has been demonstrated to have wide utility in the preparation of foods such as low-calorie whipped toppings, cake frostings, salad dressings, gravies, and sauces. At 0.3% cellulose concentration in ground meats, MFC helps retain juices during cooking. Tests were also conducted in formulating paints, emulsions, and cosmetics and in the use of MFC as a binder for nonwoven textiles and as a mineral suspending agent. From economic studies, it is estimated that a 2% MFC dispersion can be produced for about 1.5 cents/lb, total cost. 6 references, 9 figures, 2 tables.

  20. A nanocellulose polypyrrole composite based on microfibrillated cellulose from wood.

    Science.gov (United States)

    Nyström, Gustav; Mihranyan, Albert; Razaq, Aamir; Lindström, Tom; Nyholm, Leif; Strømme, Maria

    2010-04-01

    It is demonstrated that it is possible to coat the individual fibers of wood-based nanocellulose with polypyrrole using in situ chemical polymerization to obtain an electrically conducting continuous high-surface-area composite. The experimental results indicate that the high surface area of the water dispersed material, to a large extent, is maintained upon normal drying without the use of any solvent exchange. Thus, the employed chemical polymerization of polypyrrole on the microfibrillated cellulose (MFC) nanofibers in the hydrogel gives rise to a composite, the structure of which-unlike that of uncoated MFC paper-does not collapse upon drying. The dry composite has a surface area of approximately 90 m(2)/g and a conductivity of approximately 1.5 S/cm, is electrochemically active, and exhibits an ion-exchange capacity for chloride ions of 289 C/g corresponding to a specific capacity of 80 mAh/g. The straightforwardness of the fabrication of the present nanocellulose composites should significantly facilitate industrial manufacturing of highly porous, electroactive conductive paper materials for applications including ion-exchange and paper-based energy storage devices. PMID:20205378

  1. Microfibrillated cellulose coatings as new release systems for active packaging.

    Science.gov (United States)

    Lavoine, Nathalie; Desloges, Isabelle; Bras, Julien

    2014-03-15

    In this work, a new use of microfibrillated cellulose (MFC) is highlighted for high-added-value applications. For the first time, a nanoporous network formed by MFC coated on paper is used for a controlled release of molecules. The release study was carried out in water with caffeine as a model molecule. The release process was studied by means of (i) continuous, and (ii) intermittent diffusion experiments (with renewal of the medium every 10 min). The effect of the MFC was first observed for the samples impregnated in the caffeine solution. These samples, coated with MFC (coat weight of about 7 g/m(2)), released the caffeine over a longer period (29 washings compared with 16), even if the continuous diffusions were similar for both samples (without and with MFC coating). The slowest release of caffeine was observed for samples coated with the mixture (MFC+caffeine). Moreover, the caffeine was only fully released 9h after the release from the other samples was completed. This study compared two techniques for the introduction of model molecules in MFC-coated papers. The latter offers a more controlled and gradual release. This new approach creates many opportunities especially in the food-packaging field. A similar study could be carried out with an active species. PMID:24528763

  2. LUFFA CYLINDRICA AS A LIGNOCELLULOSIC SOURCE OF FIBER, MICROFIBRILLATED CELLULOSE, AND CELLULOSE NANOCRYSTALS

    Directory of Open Access Journals (Sweden)

    Gilberto Siqueira

    2010-05-01

    Full Text Available In this work the annual plant called Luffa cylindrica (LC has been characterized and used to prepare macroscopic lignocellulosic fibers and cellulosic nanoparticles, viz. microfibrillated cellulose (MFC and whiskers, each of which can be used as a reinforcing phase in bionanocomposites. The morphological, chemical, and physical properties of LC fibers were first characterized. The contents of lignin, hemicellulose, and other constituents were determined, and scanning electron microscopy (SEM observations were performed to investigate the surface morphology of the LC fibers. Sugars contents were determined by ionic chromatography, and it was shown that glucose was the main sugar present in the residue. MFC and whiskers were prepared after chemical treatments (NaOH and NaClO2, purifying cellulose by eliminating lignin and hemicellulose. Transmission electron microscopy (TEM and SEM made it possible to determine the dimensions of LC whiskers and MFC. Tensile tests were carried out to investigate the mechanical properties of LF nanoparticles.

  3. Micromechanics of Microfibrillated Cellulose Reinforced Poly(lactic acid) Composites Using Raman Spectroscopy

    OpenAIRE

    Tanpichai, Supachok

    2012-01-01

    Microfibrillated cellulose (MFC) is an alternative material that has been widely studied to enhance the mechanical properties of a polymer matrix due to a number of perceived advantages over traditional plant fibre forms. Mechanical properties of MFC networks were found to depend on parameters such as the modulus of fibrils, bonding strength, porosity, degree of crystallinity, contact area of fibrils and possibly the modulus of the cellulose crystals of the raw materials (cellulose I or II). ...

  4. Cellulose microfibril-water interaction as characterized by isothermal thermogravimetric analysis and scanning electron microscopy

    Directory of Open Access Journals (Sweden)

    Suman K. Sen

    2012-11-01

    Full Text Available Microfibrillated celluloses, liberated from macroscopic lignocellulosic fibers by mechanical means, are sub-fiber elements with lengths in the micron scale and diameters ranging from 10 to a few hundred nanometers. These materials have shown strong water interactions. This article describes an investigation and quantification of the ‘hard-to-remove (HR water content’ in cellulose fibers and microfibrillated structures prepared from fully bleached softwood pulp (BSW. The fiber/fibril structure was altered by using an extended beating process (up to 300 minutes, and water interactions were determined with isothermal thermogravimetric analysis (TGA. Isothermal TGA is shown to be a convenient and insightful characterization method for fiber-water interactions for fibers and microfibrils at small sample size. In addition, scanning electron microscopic (SEM images depict the differences between fibers and microfibrils with respect to beating time in the dried consolidated structures. Highly refined pulps with microfibrils were determined to have two critical drying points, i.e., two minima in the second derivative of weight versus time, not before reported in the literature. Also in this study, hard-to-remove (HR water content is related to the area above the first derivative curve in the constant rate and falling rate drying zones. This measure of HR water correlates with a previous measurement method of HR water but is less ambiguous for materials that lack a constant drying rate zone. Blends of unbeaten fibers and microfibril containing samples were prepared and show potential as composite materials.

  5. Highly transparent films from carboxymethylated microfibrillated cellulose: The effect of multiple homogenization steps on key properties

    DEFF Research Database (Denmark)

    Siró, Istvan; Plackett, David; Hedenqvist, M.;

    2011-01-01

    We produced microfibrillated cellulose by passing carboxymethylated sulfite-softwood-dissolving pulp with a relatively low hemicellulose content (4.5%) through a high-shear homogenizer. The resulting gel was subjected to as many as three additional homogenization steps and then used to prepare...

  6. Versatile gas-phase reactions for surface to bulk esterification of cellulose microfibrils aerogels.

    Science.gov (United States)

    Fumagalli, Matthieu; Ouhab, Djamila; Boisseau, Sonia Molina; Heux, Laurent

    2013-09-01

    Aqueous suspensions of microfibrillated cellulose obtained by a high pressure homogenization process were freeze-dried after solvent exchange into tert-butanol. The resulting aerogels, which displayed a remarkable open morphology with a surface area reaching 100 m(2)/g, were subjected to a gas-phase esterification with palmitoyl chloride. Under these conditions, variations of the reaction temperature from 100 to 200 °C, of the reaction time from 0.5 to 2 h, and of the initial quantity of reagent, led to the preparation of a library of cellulose palmitates with DS varying from zero to 2.36. These products were characterized by gravimetry, FTIR, and (13)C solid-state NMR spectroscopy. Of special interest were the cellulose palmitate samples of low DS in the range of 0.1-0.4, which corresponded to hydrophobic cellulose microfibrils exclusively esterified at their surface while keeping intact their inner structure. PMID:23889256

  7. Nanocellulose patents trends: a comprehensive review on patents on cellulose nanocrystals, microfibrillated and bacterial cellulose.

    Science.gov (United States)

    Charreau, Hernan; Foresti, Maria L; Vazquez, Analia

    2013-01-01

    Cellulose nanoparticles (i.e. cellulose elements having at least one dimension in the 1-100 nm range) have received increasing attention during the last decade. This is not only evident in academic articles, but it is also manifested by the increasing number of nanocellulose patents that are published every year. In the current review, nanocellulose patents are reviewed using specific software which provides valuable information on the annual number of patents that have been published throughout the years, main patent owners, most prolific inventors, and patents on the field that have received more citations. Patent statistics on rod-like cellulose nanoparticles extracted from plants by acid hydrolysis (nanocrystals), mechanical treatment leading to microfibrillated cellulose (MFC), and microbially produced nanofibrils (bacterial cellulose, BC) are analyzed in detail. The aim of the current review is to provide researchers with patent information which may help them in visualizing the evolution of nanocellulose technology, both as a whole and also divided among the different nanosized particles that are currently the subject of outstanding scientific attention. Then, patents are not only analyzed by their content, but also by global statistics which will reveal the moment at which different cellulose nanoparticles technologies achieved a breakthrough, the relative interest received by different nanocellulose particles throughout the years, the companies that have been most interested in this technology, the most prolific inventors, and the patents that have had more influence in further developments. It is expected that the results showing the explosion that nanocellulose technology is experiencing in current days will still bring more research on the topic and contribute to the expansion of nanocellulosics applications. PMID:22747719

  8. Microfibrillated cellulose: Energy-efficient preparation techniques and applications in paper

    OpenAIRE

    Ankerfors, Mikael

    2015-01-01

    This work describes three alternative processes for producing microfibrillated cellulose (MFC; also referred to as cellulose nanofibrils, CNF) in which bleached pulp fibres are first pretreated and then homogenized using a high-pressure homogenizer. In one process, fibre cell wall delamination was facilitated by a combined enzymatic and mechanical pretreatment. In the two other processes, cell wall delamination was facilitated by pretreatments that introduced anionically charged groups into t...

  9. Mechanical Properties of Poly(lactic acid) Sheet Reinforced with Microfibrillated Cellulose from Corn Cobs

    OpenAIRE

    Deejam Prapatsorn; Charuchinda Sireerat

    2015-01-01

    In this study, cellulose was extracted from corn cobs by successive hot NaOH solution and followed by H2O2 bleaching. XRD pattern show characteristic peak of Cellulose I. Microfibrillated cellulose (MFC) was successfully prepared by dissolving the extracted cellulose in NaOH/urea solution, shearing in a homogenizer and finally by freezing and thawing. To improve strength of MFC, MFC was physically crosslinked using PVA by freezing and thawing. The crosslinked MFC/PVA was added to poly(lactic ...

  10. Microfibrillated cellulose - its barrier properties and applications in cellulosic materials: a review.

    Science.gov (United States)

    Lavoine, Nathalie; Desloges, Isabelle; Dufresne, Alain; Bras, Julien

    2012-10-01

    Interest in microfibrillated cellulose (MFC) has been increasing exponentially. During the last decade, this bio-based nanomaterial was essentially used in nanocomposites for its reinforcement property. Its nano-scale dimensions and its ability to form a strong entangled nanoporous network, however, have encouraged the emergence of new high-value applications. In previous years, its mode of production has completely changed, as many forms of optimization have been developed. New sources, new mechanical processes, and new pre- and post-treatments are currently under development to reduce the high energy consumption and produce new types of MFC materials on an industrial scale. The nanoscale characterization possibilities of different MFC materials are thus increasing intensively. Therefore, it is critical to review such MFC materials and their properties. Moreover, very recent studies have proved the significant barrier properties of MFC. Hence, it is proposed to focus on the barrier properties of MFC used in films, in nanocomposites, or in paper coating. PMID:22839998

  11. A Nanocellulose Polypyrrole Composite Based on Microfibrillated Cellulose from Wood

    OpenAIRE

    Nyström, Gustav; Mihranyan, Albert; Razaq, Aamir; Lindström, Tom; Nyholm, Leif; Strømme, Maria

    2010-01-01

    It is demonstrated that it is possible to coat the individual fibers of wood-based nanocellulose with polypyrrole using in situ chemical polymerization to obtain an electrically conducting continuous high-surface-area composite. The experimental results indicate that the high surface area of the water dispersed material, to a large extent, is maintained upon normal drying without the use of any solvent exchange. Thus, the employed chemical polymerization of polypyrrole on the microfibrillated...

  12. Preparation and properties of self-reinforced cellulose composite films from Agave microfibrils using an ionic liquid.

    Science.gov (United States)

    Reddy, K Obi; Zhang, Jinming; Zhang, Jun; Rajulu, A Varada

    2014-12-19

    The applications of natural fibers and their microfibrils are increasing rapidly due to their environment benefits, specific strength properties and renewability. In the present work, we successfully extracted cellulose microfibrils from Agave natural fibers by chemical method. The extracted microfibrils were characterized by chemical analysis. The cellulose microfibrils were found to dissolve in an ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl) to larger extent along with little quantity of undissolved microfibrils. Using this solution, the self-reinforced regenerated cellulose composite films were prepared. The raw fiber, extracted cellulose microfibrils and regenerated cellulose composite films were characterized by FTIR, (13)C CP-MAS NMR, XRD, TGA and SEM techniques. The average tensile strength, modulus and elongation at break of the self-reinforced cellulose composite films were found to be 135 MPa, 8150 MPa and 3.2%, respectively. The high values of tensile strength and modulus were attributed to the self-reinforcement of Agave fibers in their generated matrix. These self-reinforced cellulose biodegradable composite films prepared from renewable source can find applications in packaging field. PMID:25263924

  13. Pectin/carboxymethyl cellulose/microfibrillated cellulose composite scaffolds for tissue engineering.

    Science.gov (United States)

    Ninan, Neethu; Muthiah, Muthunarayanan; Park, In-Kyu; Elain, Anne; Thomas, Sabu; Grohens, Yves

    2013-10-15

    Highly porous three-dimensional scaffolds made of biopolymers are of great interest in tissue engineering applications. A novel scaffold composed of pectin, carboxymethyl cellulose (CMC) and microfibrillated cellulose (MFC) were synthesised using lyophilisation technique. The optimised scaffold with 0.1% MFC, C(0.1%), showed highest compression modulus (~3.987 MPa) and glass transition temperature (~103 °C). The pore size for the control scaffold, C(0%), was in the range of 30-300 μm while it was significantly reduced to 10-250 μm in case of C(0.1%). Using micro computed tomography, the porosity of C(0.1%) was estimated to be 88%. C(0.1%) showed excellent thermal stability and lower degradation rate compared to C(0%). The prepared samples were also characterised using XRD and FTIR. C(0.1%) showed controlled water uptake ability and in vitro degradation in PBS. It exhibited highest cell viability on NIH3T3 fibroblast cell line. These results suggest that these biocompatible composite scaffolds can be used for tissue engineering applications. PMID:23987424

  14. Effect of stretching on the mechanical properties in melt-spun poly(butylene succinate)/microfibrillated cellulose (MFC) nanocomposites.

    Science.gov (United States)

    Zhou, Mi; Fan, Mao; Zhao, Yongsheng; Jin, Tianxiang; Fu, Qiang

    2016-04-20

    In order to prepare poly(butylene succinate)/microfibrillated cellulose composites with high performance, in this work, microfibrillated cellulose (MFC) was first treated by acetylchloride with ball-milling to improve its interfacial compatibility with poly(butylene succinate) (PBS). Then melt stretching processing was adopted to further improve the dispersion and orientation of MFC in as-spun PBS fiber. And the effect of MFC on the crystalline structure and mechanical properties were systematically investigated for the melt-spun fibers prepared with two different draw ratios. The dispersion, alignment of the MFC and interfacial crystalline structure in the composite fibers are significantly influenced by the stretching force during the melt spinning. The possible formation of nanohybrid shish kebab (NHSK) superstructure where aligned MFC as shish and PBS lamellae as kebab has been suggested via SEM and SAXS in the composite fibers prepared at the high draw ratio. Large improvement in tensile strength has been realized at the high draw ratio due to the enhanced orientation and dispersion of MFC as well as the formation of NHSK. PMID:26876865

  15. Effect of a silane coupling agent on the mechanical properties of a microfibrillated cellulose composite.

    Science.gov (United States)

    Ifuku, Shinsuke; Yano, Hiroyuki

    2015-03-01

    Composite materials reinforced with microfibrillated cellulose (MFC) fibers were prepared and characterized in terms of their mechanical properties. The surface of the MFC fibers was treated with a silane coupling reagent having an NH2 functional group to improve fiber-matrix adhesion. Due to the unique structure of the MFC, which consists of nano-order-scale interconnected fibrils and microfibrils with greatly expanded surface area and submicron pore size compared to conventional cellulose, it was possible to enhance the effect of silane coupling agent and thereby improve the compatibility between the fibers and matrix and also the dispersibility of fibers. The Young's modulus was significantly increased to more than 70%. PMID:25575951

  16. Atmospheric plasma assisted PLA/microfibrillated cellulose (MFC) multilayer biocomposite for sustainable barrier application

    DEFF Research Database (Denmark)

    Meriçer, Çağlar; Minelli, Matteo; Angelis, Maria G De;

    2016-01-01

    Fully bio-based and biodegradable materials, such as polylactic acid (PLA) and microfibrillated cellulose (MFC), are considered in order to produce a completely renewable packaging solution for oxygen barrier applications, even at medium-high relative humidity (R.H.). Thin layers of MFC were coated...... possible use in barrier packaging applications as fully biodegradable solution, coupling two primarily incompatible matrices in a multilayer film with no need of any solvent or chemical....

  17. THE FORMATION AND CHARACTERIZATION OF SUSTAINABLE LAYERED FILMS INCORPORATING MICROFIBRILLATED CELLULOSE (MFC)

    OpenAIRE

    Galina Rodionova,; Solenne Roudot; , Øyvind Eriksen,; Ferdinand Männle,; Øyvind Gregersen

    2012-01-01

    Microfibrillated cellulose (MFC), TEMPO-pretreated MFC, and hybrid polymer/MFC mix were used for the production of layered films with interesting properties for application in food packaging. The series of samples were prepared from MFC (base layers) using a dispersion-casting method. The same procedure as well as a bar coating technique was applied to form top layers of different basis weights. The barrier properties and formation of the layered films were investigated in relationship to the...

  18. Mechanism for Tuning the Hydrophobicity of Microfibrillated Cellulose Films by Controlled Thermal Release of Encapsulated Wax

    OpenAIRE

    Vibhore Kumar Rastogi; Dirk Stanssens; Pieter Samyn

    2014-01-01

    Although films of microfibrillated cellulose (MFC) have good oxygen barrier properties due to its fine network structure, properties strongly deteriorate after absorption of water. In this work, a new approach has been followed for actively tuning the water resistance of a MFC fiber network by the inclusion of dispersed organic nanoparticles with encapsulated plant wax. The modified pulp suspensions have been casted into films and were subsequently cured at 40 to 220 °C. As such, static water...

  19. Bioinspired composites from cross-linked galactoglucomannan and microfibrillated cellulose: Thermal, mechanical and oxygen barrier properties.

    Science.gov (United States)

    Oinonen, Petri; Krawczyk, Holger; Ek, Monica; Henriksson, Gunnar; Moriana, Rosana

    2016-01-20

    In this study, new wood-inspired films were developed from microfibrillated cellulose and galactoglucomannan-lignin networks isolated from chemothermomechanical pulping side streams and cross-linked using laccase enzymes. To the best of our knowledge, this is the first time that cross-linked galactoglucomannan-lignin networks have been used for the potential development of composite films inspired by woody-cell wall formation. Their capability as polymeric matrices was assessed based on thermal, structural, mechanical and oxygen permeability analyses. The addition of different amounts of microfibrillated cellulose as a reinforcing agent and glycerol as a plasticizer on the film performances was evaluated. In general, an increase in microfibrillated cellulose resulted in a film with better thermal, mechanical and oxygen barrier performance. However, the presence of glycerol decreased the thermal stability, stiffness and oxygen barrier properties of the films but improved their elongation. Therefore, depending on the application, the film properties can be tailored by adjusting the amounts of reinforcing agent and plasticizer in the film formulation. PMID:26572340

  20. Chemical Modification of Microfibrillated Cellulose: Effects on Film Barrier Properties

    OpenAIRE

    Rodionova, Galina

    2011-01-01

    A global demand for environmental sustainability is a strong driving force towards the development of enhanced barrier concepts and the use of new materials, especially for packaging applications. Abundant and renewable, cellulosic fibers have been widely used as one of the main constituents in the fiber-based packaging. However, the porous and hydrophilic structure of cellulose network requires the use of barrier polymer coatings to create an additional resistance against water, water vapors...

  1. Microtubules and cellulose microfibrils: how intimate is their relationship?

    NARCIS (Netherlands)

    Emons, A.M.C.; Höfte, H.; Mulder, B.

    2007-01-01

    The recent visualization of the motion of fluorescently labeled cellulose synthase complexes by Alexander Paredez and colleagues heralds the start of a new era in the science of the plant cell wall. Upon drug-induced complete depolymerization, the movement of the complexes does not become disordered

  2. Characteristics and application of microfibrillated cellulose. Bisho fiburiru ka serurosu no tokucho to sono yoto

    Energy Technology Data Exchange (ETDEWEB)

    Miyakawa, A. (Daicel Chemical Industries Ltd., Osaka (Japan))

    1992-10-10

    As the methods to refine or fibrillate cellulose fibers, there are the mechanical treatment, the physical treatment such as explosion, etc., and the chemical treatment such as microcrystallization, etc. In this article,, the technique to microfibrillate cellulose fibers using the high pressure homogenizer, which Daicel Chemical Industries Ltd. introduced from America ITT Leonia Co., and the features as well as use of the merchandise called Cellish, manufactured by this method are introduced. In order to microfibrillate fibers with the above device, the pressure of the aqueous suspension of raw cellulose is raised with a piston pump to several hundred kg/cm [sup 2], and the pressurized suspension is let to pass through an extremely narrow slit at more than 200m/s, then the pressure is reduced to the atmospheric pressure. Cellish has its minimum diameter of 0.01[mu]m and its surface area becomes more than 200 times bigger, since its raw cellulose fiber is split into about forty to eighty thousand pieces. Cellish is not water soluble, but has viscosity and very small adhesion, hence under no outer force, it shows the automorphic property. Its water retentivity is good and it is used as a filter and various additives. 12 refs., 8 figs., 2 tabs.

  3. Localization of cell wall polysaccharides in normal and compression wood of radiata pine: relationships with lignification and microfibril orientation.

    Science.gov (United States)

    Donaldson, Lloyd A; Knox, J Paul

    2012-02-01

    The distribution of noncellulosic polysaccharides in cell walls of tracheids and xylem parenchyma cells in normal and compression wood of Pinus radiata, was examined to determine the relationships with lignification and cellulose microfibril orientation. Using fluorescence microscopy combined with immunocytochemistry, monoclonal antibodies were used to detect xyloglucan (LM15), β(1,4)-galactan (LM5), heteroxylan (LM10 and LM11), and galactoglucomannan (LM21 and LM22). Lignin and crystalline cellulose were localized on the same sections used for immunocytochemistry by autofluorescence and polarized light microscopy, respectively. Changes in the distribution of noncellulosic polysaccharides between normal and compression wood were associated with changes in lignin distribution. Increased lignification of compression wood secondary walls was associated with novel deposition of β(1,4)-galactan and with reduced amounts of xylan and mannan in the outer S2 (S2L) region of tracheids. Xylan and mannan were detected in all lignified xylem cell types (tracheids, ray tracheids, and thick-walled ray parenchyma) but were not detected in unlignified cell types (thin-walled ray parenchyma and resin canal parenchyma). Mannan was absent from the highly lignified compound middle lamella, but xylan occurred throughout the cell walls of tracheids. Using colocalization measurements, we confirmed that polysaccharides containing galactose, mannose, and xylose have consistent correlations with lignification. Low or unsubstituted xylans were localized in cell wall layers characterized by transverse cellulose microfibril orientation in both normal and compression wood tracheids. Our results support the theory that the assembly of wood cell walls, including lignification and microfibril orientation, may be mediated by changes in the amount and distribution of noncellulosic polysaccharides. PMID:22147521

  4. Novel high-strength biocomposites based on microfibrillated cellulose having nano-order-unit web-like network structure

    Science.gov (United States)

    Nakagaito, A. N.; Yano, H.

    2005-01-01

    A completely new kind of high-strength composite was manufactured using microfibrillated cellulose (MFC) derived from kraft pulp. Because of the unique structure of nano-order-scale interconnected fibrils and microfibrils greatly expanded in the surface area that characterizes MFC, it was possible to produce composites that exploit the extremely high strength of microfibrils. The Young’s modulus (E) and bending strength (σb) of composites using phenolic resin as binder achieved values up to 19 GPa and 370 MPa, respectively, with a density of 1.45 g/cm2, exhibiting outstanding mechanical properties for a plant-fiber-based composite.

  5. Polylactide Foams Reinforced with Wood Fibers or Microfibrillated Cellulose

    OpenAIRE

    Orhan, Münire

    2010-01-01

    The growing environmental awareness of pollution and climate change has set up newrules and regulations, which forces the industries to seek and satisfy the demand formore alternative and renewable products. Research has been launched for findingnovel lightweight materials for packaging, transportation and construction. Currently,there is an interest of finding new applications of new forms of cellulose since theyoffer low density and cost, renewability and biodegradability. The potential of ...

  6. Patterns of cellulose microfibril deposition and rearrangement in Nitella: in vivo analysis by a birefringence index. [Nitella axillaris

    Energy Technology Data Exchange (ETDEWEB)

    Richmond, P.A.

    1983-01-01

    The mean alignment of cellulose microfibrils in the wall of a living Nitella internode can be quantified by polarized light microscopy. Microfibrils within the cylindrical wall of a normal internode have a scattered but generally circumferential arrangement. The action of polarized light on such a wall creates a birefringent pattern that relates to microfibrillar organization, including the degree of microfibrillar scatter or mean angular dispersion. This pattern, quantified as a birefringence index (BRI), can be followed during the growth of an individual cell. Changes in the BRI reflect shifts in the patterns of either microfibril deposition, microfibril rearrangements during growth, or both. This diagnostic capability has allowed the dynamics of the following events to be examined in vivo: response of microfibril deposition to addition and removal of antimicrotubule drugs, multinet growth under various conditions of cell expansion, and cellulose synthesis inhibition. This work has shown that cellulose microfibril synthesis is not coupled to cell expansion in Nitella and that the directionality of cell expansion is governed by only an inner portion of the cell wall. 31 references, 7 figures, 1 table.

  7. A mechanical switch device made of a polyimide-coated microfibrillated cellulose sheet

    Science.gov (United States)

    Couderc, S.; Ducloux, O.; Kim, B. J.; Someya, T.

    2009-05-01

    This paper covers innovative results on the development of an electrostatically actuated mechanical switch device made of a microfibrillated cellulose sheet coated with a thin polyimide layer. For microelectronic applications, biodegradable and biocompatible nanomaterials such as microfibrillated cellulose (MFC) have attracted attention. The studied MFC sheets reveal a fibrous-like morphology composed of cellulose nanofibres leading to a high surface roughness. Moreover, the porous microstructure and the hydrophilic nature of the MFC sheet induce poor dielectric properties. These shortcomings make MFC sheets relatively unsuitable for electronic applications. In order to overcome these drawbacks, both sides of the MFC sheet are coated with a thin polyimide layer, which greatly improves the dielectric properties, moisture sensitivity and sheet surface roughness. This new sheet is then patterned in order to be used as a substrate for the fabrication of a micromechanical switch. Gold electrodes are added onto the sheet for electrostatic actuation and switch detection. The pull-down voltage of this switch, defined as the actuation voltage needed to establish a contact between the free end of the cantilever beam and the substrate, is measured to be about 55 V.

  8. A mechanical switch device made of a polyimide-coated microfibrillated cellulose sheet

    International Nuclear Information System (INIS)

    This paper covers innovative results on the development of an electrostatically actuated mechanical switch device made of a microfibrillated cellulose sheet coated with a thin polyimide layer. For microelectronic applications, biodegradable and biocompatible nanomaterials such as microfibrillated cellulose (MFC) have attracted attention. The studied MFC sheets reveal a fibrous-like morphology composed of cellulose nanofibres leading to a high surface roughness. Moreover, the porous microstructure and the hydrophilic nature of the MFC sheet induce poor dielectric properties. These shortcomings make MFC sheets relatively unsuitable for electronic applications. In order to overcome these drawbacks, both sides of the MFC sheet are coated with a thin polyimide layer, which greatly improves the dielectric properties, moisture sensitivity and sheet surface roughness. This new sheet is then patterned in order to be used as a substrate for the fabrication of a micromechanical switch. Gold electrodes are added onto the sheet for electrostatic actuation and switch detection. The pull-down voltage of this switch, defined as the actuation voltage needed to establish a contact between the free end of the cantilever beam and the substrate, is measured to be about 55 V

  9. Influence of surface modified cellulose microfibrils on the improved mechanical properties of poly (lactic acid).

    Science.gov (United States)

    Johari, Atul P; Kurmvanshi, S K; Mohanty, S; Nayak, S K

    2016-03-01

    Cellulose microfibrils (CMF) were extracted from sisal fiber and characterized. Biocomposites of PLA reinforced with CMF were fabricated employing melt blending technique followed by injection moulding. The biocomposites were subjected to various characterization studies to investigate the effect of CMF within the PLA matrix. Differential scanning calorimetry (DSC) measurements confirmed that the addition of CMF accelerates the crystallization process of PLA matrix. Addition of 5 wt.% of CMF with and without compatibilizers and plasticizers such as maleic anhydride, polyethylene glycol and acetyltributyl citrate in PLA improved the crystallization of PLA up to 100 °C. MA grafting gave moderate effects on both the stiffness and ductility, exhibiting optimum properties. PMID:26708431

  10. Mechanical Properties of Poly(lactic acid Sheet Reinforced with Microfibrillated Cellulose from Corn Cobs

    Directory of Open Access Journals (Sweden)

    Deejam Prapatsorn

    2015-01-01

    Full Text Available In this study, cellulose was extracted from corn cobs by successive hot NaOH solution and followed by H2O2 bleaching. XRD pattern show characteristic peak of Cellulose I. Microfibrillated cellulose (MFC was successfully prepared by dissolving the extracted cellulose in NaOH/urea solution, shearing in a homogenizer and finally by freezing and thawing. To improve strength of MFC, MFC was physically crosslinked using PVA by freezing and thawing. The crosslinked MFC/PVA was added to poly(lactic acid (PLA to improve its mechanical properties. The non-crosslinked MFC/PVA was also prepared by only stirring the solution without freezing and thawing. MFC/PVA reinforced PLA films with various ratios of PLA and MFC/PVA at100:0, 99:1, 97:3 and 95:5were prepared through a solution casting method. Tensile strength and elongation at breakof PLA films increased with the addition of physically crosslinked MFC/PVA at 1%wt, whereas, the addition of non-crosslinked MFC/PVA decreased elongation at break. Crosslinking of MFC/PVA can improve tensile strength of PLA.It can render better tensile strength than that of non-crosslinked MFC/PVA. However, when MFC/PVA contents increase, tensile strength of PLA fims reinforced with non-crosslinked and crosslinked MFC/PVA decreased. Morphology of fracture surfaces reveals good dispersion and adhesion between 1% crosslinked MFC/PVA and PLA matrix.

  11. Modifying the flocculation of microfibrillated cellulose suspensions by soluble polysaccharides under conditions unfavorable to adsorption.

    Science.gov (United States)

    Sorvari, Anni; Saarinen, Tapio; Haavisto, Sanna; Salmela, Juha; Vuoriluoto, Maija; Seppälä, Jukka

    2014-06-15

    Carboxymethylcellulose (CMC) and xanthan gum were studied as dispersants for microfibrillated cellulose (MFC) suspension using a rotational rheometer and imaging methods. The imaging was a combination of photography and optical coherence tomography (OCT). Both polymers dispersed MFC fibers, although CMC was more effective than xanthan gum. The negatively charged polymer chains increased the viscosity of the suspending medium and acted as buffers in between the negatively charged fibers. This behavior decreased the number and strength of contacts between the fibers and subsequently dispersed the flocs. The stronger separation of the fibers was reflected in the frequency sweep where the MFC/polymer suspensions had lower gel strength than pure MFC suspension. Dispersing effect was also observed in the flow measurements, where the floc size was more uniform with polymers in the decelerating flow and after long, slow constant shear, which normally induces a heterogeneous structure with large flocs into the MFC suspension. PMID:24721080

  12. Effects of bagasse microfibrillated cellulose and cationic polyacrylamide on key properties of bagasse paper.

    Science.gov (United States)

    Djafari Petroudy, Seyed Rahman; Syverud, Kristin; Chinga-Carrasco, Gary; Ghasemain, Ali; Resalati, Hossein

    2014-01-01

    This study explores the benefits of using bagasse microfibrillated cellulose (MFC) in bagasse paper. Two different types of MFC were produced from DED bleached soda bagasse pulp. The MFC was added to soda bagasse pulp furnishes in different amounts. Cationic polyacrylamide (C-PAM) was selected as retention aid. The results show that addition of MFC increased the strength of paper as expected. Interestingly, 1% MFC in combination with 0.1% C-PAM yielded similar drainage time as the reference pulp, which did not contain MFC. In addition, the samples containing 1% MFC and 0.1% C-PAM yielded (i) a significant increment of the tensile index, (ii) a minor decrease of opacity and (iii) preserved Gurley porosity. Hence, this study proves that small fractions of MFC in combination with adequate retention aids can have positive effects with respect to paper properties, which is most interesting from an industrial point of view. PMID:24274512

  13. Improvement of Interfacial Adhesion in Bamboo Polymer Composite Enhanced with Micro-Fibrillated Cellulose

    Science.gov (United States)

    Okubo, Kazuya; Fujii, Toru; Yamashita, Naoya

    Current study presents one of effective techniques to improve mechanical properties of PLA (Poly-Lactic Acid)-based bamboo fiber composite. Commercially available Micro-Fibrillated Cellulose (MFC) obtained from wood pulp was applied as an enhancer to the composite. The bamboo fibers were extracted by steam explosion method and they were also rubbed in water to remove xylem (soft-wall cells). The liquid-based MFC, PLA and the bamboo fiber were mixed in water for several minutes and they were filtrated under vacuum pressure. To fabricate the composite, remained sheets were then hot pressed after dry. Three-point bending strength and Mode I fracture toughness of the composite were significantly improved, even when 10% of the MFC was added into the PLA/BF composite in weight. If small amount of MFC added into the bamboo fiber composite, tangled MFC fibers prevented the growth of micro crack along the interface between bamboo fiber and matrix.

  14. Study on the sorption process of triclosan on cationic microfibrillated cellulose and its antibacterial activity.

    Science.gov (United States)

    Zhang, Hongjie; Zeng, Xu; Xie, Jinglei; Li, Zhiqiang; Li, Hailong

    2016-01-20

    Cationic microfibrillated cellulose (CMFC), as one kind of cellulose-based materials, is widely used in many fields. In this work, it was functionalized with a traditional antibacterial agent (triclosan, TCS). The sorption process of TCS onto CMFC was expressed by kinetic and isotherm models. The results showed that there was a high correlation coefficient (R(2)>0.9) in the pseudo-second-order model and the isotherm models, indicating that CMFC had a good sorption capacity for TCS. The sorption type was chemisorption, and the reaction power was electrostatic interactions. The antibacterial activity of the assembled TCS/CMFC compound was tested by disk diffusion method, and it was found a higher antibacterial activity than CMFC alone (bigger inhibition zone diameters). Further, the functionalized TCS/CMFC compound was used in the fiber network during handsheets making, and it had a higher antibacterial rate than TCS alone (increase by 45.1% against Escherichia coli and by 54.8% against Staphylococcus aureus, respectively). PMID:26572380

  15. Microfibrillated cellulose and borax as mechanical, O2-barrier, and surface-modulating agents of pullulan biocomposite coatings on BOPP.

    Science.gov (United States)

    Cozzolino, Carlo A; Campanella, Gaetano; Türe, Hasan; Olsson, Richard T; Farris, Stefano

    2016-06-01

    Multifunctional composite coatings on bi-oriented polypropylene (BOPP) films were obtained using borax and microfibrillated cellulose (MFC) added to the main pullulan coating polymer. Spectroscopy analyses suggested that a first type of interaction occurred via hydrogen bonding between the C6OH group of pullulan and the hydroxyl groups of boric acid, while monodiol and didiol complexation represented a second mechanism. The deposition of the coatings yielded an increase in the elastic modulus of the entire plastic substrate (from ∼2GPa of the neat BOPP to ∼3.1GPa of the P/B+/MFC-coated BOPP). The addition of MFC yielded a decrease of both static and kinetic coefficients of friction of approximately 22% and 25%, respectively, as compared to the neat BOPP. All composite coatings dramatically increased the oxygen barrier performance of BOPP, especially under dry conditions. The deposition of the high hydrophilic coatings allowed to obtain highly wettable surfaces (water contact angle of ∼18°). PMID:27083358

  16. Preparation of Photocrosslinked Fish Elastin Polypeptide/Microfibrillated Cellulose Composite Gels with Elastic Properties for Biomaterial Applications

    OpenAIRE

    Shinya Yano; Megumi Mori; Naozumi Teramoto; Makoto Iisaka; Natsumi Suzuki; Masanari Noto; Yasuko Kaimoto; Masashi Kakimoto; Michio Yamada; Eri Shiratsuchi; Toshiaki Shimasaki; Mitsuhiro Shibata

    2015-01-01

    Photocrosslinked hydrogels reinforced by microfibrillated cellulose (MFC) were prepared from a methacrylate-functionalized fish elastin polypeptide and MFC dispersed in dimethylsulfoxide (DMSO). First, a water-soluble elastin peptide with a molecular weight of ca. 500 g/mol from the fish bulbus arteriosus was polymerized by N,N′-dicyclohexylcarbodiimide (DCC), a condensation reagent, and then modified with 2-isocyanatoethyl methacrylate (MOI) to yield a photocrosslinkable fish elastin polypep...

  17. THE FORMATION AND CHARACTERIZATION OF SUSTAINABLE LAYERED FILMS INCORPORATING MICROFIBRILLATED CELLULOSE (MFC

    Directory of Open Access Journals (Sweden)

    Galina Rodionova,

    2012-06-01

    Full Text Available Microfibrillated cellulose (MFC, TEMPO-pretreated MFC, and hybrid polymer/MFC mix were used for the production of layered films with interesting properties for application in food packaging. The series of samples were prepared from MFC (base layers using a dispersion-casting method. The same procedure as well as a bar coating technique was applied to form top layers of different basis weights. The barrier properties and formation of the layered films were investigated in relationship to the preparation procedures, combination of layers, and areal weight (basis weight. Characterization was done with respect to oxygen transmission rates (OTR, water vapor transmission rates (WVTR, tensile properties, and contact angles (CA with water. The produced layered films yielded OTR values of 4 mL m-2 day-1 and fulfilled oxygen barrier requirements for a modified atmosphere packaging (MAP. Hornification of the MFC films, however, occurred during drying, which may result in a loss of the film’s beneficial properties.

  18. Cationic amphiphilic microfibrillated cellulose (MFC) for potential use for bile acid sorption.

    Science.gov (United States)

    Zhu, Xuhai; Wen, Yangbing; Cheng, Dong; Li, Changmo; An, Xingye; Ni, Yonghao

    2015-11-01

    In this work, Micro-fibrillated Cellulose (MFC) was cationically modified by quaternary ammonium groups with different chemical structures aiming to improve the sorption capacity to bile acid. The in-vitro bile acid sorption was performed by investigating various factors, such as quaternary ammonium group content and length of its alkyl substituent of the modified cationic MFC (CMFC), ionic strength, initial concentration and hydrophobicity of bile acid. The results showed that the sorption behavior of the modified CMFC was strongly influenced by the quaternary ammonium group content and the lengths of its alkyl substituent, the sorption capacity for the modified CMFC with a C18 alkyl substituent, was approximately 50% of that of Cholestyramine. The experimental isotherm results were well fitted into the Temkin model. The effect of salts in the solution was smaller for the bile acid sorption onto the hydrophobic CMFC than the CMFC. It was also found that the binding capacity of CMFC was higher for more hydrophobic deoxycholate in comparison with cholate. PMID:26256387

  19. Simultaneous reinforcing and toughening of polyurethane via grafting on the surface of microfibrillated cellulose.

    Science.gov (United States)

    Yao, Xuelin; Qi, Xiaodong; He, Yuling; Tan, Dongsheng; Chen, Feng; Fu, Qiang

    2014-02-26

    In the present work, a series of thermoplastic polyurethane (TPU)/microfibrillated cellulose (MFC) nanocomposites were successfully synthesized via in situ polymerization. TPU was covalently grafted onto the MFC by particular association with the hard segments, as evidenced by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. The adequate dispersion and network structure of MFC in the TPU matrix and the strong interfacial interaction through covalent grafting and hydrogen bonding between MFC and TPU resulted in significantly improved mechanical properties and thermostability of the prepared nanocomposites. The tensile strength and elongation-at-break of the nanocomposite containing only 1 wt % MFC were increased by 4.5-fold and 1.8-fold compared with that of neat TPU, respectively. It was also very interesting to find that the glass transition temperature (Tg) of TPU was decreased significantly with the introduction of MFC, indicating potential for low-temperature resistance applications. Most importantly, compared with TPU nanocomposites reinforced with other nanofillers, the TPU/MFC nanocomposites prepared in this work exhibited excellent transparency and higher reinforcing efficiency. PMID:24476503

  20. Fischer-Tropsch diesel emulsions stabilised by microfibrillated cellulose and nonionic surfactants.

    Science.gov (United States)

    Lif, Anna; Stenstad, Per; Syverud, Kristin; Nydén, Magnus; Holmberg, Krister

    2010-12-15

    Water-in-diesel emulsion fuels have been prepared with a combination of sorbitan monolaurate and glycerol monooleate as emulsifier and with microfibrillated cellulose (MFC) of different hydrophilic/hydrophobic character as stabilizer. The MFC was treated with either octadecylamine or poly(styrene-co-maleic anhydride), resulting in very hydrophobic fibrils. The most stable emulsion was achieved with a combination of hydrophilic (untreated) and hydrophobic MFC and only minute amounts of the stabilizer gave a pronounced effect. Even with the optimized formulation the lifetime of the emulsion was shorter than previously reported when a conventional polymeric stabilizer was used, however. The water drop sizes in the emulsions were determined by three methods: optical images, light scattering, and NMR diffusometry. All three methods gave water drops sizes of ca 2 μm. The NMR diffusometry indicated that besides the micrometer-sized emulsion drops a significant fraction of the water is present in small droplets of micelle size. The chemical exchange of water between these two populations of pools is believed to be the reason for the relatively low stability of the system. PMID:20864117

  1. Mechanism for Tuning the Hydrophobicity of Microfibrillated Cellulose Films by Controlled Thermal Release of Encapsulated Wax

    Directory of Open Access Journals (Sweden)

    Vibhore Kumar Rastogi

    2014-10-01

    Full Text Available Although films of microfibrillated cellulose (MFC have good oxygen barrier properties due to its fine network structure, properties strongly deteriorate after absorption of water. In this work, a new approach has been followed for actively tuning the water resistance of a MFC fiber network by the inclusion of dispersed organic nanoparticles with encapsulated plant wax. The modified pulp suspensions have been casted into films and were subsequently cured at 40 to 220 °C. As such, static water contact angles can be specifically tuned from 120 to 150° by selection of the curing temperature in relation with the intrinsic transition temperatures of the modified pulp, as determined by thermal analysis. The appearance of encapsulated wax after curing was followed by a combination of morphological analysis, infrared spectroscopy and Raman mapping, showing balanced mechanisms of progressive release and migration of wax into the fiber network controlling the surface properties and water contact angles. Finally, the appearance of nanoparticles covered with a thin wax layer after complete thermal release provides highest hydrophobicity.

  2. Contact Antimicrobial Surface Obtained by Chemical Grafting of Microfibrillated Cellulose in Aqueous Solution Limiting Antibiotic Release.

    Science.gov (United States)

    Saini, Seema; Belgacem, Naceur; Mendes, Joana; Elegir, Graziano; Bras, Julien

    2015-08-19

    Contact active surfaces are an innovative tool for developing antibacterial products. Here, the microfibrillated cellulose (MFC) surface was modified with the β-lactam antibiotic benzyl penicillin in aqueous medium to prepare antimicrobial films. Penicillin was grafted on the MFC surface using a suspension of these nanofilaments or directly on films. Films prepared from the penicillin-modified MFC were characterized by Fourier transform infrared spectroscopy, contact angle measurements, elemental analysis, and X-ray photoelectron spectroscopy and tested for antibacterial activity against the Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. Penicillin-grafted MFC films exhibited successful killing effect on Gram-positive bacteria with 3.5-log reduction whereas bacteriostatic efficiency was found in penicillin-grafted MFC suspension. The zone of inhibition test and leaching dynamic assay demonstrated that penicillin was not diffused into the surrounding media, thus proving that the films were indeed contact active. Thus, penicillin can be chemically bound to the modified substrate surface to produce promising nonleaching antimicrobial systems. PMID:26218855

  3. Enhancement of the wet properties of transparent chitosan-acetic-acid-salt films using microfibrillated cellulose.

    Science.gov (United States)

    Nordqvist, David; Idermark, Johan; Hedenqvist, Mikael S; Gällstedt, Mikael; Ankerfors, Mikael; Lindström, Tom

    2007-08-01

    This report presents a new route to enhance the wet properties of chitosan-acetic-acid-salt films using microfibrillated cellulose (MFC). The enhancement makes it easier to form chitosan-acetic-acid-salt films into various shapes at room temperature in the wet state. Chitosan with MFC was compared with the well-known buffer treatment. It was observed that films containing 5 wt % MFC were visually identical to the buffered/unbuffered films without MFC. Field-emission scanning electron microscopy indicated that MFC formed a network with uniformly distributed fibrils and fibril bundles in the chitosan matrix. The addition of MFC reduced the risk of creases and deformation in the wet state because of a greater wet stiffness. The wet films containing MFC were also extensible. Although the stiffness, strength and extensibility were highest for the buffered films, the wet strength of the MFC-containing unbuffered films was sufficient for wet forming operations. The effects of MFC on the mechanical properties of the dry chitosan films were small or absent. It was concluded that the addition of MFC is an acceptable alternative to buffering for shaping chitosan films/products in the wet state. The advantages are that the "extra" processing step associated with buffering is unnecessary and that the film matrix remains more water-soluble. PMID:17645308

  4. Controlled release of chlorhexidine digluconate using β-cyclodextrin and microfibrillated cellulose.

    Science.gov (United States)

    Lavoine, Nathalie; Tabary, Nicolas; Desloges, Isabelle; Martel, Bernard; Bras, Julien

    2014-09-01

    This study aims to develop a high-performance delivery system using microfibrillated cellulose (MFC)-coated papers as a controlled release system combined with the well-known drug delivery agent, β-cyclodextrin (βCD). Chlorhexidine digluconate (CHX), an antibacterial molecule, was mixed with a suspension of MFC or a βCD solution or mixed with both the substances, before coating onto a cellulosic substrate. The intermittent diffusion of CHX (i.e., diffusion interrupted by the renewal of the release medium periodically) was conducted in an aqueous medium, and the release mechanism of CHX was elucidated by field emission gun-scanning electron microscopy, SEM, NMR, and Fourier transform infrared analyses. According to the literature, both βCD and MFC are efficient controlled delivery systems. This study indicated that βCD releases CHX more gradually and over a longer period of time compared to MFC, which is mainly due to the ability of βCD to form an inclusion complex with CHX. Furthermore from the release study, a complementary action when the two compounds were combined was deduced. MFC mainly affected the burst effect, while βCD primarily controlled the amount of CHX released over time. In this paper, two different types of controlled release systems are proposed and compared. Depending on the final application, the use of βCD alone would release low amounts of active molecules over time (slow delivery), whereas the combination of β-cyclodextrin and MFC would be more suitable for the release of higher amounts of active molecules over time (rapid delivery). PMID:24984267

  5. The build-up of polyelectrolyte multilayers of microfibrillated cellulose and cationic polyelectrolytes.

    Science.gov (United States)

    Wågberg, Lars; Decher, Gero; Norgren, Magnus; Lindström, Tom; Ankerfors, Mikael; Axnäs, Karl

    2008-02-01

    A new type of nanocellulosic material has been prepared by high-pressure homogenization of carboxymethylated cellulose fibers followed by ultrasonication and centrifugation. This material had a cylindrical cross-section as shown by transmission electron microscopy with a diameter of 5-15 nm and a length of up to 1 microm. Calculations, using the Poisson-Boltzmann equation, showed that the surface potential was between 200 and 250 mV, depending on the pH, the salt concentration, and the size of the fibrils. They also showed that the carboxyl groups on the surface of the nanofibrils are not fully dissociated until the pH has reached pH = approximately 10 in deionized water. Calculations of the interaction between the fibrils using the Derjaguin-Landau-Verwey-Overbeek theory and assuming a cylindrical geometry indicated that there is a large electrostatic repulsion between these fibrils, provided the carboxyl groups are dissociated. If the pH is too low and/or the salt concentration is too high, there will be a large attraction between the fibrils, leading to a rapid aggregation of the fibrils. It is also possible to form polyelectrolyte multilayers (PEMs) by combining different types of polyelectrolytes and microfibrillated cellulose (MFC). In this study, silicon oxide surfaces were first treated with cationic polyelectrolytes before the surfaces were exposed to MFC. The build-up of the layers was monitored with ellipsometry, and they show that it is possible to form very well-defined layers by combinations of MFC and different types of polyelectrolytes and different ionic strengths of the solutions during the adsorption of the polyelectrolyte. A polyelectrolyte with a three-dimensional structure leads to the build-up of thick layers of MFC, whereas the use of a highly charged linear polyelectrolyte leads to the formation of thinner layers of MFC. An increase in the salt concentration during the adsorption of the polyelectrolyte results in the formation of thicker

  6. Cellulose fibres, nanofibrils and microfibrils: The morphological sequence of MFC components from a plant physiology and fibre technology point of view

    OpenAIRE

    Chinga-Carrasco Gary

    2011-01-01

    Abstract During the last decade, major efforts have been made to develop adequate and commercially viable processes for disintegrating cellulose fibres into their structural components. Homogenisation of cellulose fibres has been one of the principal applied procedures. Homogenisation has produced materials which may be inhomogeneous, containing fibres, fibres fragments, fibrillar fines and nanofibrils. The material has been denominated microfibrillated cellulose (MFC). In addition, terms rel...

  7. Cellulose fibres, nanofibrils and microfibrils: The morphological sequence of MFC components from a plant physiology and fibre technology point of view

    Directory of Open Access Journals (Sweden)

    Chinga-Carrasco Gary

    2011-01-01

    Full Text Available Abstract During the last decade, major efforts have been made to develop adequate and commercially viable processes for disintegrating cellulose fibres into their structural components. Homogenisation of cellulose fibres has been one of the principal applied procedures. Homogenisation has produced materials which may be inhomogeneous, containing fibres, fibres fragments, fibrillar fines and nanofibrils. The material has been denominated microfibrillated cellulose (MFC. In addition, terms relating to the nano-scale have been given to the MFC material. Several modern and high-tech nano-applications have been envisaged for MFC. However, is MFC a nano-structure? It is concluded that MFC materials may be composed of (1 nanofibrils, (2 fibrillar fines, (3 fibre fragments and (4 fibres. This implies that MFC is not necessarily synonymous with nanofibrils, microfibrils or any other cellulose nano-structure. However, properly produced MFC materials contain nano-structures as a main component, i.e. nanofibrils.

  8. Cellulose fibres, nanofibrils and microfibrils: The morphological sequence of MFC components from a plant physiology and fibre technology point of view

    Science.gov (United States)

    Chinga-Carrasco, Gary

    2011-06-01

    During the last decade, major efforts have been made to develop adequate and commercially viable processes for disintegrating cellulose fibres into their structural components. Homogenisation of cellulose fibres has been one of the principal applied procedures. Homogenisation has produced materials which may be inhomogeneous, containing fibres, fibres fragments, fibrillar fines and nanofibrils. The material has been denominated microfibrillated cellulose (MFC). In addition, terms relating to the nano-scale have been given to the MFC material. Several modern and high-tech nano-applications have been envisaged for MFC. However, is MFC a nano-structure? It is concluded that MFC materials may be composed of (1) nanofibrils, (2) fibrillar fines, (3) fibre fragments and (4) fibres. This implies that MFC is not necessarily synonymous with nanofibrils, microfibrils or any other cellulose nano-structure. However, properly produced MFC materials contain nano-structures as a main component, i.e. nanofibrils.

  9. Building and degradation of secondary cell walls: are there common patterns of lamellar assembly of cellulose microfibrils and cell wall delamination?

    Science.gov (United States)

    De Micco, Veronica; Ruel, Katia; Joseleau, Jean-Paul; Aronne, Giovanna

    2010-08-01

    During cell wall formation and degradation, it is possible to detect cellulose microfibrils assembled into thicker and thinner lamellar structures, respectively, following inverse parallel patterns. The aim of this study was to analyse such patterns of microfibril aggregation and cell wall delamination. The thickness of microfibrils and lamellae was measured on digital images of both growing and degrading cell walls viewed by means of transmission electron microscopy. To objectively detect, measure and classify microfibrils and lamellae into thickness classes, a method based on the application of computerized image analysis combined with graphical and statistical methods was developed. The method allowed common classes of microfibrils and lamellae in cell walls to be identified from different origins. During both the formation and degradation of cell walls, a preferential formation of structures with specific thickness was evidenced. The results obtained with the developed method allowed objective analysis of patterns of microfibril aggregation and evidenced a trend of doubling/halving lamellar structures, during cell wall formation/degradation in materials from different origin and which have undergone different treatments. PMID:20532796

  10. Buildup of polyelectrolyte multilayers of polyethyleneimine and microfibrillated cellulose studied by in situ dual-polarization interferometry and quartz crystal microbalance with dissipation.

    Science.gov (United States)

    Aulin, Christian; Varga, Imre; Claesson, Per M; Wågberg, Lars; Lindström, Tom

    2008-03-18

    Polyethyleneimine (PEI) and Microfibrillated cellulose (MFC) have been used to buildup polyelectrolyte multilayers (PEM) on silicone oxide and silicone oxynitride surfaces at different pH values and with different electrolyte and polyelectrolyte/colloid concentrations of the components. Consecutive adsorption on these surfaces was studied by in situ dual-polarization interferometry (DPI) and quartz crystal microbalance measurements. The adsorption data obtained from both the techniques showed a steady buildup of multilayers. High pH and electrolyte concentration of the PEI solution was found to be beneficial for achieving a high adsorbed amount of PEI, and hence of MFC, during the buildup of the multilayer. On the other hand, an increase in the electrolyte concentration of the MFC dispersion was found to inhibit the adsorption of MFC onto PEI. The adsorbed amount of MFC was independent of the bulk MFC concentration in the investigated concentration range (15-250 mg/L). Atomic force microscopy measurements were used to image a MFC-treated silicone oxynitride chip from DPI measurements. The surface was found to be almost fully covered by randomly oriented microfibrils after the adsorption of only one bilayer of PEI/MFC. The surface roughness expressed as the rms-roughness over 1 microm2 was calculated to be 4.6 nm (1 bilayer). The adsorbed amount of PEI and MFC and the amount of water entrapped by the individual layers in the multilayer structures were estimated by combining results from the two analytical techniques using the de Feijter formula. These results indicate a total water content of ca. 41% in the PEM. PMID:18278961

  11. Size, Shape, and Arrangement of Cellulose Microfibril in Higher Plant Cell Walls

    Energy Technology Data Exchange (ETDEWEB)

    Ding, S. Y.

    2013-01-01

    Plant cell walls from maize (Zea mays L.) are imaged using atomic force microscopy (AFM) at the sub-nanometer resolution. We found that the size and shape of fundamental cellulose elementary fibril (CEF) is essentially identical in different cell wall types, i.e., primary wall (PW), parenchyma secondary wall (pSW), and sclerenchyma secondary wall (sSW), which is consistent with previously proposed 36-chain model (Ding et al., 2006, J. Agric. Food Chem.). The arrangement of individual CEFs in these wall types exhibits two orientations. In PW, CEFs are horizontally associated through their hydrophilic faces, and the planar faces are exposed, forming ribbon-like macrofibrils. In pSW and sSW, CEFs are vertically oriented, forming layers, in which hemicelluloses are interacted with the hydrophobic faces of the CEF and serve as spacers between CEFs. Lignification occurs between CEF-hemicelluloses layers in secondary walls. Furthermore, we demonstrated quantitative analysis of plant cell wall accessibility to and digestibility by different cellulase systems at real-time using chemical imaging (e.g., stimulated Raman scattering) and fluorescence microscopy of labeled cellulases (Ding et al., 2012, Science, in press).

  12. Cell proliferation, cell shape, and microtubule and cellulose microfibril organization of tobacco BY-2 cells are not altered by exposure to near weightlessness in space.

    Science.gov (United States)

    Sieberer, Björn J; Kieft, Henk; Franssen-Verheijen, Tiny; Emons, Anne Mie C; Vos, Jan W

    2009-11-01

    The microtubule cytoskeleton and the cell wall both play key roles in plant cell growth and division, determining the plant's final stature. At near weightlessness, tubulin polymerizes into microtubules in vitro, but these microtubules do not self-organize in the ordered patterns observed at 1g. Likewise, at near weightlessness cortical microtubules in protoplasts have difficulty organizing into parallel arrays, which are required for proper plant cell elongation. However, intact plants do grow in space and therefore should have a normally functioning microtubule cytoskeleton. Since the main difference between protoplasts and plant cells in a tissue is the presence of a cell wall, we studied single, but walled, tobacco BY-2 suspension-cultured cells during an 8-day space-flight experiment on board of the Soyuz capsule and the International Space Station during the 12S mission (March-April 2006). We show that the cortical microtubule density, ordering and orientation in isolated walled plant cells are unaffected by near weightlessness, as are the orientation of the cellulose microfibrils, cell proliferation, and cell shape. Likely, tissue organization is not essential for the organization of these structures in space. When combined with the fact that many recovering protoplasts have an aberrant cortical microtubule cytoskeleton, the results suggest a role for the cell wall, or its production machinery, in structuring the microtubule cytoskeleton. PMID:19756725

  13. The Cellulase KORRIGAN Is Part of the Cellulose Synthase Complex

    NARCIS (Netherlands)

    Vain, T.; Crowell, E.F.; Timpano, H.; Biot, E.; Desprez, T.; Mansoori Zangir, N.; Trindade, L.M.; Pagant, S.; Robert, S.; Hofte, H.; Gonneau, M.; Vernhettes, S.

    2014-01-01

    Plant growth and organ formation depend on the oriented deposition of load-bearing cellulose microfibrils in the cell wall. Cellulose is synthesized by a large relative molecular weight cellulose synthase complex (CSC), which comprises at least three distinct cellulose synthases. Cellulose synthesis

  14. Exploiting the nano-sized features of microfibrillated cellulose (MFC) for the development of controlled-release packaging.

    Science.gov (United States)

    Cozzolino, Carlo A; Nilsson, Fritjof; Iotti, Marco; Sacchi, Benedetta; Piga, Antonio; Farris, Stefano

    2013-10-01

    Microfibrillated cellulose (MFC) was used in this study to prepare films containing an active molecule, lysozyme, which is a natural antimicrobial agent. The main goal of this research was to assess the potential for exploiting the nano-sized dimension of cellulose fibrils to slow the release of the antimicrobial molecule, thus avoiding a too-quick release into the surrounding medium, which is a major disadvantage of most release systems. For this purpose, the release kinetics of lysozyme over a 10-day period in two different media (pure water and water/ethanol 10wt.%) were obtained, and the experimental data was fitted with a solution of Fick's second law to quantify the apparent diffusion coefficient (D). The results indicate that the MFC retained lysozyme, presumably due to electrostatic, hydrogen, and ion-dipole interactions, with the largest release of lysozyme-approximately 14%-occurring from the initial amount loaded on the films. As expected, ethanol as a co-solvent slightly decreased the diffusion of lysozyme from the MFC polymer network. The addition of two potential modulating release agents-glycerol and sodium chloride-was also evaluated. Findings from this work suggest that MFC-based films can be considered a suitable candidate for use in controlled-release packaging systems. PMID:23732796

  15. Synthesis and characterization of bionanocomposites with tunable properties from poly(lactic acid) and acetylated microfibrillated cellulose.

    Science.gov (United States)

    Tingaut, Philippe; Zimmermann, Tanja; Lopez-Suevos, Francisco

    2010-02-01

    In the present study, novel bionanocomposite materials with tunable properties were successfully prepared using a poly(lactic acid) (PLA) matrix and acetylated microfibrillated cellulose (MFC) as reinforcing agent. The acetylation of MFC was confirmed by FTIR and (13)C CP-MAS NMR spectroscopies. The grafting of acetyl moieties on the cellulose surface not only prevented MFC hornification upon drying but also dramatically improved redispersibility of the powdered nanofibers in chloroform, a PLA solvent of low polarity. Moreover, we demonstrate that the properties of the resulting PLA nanocomposites could be tailored by adjusting both the acetyl content (Ac%) and the amount of MFC. These nanomaterials showed improved filler dispersion, higher thermal stability, and reduced hygroscopicity with respect to those prepared with unmodified MFC. Dynamic mechanical analysis (DMA) highlighted the reinforcing potential of both the unmodified and the acetylated MFC on the viscoelastic properties of the neat PLA. But more interesting, an increase in the PLA glass transition temperature was detected when using the 8.5% acetylated MFC at 17 wt %, indicating an improved compatibility at the fiber-matrix interface. These findings suggest that the final properties of nanocomposite materials can be controlled by adjusting the %Ac of MFC. PMID:20025270

  16. Preparation of microfibrillated cellulose/chitosan-benzalkonium chloride biocomposite for enhancing antibacterium and strength of sodium alginate films.

    Science.gov (United States)

    Liu, Kai; Lin, Xinxing; Chen, Lihui; Huang, Liulian; Cao, Shilin; Wang, Huangwei

    2013-07-01

    The nonantibacterial and low strength properties of sodium alginate films negatively impact their application for food packaging. In order to improve these properties, a novel chitosan-benzalkonium chloride (C-BC) complex was prepared by ionic gelation using tripolyphosphate (TPP) as a coagulant, and a biocomposite obtained through the adsorption of C-BC complex on microfibrillated cellulose, MFC/C-BC, was then incorporated into a sodium alginate film. The TEM image showed that the C-BC nanoparticles were spherical in shape with a diameter of about 30 nm, and the adsorption equilibrium time of these nanoparticles on the surface of MFC was estimated to be 6 min under the driving forces of hydrogen bonds and electrostatic interactions. According to the disc diffusion method, the MFC/C-BC biocomposite-incorporated sodium alginate film exhibited remarkable antibacterial activity against Staphylococcus aureus and certain antibacterial activity against Escherichia coli . The strength tests indicated that the tensile strength of the composite sodium alginate film increased about 225% when the loading of MFC/C-BC biocomposite was 10 wt %. These results suggested that the MFC/C-BC biocomposite-incorporated sodium alginate film with excellent antibacterial and strength properties would be a promising material for food packaging, and the MFC/C-BC may also be a potential multifunctional biocomposite for other biodegradable materials. PMID:23750871

  17. Preparation of photocrosslinked fish elastin polypeptide/microfibrillated cellulose composite gels with elastic properties for biomaterial applications.

    Science.gov (United States)

    Yano, Shinya; Mori, Megumi; Teramoto, Naozumi; Iisaka, Makoto; Suzuki, Natsumi; Noto, Masanari; Kaimoto, Yasuko; Kakimoto, Masashi; Yamada, Michio; Shiratsuchi, Eri; Shimasaki, Toshiaki; Shibata, Mitsuhiro

    2015-01-01

    Photocrosslinked hydrogels reinforced by microfibrillated cellulose (MFC) were prepared from a methacrylate-functionalized fish elastin polypeptide and MFC dispersed in dimethylsulfoxide (DMSO). First, a water-soluble elastin peptide with a molecular weight of ca. 500 g/mol from the fish bulbus arteriosus was polymerized by N,N'-dicyclohexylcarbodiimide (DCC), a condensation reagent, and then modified with 2-isocyanatoethyl methacrylate (MOI) to yield a photocrosslinkable fish elastin polypeptide. The product was dissolved in DMSO and irradiated with UV light in the presence of a radical photoinitiator. We obtained hydrogels successfully by substitution of DMSO with water. The composite gel with MFC was prepared by UV irradiation of the photocrosslinkable elastin polypeptide mixed with dispersed MFC in DMSO, followed by substitution of DMSO with water. The tensile test of the composite gels revealed that the addition of MFC improved the tensile properties, and the shape of the stress-strain curve of the composite gel became more similar to the typical shape of an elastic material with an increase of MFC content. The rheology measurement showed that the elastic modulus of the composite gel increased with an increase of MFC content. The cell proliferation test on the composite gel showed no toxicity. PMID:25584682

  18. Preparation of Photocrosslinked Fish Elastin Polypeptide/Microfibrillated Cellulose Composite Gels with Elastic Properties for Biomaterial Applications

    Directory of Open Access Journals (Sweden)

    Shinya Yano

    2015-01-01

    Full Text Available Photocrosslinked hydrogels reinforced by microfibrillated cellulose (MFC were prepared from a methacrylate-functionalized fish elastin polypeptide and MFC dispersed in dimethylsulfoxide (DMSO. First, a water-soluble elastin peptide with a molecular weight of ca. 500 g/mol from the fish bulbus arteriosus was polymerized by N,N′-dicyclohexylcarbodiimide (DCC, a condensation reagent, and then modified with 2-isocyanatoethyl methacrylate (MOI to yield a photocrosslinkable fish elastin polypeptide. The product was dissolved in DMSO and irradiated with UV light in the presence of a radical photoinitiator. We obtained hydrogels successfully by substitution of DMSO with water. The composite gel with MFC was prepared by UV irradiation of the photocrosslinkable elastin polypeptide mixed with dispersed MFC in DMSO, followed by substitution of DMSO with water. The tensile test of the composite gels revealed that the addition of MFC improved the tensile properties, and the shape of the stress–strain curve of the composite gel became more similar to the typical shape of an elastic material with an increase of MFC content. The rheology measurement showed that the elastic modulus of the composite gel increased with an increase of MFC content. The cell proliferation test on the composite gel showed no toxicity.

  19. Cellulose whiskers versus microfibrils: influence of the nature of the nanoparticle and its surface functionalization on the thermal and mechanical properties of nanocomposites.

    Science.gov (United States)

    Siqueira, Gilberto; Bras, Julien; Dufresne, Alain

    2009-02-01

    In the present work, nanowhiskers and microfibrillated cellulose (MFC) both extracted from sisal were used to reinforce polycaprolactone (PCL). We report the influence of the nanoparticle's nature on the mechanical and thermal properties of the ensuing nanocomposites. The surface of both the nanoparticles was chemically modified to improve their compatibilization with the polymeric matrix. N-Octadecyl isocyanate (C18H37NCO) was used as the grafting agent. PCL nanocomposite films reinforced with sisal whiskers or MFC (raw or chemically modified) were prepared by film casting. The thermal behavior (Tg, Tm, Tc, and degree of crystallinity) and the mechanical properties of the nanocomposites in both the linear and the nonlinear range were determined using differential scanning calorimetry (DSC), dynamical mechanical analysis (DMA), and tensile tests, respectively. Significant differences were reported according to the nature of the nanoparticle and amount of nanofillers used as reinforcement. It was also proved that the chemical treatment clearly improves the ultimate properties of the nanocomposites. PMID:19113881

  20. Super-resolution imaging with Pontamine Fast Scarlet 4BS enables direct visualization of cellulose orientation and cell connection architecture in onion epidermis cells

    DEFF Research Database (Denmark)

    Liesche, Johannes; Ziomkiewicz, Iwona; Schulz, Alexander

    2013-01-01

    microscopy of some 200 nm in xy and 550 nm in z for green light, restricts the direct visualization of cellulose to relatively large bundles, whereas the structure of cellulose microfibrils with their diameter below 10 nm remains unresolved. Over the last decade, several so-called super-resolution microscopy...... approaches have been developed; in this paper we explore the potential of such approaches for the direct visualization of cellulose. Results To ensure optimal imaging we determined the spectral properties of PFS-stained tissue. PFS was found not to affect cell viability in the onion bulb scale epidermis. We...... confocal microscopy and the approach could be used to demonstrate differences in fibril orientation in different layers of the cell wall as well as particular cellulose fortifications around plasmodesmata. Conclusions Super-resolution light microscopy of PFS-stained cellulose fibrils is possible...

  1. Microfibrillated cellulose sheets coating oxygen-permeable PDMS membranes induce rat hepatocytes 3D aggregation into stably-attached 3D hemispheroids.

    Science.gov (United States)

    Evenou, Fanny; Couderc, Sandrine; Kim, Beomjoon; Fujii, Teruo; Sakai, Yasuyuki

    2011-01-01

    Here we report the use of natural, chemically-unmodified, microfibrillated cellulose (MFC) as a matrix for hepatocyte culture. We developed an original cell-culture design composed of a thin 3D-microstructured fibrous substrate consisting of a MFC sheet coating a highly O(2)-permeable polydimethylsiloxane (PDMS) membrane. The MFC-coated PDMS membranes were obtained according to a simple process where cellulose fibres were deposited from an aqueous suspension on the PDMS surfaces and the films were dried under mild conditions. To enable oxygen diffusion through the membranes, they were assembled on bottomless frames ('O(2)+' condition). Rat hepatocytes primary-cultured on such MFC-PDMS membranes quickly organized themselves into large hemispherical 3D aggregates which were tightly anchored to the MFC sheets. In contrast, hepatocytes cultured on smooth PDMS membranes in the O(2)+ system (O(2)+, PDMS) organized into unstable 2D monolayers which easily detached from the surfaces. Hepatocyte 3D cultures obtained on MFC-PDMS membranes exhibited higher liver-specific functions over a 2-week culture period, as assessed by both the higher albumin secretion and urea synthesis rate. The MFC-PDMS membranes appear suitable for obtaining stably-attached and functional hepatocyte 3D cultures and appear interesting for drug/chemical screenings in a microplate format, but also for microfluidic applications. PMID:20626957

  2. Fibril orientation redistribution induced by stretching of cellulose nanofibril hydrogels

    International Nuclear Information System (INIS)

    The mechanical performance of materials reinforced by cellulose nanofibrils is highly affected by the orientation of these fibrils. This paper investigates the nanofibril orientation distribution of films of partly oriented cellulose nanofibrils. Stripes of hydrogel films were subjected to different amount of strain and, after drying, examined with X-ray diffraction to obtain the orientation of the nanofibrils in the films, caused by the stretching. The cellulose nanofibrils had initially a random in-plane orientation in the hydrogel films and the strain was applied to the films before the nanofibrils bond tightly together, which occurs during drying. The stretching resulted in a reorientation of the nanofibrils in the films, with monotonically increasing orientation towards the load direction with increasing strain. Estimation of nanofibril reorientation by X-ray diffraction enables quantitative comparison of the stretch-induced orientation ability of different cellulose nanofibril systems. The reorientation of nanofibrils as a consequence of an applied strain is also predicted by a geometrical model of deformation of nanofibril hydrogels. Conversely, in high-strain cold-drawing of wet cellulose nanofibril materials, the enhanced orientation is promoted by slipping of the effectively stiff fibrils

  3. Fibril orientation redistribution induced by stretching of cellulose nanofibril hydrogels

    Energy Technology Data Exchange (ETDEWEB)

    Josefsson, Gabriella; Gamstedt, E. Kristofer [The Ångström Laboratory, Department of Engineering Sciences, Division of Applied Mechanics, Uppsala University, Box 534, SE-751 21 Uppsala (Sweden); Ahvenainen, Patrik [Department of Physics, University of Helsinki, P.O. Box 64, FI-00014 University of Helsinki (Finland); Mushi, Ngesa Ezekiel [Department of Fiber and Polymer Technology, Royal Institute of Technology (KTH), SE-100 44 Stockholm (Sweden)

    2015-06-07

    The mechanical performance of materials reinforced by cellulose nanofibrils is highly affected by the orientation of these fibrils. This paper investigates the nanofibril orientation distribution of films of partly oriented cellulose nanofibrils. Stripes of hydrogel films were subjected to different amount of strain and, after drying, examined with X-ray diffraction to obtain the orientation of the nanofibrils in the films, caused by the stretching. The cellulose nanofibrils had initially a random in-plane orientation in the hydrogel films and the strain was applied to the films before the nanofibrils bond tightly together, which occurs during drying. The stretching resulted in a reorientation of the nanofibrils in the films, with monotonically increasing orientation towards the load direction with increasing strain. Estimation of nanofibril reorientation by X-ray diffraction enables quantitative comparison of the stretch-induced orientation ability of different cellulose nanofibril systems. The reorientation of nanofibrils as a consequence of an applied strain is also predicted by a geometrical model of deformation of nanofibril hydrogels. Conversely, in high-strain cold-drawing of wet cellulose nanofibril materials, the enhanced orientation is promoted by slipping of the effectively stiff fibrils.

  4. Synthesis of polycaprolactone-grafted microfibrillated cellulose for use in novel bionanocomposites--influence of the graft length on the mechanical properties.

    Science.gov (United States)

    Lönnberg, Hanna; Larsson, Karolina; Lindström, Tom; Hult, Anders; Malmström, Eva

    2011-05-01

    In the present work, microfibrillated cellulose (MFC) made from bleached sulfite softwood dissolving pulp was utilized to reinforce a poly(ε-caprolactone) (PCL) biopolymer matrix. To improve the dispersibility of the hydrophilic MFC in the nonpolar matrix and the interfacial adhesion in the composite material, we covalently grafted the MFC with PCL via ring-opening polymerization (ROP) of ε-caprolactone (ε-CL). To be able to investigate the effect of the PCL graft length on the mechanical properties of the composite material, we performed ROP to different molecular weights of the grafts. Bionanocomposites containing 0, 3, and 10 wt % MFC were prepared via hot pressing using both unmodified and PCL grafted MFC (MFC-g-PCL) as reinforcement. PCL grafting resulted in improved dispersion of the MFC in a nonpolar solvent and in the PCL matrix. The mechanical testing of the biocomposites showed an improvement in the mechanical properties for the PCL grafted MFC in comparison to ungrafted MFC. It was also shown that there was an impact on the mechanical properties with respect to the PCL graft lengths, and the strongest biocomposites were obtained after reinforcement with MFC grafted with the longest PCL graft length. PMID:21473594

  5. Mechanical reinforcement of Bioglass (R)-based scaffolds by novel polyvinyl-alcohol/microfibrillated cellulose composite coating

    Czech Academy of Sciences Publication Activity Database

    Bertolla, Luca; Dlouhý, Ivo; Philippart, A.; Boccaccini, A. R.

    2014-01-01

    Roč. 118, MAR (2014), s. 204-207. ISSN 0167-577X R&D Projects: GA MŠk(CZ) ED1.1.00/02.0068 EU Projects: European Commission(XE) 264526 - GLACERCO Institutional support: RVO:68081723 Keywords : bioactive glass * mechanical properties * scaffolds * cellulose * coatings Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 2.489, year: 2014

  6. The Cellulose System in the Cell Wall of Micrasterias

    Science.gov (United States)

    Kim; Herth; Vuong; Chanzy

    1996-11-01

    The cellulose system of the cell wall of Micrasterias denticulata and Micrasterias rotata was analyzed by diffraction contrast transmission electron microscopy, electron diffraction, and X-ray analysis. The studies, achieved on disencrusted cell ghosts, confirmed that the cellulose microfibrils occurred in crisscrossed bands consisting of a number of parallel ribbon-like microfibrils. The individual microfibrils had thicknesses of 5 nm for a width of around 20 nm, but in some instances, two or three microfibrils merged into one another to yield larger monocrystalline domains reaching up to 60 nm in lateral size. The orientation of the cellulose of Micrasterias is very unusual, as it was found that in the cell wall, the equatorial crystallographic planes of cellulose having a d-spacing of 0.60 nm [(11;0) in the Ibeta cellulose unit cell defined by Sugiyama et al., 1991, Macromolecules 24, 4168-4175] were oriented perpendicular to the cell wall surface. Up to now, such orientation has been found only in Spirogyra, another member of the Zygnemataceae group. The unusual structure of the secondary wall cellulose of Micrasterias may be tentatively correlated with the unique organization of the terminal complexes, which in this alga occur as hexagonal arrays of rosettes. PMID:8986649

  7. Cellulose biogenesis in Dictyostelium discoideum

    Energy Technology Data Exchange (ETDEWEB)

    Blanton, R.L.

    1993-12-31

    Organisms that synthesize cellulose can be found amongst the bacteria, protistans, fungi, and animals, but it is in plants that the importance of cellulose in function (as the major structural constituent of plant cell walls) and economic use (as wood and fiber) can be best appreciated. The structure of cellulose and its biosynthesis have been the subjects of intense investigation. One of the most important insights gained from these studies is that the synthesis of cellulose by living organisms involves much more than simply the polymerization of glucose into a (1{r_arrow}4)-{beta}-linked polymer. The number of glucoses in a polymer (the degree of polymerization), the crystalline form assumed by the glucan chains when they crystallize to form a microfibril, and the dimensions and orientation of the microfibrils are all subject to cellular control. Instead of cellulose biosynthesis, a more appropriate term might be cellulose biogenesis, to emphasize the involvement of cellular structures and mechanisms in controlling polymerization and directing crystallization and deposition. Dictyostelium discoideum is uniquely suitable for the study of cellulose biogenesis because of its amenability to experimental study and manipulation and the extent of our knowledge of its basic cellular mechanisms (as will be evident from the rest of this volume). In this chapter, I will summarize what is known about cellulose biogenesis in D. discoideum, emphasizing its potential to illuminate our understanding both of D. discoideum development and plant cellulose biogenesis.

  8. Cellulose nanofiber orientation in nanopaper and nanocomposites by cold drawing.

    Science.gov (United States)

    Sehaqui, Houssine; Ezekiel Mushi, Ngesa; Morimune, Seira; Salajkova, Michaela; Nishino, Takashi; Berglund, Lars A

    2012-02-01

    To exploit the mechanical potential of native cellulose fibrils, we report on the preparation of nanopaper with preferred orientation of nanofibrillated cellulose (TEMPO-NFC) by cold drawing. The preparation route is papermaking-like and includes vacuum filtering of a TEMPO-oxidated NFC water dispersion, drawing in wet state and drying. The orientation of the fibrils in the nanopaper was assessed by AFM and wide-angle X-ray diffraction analysis, and the effect on mechanical properties of the resulting nanopaper structure was investigated by tensile tests. At high draw ratio, the degree of orientation is as high as 82 and 89% in-the-plane and cross-sectional planes of the nanopaper, respectively, and the Young's modulus is 33 GPa. This is much higher than mechanical properties of isotropic nanopaper. The cold drawing method can be also applied to NFC nanocomposites as demonstrated by preparation of TEMPO-NFC/hydroxyethyl cellulose (HEC) nanocomposites. The introduction of the soft HEC matrix allows further tailoring of the mechanical properties. PMID:22257144

  9. Arabidopsis thaliana KORRIGAN1 protein: N-glycan modification, localization, and function in cellulose biosynthesis and osmotic stress responses

    OpenAIRE

    von Schaewen, Antje; Rips, Stephan; Jeong, In Sil; Koiwa, Hisashi

    2015-01-01

    Plant cellulose biosynthesis is a complex process involving cellulose-synthase complexes (CSCs) and various auxiliary factors essential for proper orientation and crystallinity of cellulose microfibrils in the apoplast. Among them is KORRIGAN1 (KOR1), a type-II membrane protein with multiple N-glycans within its C-terminal cellulase domain. N-glycosylation of the cellulase domain was important for KOR1 targeting to and retention within the trans-Golgi network (TGN), and prevented accumulation...

  10. Cellulose structure and lignin distribution in normal and compression wood of the Maidenhair tree (Ginkgo biloba L.)

    Institute of Scientific and Technical Information of China (English)

    Seppo Andersson; Yurong Wang; Raili Ponni; Tuomas Hanninen; Marko Mononen; Haiqing Ren; Ritva Serimaa; Pekka Saranpaa

    2015-01-01

    We studied in detail the mean microfibril angle and the width of cellulose crystals from the pith to the bark of a 15-year-old Maidenhair tree (Ginkgo biloba L.). The orientation of cellulose microfibrils with respect to the cell axis and the width and length of cellulose crystallites were determined using X-ray diffraction. Raman microscopy was used to compare the lignin distribution in the cell wall of normal/opposite and compression wood, which was found near the pith. Ginkgo biloba showed a relatively large mean microfibril angle, varying between 19° and 39° in the S2 layer, and the average width of cellulose crystallites was 3.1–3.2 nm. Mild compres-sion wood without any intercellular spaces or helical cavities was observed near the pith. Slit-like bordered pit openings and a heavily lignified S2L layer confirmed the presence of compression wood. Ginkgo biloba showed typical features present in the juvenile wood of conifers. The microfibril angle remained large over the 14 annual rings. The entire stem disc, with a diameter of 18 cm, was considered to consist of juvenile wood. The properties of juvenile and compression wood as well as the cellulose orientation and crystalline width indicate that the wood formation of G. biloba is similar to that of modern conifers.

  11. Microstructure and rheology of microfibril-polymer networks.

    Science.gov (United States)

    Veen, Sandra J; Versluis, Peter; Kuijk, Anke; Velikov, Krassimir P

    2015-12-14

    By using an adsorbing polymer in combination with mechanical de-agglomeration, the microstructure and rheological properties of networks of microfibrils could be controlled. By the addition of sodium carboxymethyl cellulose during de-agglomeration of networks of bacterial cellulose, the microstructure could be changed from an inhomogeneous network with bundles of microfibrils and voids to a more homogeneous spread and alignment of the particles. As a result the macroscopic rheological properties were altered. Although still elastic and gel-like in nature, the elasticity and viscous behavior of the network as a function of microfibril concentration is altered. The microstructure is thus changed by changing the surface properties of the building blocks leading to a direct influence on the materials macroscopic behavior. PMID:26434637

  12. Characterization of Cellulose Synthesis in Plant Cells

    OpenAIRE

    Samaneh Sadat Maleki; Kourosh Mohammadi; Kong-shu Ji

    2016-01-01

    Cellulose is the most significant structural component of plant cell wall. Cellulose, polysaccharide containing repeated unbranched β (1-4) D-glucose units, is synthesized at the plasma membrane by the cellulose synthase complex (CSC) from bacteria to plants. The CSC is involved in biosynthesis of cellulose microfibrils containing 18 cellulose synthase (CesA) proteins. Macrofibrils can be formed with side by side arrangement of microfibrils. In addition, beside CesA, various proteins like the...

  13. A route to uniaxially oriented ribbons of bacterial cellulose nanocrystals based on isomalt spun sacrificial template

    OpenAIRE

    Bizot, Herve; Cathala, Bernard

    2014-01-01

    We have carried out orientation of bacterial cellulose nanocrystals (BCNC) by implementing a process based on mechanical shearing BCNC dispersed in a viscous temporary isomalt glass. After the orientation, the isomalt matrix was selectively solubilized to afford uniaxially highly oriented BCNC ribbons as demonstrated by SEM and X-Ray studies. The 2D WAXS determined Herman's order parameter reached 0.85.

  14. Cellulose Orientation in the Outer Epidermal Wall of Angiosperm Roots: Implications for Biosystematics

    OpenAIRE

    KERSTENS, SVEN; VERBELEN, JEAN‐PIERRE

    2002-01-01

    The net orientation of cellulose fibrils in the outer epidermal wall of the root elongation zone of 57 angiosperm species belonging to 29 families was determined by means of Congo Red fluorescence and polarization confocal microscopy. The angiosperms can be divided in three groups. In all but four plant families, the net orientation of the cellulose fibrils is transverse to the root axis. Three families, the Poaceae, Juncaceae and Cyperaceae, have a totally different organization. In the root...

  15. Cellulose synthase interacting protein: A new factor in cellulose synthesis

    OpenAIRE

    Gu, Ying; Somerville, Chris

    2010-01-01

    Cellulose is the most abundant biopolymer on earth. The great abundance of cellulose places it at the forefront as a primary source of biomass for renewable biofuels. However, the knowledge of how plant cells make cellulose remains very rudimentary. Cellulose microfibrils are synthesized at the plasma membrane by hexameric protein complexes, also known as cellulose synthase complexes. The only known components of cellulose synthase complexes are cellulose synthase (CESA) proteins until the re...

  16. Corneal stroma microfibrils

    KAUST Repository

    Hanlon, Samuel D.

    2015-03-01

    Elastic tissue was first described well over a hundred years ago and has since been identified in nearly every part of the body. In this review, we examine elastic tissue in the corneal stroma with some mention of other ocular structures which have been more thoroughly described in the past. True elastic fibers consist of an elastin core surrounded by fibrillin microfibrils. However, the presence of elastin fibers is not a requirement and some elastic tissue is comprised of non-elastin-containing bundles of microfibrils. Fibers containing a higher relative amount of elastin are associated with greater elasticity and those without elastin, with structural support. Recently it has been shown that the microfibrils, not only serve mechanical roles, but are also involved in cell signaling through force transduction and the release of TGF-β. A well characterized example of elastin-free microfibril bundles (EFMBs) is found in the ciliary zonules which suspend the crystalline lens in the eye. Through contraction of the ciliary muscle they exert enough force to reshape the lens and thereby change its focal point. It is believed that the molecules comprising these fibers do not turn-over and yet retain their tensile strength for the life of the animal. The mechanical properties of the cornea (strength, elasticity, resiliency) would suggest that EFMBs are present there as well. However, many authors have reported that, although present during embryonic and early postnatal development, EFMBs are generally not present in adults. Serial-block-face imaging with a scanning electron microscope enabled 3D reconstruction of elements in murine corneas. Among these elements were found fibers that formed an extensive network throughout the cornea. In single sections these fibers appeared as electron dense patches. Transmission electron microscopy provided additional detail of these patches and showed them to be composed of fibrils (~10nm diameter). Immunogold evidence clearly

  17. Cellulose

    Science.gov (United States)

    Cellulose properties and structure are reviewed, with a primary focus on crystal structure and polymorphy. This focus highlights the conversion from cellulose I to cellulose II, which converts the molecules to being all parallel to each other in the crystal to being antiparallel. This has been co...

  18. A uniaxially oriented nanofibrous cellulose scaffold from pellicles produced by Gluconacetobacter xylinus in dissolved oxygen culture.

    Science.gov (United States)

    Nagashima, Aya; Tsuji, Tsubasa; Kondo, Tetsuo

    2016-01-01

    An aerobic, Gram-negative bacterium, Gluconacetobacter xylinus, was successfully employed to produce a stretchable cellulose nanofiber pellicle using dissolved oxygen in a conventional cultured medium. The obtained nanofibers were highly crystalline with the metastable cellulose Iα phase being apparently the dominant phase by more than 90%. The obtained pellicle could be stretched by up to 1.5 times to provide oriented crystalline nanofibrous films. Low heating of the nanofibrous film induced the transformation of the dominant cellulose Iα crystalline phase into the Iβ crystalline phase without a loss of crystallinity or the high Young's modulus. The film also exhibited unique and anisotropic viscoelastic and mechanical properties as well as superior thermal stability compared with conventional high-performance synthetic polymeric materials. In addition, when G. xylinus cells were transferred to the oriented surface after stretched, they started to synthesize cellulose ribbons that parallel the nanofiber orientation of the substrate. This function as a template was evidenced by direct video imaging of the motion of the bacteria. The application of a bacterial culture using dissolved oxygen in the medium offers the fabrication of novel anisotropic and nanofibrous scaffold of cellulose Iα. PMID:26453871

  19. Cellulose Synthesis and Its Regulation

    OpenAIRE

    Li, Shundai; Bashline, Logan; Lei, Lei; Gu, Ying

    2014-01-01

    Cellulose, the most abundant biopolymer synthesized on land, is made of linear chains of ß (1–4) linked D-glucose. As a major structural component of the cell wall, cellulose is important not only for industrial use but also for plant growth and development. Cellulose microfibrils are tethered by other cell wall polysaccharides such as hemicellulose, pectin, and lignin. In higher plants, cellulose is synthesized by plasma membrane-localized rosette cellulose synthase complexes. Despite the re...

  20. Film morphology and orientation of amino silicone adsorbed onto cellulose substrate

    International Nuclear Information System (INIS)

    A series of amino silicones with different amino values were synthesized and adsorbed onto surfaces of cotton fibers and cellulose substrates. The film morphology, hydrophobic properties and surface composition of the silicones are investigated and characterized by field emission scanning electron microscope (FESEM), atomic force microscope (AFM), contact angle measurement, X-ray photoelectron spectroscopy (XPS) and attenuated total reflectance infrared (ATR-IR). The results of the experiments indicate that the amino silicone can form a hydrophobic film on both cotton fibers and cellulose substrates and reduce the surface roughness significantly. Furthermore, the roughness becomes smaller with an increase in the amino value. All these results suggest that the orientation of amino silicone molecule is with the amino functional groups of amino silicone molecule adsorbed onto the cellulose interface while the main polymer chains and the hydrophobic Si-CH3 groups extend toward the air.

  1. Cellulose Assemblies Produced by Acetobacter Xylinum (FUNDAMENTAL MATERIAL PROPERTIES-Molecular Dynamic Characteristics)

    OpenAIRE

    Hirai, Asako; Horii, Fumitaka

    2000-01-01

    Structures of cellulose assemblies produced by Acetobacter xylinum under various conditions have been studied mainly by transmission electron microscopy. Native cellulose crystals are composites of cellulose Iα and Iβ . Twisted-ribbn cellulose assemblies produced in the HS medium at 28 °C were rich in cellulose Iα . On the contrary, splayed microfibrils produced in the presence of CMC at 28 °C were rich in Iβ . Not only the ribbon assembly but also the bundle of splayed microfibrils was deter...

  2. Binding Preferences, Surface Attachment, Diffusivity, and Orientation of a Family 1 Carbohydrate-Binding Module on Cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Nimlos, M. R.; Beckham, G. T.; Matthews, J. F.; Bu, L.; Himmel, M. E.; Crowley, M. F.

    2012-06-08

    Cellulase enzymes often contain carbohydrate-binding modules (CBMs) for binding to cellulose. The mechanisms by which CBMs recognize specific surfaces of cellulose and aid in deconstruction are essential to understand cellulase action. The Family 1 CBM from the Trichoderma reesei Family 7 cellobiohydrolase, Cel7A, is known to selectively bind to hydrophobic surfaces of native cellulose. It is most commonly suggested that three aromatic residues identify the planar binding face of this CBM, but several recent studies have challenged this hypothesis. Here, we use molecular simulation to study the CBM binding orientation and affinity on hydrophilic and hydrophobic cellulose surfaces. Roughly 43 {mu}s of molecular dynamics simulations were conducted, which enables statistically significant observations. We quantify the fractions of the CBMs that detach from crystal surfaces or diffuse to other surfaces, the diffusivity along the hydrophobic surface, and the overall orientation of the CBM on both hydrophobic and hydrophilic faces. The simulations demonstrate that there is a thermodynamic driving force for the Cel7A CBM to bind preferentially to the hydrophobic surface of cellulose relative to hydrophilic surfaces. In addition, the simulations demonstrate that the CBM can diffuse from hydrophilic surfaces to the hydrophobic surface, whereas the reverse transition is not observed. Lastly, our simulations suggest that the flat faces of Family 1 CBMs are the preferred binding surfaces. These results enhance our understanding of how Family 1 CBMs interact with and recognize specific cellulose surfaces and provide insights into the initial events of cellulase adsorption and diffusion on cellulose.

  3. Super-resolution imaging with Pontamine Fast Scarlet 4BS enables direct visualization of cellulose orientation and cell connection architecture in onion epidermis cells

    OpenAIRE

    Liesche, Johannes; Ziomkiewicz, Iwona; Schulz, Alexander

    2013-01-01

    BackgroundIn plants, a complex cell wall protects cells and defines their shape. Cellulose fibrils form a multilayered network inside the cell-wall matrix that plays a direct role in controlling cell expansion. Resolving the structure of this network will allow us to comprehend the relationship of cellulose fibril orientation and growth.The fluorescent dye Pontamine Fast Scarlet 4BS (PFS) was shown to stain cellulose with high specificity and could be used to visualize cellulose bundles in ce...

  4. Characterization of Cellulose Synthesis in Plant Cells

    Directory of Open Access Journals (Sweden)

    Samaneh Sadat Maleki

    2016-01-01

    Full Text Available Cellulose is the most significant structural component of plant cell wall. Cellulose, polysaccharide containing repeated unbranched β (1-4 D-glucose units, is synthesized at the plasma membrane by the cellulose synthase complex (CSC from bacteria to plants. The CSC is involved in biosynthesis of cellulose microfibrils containing 18 cellulose synthase (CesA proteins. Macrofibrils can be formed with side by side arrangement of microfibrils. In addition, beside CesA, various proteins like the KORRIGAN, sucrose synthase, cytoskeletal components, and COBRA-like proteins have been involved in cellulose biosynthesis. Understanding the mechanisms of cellulose biosynthesis is of great importance not only for improving wood production in economically important forest trees to mankind but also for plant development. This review article covers the current knowledge about the cellulose biosynthesis-related gene family.

  5. Characterization of Cellulose Synthesis in Plant Cells.

    Science.gov (United States)

    Maleki, Samaneh Sadat; Mohammadi, Kourosh; Ji, Kong-Shu

    2016-01-01

    Cellulose is the most significant structural component of plant cell wall. Cellulose, polysaccharide containing repeated unbranched β (1-4) D-glucose units, is synthesized at the plasma membrane by the cellulose synthase complex (CSC) from bacteria to plants. The CSC is involved in biosynthesis of cellulose microfibrils containing 18 cellulose synthase (CesA) proteins. Macrofibrils can be formed with side by side arrangement of microfibrils. In addition, beside CesA, various proteins like the KORRIGAN, sucrose synthase, cytoskeletal components, and COBRA-like proteins have been involved in cellulose biosynthesis. Understanding the mechanisms of cellulose biosynthesis is of great importance not only for improving wood production in economically important forest trees to mankind but also for plant development. This review article covers the current knowledge about the cellulose biosynthesis-related gene family. PMID:27314060

  6. Alteration of in vivo cellulose ribbon assembly by carboxymethylcellulose and other cellulose derivatives

    OpenAIRE

    1982-01-01

    In vivo cellulose ribbon assembly by the Gram-negative bacterium Acetobacter xylinum can be altered by incubation in carboxymethylcellulose (CMC), a negatively charged water-soluble cellulose derivative, and also by incubation in a variety of neutral, water-soluble cellulose derivatives. In the presence of all of these substituted celluloses, normal fasciation of microfibril bundles to form the typical twisting ribbon is prevented. Alteration of ribbon assembly is most extensive in the presen...

  7. Biomimetic polysaccharide nanocomposites of high cellulose content and high toughness.

    Science.gov (United States)

    Svagan, Anna J; Samir, My A S Azizi; Berglund, Lars A

    2007-08-01

    Plant cell walls combine mechanical stiffness, strength and toughness despite a highly hydrated state. Inspired by this, a nanostructured cellulose network is combined with an almost viscous polysaccharide matrix in the form of a 50/50 amylopectin-glycerol blend. Homogeneous films with a microfibrillated cellulose (MFC) nanofiber content in the range of 10-70 wt % are successfully cast. Characterization is carried out by dynamic mechanical analysis, field-emission scanning electron microscopy, X-ray diffraction, and mercury density measurements. The MFC is well dispersed and predominantly oriented random-in-the-plane. High tensile strength is combined with high modulus and very high work of fracture in the nanocomposite with 70 wt % MFC. The reasons for this interesting combination of properties include nanofiber and matrix properties, favorable nanofiber-matrix interaction, good dispersion, and the ability of the MFC network to maintain its integrity to a strain of at least 8%. PMID:17655354

  8. Re-constructing our models of cellulose and primary cell wall assembly

    OpenAIRE

    Cosgrove, Daniel J.

    2014-01-01

    The cellulose microfibril has more subtlety than is commonly recognized. Details of its structure may influence how matrix polysaccharides interact with its distinctive hydrophobic and hydrophilic surfaces to form a strong yet extensible structure. Recent advances in this field include the first structures of bacterial and plant cellulose synthases and revised estimates of microfibril structure, reduced from 36 to 18 chains. New results also indicate that cellulose interactions with xylogluca...

  9. Preparation, characterisation and wetting of fluorinated cellulose surfaces

    OpenAIRE

    Aulin, Christian

    2007-01-01

    This thesis deals with the wetting by oil mixtures of two different model cellulose surfaces. The surfaces studied were a regenerated cellulose (RG) surface prepared by spin-coating, and a film consisting of polyelectrolyte multilayers (PEM) of Poly(ethyleneimine) (PEI) and a carboxymethylated Microfibrillated Cellulose (MFC). After coating or covalently modifying the cellulose surfaces with various amounts of fluorosurfactants, the fluorinated cellulose films were used to follow the spreadin...

  10. Cellulosic Bionanocomposites: A Review of Preparation, Properties and Applications

    OpenAIRE

    Alain Dufresne; Gilberto Siqueira; Julien Bras

    2010-01-01

    Cellulose is the most abundant biomass material in nature. Extracted from natural fibers, its hierarchical and multi-level organization allows different kinds of nanoscaled cellulosic fillers—called cellulose nanocrystals or microfibrillated cellulose (MFC)—to be obtained. Recently, such cellulose nanoparticles have been the focus of an exponentially increasing number of works or reviews devoted to understanding such materials and their applications. Major studies over the last decades have s...

  11. Spray-Dried Cellulose Nanofibers as Novel Tablet Excipient

    OpenAIRE

    Kolakovic, Ruzica; Peltonen, Leena; Laaksonen, Timo; Putkisto, Kaisa; Laukkanen, Antti; Hirvonen, Jouni

    2011-01-01

    The purpose of this study was to evaluate the potential of cellulose nanofibers (also referred as microfibrillated cellulose, nanocellulose, nanofibrillated, or nanofibrillar cellulose) as novel tabletting material. For this purpose, physical and mechanical properties of spray-dried cellulose nanofibers (CNF) were examined, and results were compared to those of two commercial grades of microcrystalline cellulose (MCC), Avicel PH101 and Avicel PH102, which are the most commonly and widely used...

  12. Fibrillin microfibrils in bone physiology.

    Science.gov (United States)

    Smaldone, Silvia; Ramirez, Francesco

    2016-01-01

    The severe skeletal abnormalities associated with Marfan syndrome (MFS) and congenital contractural arachnodactyly (CCA) underscore the notion that fibrillin assemblies (microfibrils and elastic fibers) play a critical role in bone formation and function in spite of representing a low abundance component of skeletal matrices. Studies of MFS and CCA mice have correlated the skeletal phenotypes of these mutant animals with distinct pathophysiological mechanisms that reflect the contextual contribution of fibrillin-1 and -2 scaffolds to TGFβ and BMP signaling during bone patterning, growth and metabolism. Illustrative examples include the unique role of fibrillin-2 in regulating BMP-dependent limb patterning and the distinct impact of the two fibrillin proteins on the commitment and differentiation of marrow mesenchymal stem cells. Collectively, these findings have important implication for our understanding of the pathophysiological mechanisms that drive age- and injury-related processes of bone degeneration. PMID:26408953

  13. Three-dimensional orientation of cellulose crystals under dynamic elliptic magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, F; Kimura, T [Division of Forest and Biomaterials Science, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502 (Japan)], E-mail: fkimura@kais.kyoto-u.ac.jp

    2009-03-01

    Cellulose microparticles prepared by hydrochloric acid hydrolysis of cotton cellulose were mixed with UV-curable resin precursor and subjected to a frequency modulated magnetic field. The obtained alignment was fixed by photopolymerization of the matrix resin precursor. The observation of the obtained sample from three different orthogonal directions exhibited optical anisotropy, indicating that the three-dimensional alignment is achieved.

  14. The Stability of Cellulose: A Statistical Perspective from a Coarse-Grained Model of Hydrogen-Bond Networks

    OpenAIRE

    Shen, Tongye; Gnanakaran, S.

    2009-01-01

    A critical roadblock to the production of biofuels from lignocellulosic biomass is the efficient degradation of crystalline microfibrils of cellulose to glucose. A microscopic understanding of how different physical conditions affect the overall stability of the crystalline structure of microfibrils could facilitate the design of more effective protocols for their degradation. One of the essential physical interactions that stabilizes microfibrils is a network of hydrogen (H) bonds: both intr...

  15. TEMPO-oxidized cellulose nanofibers

    Science.gov (United States)

    Isogai, Akira; Saito, Tsuguyuki; Fukuzumi, Hayaka

    2011-01-01

    Native wood celluloses can be converted to individual nanofibers 3-4 nm wide that are at least several microns in length, i.e. with aspect ratios >100, by TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical)-mediated oxidation and successive mild disintegration in water. Preparation methods and fundamental characteristics of TEMPO-oxidized cellulose nanofibers (TOCN) are reviewed in this paper. Significant amounts of C6 carboxylate groups are selectively formed on each cellulose microfibril surface by TEMPO-mediated oxidation without any changes to the original crystallinity (~74%) or crystal width of wood celluloses. Electrostatic repulsion and/or osmotic effects working between anionically-charged cellulose microfibrils, the ζ-potentials of which are approximately -75 mV in water, cause the formation of completely individualized TOCN dispersed in water by gentle mechanical disintegration treatment of TEMPO-oxidized wood cellulose fibers. Self-standing TOCN films are transparent and flexible, with high tensile strengths of 200-300 MPa and elastic moduli of 6-7 GPa. Moreover, TOCN-coated poly(lactic acid) films have extremely low oxygen permeability. The new cellulose-based nanofibers formed by size reduction process of native cellulose fibers by TEMPO-mediated oxidation have potential application as environmentally friendly and new bio-based nanomaterials in high-tech fields.

  16. Parallel-up structure evidences the molecular directionality during biosynthesis of bacterial cellulose

    OpenAIRE

    Koyama, Makiko; Helbert, William; Imai, Tomoya; Sugiyama, Junji; Henrissat, Bernard

    1997-01-01

    The “parallel-up” packing in cellulose Iα and Iβ unit cells was experimentally demonstrated by a combination of direct-staining the reducing ends of cellulose chains and microdiffraction-tilting electron crystallographic analysis. Microdiffraction investigation of nascent bacterial cellulose microfibrils showed that the reducing end of the growing cellulose chains points away from the bacterium, and this provides direct evidence that polymerization by the cellulose synthase takes place at the...

  17. Surface properties of woody thin boards composed of commercially available lignin and cellulose: Relationship between the orientation of lignin and water repellency

    Energy Technology Data Exchange (ETDEWEB)

    Shimanouchi, Toshinori; Kamba, Tomoya; Yang, Wei [Graduate School of Environmental and Life Science, Okayama University, 3-1-1 Tsushimanaka, Kita-ku, Okayama 700-8530 (Japan); Aoyagi, Satoka [Department of Material and Lie Science, Seikei University, 3-3-1 Musashino, Tokyo 180-8633 (Japan); Kimura, Yukitaka, E-mail: yktkkimu@cc.okayama-u.ac.jp [Graduate School of Environmental and Life Science, Okayama University, 3-1-1 Tsushimanaka, Kita-ku, Okayama 700-8530 (Japan)

    2015-08-30

    Highlights: • Woody thin boards were formed by adequate ratio of lignin/cellulose/moisture. • Component ratio of lignin/cellulose/moisture determined water repellency. • Increase of water repellency resulted from the surface orientation of lignin. - Abstract: Woody thin boards were prepared from lignin, cellulose, and water by compression molding at 180 °C and 25 MPa for 10 min. Boards with higher contact angles gave lower values of relative permittivity on their surface. Attenuated-total reflection Fourier transfer infrared spectroscopy suggested that more lignin existed on the surface of the boards with the high contact angle, which was also supported by scanning electron microscopy and atomic force microscopy. Our findings thus revealed that the orientation of lignin at the surface resulted in increased hydrophobicity of the surface and contributed to the enhancement of water repellency.

  18. Surface properties of woody thin boards composed of commercially available lignin and cellulose: Relationship between the orientation of lignin and water repellency

    International Nuclear Information System (INIS)

    Highlights: • Woody thin boards were formed by adequate ratio of lignin/cellulose/moisture. • Component ratio of lignin/cellulose/moisture determined water repellency. • Increase of water repellency resulted from the surface orientation of lignin. - Abstract: Woody thin boards were prepared from lignin, cellulose, and water by compression molding at 180 °C and 25 MPa for 10 min. Boards with higher contact angles gave lower values of relative permittivity on their surface. Attenuated-total reflection Fourier transfer infrared spectroscopy suggested that more lignin existed on the surface of the boards with the high contact angle, which was also supported by scanning electron microscopy and atomic force microscopy. Our findings thus revealed that the orientation of lignin at the surface resulted in increased hydrophobicity of the surface and contributed to the enhancement of water repellency

  19. Water Adsorption in Wood Microfibril-Hemicellulose System: Role of the Crystalline-Amorphous Interface.

    Science.gov (United States)

    Kulasinski, Karol; Guyer, Robert; Derome, Dominique; Carmeliet, Jan

    2015-09-14

    A two-phase model of a wood microfibril consisting of crystalline cellulose and amorphous hemicellulose is investigated with molecular dynamics in full range of sorption to understand the molecular origin of swelling and weakening of wood. Water is adsorbed in hemicellulose, and an excess of sorption is found at the interface, while no sorption occurs within cellulose. Water molecules adsorbed on the interface push away polymer chains, forcing the two phases to separate and causing breaking of h-bonds, particularly pronounced on the interface. Existence of two different regions in moisture response is demonstrated. At low moisture content, water is uniformly adsorbed within hemicellulose, breaking a small amount of hydrogen bonds. Microfibril does not swell, and the porosity does not change. As moisture content increases, water is adsorbed preferentially at the interface, which leads to additional swelling and porosity increase at the interface. Young's and shear moduli decrease importantly due to breaking of h-bonds and screening of the long-range interactions. PMID:26313656

  20. Cellulose-hemicellulose interaction in wood secondary cell-wall

    Science.gov (United States)

    Zhang, Ning; Li, Shi; Xiong, Liming; Hong, Yu; Chen, Youping

    2015-12-01

    The wood cell wall features a tough and relatively rigid fiber reinforced composite structure. It acts as a pressure vessel, offering protection against mechanical stress. Cellulose microfibrils, hemicellulose and amorphous lignin are the three major components of wood. The structure of secondary cell wall could be imagined as the same as reinforced concrete, in which cellulose microfibrils acts as reinforcing steel bar and hemicellulose-lignin matrices act as the concrete. Therefore, the interface between cellulose and hemicellulose/lignin plays a significant role in determine the mechanical behavior of wood secondary cell wall. To this end, we present a molecular dynamics (MD) simulation study attempting to quantify the strength of the interface between cellulose microfibrils and hemicellulose. Since hemicellulose binds with adjacent cellulose microfibrils in various patterns, the atomistic models of hemicellulose-cellulose composites with three typical binding modes, i.e. bridge, loop and random binding modes are constructed. The effect of the shape of hemicellulose chain on the strength of hemicellulose-cellulose composites under shear loadings is investigated. The contact area as well as hydrogen bonds between cellulose and hemicellulose, together with the covalent bonds in backbone of hemicellulose chain are found to be the controlling parameters which determine the strength of the interfaces in the composite system. For the bridge binding model, the effect of shear loading direction on the strength of the cellulose material is also studied. The obtained results suggest that the shear strength of wood-inspired engineering composites can be optimized through maximizing the formations of the contributing hydrogen bonds between cellulose and hemicellulose.

  1. Cellulose Synthases and Synthesis in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Anne Endler; Staffan Persson

    2011-01-01

    Plant cell walls are complex structures composed of high-molecular-weight polysaccharides,proteins,and lignins. Among the wall polysaccharides,cellulose,a hydrogen-bonded β-1,4-linked glucan microfibril,is the main load-bearing wall component and a key precursor for industrial applications. Cellulose is synthesized by large multi-meric cellulose synthase (CesA) complexes,tracking along cortical microtubules at the plasma membrane. The only known components of these complexes are the cellulose synthase proteins. Recent studies have identified tentative interaction partners for the CesAs and shown that the migratory patterns of the CesA complexes depend on phosphorylation status. These advances may become good platforms for expanding our knowledge about cellulose synthesis in the near future. In addition,our current understanding of cellulose chain polymerization in the context of the CesA complex is discussed.

  2. Multi-scale model for the hierarchical architecture of native cellulose hydrogels.

    Science.gov (United States)

    Martínez-Sanz, Marta; Mikkelsen, Deirdre; Flanagan, Bernadine; Gidley, Michael J; Gilbert, Elliot P

    2016-08-20

    The structure of protiated and deuterated cellulose hydrogels has been investigated using a multi-technique approach combining small-angle scattering with diffraction, spectroscopy and microscopy. A model for the multi-scale structure of native cellulose hydrogels is proposed which highlights the essential role of water at different structural levels characterised by: (i) the existence of cellulose microfibrils containing an impermeable crystalline core surrounded by a partially hydrated paracrystalline shell, (ii) the creation of a strong network of cellulose microfibrils held together by hydrogen bonding to form cellulose ribbons and (iii) the differential behaviour of tightly bound water held within the ribbons compared to bulk solvent. Deuterium labelling provides an effective platform on which to further investigate the role of different plant cell wall polysaccharides in cellulose composite formation through the production of selectively deuterated cellulose composite hydrogels. PMID:27178962

  3. Arabidopsis cortical microtubules position cellulose synthase delivery to the plasma membrane and interact with cellulose synthase trafficking compartments.

    NARCIS (Netherlands)

    Gutierrez, R.; Lindeboom, J.J.; Paredez, A.R.; Emons, A.M.C.; Ehrhardt, D.W.

    2009-01-01

    Plant cell morphogenesis relies on the organization and function of two polymer arrays separated by the plasma membrane: the cortical microtubule cytoskeleton and cellulose microfibrils in the cell wall. Studies using in vivo markers confirmed that one function of the cortical microtubule array is t

  4. Mechanism of cellobiose inhibition in cellulose hydrolysis by cellobiohydrolase

    Institute of Scientific and Technical Information of China (English)

    ZHAO; Yue; WU; Bin; YAN; Baixu; GAO; Peiji

    2004-01-01

    An experimental study of cellobiose inhibition in cellulose hydrolysis by synergism of cellobiohydrolyse I and endoglucanase I is presented. Cellobiose is the structural unit of cellulose molecules and also the main product in enzymatic hydrolysis of cellulose. It has been identified that cellobiose can strongly inhibit hydrolysis reaction of cellulase, whereas it has no effect on the adsorption of cellulase on cellulose surface. The experimental data of FT-IR spectra, fluorescence spectrum and circular dichroism suggested that cellobiose can be combined with tryptophan residue located near the active site of cellobiohydrolase and then form steric hindrance, which prevents cellulose molecule chains from diffusing into active site of cellulase. In addition, the molecular conformation of cellobiohydrolase changes after cellobiose binding, which also causes most of the non-productive adsorption. Under these conditions, microfibrils cannot be separated from cellulose chains, thus further hydrolysis of cellulose can hardly proceed.

  5. Technique for the measurement of dimensional changes of natural microfibril materials under variable humidity environments

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jung Myoung [Department of Wood and Paper Science, North Carolina State University, Raleigh, NC 27695-8005 (United States); Heitmann, John A. [Department of Wood and Paper Science, North Carolina State University, Raleigh, NC 27695-8005 (United States); Pawlak, Joel J. [Department of Wood and Paper Science, North Carolina State University, Raleigh, NC 27695-8005 (United States)]. E-mail: jjpawlak@ncsu.edu

    2007-02-15

    An algorithm was developed to analyze the dimensions of line scan data of step-shaped disconitunities acquired with an atomic force microscope. The effect of a number of AFM parameters on the quantitative imaging of step features was discussed. Quantitiative imaging using AFM was shown to be very reproducible as five successive scans of a standard step height grating produced less than 3% variation in measured parameters. A cellulose microfibril, called cellulose aggregate fibril (CAF), with dimensions of {approx}50,000 nm x 2000 nm x 300 nm derived from papermaking fibers was scanned under cyclic relative humdity conditions with the relative humidity starting at 50% then raising to 80% followed by a decrease in the relative humidity to 28%. Changes in the width of the CAF were weakly correlated with changes in the relative humdity, while changes in the height and area of the CAF were positively correlated with the relative humdity. The length of the CAF was negatively correlated with the given relative humdity cycle. These findings have significant implications in paper dimensional stability and the engineering of cellulose micro and nano-fiber composites.

  6. Technique for the measurement of dimensional changes of natural microfibril materials under variable humidity environments

    International Nuclear Information System (INIS)

    An algorithm was developed to analyze the dimensions of line scan data of step-shaped disconitunities acquired with an atomic force microscope. The effect of a number of AFM parameters on the quantitative imaging of step features was discussed. Quantitiative imaging using AFM was shown to be very reproducible as five successive scans of a standard step height grating produced less than 3% variation in measured parameters. A cellulose microfibril, called cellulose aggregate fibril (CAF), with dimensions of ∼50,000 nm x 2000 nm x 300 nm derived from papermaking fibers was scanned under cyclic relative humdity conditions with the relative humidity starting at 50% then raising to 80% followed by a decrease in the relative humidity to 28%. Changes in the width of the CAF were weakly correlated with changes in the relative humdity, while changes in the height and area of the CAF were positively correlated with the relative humdity. The length of the CAF was negatively correlated with the given relative humdity cycle. These findings have significant implications in paper dimensional stability and the engineering of cellulose micro and nano-fiber composites

  7. Comparative Structural and Computational Analysis Supports Eighteen Cellulose Synthases in the Plant Cellulose Synthesis Complex.

    Science.gov (United States)

    Nixon, B Tracy; Mansouri, Katayoun; Singh, Abhishek; Du, Juan; Davis, Jonathan K; Lee, Jung-Goo; Slabaugh, Erin; Vandavasi, Venu Gopal; O'Neill, Hugh; Roberts, Eric M; Roberts, Alison W; Yingling, Yaroslava G; Haigler, Candace H

    2016-01-01

    A six-lobed membrane spanning cellulose synthesis complex (CSC) containing multiple cellulose synthase (CESA) glycosyltransferases mediates cellulose microfibril formation. The number of CESAs in the CSC has been debated for decades in light of changing estimates of the diameter of the smallest microfibril formed from the β-1,4 glucan chains synthesized by one CSC. We obtained more direct evidence through generating improved transmission electron microscopy (TEM) images and image averages of the rosette-type CSC, revealing the frequent triangularity and average cross-sectional area in the plasma membrane of its individual lobes. Trimeric oligomers of two alternative CESA computational models corresponded well with individual lobe geometry. A six-fold assembly of the trimeric computational oligomer had the lowest potential energy per monomer and was consistent with rosette CSC morphology. Negative stain TEM and image averaging showed the triangularity of a recombinant CESA cytosolic domain, consistent with previous modeling of its trimeric nature from small angle scattering (SAXS) data. Six trimeric SAXS models nearly filled the space below an average FF-TEM image of the rosette CSC. In summary, the multifaceted data support a rosette CSC with 18 CESAs that mediates the synthesis of a fundamental microfibril composed of 18 glucan chains. PMID:27345599

  8. Cellulose produced by Gluconacetobacter xylinus strains ATCC 53524 and ATCC 23768: Pellicle formation, post-synthesis aggregation and fiber density.

    Science.gov (United States)

    Lee, Christopher M; Gu, Jin; Kafle, Kabindra; Catchmark, Jeffrey; Kim, Seong H

    2015-11-20

    The pellicle formation, crystallinity, and bundling of cellulose microfibrils produced by bacterium Gluconacetobacter xylinus were studied. Cellulose pellicles were produced by two strains (ATCC 53524 and ATCC 23769) for 1 and 7 days; pellicles were analyzed with scanning electron microscopy (SEM), X-ray diffraction (XRD), vibrational sum-frequency-generation (SFG) spectroscopy, and attenuated total reflectance infrared (ATR-IR) spectroscopy. The bacterial cell population was higher at the surface exposed to air, indicating that the newly synthesized cellulose is deposited at the top of the pellicle. XRD, ATR-IR, and SFG analyses found no significant changes in the cellulose crystallinity, crystal size or polymorphic distribution with the culture time. However, SEM and SFG analyses revealed cellulose macrofibrils produced for 7 days had a higher packing density at the top of the pellicle, compared to the bottom. These findings suggest that the physical properties of cellulose microfibrils are different locally within the bacterial pellicles. PMID:26344281

  9. Biocomposite cellulose-alginate films: promising packaging materials.

    Science.gov (United States)

    Sirviö, Juho Antti; Kolehmainen, Aleksi; Liimatainen, Henrikki; Niinimäki, Jouko; Hormi, Osmo E O

    2014-05-15

    Biocomposite films based on cellulose and alginate were produced using unmodified birch pulp, microfibrillated cellulose (MFC), nanofibrillated cellulose (NFC) and birch pulp derivate, nanofibrillated anionic dicarboxylic acid cellulose (DCC), having widths of fibres ranging from 19.0 μm to 25 nm as cellulose fibre materials. Ionically cross-linked biocomposites were produced using Ca(2+) cross-linking. Addition of micro- and nanocelluloses as a reinforcement increased the mechanical properties of the alginate films remarkably, e.g. addition of 15% of NFC increased a tensile strength of the film from 70.02 to 97.97 MPa. After ionic cross-linking, the tensile strength of the film containing 10% of DCC was increased from 69.63 to 125.31 MPa. The biocomposite films showed excellent grease barrier properties and reduced water vapour permeability (WVP) after the addition of cellulose fibres, except when unmodified birch pulp was used. PMID:24423542

  10. Isolation of Cellulose Nanofibers: Effect of Biotreatment on Hydrogen Bonding Network in Wood Fibers

    OpenAIRE

    Sreekumar Janardhnan; Mohini Sain

    2011-01-01

    The use of cellulose nanofibres as high-strength reinforcement in nano-biocomposites is very enthusiastically being explored due to their biodegradability, renewability, and high specific strength properties. Cellulose, through a regular network of inter- and intramolecular hydrogen bonds, is organized into perfect stereoregular configuration called microfibrils which further aggregate to different levels to form the fibre. Intermolecular hydrogen bonding at various levels, especially at the ...

  11. Enzymic modification of cellulose-xyloglucan networks - implifications for fruit juice processing.

    OpenAIRE

    Vincken, J.P.

    1996-01-01

    Xyloglucans play an important role in connecting cellulose microfibrils in the primary coli wall of plants, and the resulting cellulose-xyloglucan network is thought to determine the strength of these walls. Xyloglucans were isolated from apple fruit and potato tuber cell wall material by alkaline extraction and their primary structures were determined. Major differences between these two polysaccharides were their degree of backbone branching and the presence of fucosyl and arabinosyl residu...

  12. Isolation and characterization of two cellulose morphology mutants of Gluconacetobacter hansenii ATCC23769 producing cellulose with lower crystallinity.

    Science.gov (United States)

    Deng, Ying; Nagachar, Nivedita; Fang, Lin; Luan, Xin; Catchmark, Jeffrey M; Tien, Ming; Kao, Teh-hui

    2015-01-01

    Gluconacetobacter hansenii, a Gram-negative bacterium, produces and secrets highly crystalline cellulose into growth medium, and has long been used as a model system for studying cellulose synthesis in higher plants. Cellulose synthesis involves the formation of β-1,4 glucan chains via the polymerization of glucose units by a multi-enzyme cellulose synthase complex (CSC). These glucan chains assemble into ordered structures including crystalline microfibrils. AcsA is the catalytic subunit of the cellulose synthase enzymes in the CSC, and AcsC is required for the secretion of cellulose. However, little is known about other proteins required for the assembly of crystalline cellulose. To address this question, we visually examined cellulose pellicles formed in growth media of 763 individual colonies of G. hansenii generated via Tn5 transposon insertion mutagenesis, and identified 85 that produced cellulose with altered morphologies. X-ray diffraction analysis of these 85 mutants identified two that produced cellulose with significantly lower crystallinity than wild type. The gene disrupted in one of these two mutants encoded a lysine decarboxylase and that in the other encoded an alanine racemase. Solid-state NMR analysis revealed that cellulose produced by these two mutants contained increased amounts of non-crystalline cellulose and monosaccharides associated with non-cellulosic polysaccharides as compared to the wild type. Monosaccharide analysis detected higher percentages of galactose and mannose in cellulose produced by both mutants. Field emission scanning electron microscopy showed that cellulose produced by the mutants was unevenly distributed, with some regions appearing to contain deposition of non-cellulosic polysaccharides; however, the width of the ribbon was comparable to that of normal cellulose. As both lysine decarboxylase and alanine racemase are required for the integrity of peptidoglycan, we propose a model for the role of peptidoglycan in the

  13. Isolation and characterization of two cellulose morphology mutants of Gluconacetobacter hansenii ATCC23769 producing cellulose with lower crystallinity.

    Directory of Open Access Journals (Sweden)

    Ying Deng

    Full Text Available Gluconacetobacter hansenii, a Gram-negative bacterium, produces and secrets highly crystalline cellulose into growth medium, and has long been used as a model system for studying cellulose synthesis in higher plants. Cellulose synthesis involves the formation of β-1,4 glucan chains via the polymerization of glucose units by a multi-enzyme cellulose synthase complex (CSC. These glucan chains assemble into ordered structures including crystalline microfibrils. AcsA is the catalytic subunit of the cellulose synthase enzymes in the CSC, and AcsC is required for the secretion of cellulose. However, little is known about other proteins required for the assembly of crystalline cellulose. To address this question, we visually examined cellulose pellicles formed in growth media of 763 individual colonies of G. hansenii generated via Tn5 transposon insertion mutagenesis, and identified 85 that produced cellulose with altered morphologies. X-ray diffraction analysis of these 85 mutants identified two that produced cellulose with significantly lower crystallinity than wild type. The gene disrupted in one of these two mutants encoded a lysine decarboxylase and that in the other encoded an alanine racemase. Solid-state NMR analysis revealed that cellulose produced by these two mutants contained increased amounts of non-crystalline cellulose and monosaccharides associated with non-cellulosic polysaccharides as compared to the wild type. Monosaccharide analysis detected higher percentages of galactose and mannose in cellulose produced by both mutants. Field emission scanning electron microscopy showed that cellulose produced by the mutants was unevenly distributed, with some regions appearing to contain deposition of non-cellulosic polysaccharides; however, the width of the ribbon was comparable to that of normal cellulose. As both lysine decarboxylase and alanine racemase are required for the integrity of peptidoglycan, we propose a model for the role of

  14. Cellulose synthesis inhibition, cell expansion, and patterns of cell wall deposition in Nitella internodes

    International Nuclear Information System (INIS)

    The authors have investigated the pattern of wall deposition and maturation and correlated it with cell expansion and cellulose biosynthesis. The herbicide 2,6-dichlorobenzonitrile (DCB) was found to be a potent inhibitor of cellulose synthesis, but not of cell expansion in Nitella internodal cells. Although cellulose synthesis is inhibited during DCB treatment, matrix substances continue to be synthesized and deposited. The inhibition of cellulose microfibril deposition can be demonstrated by various techniques. These results demonstrate that matrix deposition is by apposition, not by intussusception, and that the previously deposited wall moves progressively outward while stretching and thinning as a result of cell expansion

  15. Modification of bacterial cellulose through exposure to the rotating magnetic field.

    Science.gov (United States)

    Fijałkowski, Karol; Żywicka, Anna; Drozd, Radosław; Niemczyk, Agata; Junka, Adam Feliks; Peitler, Dorota; Kordas, Marian; Konopacki, Maciej; Szymczyk, Patrycja; Fray, Mirosława El; Rakoczy, Rafał

    2015-11-20

    The aim of the study was to assess the influence of rotating magnetic field (RMF) on production rate and quality parameters of bacterial cellulose synthetized by Glucanacetobacter xylinus. Bacterial cultures were exposed to RMF (frequency f=50Hz, magnetic induction B=34mT) for 72h at 28°C. The study revealed that cellulose obtained under RMF influence displayed higher water absorption, lower density and less interassociated microfibrils comparing to unexposed control. The application of RMF significantly increased the amount of obtained wet cellulose pellicles but decreased the weight and thickness of dry cellulose. Summarizing, the exposure of cellulose-synthesizing G. xylinus to RMF alters cellulose biogenesis and may offer a new biotechnological tool to control this process. As RMF-modified cellulose displays better absorbing properties comparing to non-modified cellulose, our finding, if developed, may find application in the production of dressings for highly exudative wounds. PMID:26344254

  16. Loosening Xyloglucan Accelerates the Enzymatic Degradation of Cellulose in Wood

    Institute of Scientific and Technical Information of China (English)

    Rumi Kaida; Tomomi Kaku; Kei'ichi Baba; Masafumi Oyadomari; Takashi Watanabe; Koji Nishida; Toshiji Kanaya; Ziv Shani; Oded Shoseyov; Takahisa Hayashi

    2009-01-01

    In order to create trees in which cellulose, the most abundant component in biomass, can be enzymatically hydrolyzed highly for the production of bioethanol, we examined the saccharification of xylem from several transgenic poplars, each overexpressing either xyloglucanase, cellulase, xylanase, or galactanase. The level of cellulose degradation achieved by a cellulase preparation was markedly greater in the xylem overexpressing xyloglucanase and much greater in the xylems overexpressing xylanase and cellulase than in the xylem of the wild-type plant. Although a high degree of degradation occurred in all xylems at all loci, the crystalline region of the cellulose microfibrUs was highly degraded in the xylem overexpressing xyloglucanase. Since the complex between microfibrils and xyloglucans could be one region that is particularly resistant to cellulose degradation, loosening xyloglucan could facilitate the enzymatic hydrolysis of cellulose in wood.

  17. Non-destructive determination of moisture content and micro-fibril angle of wood using a poly-chromatic X-ray beam theoretical and experimental approach

    International Nuclear Information System (INIS)

    Non-destructive determination of moisture content and micro-fibril angle are important stakes for the sciences of the wood because these two parameters influence strongly the macroscopic behavior of the wood. For example, the shrinkage, the mechanical properties, the thermal and acoustic conductivity are dependent on the moisture content and their anisotropic character is largely governed by the micro-fibril angle. We used the light difference between X-ray mass attenuation coefficient for the water and for the wood in transmission. Regrettably, the results show that this difference between X-ray mass attenuation coefficient is insufficient to allow the precise measurement of the moisture content.In spite of this, the coherent scattering shows sensitive effects. So, by using a poly-energetic beam and a spectrometric system, we were able to discriminate between the crystalline constituent (cellulose) of the amorphous constituent (water) in a sample of wet wood, because for a given angle these phases scatter in different energy. Besides, the device created allowed us to study the crystalline phase of the wood. We were able to confront experimental profiles of diffraction with theoretical profiles of diffraction, obtained by means of a rigorous simulation, in the objective to estimate the average micro-fibril angle and its standard deviation. (author)

  18. Isolation of Cellulose Nanofibers: Effect of Biotreatment on Hydrogen Bonding Network in Wood Fibers

    Directory of Open Access Journals (Sweden)

    Sreekumar Janardhnan

    2011-01-01

    Full Text Available The use of cellulose nanofibres as high-strength reinforcement in nano-biocomposites is very enthusiastically being explored due to their biodegradability, renewability, and high specific strength properties. Cellulose, through a regular network of inter- and intramolecular hydrogen bonds, is organized into perfect stereoregular configuration called microfibrils which further aggregate to different levels to form the fibre. Intermolecular hydrogen bonding at various levels, especially at the elementary level, is the major binding force that one need to overcome to reverse engineer these fibres into their microfibrillar level. This paper briefly describes a novel enzymatic fibre pretreatment developed to facilitate the isolation of cellulose microfibrils and explores effectiveness of biotreatment on the intermolecular and intramolecular hydrogen bonding in the fiber. Bleached Kraft Softwood Pulp was treated with a fungus (OS1 isolated from elm tree infected with Dutch elm disease. Cellulose microfibrils were isolated from these treated fibers by high-shear refining. The % yield of nanofibres and their diameter distribution (<50 nm isolated from the bio-treated fibers indicated a substantial increase compared to those isolated from untreated fibers. FT-IR spectral analysis indicated a reduction in the density of intermolecular and intramolecular hydrogen bonding within the fiber. X-ray spectrometry indicated a reduction in the crystallinity. Hydrogen bond-specific enzyme and its application in the isolation of new generation cellulose nano-fibers can be a huge leap forward in the field of nano-biocomposites.

  19. Nanofibrillar cellulose films for controlled drug delivery.

    Science.gov (United States)

    Kolakovic, Ruzica; Peltonen, Leena; Laukkanen, Antti; Hirvonen, Jouni; Laaksonen, Timo

    2012-10-01

    Nanofibrillar cellulose (NFC) (also referred to as cellulose nanofibers, nanocellulose, microfibrillated, or nanofibrillated cellulose) has gotten recent and wide attention in various research areas. Here, we report the application of nanofibrillar cellulose as a matrix-former material for long-lasting (up to three months) sustained drug delivery. Film-like matrix systems with drug loadings between 20% and 40% were produced by a filtration method. This simple production method had an entrapment efficacy>90% and offers a possibility for the film thickness adjustment as well as applicability in the incorporation of heat sensitive compounds. The films had excellent mechanical properties suitable for easy handling and shape tailoring of the drug release systems. They were characterized in terms of the internal morphology, and the physical state of the encapsulated drug. The drug release was assessed by dissolution tests, and suitable mathematical models were used to explain the releasing kinetics. The drug release was sustained for a three month period with very close to zero-order kinetics. It is assumed that the nanofibrillar cellulose film sustains the drug release by forming a tight fiber network around the incorporated drug entities. The results indicate that the nanofibrillar cellulose is a highly promising new material for sustained release drug delivery applications. PMID:22750440

  20. Visualization of Trichoderma reesei Cellobiohydrolase I and Endoglucanase I on Aspen Cellulose by Using Monoclonal Antibody-Colloidal Gold Conjugates

    OpenAIRE

    Nieves, Rafael A.; Robert P. Ellis; Todd, Roberta J.; Johnson, Timothy J. A.; Grohmann, Karel; Himmel, Michael E.

    1991-01-01

    Monoclonal antibodies (MAbs) specific for cellobiohydrolase I (CBH I) and endoglucanase I (EG I) were conjugated to 10- and 15-nm colloidal gold particles, respectively. The binding of CBH I and EG I was visualized by utilizing the MAb-colloidal gold probes. The visualization procedure involved immobilization of cellulose microfibrils on copper electron microscopy grids, incubation of the cellulose-coated grids with cellulase(s), binding of MAb-colloidal gold conjugates to cellulase(s), and v...

  1. Liquid crystal-type assembly of native cellulose-glucuronoxylans extracted from plant cell wall.

    Science.gov (United States)

    Reis, D; Vian, B; Chanzy, H; Roland, J C

    1991-01-01

    In numerous plant cell walls, the cellulose microfibrils are arranged in a helicoidal pattern which has been considered as an analog to a cholesteric order. Here, we report on the spontaneous helicoidal organization which occurs in acellular conditions from aqueous suspensions of cellulose. The cellulosic mucilage of mature seeds of quince (Cydonia oblonga L) was studied both in situ (pre-release mucilage) and after water extraction and in in vitro re-assembly (prolonged high speed ultracentrifugation, further progressive dehydration and embedding in LR White methacrylate or hydrosoluble melamine resin). The cellulosic component was characterized by the use of cellobiohydrolase (CBH1) bound to colloidal gold, and the glucuronic acid residues of the xylan matrix were characterized by the use of cationised gold. Inside the seeds, the pre-release mucilage is mostly helicoidal, with the occurrence of more or less ordered domains, which indicate a fluid organization relevant to an actual liquid crystal state. Cytochemical tests revealed the tight association between cellulose and glucuronoxylans, the latter constituting a charged coat around each microfibril. Following the hydration of the seed, a cellulosic suspension was extracted in which microfibrils were totally dispersed. The progressive dehydration of the suspension gave rise to concentrated viscous drops. Ultrastructural observations revealed the occurrence of multidomain organization, from non-ordered to cholesteric-like regions, revealing that the mucilage is at the same time crystalline and liquid. This constitutes the first demonstration that liquid crystal type assemblies can arise from crystalline and biological cellulose in aqueous suspension. It strengthens the hypothesis that a transient liquid crystal state must occur during the cellulose ordering. The possible morphogenetic role of the glucuronoxylans in the cholesteric organization of the cellulose is discussed. PMID:1804508

  2. Macromolecular organization of xyloglucan and cellulose in pea epicotyls

    International Nuclear Information System (INIS)

    Xyloglucan is known to occur widely in the primary cell walls of higher plants. This polysaccharide in most dicots possesses a cellulose-like main chain with three of every four consecutive residues substituted with xylose and minor addition of other sugars. Xyloglucan and cellulose metabolism is regulated by different processes; since different enzyme systems are probably required for the synthesis of their 1,4-β-linkages. A macromolecular complex composed of xyloglucan and cellulose only was obtained from elongating regions of etiolated pea stems. It was examined by light microscopy using iodine staining, by radioautography after labeling with [3H]fructose, by fluorescence microscopy using a fluorescein-lectin (fructose-binding) as probe, and by electron microscopy after shadowing. The techniques all demonstrated that the macromolecule was present in files of cell shapes, referred to here as cell-wall ghosts, in which xyloglucan was localized both on and between the cellulose microfibrils

  3. Influence of microfibril angle on the thermal and dynamic-mechanical properties of Acacia Mangium wood using X-ray diffraction and dynamics-mechanical test

    International Nuclear Information System (INIS)

    The term microfibril angle, MFA in wood science refers to the angle between the direction of the helical windings of cellulose microfibrils in the secondary cell wall, S2 layer of fibers and tracheids and the long axis of the cell. In this study, the mean MFA of the cell walls were determined for thin samples of thickness 200.0 μm from pith and outwards, for eight ages of Acacia Mangium wood. The determination of MFA was based on a diffraction pattern arising from cellulose crystal planes of the type 002 generated by x-ray diffraction and recorded using an electronic detector. The results show an inversely relationship between MFA and age of tree in Acacia mangium wood. MFA decreased from 26.13 degree at age 3 year-old to 0.20 degree at tree of age 15 year-old for the pith region. The most significant drop occurred from 16.14 degree at age 7 year-old to 11.30 degree at age 9 year-old. an inversely relationship between MFA and storage modulus E' was evidence in Acacia mangium at age 10 year-old. The results showed that about 76.22 % variation of loss modulus E was attributed to the MFA, while about 66.4 % of the variation of glass transition Tg was explained by MFA under the same experimental conditions. (author)

  4. Wetting kinetics of oil mixtures on fluorinated model cellulose surfaces.

    Science.gov (United States)

    Aulin, Christian; Shchukarev, Andrei; Lindqvist, Josefina; Malmström, Eva; Wågberg, Lars; Lindström, Tom

    2008-01-15

    The wetting of two different model cellulose surfaces has been studied; a regenerated cellulose (RG) surface prepared by spin-coating, and a novel multilayer film of poly(ethyleneimine) and a carboxymethylated microfibrillated cellulose (MFC). The cellulose films were characterized in detail using atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). AFM indicates smooth and continuous films on a nanometer scale and the RMS roughness of the RG cellulose and MFC surfaces was determined to be 3 and 6 nm, respectively. The cellulose films were modified by coating with various amounts of an anionic fluorosurfactant, perfluorooctadecanoic acid, or covalently modified with pentadecafluorooctanyl chloride. The fluorinated cellulose films were used to follow the spreading mechanisms of three different oil mixtures. The viscosity and surface tension of the oils were found to be essential parameters governing the spreading kinetics on these surfaces. XPS and dispersive surface energy measurements were made on the cellulose films coated with perfluorooctadecanoic acid. A strong correlation was found between the surface concentration of fluorine, the dispersive surface energy and the contact angle of castor oil on the surface. A dispersive surface energy less than 18 mN/m was required in order for the cellulose surface to be non-wetting (theta e>90 degrees ) by castor oil. PMID:17964593

  5. Understanding the Role of Physical Properties of Cellulose on Its Hydrolyzability by Cellulases

    Science.gov (United States)

    O'Dell, Patrick Jonathan

    Cellulose has long been explored as a potential feedstock for biofuel, however the recalcitrance of cellulose makes its conversion into biofuel much more challenging and economically unfavorable compared to well-established processes for converting starch or sugar feedstocks into biofuel. Enzymes capable of hydrolyzing cellulose into soluble sugars, glucose and cellobiose, have been found to work processively along cellulose microfibrils starting from reducing end groups. For this study, cellulose was produced and purified in-house from Gluconacetobacter xylinum cultures, and characterized by quantifying functional groups (aldehyde, ketone, and carboxyl groups) to determine the extent of oxidation of cellulose due to the processing steps. The main goal of this study was to look at the impacts of ultrasonication on cellulose's structure and the enzymatic hydrolyzability of cellulose. A completely randomized experimental design was used to test the effect of ultrasonication time and amplitude (intensity) on changes in cellulose fibril length, degree of polymerization, and rates and extents of hydrolysis. Results indicated that sonication time does significantly impact both the fibril length and average degree of polymerization of cellulose. The impact of ultrasonication on the hydrolyzability of cellulose by commercial cellulase and beta-glucosidase preparations could not be effectively resolved due to high variability in the experimental results. These studies serve as a basis for future studies understanding the role of cellulose microstructure in the mechanism of cellulase hydrolysis of cellulose.

  6. Cellulose-Microtubule Uncoupling Proteins Prevent Lateral Displacement of Microtubules during Cellulose Synthesis in Arabidopsis.

    Science.gov (United States)

    Liu, Zengyu; Schneider, Rene; Kesten, Christopher; Zhang, Yi; Somssich, Marc; Zhang, Youjun; Fernie, Alisdair R; Persson, Staffan

    2016-08-01

    Cellulose is the most abundant biopolymer on Earth and is the major contributor to plant morphogenesis. Cellulose is synthesized by plasma membrane-localized cellulose synthase complexes (CSCs). Nascent cellulose microfibrils become entangled in the cell wall, and further catalysis therefore drives the CSC forward through the membrane: a process guided by cortical microtubules via the protein CSI1/POM2. Still, it is unclear how the microtubules can withstand the forces generated by the motile CSCs to effectively direct CSC movement. Here, we identified a family of microtubule-associated proteins, the cellulose synthase-microtubule uncouplings (CMUs), that located as static puncta along cortical microtubules. Functional disruption of the CMUs caused lateral microtubule displacement and compromised microtubule-based guidance of CSC movement. CSCs that traversed the microtubules interacted with the microtubules via CSI1/POM2, which prompted the lateral microtubule displacement. Hence, we have revealed how microtubules can withstand the propulsion of the CSCs during cellulose biosynthesis and thus sustain anisotropic plant cell growth. PMID:27477947

  7. Cellulose Structural Polymorphism in Plant Primary Cell Walls Investigated by High-Field 2D Solid-State NMR Spectroscopy and Density Functional Theory Calculations.

    Science.gov (United States)

    Wang, Tuo; Yang, Hui; Kubicki, James D; Hong, Mei

    2016-06-13

    The native cellulose of bacterial, algal, and animal origins has been well studied structurally using X-ray and neutron diffraction and solid-state NMR spectroscopy, and is known to consist of varying proportions of two allomorphs, Iα and Iβ, which differ in hydrogen bonding, chain packing, and local conformation. In comparison, cellulose structure in plant primary cell walls is much less understood because plant cellulose has lower crystallinity and extensive interactions with matrix polysaccharides. Here we have combined two-dimensional magic-angle-spinning (MAS) solid-state nuclear magnetic resonance (solid-state NMR) spectroscopy at high magnetic fields with density functional theory (DFT) calculations to obtain detailed information about the structural polymorphism and spatial distributions of plant primary-wall cellulose. 2D (13)C-(13)C correlation spectra of uniformly (13)C-labeled cell walls of several model plants resolved seven sets of cellulose chemical shifts. Among these, five sets (denoted a-e) belong to cellulose in the interior of the microfibril while two sets (f and g) can be assigned to surface cellulose. Importantly, most of the interior cellulose (13)C chemical shifts differ significantly from the (13)C chemical shifts of the Iα and Iβ allomorphs, indicating that plant primary-wall cellulose has different conformations, packing, and hydrogen bonding from celluloses of other organisms. 2D (13)C-(13)C correlation experiments with long mixing times and with water polarization transfer revealed the spatial distributions and matrix-polysaccharide interactions of these cellulose structures. Celluloses f and g are well mixed chains on the microfibril surface, celluloses a and b are interior chains that are in molecular contact with the surface chains, while cellulose c resides in the core of the microfibril, outside spin diffusion contact with the surface. Interestingly, cellulose d, whose chemical shifts differ most significantly from those of

  8. Development of the metrology and imaging of cellulose nanocrystals

    International Nuclear Information System (INIS)

    The development of metrology for nanoparticles is a significant challenge. Cellulose nanocrystals (CNCs) are one group of nanoparticles that have high potential economic value but present substantial challenges to the development of the measurement science. Even the largest trees owe their strength to this newly appreciated class of nanomaterials. Cellulose is the world's most abundant natural, renewable, biodegradable polymer. Cellulose occurs as whisker-like microfibrils that are biosynthesized and deposited in plant material in a continuous fashion. The nanocrystals are isolated by hydrolyzing away the amorphous segments leaving the acid resistant crystalline fragments. Therefore, the basic raw material for new nanomaterial products already abounds in nature and is available to be utilized in an array of future materials. However, commercialization requires the development of efficient manufacturing processes and nanometrology to monitor quality. This paper discusses some of the instrumentation, metrology and standards issues associated with the ramping up for production and use of CNCs

  9. Poly(lactic acid) /kenaf fiber composites: effect of microfibrillated cellulose on interface-sensitive properties

    OpenAIRE

    Bogoeva-Gaceva, Gordana; Dimeski, Dimko; Srebrenkoska, Vineta

    2012-01-01

    Ecologically friendly composites consist of a biodegradable matrix and natural fibers (such as cotton, sisal, kenaf, bamboo, etc.), which have been successfully used for reinforcing of different polymer matrices. Quite recently, poly(lactic acid) (PLA) was used as a matrix for biodegradable eco-composites. Natural fibers (NFs) offer both cost savings and a reduction in density when compared to glass fibers. Though the strength of NFs is not as great as glass, the specific properti...

  10. Loosenin, a novel protein with cellulose-disrupting activity from Bjerkandera adusta

    OpenAIRE

    Segovia Lorenzo; Cuervo-Soto Laura I; Martínez-Anaya Claudia; Quiroz-Castañeda Rosa E; Folch-Mallol Jorge L

    2011-01-01

    Abstract Background Expansins and expansin-like proteins loosen cellulose microfibrils, possibly through the rupture of intramolecular hydrogen bonds. Together with the use of lignocellulolytic enzymes, these proteins are potential molecular tools to treat plant biomass to improve saccharification yields. Results Here we describe a new type of expansin-related fungal protein that we have called loosenin. Its corresponding gene, loos1, from the basidiomycete Bjerkandera adusta, was cloned and ...

  11. Cellulose synthesis in two secondary cell wall processes in a single cell type

    OpenAIRE

    Mendu, Venugopal; Stork, Jozsef; Harris, Darby; DeBolt, Seth

    2011-01-01

    Plant cells have a rigid cell wall that constrains internal turgor pressure yet extends in a regulated and organized manner to allow the cell to acquire shape. The primary load-bearing macromolecule of a plant cell wall is cellulose, which forms crystalline microfibrils that are organized with respect to a cell's function and shape requirements. A primary cell wall is deposited during expansion whereas secondary cell wall is synthesized post expansion during differentiation. A complex form of...

  12. Mechanical Properties of Rotationally Molded PET Microfibril Reinforced Composites

    Science.gov (United States)

    Lin, R. J. T.; Bhattacharyya, D.; Fakirov, S.

    Being a fast growing plastic manufacturing industry, rotational molding has been using the linear polyethylenes extensively as the raw material. As these materials have shown insufficient mechanical properties for certain applications where strength and stiffness of the products are the main concerns, worldwide rotational molders have expressed a need for stronger and stiffer materials to be available for rotomolding. A possible attractive solution may be the recently developed microfibril reinforced composites (MFCs). Blends of linear medium density polyethylene/polyethylene terephthalate (LMDPE/PET) with an MFC structure are manufactured on a commercial-scale set-up and thereafter used in rotational molding. The samples are characterized morphologically and tested mechanically. The results obtained show that the MFC-concept has good application opportunities in the polymer processing including rotational molding.

  13. Evaluation of drug interactions with nanofibrillar cellulose.

    Science.gov (United States)

    Kolakovic, Ruzica; Peltonen, Leena; Laukkanen, Antti; Hellman, Maarit; Laaksonen, Päivi; Linder, Markus B; Hirvonen, Jouni; Laaksonen, Timo

    2013-11-01

    Nanofibrillar cellulose (NFC) (also referred to as cellulose nanofibers, nanocellulose, microfibrillated, or nanofibrillated cellulose) has recently gotten wide attention in various research areas and it has also been studied as excipient in formulation of the pharmaceutical dosage forms. Here, we have evaluated the interactions between NFC and the model drugs of different structural characteristics (size, charge, etc.). The series of permeation studies were utilized to evaluate the ability of the drugs in solution to diffuse through the thin, porous, dry NFC films. An incubation method was used to determine capacity of binding of chosen model drugs to NFC as well as isothermal titration calorimetry (ITC) to study thermodynamics of the binding process. A genetically engineered fusion protein carrying double cellulose binding domain was used as a positive control since its affinity and capacity of binding for NFC have already been reported. The permeation studies revealed the size dependent diffusion rate of the model drugs through the NFC films. The results of both binding and ITC studies showed that the studied drugs bind to the NFC material and indicated the pH dependence of the binding and electrostatic forces as the main mechanism. PMID:23774185

  14. Microfibril angle variability in Masson Pine (Pinus massoniana Lamb.) using X-ray diffraction

    Institute of Scientific and Technical Information of China (English)

    Zhang Bo; Fei Ben-hua; Yu Yan; Zhao Rong-jun

    2007-01-01

    The microfibril angle of fiber walls is an ultra-microscopic feature affecting the performance of wood products. It is therefore essential to get more definitive information to improve selection and utilization. X-ray diffraction is a rapid method for measuring micro fibril angles. In this paper, the variability of microfibril angle in plantation-grown Masson pine was investigated by peak-fitting method. This method was compared with the traditional hand-drawn method, 40% peak height method and half peak height method. X-ray diffraction measurements indicated that the microfibril angle changed as a function of the position in the tree.The mean micro fibril angle decreased more gradually as the distance increased from the pith and reached the same level in mature wood. The microfibril angle also seemed to decrease clearly from the base upward. Differences of angle-intensity curves between heartwood and sapwood were also examined.

  15. WATER RETENTION VALUE MEASUREMENTS OF CELLULOSIC MATERIALS USING A CENTRIFUGE TECHNIQUE

    Directory of Open Access Journals (Sweden)

    Jinxin Wang

    2010-07-01

    Full Text Available A centrifugal method has been modified and applied to the assessment of water retention value (WRV in cellulosic materials. Microcrystalline cellulose (MCC, small particles/fibrils isolated from MCC using high-pressure homogenizer, and pulp fibers saturated in water were centrifuged at different speeds and times with filter paper and/or a membrane acting as the filter in the WRV measurement setup. As centrifugal speed, time, and filter pore-size increased, lower WRVs were obtained. Smaller MCC particles/fibrils retained more water than the as-received MCC and pulp fibers. The results are useful for WRV measurements of cellulosic materials, especially for microfibrillated cellulose and small cellulosic fibrils.

  16. Cellulosic Bionanocomposites: A Review of Preparation, Properties and Applications

    Directory of Open Access Journals (Sweden)

    Alain Dufresne

    2010-12-01

    Full Text Available Cellulose is the most abundant biomass material in nature. Extracted from natural fibers, its hierarchical and multi-level organization allows different kinds of nanoscaled cellulosic fillers—called cellulose nanocrystals or microfibrillated cellulose (MFC—to be obtained. Recently, such cellulose nanoparticles have been the focus of an exponentially increasing number of works or reviews devoted to understanding such materials and their applications. Major studies over the last decades have shown that cellulose nanoparticles could be used as fillers to improve mechanical and barrier properties of biocomposites. Their use for industrial packaging is being investigated, with continuous studies to find innovative solutions for efficient and sustainable systems. Processing is more and more important and different systems are detailed in this paper depending on the polymer solubility, i.e., (i hydrosoluble systems, (ii non-hydrosoluble systems, and (iii emulsion systems. This paper intends to give a clear overview of cellulose nanoparticles reinforced composites with more than 150 references by describing their preparation, characterization, properties and applications.

  17. Consequences of Marfan mutations to expression of fibrillin gene and to the structure of microfibrils

    Energy Technology Data Exchange (ETDEWEB)

    Peltonen, L.; Karttunen, L.; Rantamaeki, T. [NPHI, Helsinki (Finland)] [and others

    1994-09-01

    Marfan syndrome (MFS) is a dominantly inherited connective tissue disorder which is caused by mutations in the fibrillin-1 gene (FBN1). Over 40 family-specific FBN1 mutations have been identified. We have characterized 18 different heterozygous mutations including amino acid substitutions, premature stop, and splicing defects leading to deletions or one insertion, and one compound heterozygote with two differently mutated FBN1 alleles inherited from his affected parents. To unravel the consequences of FBN1 mutations to the transcription of FBN1 gene, we have measured the steady state levels of mRNA transcribed from the normal and mutated alleles. The missense mutations do not affect the transcription of the allele while the nonsense mutation leads to lower steady state amount of mutated allele. For the dissection of molecular pathogenesis of FBN1 mutations we have performed rotary shadowing of the microfibrils produced by the cell cultures from MFS patients. The cells from the neonatal patients with established mutations produced only disorganized fibrillin aggregates but no clearly defined microfibrils could be detected, suggesting a major role of this gene region coding for exons 24-26 in stabilization and organization of the bead structure of microfibrils. From the cells of a rare compound heterozygote case carrying two different mutations, no detectable microfibrils could be detected whereas the cells of his parents with heterozygous mutations were able to form identifiable but disorganized microfibrils. In the cells of an MFS case caused by a premature stop removing the C-terminus of fibrillin, the microfibril assembly takes place but the appropriate packing of the microfibrils is disturbed suggesting that C-terminae are actually located within the interbead domain of the microfibrils.

  18. How recombinant swollenin from Kluyveromyces lactis affects cellulosic substrates and accelerates their hydrolysis

    Directory of Open Access Journals (Sweden)

    Jäger Gernot

    2011-09-01

    Full Text Available Abstract Background In order to generate biofuels, insoluble cellulosic substrates are pretreated and subsequently hydrolyzed with cellulases. One way to pretreat cellulose in a safe and environmentally friendly manner is to apply, under mild conditions, non-hydrolyzing proteins such as swollenin - naturally produced in low yields by the fungus Trichoderma reesei. To yield sufficient swollenin for industrial applications, the first aim of this study is to present a new way of producing recombinant swollenin. The main objective is to show how swollenin quantitatively affects relevant physical properties of cellulosic substrates and how it affects subsequent hydrolysis. Results After expression in the yeast Kluyveromyces lactis, the resulting swollenin was purified. The adsorption parameters of the recombinant swollenin onto cellulose were quantified for the first time and were comparable to those of individual cellulases from T. reesei. Four different insoluble cellulosic substrates were then pretreated with swollenin. At first, it could be qualitatively shown by macroscopic evaluation and microscopy that swollenin caused deagglomeration of bigger cellulose agglomerates as well as dispersion of cellulose microfibrils (amorphogenesis. Afterwards, the effects of swollenin on cellulose particle size, maximum cellulase adsorption and cellulose crystallinity were quantified. The pretreatment with swollenin resulted in a significant decrease in particle size of the cellulosic substrates as well as in their crystallinity, thereby substantially increasing maximum cellulase adsorption onto these substrates. Subsequently, the pretreated cellulosic substrates were hydrolyzed with cellulases. Here, pretreatment of cellulosic substrates with swollenin, even in non-saturating concentrations, significantly accelerated the hydrolysis. By correlating particle size and crystallinity of the cellulosic substrates with initial hydrolysis rates, it could be shown that

  19. A Analysis of Molecular Dynamics in Water-Cellulose Systems by Pulsed NMR

    Science.gov (United States)

    Hale, Michael Edward

    1990-01-01

    This thesis presents important advances in the application of Nuclear Magnetic Resonance (NMR) in three different areas: experimental apparatus, data analysis techniques in heterogeneous systems, and understanding of the determinants of the water relaxation in water-cellulose systems. A microprocessor-based pulse programmer is described which can conveniently produce virtually any conceivable pulse sequence, is synchronized with the spectrometer rf source, and is suitable for external computer control and automated data acquisition. A special programming language was implemented for use in the pulse programmer to allow it to be controlled by simple strings of ASCII characters. The common use of models based on a distribution of correlation times to analyze NMR relaxation time data in heterogeneous systems has been critically examined. Serious difficulties of principle in such analyses have been found. An adaptive numerical integration strategy is necessary for accurate results. Nonlinear least squares analysis of the relaxation data requires the use of slower, but more stable techniques than those considered standard. A single fit requires a daunting amount of computing under these conditions. These numerical techniques lead to a unique set of parameters in cases where the error on the data is very small. However, when data with reasonable experimental errors are analyzed, the fitting routines become sensitive to the starting parameters. The usefulness of a distribution of correlation times model for routine analysis of relaxation data in heterogeneous systems must be seriously questioned. NMR relaxation in three systems is analyzed: (a) dry Sigmacell cellulose and samples hydrated with H _2O; (b) deuterated Sigmacell 50 hydrated with D_2O; and (c) microfibrillated cellulose with high water content (less than 3% by weight cellulose). Two similar models are considered to explain T_1 and T_2 data. Both adequately describe the data. The first is an anisotropic motion

  20. Cellulose is not just cellulose

    DEFF Research Database (Denmark)

    Hidayat, Budi Juliman; Felby, Claus; Johansen, Katja S.;

    2012-01-01

    Most secondary plant cell walls contain irregular regions known as dislocations or slip planes. Under industrial biorefining conditions dislocations have recently been shown to play a key role during the initial phase of the enzymatic hydrolysis of cellulose in plant cell walls. In this review we...... not regions where free cellulose ends are more abundant than in the bulk cell wall. In more severe cases cracks between fibrils form at dislocations and it is possible that the increased accessibility that these cracks give is the reason why hydrolysis of cellulose starts at these locations. If acid...

  1. The Arabidopsis Cellulose Synthase Complex: A Proposed Hexamer of CESA Trimers in an Equimolar Stoichiometry

    Energy Technology Data Exchange (ETDEWEB)

    Hill, Joseph L. [Pennsylvania State Univ., University Park, PA (United States); Hammudi, Mustafa B. [Pennsylvania State Univ., University Park, PA (United States); Tien, Ming [Pennsylvania State Univ., University Park, PA (United States)

    2014-12-01

    In this study, we show a 1:1:1 stoichiometry between the three Arabidopsis thaliana secondary cell wall isozymes: CESA4, CESA7, and CESA8. This ratio was determined utilizing a simple but elegant method of quantitative immunoblotting using isoform-specific antibodies and 35S-labeled protein standards for each CESA. Additionally, the observed equimolar stoichiometry was found to be fixed along the axis of the stem, which represents a developmental gradient. Our results complement recent spectroscopic analyses pointing toward an 18-chain cellulose microfibril. Taken together, we propose that the CSC is composed of a hexamer of catalytically active CESA trimers, with each CESA in equimolar amounts. This finding is a crucial advance in understanding how CESAs integrate to form higher order complexes, which is a key determinate of cellulose microfibril and cell wall properties.

  2. Surface functionalization of nanofibrillated cellulose extracted from wheat straw: Effect of process parameters.

    Science.gov (United States)

    Singh, Mandeep; Kaushik, Anupama; Ahuja, Dheeraj

    2016-10-01

    Aggregates of microfibrillated cellulose isolated from wheat straw fibers were subjected to propionylation under different processing conditions of time, temperature and concentration. The treated fibers were then homogenized to obtain surface modified nanofibrillated cellulose. For varying parameters, progress of propionylation and its effects on various characteristics was investigated by FTIR, degree of substitution, elemental analysis, SEM, EDX, TEM, X-ray diffraction, static and dynamic contact angle measurements. Thermal stability of the nanofibrils was also investigated using thermogravimetric technique. FTIR analysis confirmed the propionylation of the hydroxyl groups of the cellulose fibers. The variations in reaction conditions such as time and temperature had shown considerable effect on degree of substitution (DS) and surface contact angle (CA). These characterization results represent the optimizing conditions under which cellulose nanofibrils with hydrophobic characteristics up to contact angle of 120° can be obtained. PMID:27312612

  3. Role of supramolecular cellulose structures in enzymatic hydrolysis of plant cell walls

    DEFF Research Database (Denmark)

    Thygesen, Lisbeth Garbrecht; Hidayat, Budi Juliman; Johansen, Katja Salomon;

    2011-01-01

    The study of biomass deconstruction by enzymatic hydrolysis has hitherto not focussed on the importance of supramolecular structures of cellulose. In lignocellulose fibres, regions with a different organisation of the microfibrils are present. These regions are called dislocations or slip planes...... important during the initial part of enzymatic hydrolysis of cellulose. The implications of this phenomenon have not yet been recognized or explored within cellulosic biofuels....... and they are known to be more susceptible to various forms of degradation such as acid hydrolysis. Traditionally the cellulose within these regions has been assumed to be amorphous, but in this study it is shown by use of polarized light microscopy that dislocations are birefringent. This indicates...

  4. Effect of cooking temperature on the crystallinity of acid hydrolysed-oil palm cellulose

    Science.gov (United States)

    Kuthi, Fatin Afifah Binti Ahmad; Badri, Khairiah Haji

    2014-09-01

    In this research, we studied the effect of acid hydrolysis temperature on the crystallinity of cellulose produced from empty fruit bunch (EFB). The hydrolysis temperature was studied from 120 to 140 °C at a fixed time and sulfuric acid, H2SO4 concentration which were 1 h and 1% (v/v) respectively. X-ray diffractometry (XRD) was carried out to measure the crystallinity of cellulose produced at varying hydrolysis temperatures. During hydrolysis, the amorphous region of α-cellulose was removed and the crystalline region was obtained. Percentage of crystallinity (CrI) for acid hydrolysed cellulose at 120, 130 and 140 °C were 54.21, 50.59 and 50.55 % respectively. Morphological studies using scanning electron microscope (SEM) showed that acid hydrolysis defibrilised to microfibrils in α-cellulose. The extraction process to produce α-cellulose has also been successfully carried out as the impurities at the outer surface, lignin and hemicellulose were removed. These findings were supported by the disappearance of peaks at 1732, 1512 and 1243 cm-1 on Fourier Transform infrared (FTIR) spectrum of α-cellulose. Similar peaks were identified in both the commercial microcrystalline cellulose (C-MCC) and acid hydrolysed cellulose (H-EFB), indicating the effectiveness of heat-catalysed acid hydrolysis.

  5. 3D multiscale micromechanical model of wood: From annual rings to microfibrils

    DEFF Research Database (Denmark)

    Qing, Hai; Mishnaevsky, Leon

    2010-01-01

    A 3D micromechanical analytical-computational model of softwood, which takes into account the wood microstructures at four scale levels, from microfibrils to annual rings, is developed. For the analysis of the effect of the annual rings structure on the properties of softwood, an improved rule......M) and finite element method (FEM) simulations. It was shown that IRoM gives almost as good results as FEM. The analytical model of annual rings is combined with the 3D finite element model of softwood as cellular material with multilayered, microfibril reinforced cell walls, developed by (Qing and...... Mishnaevsky, 2009a) and (Qing and Mishnaevsky, 2009b). Using the combined four-level model, the effect of wood density, microfibril angle (MFA) and cell shape angle (CSA) on the Young’s moduli, Poisson’s ratios and shrinkage properties of softwood has been investigated in numerical experiments. The...

  6. Spray-dried cellulose nanofibers as novel tablet excipient.

    Science.gov (United States)

    Kolakovic, Ruzica; Peltonen, Leena; Laaksonen, Timo; Putkisto, Kaisa; Laukkanen, Antti; Hirvonen, Jouni

    2011-12-01

    The purpose of this study was to evaluate the potential of cellulose nanofibers (also referred as microfibrillated cellulose, nanocellulose, nanofibrillated, or nanofibrillar cellulose) as novel tabletting material. For this purpose, physical and mechanical properties of spray-dried cellulose nanofibers (CNF) were examined, and results were compared to those of two commercial grades of microcrystalline cellulose (MCC), Avicel PH101 and Avicel PH102, which are the most commonly and widely used direct compression excipients. Chemically, MCC and CNF are almost identical, but their physical characteristics, like mechanical properties and surface-to-volume ratio, differ remarkably. The novel material was characterized with respect to bulk and tapped as well as true density, moisture content, and flow properties. Tablets made of CNF powder and its mixtures with MCC with or without paracetamol as model compound were produced by direct compression and after wet granulation. The tensile strength of the tablets made in a series of applied pressures was determined, and yield pressure values were calculated from the measurements. With CNF, both wet granulation and direct compression were successful. During tablet compression, CNF particles were less prone to permanent deformation and had less pronounced ductile characteristics. Disintegration and dissolution studies showed slightly faster drug release from direct compression tablets with CNF, while wet granulated systems did not have any significant difference. PMID:22005956

  7. Evolution of Xylan Substitution Patterns in Gymnosperms and Angiosperms: Implications for Xylan Interaction with Cellulose.

    Science.gov (United States)

    Busse-Wicher, Marta; Li, An; Silveira, Rodrigo L; Pereira, Caroline S; Tryfona, Theodora; Gomes, Thiago C F; Skaf, Munir S; Dupree, Paul

    2016-08-01

    The interaction between cellulose and xylan is important for the load-bearing secondary cell wall of flowering plants. Based on the precise, evenly spaced pattern of acetyl and glucuronosyl (MeGlcA) xylan substitutions in eudicots, we recently proposed that an unsubstituted face of xylan in a 2-fold helical screw can hydrogen bond to the hydrophilic surfaces of cellulose microfibrils. In gymnosperm cell walls, any role for xylan is unclear, and glucomannan is thought to be the important cellulose-binding polysaccharide. Here, we analyzed xylan from the secondary cell walls of the four gymnosperm lineages (Conifer, Gingko, Cycad, and Gnetophyta). Conifer, Gingko, and Cycad xylan lacks acetylation but is modified by arabinose and MeGlcA. Interestingly, the arabinosyl substitutions are located two xylosyl residues from MeGlcA, which is itself placed precisely on every sixth xylosyl residue. Notably, the Gnetophyta xylan is more akin to early-branching angiosperms and eudicot xylan, lacking arabinose but possessing acetylation on alternate xylosyl residues. All these precise substitution patterns are compatible with gymnosperm xylan binding to hydrophilic surfaces of cellulose. Molecular dynamics simulations support the stable binding of 2-fold screw conifer xylan to the hydrophilic face of cellulose microfibrils. Moreover, the binding of multiple xylan chains to adjacent planes of the cellulose fibril stabilizes the interaction further. Our results show that the type of xylan substitution varies, but an even pattern of xylan substitution is maintained among vascular plants. This suggests that 2-fold screw xylan binds hydrophilic faces of cellulose in eudicots, early-branching angiosperm, and gymnosperm cell walls. PMID:27325663

  8. Binding of MAGP2 to microfibrils is regulated by proprotein convertase cleavage.

    Science.gov (United States)

    Miyamoto, Alison; Donovan, Lauren J; Perez, Edgar; Connett, Breanna; Cervantes, Richard; Lai, Khang; Withers, Gordon; Hogrebe, Gregory

    2014-11-01

    MAGP2 is a small extracellular protein with both tumor angiogenesis and cell signaling activity. MAGP2 was originally isolated biochemically from microfibril-rich connective tissue. The localization of MAGP2 to microfibrils has been confirmed by both immunohistochemistry and immunogold electron microscopy. Whether MAGP2 binding to microfibrils is regulated post-translationally is still unclear, however, and a better understanding of this process would be instructive to understanding the angiogenesis and signaling functions ascribed to MAGP2. Here we show via immunofluorescence studies that the T3 cell line, derived from ovarian mouse tumor cells, produces abundant fibrillin-2 microfibrils to which MAGP2 can bind. Co-localization of MAGP2 and fibrillin-2 can be detected either when MAGP2 is overexpressed in, or exogenously introduced to, the cells. As expected, matrix association of MAGP2 required its conserved Matrix Binding Domain. Matrix association was positively regulated by proprotein convertase (PC) cleavage of MAGP2; mutation of the MAGP2 PC consensus site reduced the amount of matrix-associated MAGP2. Deletion analysis of the C-terminal 20-amino acid domain that is defined by the PC cleavage site suggests that this domain also positively modulates matrix localization of MAGP2, in a manner that requires the amino-terminal half of the protein. Together, our data indicate that matrix localization of MAGP2 by its Matrix Binding Domain is promoted by PC cleavage and the presence of its C-terminal 20 amino acids. PMID:25153248

  9. S-Acylation of the cellulose synthase complex is essential for its plasma membrane localization.

    Science.gov (United States)

    Kumar, Manoj; Wightman, Raymond; Atanassov, Ivan; Gupta, Anjali; Hurst, Charlotte H; Hemsley, Piers A; Turner, Simon

    2016-07-01

    Plant cellulose microfibrils are synthesized by a process that propels the cellulose synthase complex (CSC) through the plane of the plasma membrane. How interactions between membranes and the CSC are regulated is currently unknown. Here, we demonstrate that all catalytic subunits of the CSC, known as cellulose synthase A (CESA) proteins, are S-acylated. Analysis of Arabidopsis CESA7 reveals four cysteines in variable region 2 (VR2) and two cysteines at the carboxy terminus (CT) as S-acylation sites. Mutating both the VR2 and CT cysteines permits CSC assembly and trafficking to the Golgi but prevents localization to the plasma membrane. Estimates suggest that a single CSC contains more than 100 S-acyl groups, which greatly increase the hydrophobic nature of the CSC and likely influence its immediate membrane environment. PMID:27387950

  10. Thermally induced gel from cellulose/NaOH/PEG solution: preparation, characterization and mechanical properties

    Science.gov (United States)

    Wan, Caichao; Lu, Yun; Jin, Chunde; Sun, Qingfeng; Li, Jian

    2015-04-01

    In this paper, we reported a thermally induced gel with strong mechanical properties prepared from cellulose/NaOH/PEG aqueous solution following the procedures of dissolution, heating and freeze-drying. The as-prepared gel showed undeveloped networks composed of cross-linked fiber aggregations tightly coated with plenty of NaOH·H2O and PEG-aggregated fine particles, which led to the significant enhancement of thermal stability and the disappearance of the original cellulose crystalline structures. Furthermore, the elastic modulus, yield stress and toughness of the mechanically strong gel were measured to be up to 3,210, 325 kPa and 389 kJ m-3, respectively, comparable to those of cross-linked polymer gel materials with strong mechanical strength such as the microfibrillated cellulose aerogels and the three-dimensional architectures of graphene hydrogels.

  11. Effect of γ irradiation on poly(vinyl alcohol) and bacterial cellulose composites used as packaging materials

    Science.gov (United States)

    Stoica-Guzun, Anicuta; Stroescu, Marta; Jipa, Iuliana; Dobre, Loredana; Zaharescu, Traian

    2013-03-01

    The aim of this paper is to present the influence of bacterial cellulose microfibrils and γ-radiation dose on poly(vinyl alcohol) (PVA)-bacterial cellulose (BC) composites. Two composite materials were obtained: the first one from PVA aqueous solution 4% and 5% wet bacterial cellulose and the second from the same PVA solution and 10% wet bacterial cellulose. In terms of PVA/dry BC ratios (w/w) for these films the ratios are 1/0.025 and 1/0.050. The obtained composite materials were characterized by infrared spectroscopy with Fourier transform (FT-IR) and UV-vis spectroscopy in order to evaluate the irradiation effect on their stability. The swelling behavior of the polymeric composites was also studied. The composite materials were compared with a film of pure PVA and a dry BC membrane.

  12. Spray-dried nanofibrillar cellulose microparticles for sustained drug release.

    Science.gov (United States)

    Kolakovic, Ruzica; Laaksonen, Timo; Peltonen, Leena; Laukkanen, Antti; Hirvonen, Jouni

    2012-07-01

    Nanofibrillar cellulose (also referred to as cellulose nanofibers, nanocellulose, microfibrillated or nanofibrillated cellulose) has gained a lot of attention in recent years in different research areas including biomedical applications. In this study we have evaluated the applicability of nanofibrillar cellulose (NFC) as a material for the formation of matrix systems for sustained drug delivery. For that purpose, drug loaded NFC microparticles were produced by a spray drying method. The microparticles were characterized in terms of size and morphology, total drug loading, and physical state of the encapsulated drug. Drug release from the microparticles was assessed by dissolution tests, and suitable mathematical models were used to explain the drug releasing kinetics. The particles had spherical shapes with diameters of around 5 μm; the encapsulated drug was mainly in amorphous form. The controlled drug release was achieved. The drug releasing curves were fitted to a mathematical model describing the drug releasing kinetics from a spherical matrix. Different drugs had different release kinetics, which was a consequence of several factors, including different solubilities of the drugs in the chosen medium and different affinities of the drugs to the NFC. It can be concluded that NFC microparticles can sustain drug release by forming a tight fiber network and thus limit drug diffusion from the system. PMID:22465549

  13. Longitudinal and concurrent dimensional changes of cellulose aggregate fibrils during sorption stages

    International Nuclear Information System (INIS)

    Atomic force microscopy (AFM) studies of the dimensional changes of cellulose microfibril materials, called cellulose aggregate fibrils (approx. 100 μm x 3 μm x 300 nm), exposed to two distinct relative humidities of 80% and 23% for 24 h and then suddenly subjected to 50% RH and 23 deg. C show that the fibrils are responsive to the surrounding environments in a nonspecific fashion. AFM images (10 μm x 10 μm) of the individual straight cellulose aggregate fibrils were taken as a function of elapsed time during both desorption and adsorption of moisture. The longitudinal distance between discrete natural defects observed on the cellulose aggregate fibrils as well as the width, cross-sectional area, and height of the cellulose aggregate fibril were measured from the AFM images. The length of the cellulose aggregate fibrils was found to have reduced after exposure to either high or low relative humidity, and then placement in ambient conditions. Over time in ambient conditions, the cellulose aggregate fibrils progressively relaxed to their original length during both desorption and adsorption of moisture. However, the relaxation rate during adsorption was faster than that during desorption. The possible explanations for this phenomenon are discussed including the sample preparation method, volume conservation, entropy elasticity, and free volume theory. The changes in the width, height, and cross-sectional area are also discussed.

  14. Functional Analysis of Cellulose and Xyloglucan in the Walls of Stomatal Guard Cells of Arabidopsis.

    Science.gov (United States)

    Rui, Yue; Anderson, Charles T

    2016-03-01

    Stomatal guard cells are pairs of specialized epidermal cells that control water and CO2 exchange between the plant and the environment. To fulfill the functions of stomatal opening and closure that are driven by changes in turgor pressure, guard cell walls must be both strong and flexible, but how the structure and dynamics of guard cell walls enable stomatal function remains poorly understood. To address this question, we applied cell biological and genetic analyses to investigate guard cell walls and their relationship to stomatal function in Arabidopsis (Arabidopsis thaliana). Using live-cell spinning disk confocal microscopy, we measured the motility of cellulose synthase (CESA)-containing complexes labeled by green fluorescent protein (GFP)-CESA3 and observed a reduced proportion of GFP-CESA3 particles colocalizing with microtubules upon stomatal closure. Imaging cellulose organization in guard cells revealed a relatively uniform distribution of cellulose in the open state and a more fibrillar pattern in the closed state, indicating that cellulose microfibrils undergo dynamic reorganization during stomatal movements. In cesa3(je5) mutants defective in cellulose synthesis and xxt1 xxt2 mutants lacking the hemicellulose xyloglucan, stomatal apertures, changes in guard cell length, and cellulose reorganization were aberrant during fusicoccin-induced stomatal opening or abscisic acid-induced stomatal closure, indicating that sufficient cellulose and xyloglucan are required for normal guard cell dynamics. Together, these results provide new insights into how guard cell walls allow stomata to function as responsive mediators of gas exchange at the plant surface. PMID:26729799

  15. Hierarchical pattern of microfibrils in a 3D fluorapatite-gelatine nanocomposite: simulation of a bio-related structure building process.

    Science.gov (United States)

    Paparcone, Raffaella; Kniep, Rüdiger; Brickmann, Jürgen

    2009-04-01

    The shape development of a biomimetic fluorapatite-gelatine nanocomposite on the mum scale is characterised by a fractal mechanism with the origin being intrinsically coded in a (central) elongated hexagonal-prismatic seed. The 3D superstructure of the seed is distinctively overlaid by a pattern consisting of gelatine microfibrils. The orientation of the microfibrils is assumed to be controlled by an intrinsic electrical field generated by the nanocomposite during development and growth of the seed. In order to confirm this assumption and to get more detailed information on orientational relations of the complex nanocomposite we simulated the pattern formation process up to the microm scale. The results from experimental studies and simulation results on an atomistic level support a model scenario wherein the elementary building blocks for the aggregation are represented by elongated hexagonal-prismatic objects (A-units), with the embedded collagen triple-helices in their centers. The interactions of the A-units are consequently modelled by three contributions: the crystal energy part (originating from the pair-wise interactions of the "apatite shells" of the prismatic units), the electrostatic interaction (originating from the unit charges located at the ends of the collagen triple helices), and the interaction energy of the A-units mediated by the solvent. The next level of complexity is related to the fact that micro fibrils were found in the fluorapatite-gelatine nanocomposites. They consist of bundles of triple helical protein molecules, which are embedded within the 3D-hexagonal prismatic arrangement of the A-units. In our approach we consider the microfibrils as chains of flexible dipoles with effective dipole moments. The crystal growth processes is modelled as an energetically controlled stepwise association of elementary building blocks of different kind on a 3D-grid. The remarkable and excellent qualitative agreement between the simulated fibril patterns

  16. Non-destructive determination of moisture content and micro-fibril angle of wood using a poly-chromatic X-ray beam theoretical and experimental approach; Exploitation d'un rayonnement X poly-energetique pour la determination de la teneur en eau et de l'angle de microfibrilles du bois: approche theorique et experimentale

    Energy Technology Data Exchange (ETDEWEB)

    Baettig, R

    2005-07-15

    Non-destructive determination of moisture content and micro-fibril angle are important stakes for the sciences of the wood because these two parameters influence strongly the macroscopic behavior of the wood. For example, the shrinkage, the mechanical properties, the thermal and acoustic conductivity are dependent on the moisture content and their anisotropic character is largely governed by the micro-fibril angle. We used the light difference between X-ray mass attenuation coefficient for the water and for the wood in transmission. Regrettably, the results show that this difference between X-ray mass attenuation coefficient is insufficient to allow the precise measurement of the moisture content.In spite of this, the coherent scattering shows sensitive effects. So, by using a poly-energetic beam and a spectrometric system, we were able to discriminate between the crystalline constituent (cellulose) of the amorphous constituent (water) in a sample of wet wood, because for a given angle these phases scatter in different energy. Besides, the device created allowed us to study the crystalline phase of the wood. We were able to confront experimental profiles of diffraction with theoretical profiles of diffraction, obtained by means of a rigorous simulation, in the objective to estimate the average micro-fibril angle and its standard deviation. (author)

  17. Cross-linking oxidized cellulose nanofibrils for the formation of stable hydrogel structures

    OpenAIRE

    Pettersen, Sigurd Rolland

    2013-01-01

    The main goal of this project was to investigate whether the elastic properties of microfibrillated cellulose (MFC) suspensions pre-treated by TEMPO-mediated oxidation could be controlled by inducing cross-links between the nanofibrils with short diamines. Using conductometric titration, the total carboxylate and aldehyde content in the MFC was measured as 0.810 mmol/g MFC and 0.181 mmol/g MFC, respectively.The viscoelastic properties of the MFC were investigated by dynamic measurements. The ...

  18. Endoglucanase Peripheral Loops Facilitate Complexation of Glucan Chains on Cellulose via Adaptive Coupling to the Emergent Substrate Structures

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Yuchun; Beckham, Gregg T.; Himmel, Michael E.; Crowley, Michael F.; Chu, Jhih-wei

    2013-09-19

    We examine how the catalytic domain of a glycoside hydrolase family 7 endoglucanase catalytic domain (Cel7B CD) facilitates complexation of cellulose chains from a crystal surface. With direct relevance to the science of biofuel production, this problem also represents a model system of biopolymer processing by proteins in Nature. Interactions of Cel7B CD with a cellulose microfibril along different paths of complexation are characterized by mapping the atomistic fluctuations recorded in free-energy simulations onto the parameters of a coarse-grain model. The resulting patterns of protein-biopolymer couplings also uncover the sequence signatures of the enzyme in peeling off glucan chains from the microfibril substrate. We show that the semiopen active site of Cel7B CD exhibits similar barriers and free energies of complexation over two distinct routes; namely, scooping of a chain into the active-site cleft and threading from the chain end into the channel. On the other hand, the complexation energetics strongly depends on the surface packing of the targeted chain and the resulting interaction sites with the enzyme. A revealed principle is that Cel7B CD facilitates cellulose deconstruction via adaptive coupling to the emergent substrate. The flexible, peripheral segments of the protein outside of the active-site cleft are able to accommodate the varying features of cellulose along the simulated paths of complexation. The general strategy of linking physics-based molecular interactions to protein sequence could also be helpful in elucidating how other protein machines process biopolymers.

  19. Finite element 3D modeling of mechanical behavior of mineralized collagen microfibrils

    CERN Document Server

    Barkaoui, Abdelwahed

    2011-01-01

    The aim of this work is to develop a 3D finite elements model to study the nanomechanical behaviour of mineralized collagen microfibrils, which consists of three phases, (i) collagen phase formed by five tropocollagen (TC) molecules linked together with cross links, (ii) a mineral phase (Hydroxyapatite) and (iii) impure mineral phase, and to investigate the important role of individual properties of every constituent. The mechanical and the geometrical properties (TC molecule diameter) of both tropocollagen and mineral were taken into consideration as well as cross-links, which was represented by spring elements with adjusted properties based on experimental data. In the present paper an equivalent homogenised model was developed to assess the whole microfibril mechanical properties (Young's modulus and Poisson's ratio) under varying mechanical properties of each phase. In this study both equivalent Young's modulus and Poisson's ratio which were expressed as functions of Young's modulus of each phase were obt...

  20. Cellulose based conductive polymers

    OpenAIRE

    Lin, Haishu

    2015-01-01

    Conductive fibers show potential applications in different areas. In this thesis, cellulose and its derivatives, including carboxymethyl cellulose, cellulose acetate as well as methyl cellulose were used to produce fibers via wet spinning. Different conductive materials were also introduced in an attempt to obtain cellulose-derived conductive fibers. Different conductive fillers (Zelec, carbon black, conductive polymers) were evaluated. Among them, PEDOT and PPy conductive polymers showed...

  1. Characterization of new natural cellulosic fiber from Cissus quadrangularis root.

    Science.gov (United States)

    Indran, S; Raj, R Edwin; Sreenivasan, V S

    2014-09-22

    Fiber reinforced polymer composites are replacing many metallic structures due to its high specific strength and modulus. However commonly used man-made E-glass fibers are hazardous for health and carcinogenic by nature. Comprehensive characterization of Cissus quadrangularis root fiber such as anatomical study, chemical analysis, physical analysis, FTIR, XRD, SEM analysis and thermo gravimetric analysis are done. The results are very encouraging for its application in fiber industries, composite manufacturing, etc. Due to its light weight and the presence of high cellulose content (77.17%) with very little wax (0.14%) provide high specific strength and good bonding properties. The flaky honeycomb outer surface and low microfibril angle revealed through electron microscopy contributes for its high modulus. The thermo gravimetric analysis indicates better thermal stability of the fiber up to 230°C, which is well within the polymerization process temperature. PMID:24906775

  2. Structural characterization of cellulosic materials using x-ray and neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Penttila, P.

    2013-11-01

    Cellulosic biomass can be used as a feedstock for sustainable production of biofuels and various other products. A complete utilization of the raw material requires understanding on its structural aspects and their role in the various processes. In this thesis, x-ray and neutron scattering methods were applied to study the structure of various cellulosic materials and how they are affected in different processes. The obtained results were reviewed in the context of a model for the cellulose nanostructure. The dimensions of cellulose crystallites and the crystallinity were determined with wide-angle x-ray scattering (WAXS), whereas the nanoscale fibrillar structure of cellulose was characterized with small-angle x-ray and neutron scattering (SAXS and SANS). The properties determined with the small-angle scattering methods included specific surface areas and distances characteristic of the packing of cellulose microfibrils. Also other physical characterization methods, such as x-ray microtomography, infrared spectroscopy, and solid-state NMR were utilized in this work. In the analysis of the results, a comprehensive understanding of the structural changes throughout a range of length scales was aimed at. Pretreatment of birch sawdust by pressurized hot water extraction was observed to increase the crystal width of cellulose, as determined with WAXS, even though the cellulose crystallinity was slightly decreased. A denser packing of microfibrils caused by the removal of hemicelluloses and lignin in the extraction was evidenced by SAXS. This resulted in the opening of new pores between the microfibril bundles and an increase of the specific surface area. Enzymatic hydrolysis of microcrystalline cellulose (MCC) did not lead to differences in the average crystallinity or crystal size of the hydrolysis residues, which was explained to be caused by limitations due to the large size of the enzymes as compared to the pores inside the fibril aggregates. The SAXS intensities

  3. Micromechanics of TEMPO-oxidized fibrillated cellulose composites.

    Science.gov (United States)

    Bulota, Mindaugas; Tanpichai, Supachok; Hughes, Mark; Eichhorn, Stephen J

    2012-01-01

    Composites of poly(lactic) acid (PLA) reinforced with TEMPO-oxidized fibrillated cellulose (TOFC) were prepared to 15, 20, 25, and 30% fiber weight fractions. To aid dispersion and to improve stress transfer, we acetylated the TOFC prior to the fabrication of TOFC-PLA composite films. Raman spectroscopy was employed to study the deformation micromechanics in these systems. Microtensile specimens were prepared from the films and deformed in tension with Raman spectra being collected simultaneously during deformation. A shift in a Raman peak initially located at ~1095 cm(-1), assigned to C-O-C stretching of the cellulose backbone, was observed upon deformation, indicating stress transfer from the matrix to the TOFC reinforcement. The highest band shift rate, with respect to strain, was observed in composites having a 30% weight fraction of TOFC. These composites also displayed a significantly higher strain to failure compared to pure acetylated TOFC film, and to the composites having lower weight fractions of TOFC. The stress-transfer processes that occur in microfibrillated cellulose composites are discussed with reference to the micromechanical data presented. It is shown that these TOFC-based composite materials are progressively dominated by the mechanics of the networks, and a shear-lag type stress transfer between fibers. PMID:22181067

  4. Reliable dn/dc Values of Cellulose, Chitin, and Cellulose Triacetate Dissolved in LiCl/N,N-Dimethylacetamide for Molecular Mass Analysis.

    Science.gov (United States)

    Ono, Yuko; Ishida, Takashi; Soeta, Hiroto; Saito, Tsuguyuki; Isogai, Akira

    2016-01-11

    Freeze-dried microfibrillated cellulose (MFC) was directly dissolved in 8.0% w/w lithium chloride/N,N-dimethylacetamide (LiCl/DMAc), and MFC/LiCl/DMAc solutions with accurate MFC concentrations were prepared. The different MFC solutions were diluted to 1.0% and 0.5% w/v LiCl/DMAc, and subjected to size-exclusion chromatography with multiangle laser-light scattering and refractive index analyses (SEC/MALLS/RI), and off-line RI analysis to determine their refractive index increments (dn/dc). Chitin, cellulose triacetate, a poly(styrene) standard, and cellobiose were used for comparison. Each of the two determination methods gave different dn/dc values for MFC and chitin but similar dn/dc values for cellulose triacetate and poly(styrene). The anomalously small dn/dc values of MFC and chitin were explainable in terms of stable cellulose-LiCl and chitin-LiCl structures (i.e., formation of apparent covalent bonds between hydroxyl groups and LiCl) in the solutions. Thus, the SEC/MALLS/RI method provides reliable molecular mass parameters for cellulose and chitin. PMID:26618937

  5. Preparation and characterization of Bioglass®-based scaffolds reinforced bypoly-vinyl alcohol/microfibrillated cellulose composite coating

    Czech Academy of Sciences Publication Activity Database

    Bertolla, Luca; Dlouhý, Ivo; Boccaccini, A. R.

    2014-01-01

    Roč. 34, č. 14 (2014), s. 3379-3387. ISSN 0955-2219. [Fractography of Advanced Ceramics IV. Smolenice Castle Congres Center, Smolenice SAS, 29.09.13-02.10.13] R&D Projects: GA MŠk(CZ) ED1.1.00/02.0068 EU Projects: European Commission(XE) 264526 - GLACERCO Institutional support: RVO:68081723 Keywords : bioceramcs * bioglass (R) scaffolds * porous materials * polymer coating * composite coating Subject RIV: JI - Composite Materials Impact factor: 2.947, year: 2014 http://www.imr.saske.sk/confer/fac2013/publication.htm

  6. Simulations of Cellulose Translocation in the Bacterial Cellulose Synthase Suggest a Regulatory Mechanism for the Dimeric Structure of Cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Knott, Brandon C.; Crowley, Michael F.; Himmel, Michael E.; Zimmer, Jochen; Beckham, Gregg T.

    2016-05-01

    The processive cycle of the bacterial cellulose synthase (Bcs) includes the addition of a single glucose moiety to the end of a growing cellulose chain followed by the translocation of the nascent chain across the plasma membrane. The mechanism of this translocation and its precise location within the processive cycle are not well understood. In particular, the molecular details of how a polymer (cellulose) whose basic structural unit is a dimer (cellobiose) can be constructed by adding one monomer (glucose) at a time are yet to be elucidated. Here, we have utilized molecular dynamics simulations and free energy calculations to the shed light on these questions. We find that translocation forward by one glucose unit is quite favorable energetically, giving a free energy stabilization of greater than 10 kcal mol-1. In addition, there is only a small barrier to translocation, implying that translocation is not rate limiting within the Bcs processive cycle (given experimental rates for cellulose synthesis in vitro). Perhaps most significantly, our results also indicate that steric constraints at the transmembrane tunnel entrance regulate the dimeric structure of cellulose. Namely, when a glucose molecule is added to the cellulose chain in the same orientation as the acceptor glucose, the terminal glucose freely rotates upon forward motion, thus suggesting a regulatory mechanism for the dimeric structure of cellulose. We characterize both the conserved and non-conserved enzyme-polysaccharide interactions that drive translocation, and find that 20 of the 25 residues that strongly interact with the translocating cellulose chain in the simulations are well conserved, mostly with polar or aromatic side chains. Our results also allow for a dynamical analysis of the role of the so-called 'finger helix' in cellulose translocation that has been observed structurally. Taken together, these findings aid in the elucidation of the translocation steps of the Bcs

  7. Cellulose-clay layered nanocomposite films fabricated from aqueous cellulose/LiOH/urea solution.

    Science.gov (United States)

    Yang, Quanling; Wu, Chun-Nan; Saito, Tsuguyuki; Isogai, Akira

    2014-01-16

    Transparent and flexible cellulose-clay (montmorillonite, MTM) nanocomposite films are prepared from cellulose/LiOH/urea solutions. The results show that the composites possess intercalated nanolayered structures. Almost no Na ions are present in MTM, probably because they are substituted by Li ions. The nanocomposite films possess high mechanical strength and gas barrier properties, and lower coefficients of thermal expansion than those of the original cellulose film. In particular, the composite film of 85% cellulose and 15% MTM has the highest tensile strength and Young's modulus 161 and 180% greater than those of the 100% cellulose film, and coefficient of thermal expansion and oxygen permeability at 50-75% RH decrease to 60 and 42-33%, respectively. Moreover, the initial hydrophilic nature of cellulose film changes to somewhat hydrophobic through incorporation of hydrophilic MTM platelets. This is probably because the orientation of cellulose chains on the film surface changes by the formation of numerous hydrogen bonds between cellulose molecules and MTM platelets. PMID:24188852

  8. Isolation and Characterization of Cellulose Nanofibers from Gigantochloa scortechinii as a Reinforcement Material

    Directory of Open Access Journals (Sweden)

    Chaturbhuj K. Saurabh

    2016-01-01

    Full Text Available Cellulose nanofibers (CNF were isolated from Gigantochloa scortechinii bamboo fibers using sulphuric acid hydrolysis. This method was compared with pulping and bleaching process for bamboo fiber. Scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and thermogravimetric analysis were used to determine the properties of CNF. Structural analysis by FT-IR showed that lignin and hemicelluloses were effectively removed from pulp, bleached fibers, and CNF. It was found that CNF exhibited uniform and smooth morphological structures, with fiber diameter ranges from 5 to 10 nm. The percentage of crystallinity was significantly increased from raw fibers to cellulose nanofibers, microfibrillated, along with significant improvement in thermal stability. Further, obtained CNF were used as reinforcement material in epoxy based nanocomposites where tensile strength, flexural strength, and modulus of nanocomposites improved with the addition of CNF loading concentration ranges from 0 to 0.7%.

  9. New process of chemical grafting of cellulose nanoparticles with a long chain isocyanate.

    Science.gov (United States)

    Siqueira, Gilberto; Bras, Julien; Dufresne, Alain

    2010-01-01

    Cellulose nanocrystals (or whiskers) and microfibrillated cellulose (MFC) were successfully obtained from sisal fibers and modified with n-octadecyl isocyanate (C(18)H(37)NCO) using two different methods with one innovation that consists of an in situ solvent exchange procedure. The surface chemical modification was characterized by elemental analysis, as well as FTIR and XPS spectroscopies. The crystalline structure of both unmodified and modified nanoparticles was investigated through X-ray diffraction measurements. It was shown that the efficiency of the chemical modification is strongly dependent on the nature of the nanoparticle with explanation linked to specific area, ability of peeling, and solvent dispersion. The surface chemical modification with n-octadecyl isocyanate allows dispersion of the nanoparticles in organic solvents and may allow processing of nanocomposite films from a casting/evaporation technique for a broad range of polymeric matrices. PMID:19921797

  10. Functional Analysis of Cellulose and Xyloglucan in the Walls of Stomatal Guard Cells of Arabidopsis1[OPEN

    Science.gov (United States)

    Rui, Yue; Anderson, Charles T.

    2016-01-01

    Stomatal guard cells are pairs of specialized epidermal cells that control water and CO2 exchange between the plant and the environment. To fulfill the functions of stomatal opening and closure that are driven by changes in turgor pressure, guard cell walls must be both strong and flexible, but how the structure and dynamics of guard cell walls enable stomatal function remains poorly understood. To address this question, we applied cell biological and genetic analyses to investigate guard cell walls and their relationship to stomatal function in Arabidopsis (Arabidopsis thaliana). Using live-cell spinning disk confocal microscopy, we measured the motility of cellulose synthase (CESA)-containing complexes labeled by green fluorescent protein (GFP)-CESA3 and observed a reduced proportion of GFP-CESA3 particles colocalizing with microtubules upon stomatal closure. Imaging cellulose organization in guard cells revealed a relatively uniform distribution of cellulose in the open state and a more fibrillar pattern in the closed state, indicating that cellulose microfibrils undergo dynamic reorganization during stomatal movements. In cesa3je5 mutants defective in cellulose synthesis and xxt1 xxt2 mutants lacking the hemicellulose xyloglucan, stomatal apertures, changes in guard cell length, and cellulose reorganization were aberrant during fusicoccin-induced stomatal opening or abscisic acid-induced stomatal closure, indicating that sufficient cellulose and xyloglucan are required for normal guard cell dynamics. Together, these results provide new insights into how guard cell walls allow stomata to function as responsive mediators of gas exchange at the plant surface. PMID:26729799

  11. BIOINFORMATICS AND BIOSYNTHESIS ANALYSIS OF CELLULOSE SYNTHASE OPERON IN ZYMOMONAS MOBILIS ZM4

    Directory of Open Access Journals (Sweden)

    Sheik Abdul Kader Sheik Asraf, K. Narayanan Rajnish, and Paramasamy Gunasekaran

    2011-03-01

    Full Text Available Biosynthesis of cellulose has been reported in many species of bacteria. The genes encoding cellulose biosynthetic enzymes of Z. mobilis have not been studied so far. Preliminary sequence analysis of the Z. mobilis ZM4 genome revealed the presence of a cellulose synthase operon comprised of Open Reading Frames (ORFs ZMO01083 (bcsA, ZMO1084 (bcsB and ZMO1085 (bcsC. The first gene of the operon bcsA encodes the cellulose synthase catalytic subunit BcsA. The second gene of the operon bcsB encodes the cellulose synthase subunit B (BcsB, which shows the presence of BcsB multi-domain and is inferred to bind c-di-GMP, the regulator of cellulose biosynthesis. The third gene of the operon bcsC encodes the cellulose synthase operon C domain protein (BcsC, which belongs to super family of teratrico peptide repeat (TPR that are believed to mediate protein – protein interactions for the formation of cellulose. Multiple sequence alignment of the deduced amino acid sequences of BcsA and BcsC with other closely related homologs showed the presence of PVDPYE, HAKAGNLN, DCD motif and TPR motif, the characteristic motifs of bacterial cellulose synthases. Analysis of the nucleotide sequence of the ORF ZMO1085 and neighboring ORFs namely ZMO1083 and ZMO1084 indicated that all the ORFs are translationally linked and form an operon. Transcript analysis using Real-time PCR indicated the expression of the genes involved in cellulose synthase operon in Zymomonas mobilis ZM4. Z. mobilis colonies grown on RM-glucose containing Congo red displayed a characteristic bright red-brown colour. Z. mobilis colonies grown on RM-glucose medium supplemented with Calcoflour exhibited fluorescence. The arrangement of Calcofluor stained microfibrils can be seen in fluorescence microscopy which is an indicative for cellulose biosynthesis. AFM micrograph of the extracellular matrix of Z. mobilis shows a relatively dense matrix with bacterial cell residues. The presence of cellulose was

  12. Electrically conductive cellulose composite

    Science.gov (United States)

    Evans, Barbara R.; O'Neill, Hugh M.; Woodward, Jonathan

    2010-05-04

    An electrically conductive cellulose composite includes a cellulose matrix and an electrically conductive carbonaceous material incorporated into the cellulose matrix. The electrical conductivity of the cellulose composite is at least 10 .mu.S/cm at 25.degree. C. The composite can be made by incorporating the electrically conductive carbonaceous material into a culture medium with a cellulose-producing organism, such as Gluconoacetobacter hansenii. The composites can be used to form electrodes, such as for use in membrane electrode assemblies for fuel cells.

  13. Selectively Structural Determination of Cellulose and Hemicellulose in Plant Cell Wall

    Science.gov (United States)

    Huang, Shih-Chun; Park, Yong; Cosgrove, Daniel; Maranas, Janna; Janna Maranas Team; Daniel Cosgrove Team

    2013-03-01

    Primary plant cell walls support the plant body, and regulate cell size, and plant growth. It contains several biopolymers that can be categorized into three groups: cellulose, hemicellulose and pectin. To determine the structure of plant cell wall, we use small angle neutron scattering in combination with selective deuteration and contrast matching method. We compare the structure between wild Arabidopsis thaliana and its xyloglucan-deficient mutant. Hemicellulose in both samples forms coil with similar radii of gyration, and weak scattering from the mutant suggests a limited amount of hemicellulose in the xyloglucan-deficient mutant. We observe good amount of hemicellulose coating on cellulose microfibrils only in wild Arabidopsis. The absence of coating in its xyloglucan-deficient mutation suggests the other polysaccharides do not have comparable interaction with cellulose. This highlights the importance of xyloglucan in plant cell wall. At larger scale, the average distance between cellulose fibril is found smaller than reported value, which directly reflects on their smaller matured plant size. U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Center for LignoCellulose Structure and Formation

  14. Properties of cellulose/pectins composites: implication for structural and mechanical properties of cell wall.

    Science.gov (United States)

    Agoda-Tandjawa, G; Durand, S; Gaillard, C; Garnier, C; Doublier, J L

    2012-10-01

    The primary cell wall of dicotyledonous plants can be considered as a concentrated polymer assembly, containing in particular polysaccharides among which cellulose and pectins are known to be the major components. In order to understand and control the textural quality of plant-derived foods, it is highly important to elucidate the rheological and microstructural properties of these components, individually and in mixture, in order to define their implication for structural and mechanical properties of primary plant cell wall. In this study, the rheological and microstructural properties of model systems composed of sugar-beet microfibrillated cellulose and HM pectins from various sources, with varied degrees of methylation and containing different amounts of neutral sugar side chains, were investigated. The influence of the presence of calcium and/or sodium ions and the biopolymer concentrations on the properties of the mixed systems were also studied. The characterizations of the mixed system, considered as a simplified model of primary plant cell wall, showed that whatever the structural characteristics of the pectins, the ionic conditions of the medium and the biopolymer concentrations, the gelation of the composite was mainly controlled by cellulose. Thus, the cellulose network would be the principal component governing the mechanical properties of the cell walls. However, the neutral sugar side chains of the pectins seem to play a part in the interactions with cellulose, as shown by the interesting viscoelastic properties of cellulose/apple HM pectins systems. The rigidity of cellulose/pectins composite was strongly influenced by the structural characteristics of pectins. The particular properties of primary plant cell walls would thus result from the solid viscoelastic properties of cellulose, its interactions with pectins according to their structural characteristics (implication of the neutral sugar side chains and the specific potential calcic

  15. Characterisation of hierarchically-structured cellulose hydrogels by small angle neutron scattering

    International Nuclear Information System (INIS)

    This work reports on the characterisation of cellulose hydrogels by means of small angle neutron scattering (SANS), combined with complementary techniques such as small angle X-ray scattering, X-ray diffraction, NMR spectroscopy and electron microscopy. Pure cellulose hydrogels were synthesized by cultivation of Gluconacetobacter xylinus strains in glucosecontaining media. Composites were also produced by incorporating polysaccharides typically found in plant cell walls (PCW) into the culture media. The application of a multi-technique characterisation approach enabled elucidation of the complex hierarchical architecture of cellulose hydrogels. Cellulose ribbons, typically modelled as solid one-phase structures, were proven to consist of a sub-structure of cellulose microfibrils interacting with each other and with solvent by means of a dense hydrogen bonding network. The existence of such sub-structure led to the creation of regions with different solvent accessibility within the ribbons, as indicated by the SANS data of pure and composite cellulose hydrogels. Based on this, a core-shell cylinder model combined with an interfacial scattering term was applied to fit the SANS contrast variation data. The fitting results suggested a different effect on the ribbons’ solvent exchange for the diverse composite hydrogels and, supported by additional characterisation, highlighted the distinct interaction mechanisms between cellulose and PCW polysaccharides. Furthermore, the production of partially deuterated cellulose hydrogels by using a deuterated glucose-based feedstock was seen to effectively enhance the neutron scattering length density contrast, opening new possibilities to selectively match the different components in composite hydrogels. The structure of the deuterated cellulose was compared with the native protiated cellulose and SANS contrast variation experiments confirmed the presence of solvent trapped within the cellulose ribbons, behaving differently to

  16. New insights into the structure, assembly and biological roles of 10-12 nm connective tissue microfibrils from fibrillin-1 studies.

    Science.gov (United States)

    Jensen, Sacha A; Handford, Penny A

    2016-04-01

    The 10-12 nm diameter microfibrils of the extracellular matrix (ECM) impart both structural and regulatory properties to load-bearing connective tissues. The main protein component is the calcium-dependent glycoprotein fibrillin, which assembles into microfibrils at the cell surface in a highly regulated process involving specific proteolysis, multimerization and glycosaminoglycan interactions. In higher metazoans, microfibrils act as a framework for elastin deposition and modification, resulting in the formation of elastic fibres, but they can also occur in elastin-free tissues where they perform structural roles. Fibrillin microfibrils are further engaged in a number of cell matrix interactions such as with integrins, bone morphogenetic proteins (BMPs) and the large latent complex of transforming growth factor-β (TGFβ). Fibrillin-1 (FBN1) mutations are associated with a range of heritable connective disorders, including Marfan syndrome (MFS) and the acromelic dysplasias, suggesting that the roles of 10-12 nm diameter microfibrils are pleiotropic. In recent years the use of molecular, cellular and whole-organism studies has revealed that the microfibril is not just a structural component of the ECM, but through its network of cell and matrix interactions it can exert profound regulatory effects on cell function. In this review we assess what is known about the molecular properties of fibrillin that enable it to assemble into the 10-12 nm diameter microfibril and perform such diverse roles. PMID:27026396

  17. Targeting of EMILIN-1 and EMILIN-2 to Fibrillin Microfibrils Facilitates their Incorporation into the Extracellular Matrix.

    Science.gov (United States)

    Schiavinato, Alvise; Keene, Douglas R; Wohl, Alexander P; Corallo, Diana; Colombatti, Alfonso; Wagener, Raimund; Paulsson, Mats; Bonaldo, Paolo; Sengle, Gerhard

    2016-06-01

    Elastin microfibril interface-located proteins (EMILINs) 1 and 2 belong to a family of structurally related extracellular glycoproteins with unique functions in the extracellular space, such as modulation of pro-transforming growth factor-β processing, activation of the extrinsic apoptotic pathway, and regulation of Hedgehog and Wnt ligand bioavailability. However, little is known about how EMILINs may exert their extracellular functions. We therefore investigated the spatiotemporal localization and deposition of EMILIN-1 and -2 within the extracellular space. By using immunoelectron and immunofluorescence microscopy together with biochemical extraction, we showed that EMILIN-1 and -2 are targeted to fibrillin microfibrils in the skin. In addition, during skin wound healing and in vitro matrix fiber assembly by primary dermal fibroblasts, EMILIN-1 and -2 are deposited on and coregulated with fibrillin. Analysis of wounds and mouse embryonic fibroblast cultures showed that EMILIN-1 and -2 network formation also requires the presence of fibronectin. Disruption of microfibrils in fibrillin-1-deficient mice leads to fragmentation of the EMILIN-1 and -2 networks, suggesting an involvement of EMILINs in fibrillin-related skin disorders. The addition of EMILINs to the ligand repertoire of fibrillin strengthens the concept of fibrillin microfibrils as extracellular scaffolds integrating cellular force transmission and growth factor bioactivity. PMID:26945878

  18. CELLULOSIC NANOCOMPOSITES: A REVIEW

    Directory of Open Access Journals (Sweden)

    Martin A. Hubbe

    2008-08-01

    Full Text Available Because of their wide abundance, their renewable and environmentally benign nature, and their outstanding mechanical properties, a great deal of attention has been paid recently to cellulosic nanofibrillar structures as components in nanocomposites. A first major challenge has been to find efficient ways to liberate cellulosic fibrils from different source materials, including wood, agricultural residues, or bacterial cellulose. A second major challenge has involved the lack of compatibility of cellulosic surfaces with a variety of plastic materials. The water-swellable nature of cellulose, especially in its non-crystalline regions, also can be a concern in various composite materials. This review of recent work shows that considerable progress has been achieved in addressing these issues and that there is potential to use cellulosic nano-components in a wide range of high-tech applications.

  19. Cellulose-silica aerogels.

    Science.gov (United States)

    Demilecamps, Arnaud; Beauger, Christian; Hildenbrand, Claudia; Rigacci, Arnaud; Budtova, Tatiana

    2015-05-20

    Aerogels based on interpenetrated cellulose-silica networks were prepared and characterised. Wet coagulated cellulose was impregnated with silica phase, polyethoxydisiloxane, using two methods: (i) molecular diffusion and (ii) forced flow induced by pressure difference. The latter allowed an enormous decrease in the impregnation times, by almost three orders of magnitude, for a sample with the same geometry. In both cases, nanostructured silica gel was in situ formed inside cellulose matrix. Nitrogen adsorption analysis revealed an almost threefold increase in pores specific surface area, from cellulose aerogel alone to organic-inorganic composite. Morphology, thermal conductivity and mechanical properties under uniaxial compression were investigated. Thermal conductivity of composite aerogels was lower than that of cellulose aerogel due to the formation of superinsulating mesoporous silica inside cellulose pores. Furthermore, composite aerogels were stiffer than each of reference aerogels. PMID:25817671

  20. Elucidation of Xylem-Specific Transcription Factors and Absolute Quantification of Enzymes Regulating Cellulose Biosynthesis in Populus trichocarpa.

    Science.gov (United States)

    Loziuk, Philip L; Parker, Jennifer; Li, Wei; Lin, Chien-Yuan; Wang, Jack P; Li, Quanzi; Sederoff, Ronald R; Chiang, Vincent L; Muddiman, David C

    2015-10-01

    Cellulose, the main chemical polymer of wood, is the most abundant polysaccharide in nature.1 The ability to perturb the abundance and structure of cellulose microfibrils is of critical importance to the pulp and paper industry as well as for the textile, wood products, and liquid biofuels industries. Although much has been learned at the transcript level about the biosynthesis of cellulose, a quantitative understanding at the proteome level has yet to be established. The study described herein sought to identify the proteins directly involved in cellulose biosynthesis during wood formation in Populus trichocarpa along with known xylem-specific transcription factors involved in regulating these key proteins. Development of an effective discovery proteomic strategy through a combination of subcellular fractionation of stem differentiating xylem tissue (SDX) with recently optimized FASP digestion protocols, StageTip fractionation, as well as optimized instrument parameters for global proteomic analysis using the quadrupole-orbitrap mass spectrometer resulted in the deepest proteomic coverage of SDX protein from P. trichocarpa with 9,146 protein groups being identified (1% FDR). Of these, 20 cellulosic/hemicellulosic enzymes and 43 xylem-specific transcription factor groups were identified. Finally, selection of surrogate peptides led to an assay for absolute quantification of 14 cellulosic proteins in SDX of P. trichocarpa. PMID:26325666

  1. Mechanical and structural property analysis of bacterial cellulose composites.

    Science.gov (United States)

    Dayal, Manmeet Singh; Catchmark, Jeffrey M

    2016-06-25

    Bacterial cellulose (BC) exhibits unique properties including high mechanical strength and high crystallinity. Improvement in the mechanical properties of BC is sought for many applications ranging from food to structural composites to biomedical materials. In this study, different additives including carboxymethyl cellulose (CMC), pectin, gelatin, cornstarch, and corn steep liquor were included in the fermentation media to alter the BC produced. Three different concentrations (1%, 3% and 5%) were chosen for each of the additives, with no additive (0%) as the control. The produced BC was then analyzed to determine tensile and compression modulus. Amongst the tested additives, BC produced in media containing 3% (w/v) pectin had the maximum compressive modulus (142kPa), and BC produced in media containing 1% (w/v) gelatin exhibited the maximum tensile modulus (21MPa). Structural characteristics of BC and BC-additive composites were compared using X-Ray diffraction (XRD). The crystal size and crystallinity of BC was reduced when grown in the presence of CMC and gelatin while pectin only decreased the crystallite size. This suggested that CMC and gelatin may be incorporated into the BC fibril structure. The field emission scanning electron microscopy (FESEM) images showed the increased micro-fibril aggregation in BC pellicles grown in the presence of additives to the culture media. PMID:27083837

  2. Nanoscale cellulose films with different crystallinities and mesostructures--their surface properties and interaction with water.

    Science.gov (United States)

    Aulin, Christian; Ahola, Susanna; Josefsson, Peter; Nishino, Takashi; Hirose, Yasuo; Osterberg, Monika; Wågberg, Lars

    2009-07-01

    A systematic study of the degree of molecular ordering and swelling of different nanocellulose model films has been conducted. Crystalline cellulose II surfaces were prepared by spin-coating of the precursor cellulose solutions onto oxidized silicon wafers before regeneration in water or by using the Langmuir-Schaefer (LS) technique. Amorphous cellulose films were also prepared by spin-coating of a precursor cellulose solution onto oxidized silicon wafers. Crystalline cellulose I surfaces were prepared by spin-coating wafers with aqueous suspensions of sulfate-stabilized cellulose I nanocrystals and low-charged microfibrillated cellulose (LC-MFC). In addition, a dispersion of high-charged MFC was used for the buildup of polyelectrolyte multilayers with polyetheyleneimine on silica with the aid of the layer-by-layer (LbL) technique. These preparation methods produced smooth thin films on the nanometer scale suitable for X-ray diffraction and swelling measurements. The surface morphology and thickness of the cellulose films were characterized in detail by atomic force microscopy (AFM) and ellipsometry measurements, respectively. To determine the surface energy of the cellulose surfaces, that is, their ability to engage in different interactions with different materials, they were characterized through contact angle measurements against water, glycerol, and methylene iodide. Small incidence angle X-ray diffraction revealed that the nanocrystal and MFC films exhibited a cellulose I crystal structure and that the films prepared from N-methylmorpholine-N-oxide (NMMO), LiCl/DMAc solutions, using the LS technique, possessed a cellulose II structure. The degree of crystalline ordering was highest in the nanocrystal films (approximately 87%), whereas the MFC, NMMO, and LS films exhibited a degree of crystallinity of about 60%. The N,N-dimethylacetamide (DMAc)/LiCl film possessed very low crystalline ordering (<15%). It was also established that the films had different

  3. SURFACE HYDROPHOBICITY MODIFICATION OF CELLULOSE FIBERS BY LAYER-BY-LAYER SELF-ASSSEMBLY OF LIGNOSULFONATES

    Directory of Open Access Journals (Sweden)

    Hui Li

    2011-03-01

    Full Text Available Self-assembled multilayers of lignosulfonates (LS were built up on both quartz slides and cellulose fibers using a Cu2+-mediated layer-by-layer (LBL technique. The growth of LS multilayers on quartz slides was monitored by UV-Vis spectroscopy, and the absorbance at 205 nm as well as at 280 nm was found to linearly increase with the number of layers. The formation of LS multilayers on fibers surfaces was characterized by X-ray photoelectron spectroscopy (XPS and atomic force microscopy (AFM. The XPS results showed that the surface contents of the characteristic elements, S and Cu, of LS multilayers were increased with the number of layers, which suggests the deposition of LS-Cu2+ complexes on cellulose fibers. Furthermore, there was a good linear relationship between the calculated surface LS content and the increment of LS layers. The AFM morphology results confirmed that the cellulose microfibrils on fiber surface were gradually covered by LS particles, resulting in the increase of surface roughness as self-assembly proceeded. The hydrophobicity of cellulose fiber probed by dynamic contact angle was significantly increased due to LBL self-assembly of LS on its surface. The initial contact angle was increased from 0° to 115° as the cellulose fibers were modified with a 5-layer LS multilayer. The reduction rate of the contact angle was dependent on the number of layers. When the cellulose fiber was modified by a 5-layer LS multilayer, the contact angle shifted from 115 to 98° after 0.12 s, suggesting some degree of hydrophobic character. Therefore, this technique provides a simple but effective way for promoting hydrophobicity of cellulose fibers in a controllable manner.

  4. Cellulose nanoparticles as modifiers for rheology and fluid loss in bentonite water-based fluids.

    Science.gov (United States)

    Li, Mei-Chun; Wu, Qinglin; Song, Kunlin; Qing, Yan; Wu, Yiqiang

    2015-03-01

    Rheological and filtration characteristics of drilling fluids are considered as two critical aspects to ensure the success of a drilling operation. This research demonstrates the effectiveness of cellulose nanoparticles (CNPs), including microfibrillated cellulose (MFC) and cellulose nanocrystals (CNCs) in enhancing the rheological and filtration performances of bentonite (BT) water-based drilling fluids (WDFs). CNCs were isolated from MFC through sulfuric acid hydrolysis. In comparison with MFC, the resultant CNCs had much smaller dimensions, more negative surface charge, higher stability in aqueous solutions, lower viscosity, and less evident shear thinning behavior. These differences resulted in the distinctive microstructures between MFC/BT- and CNC/BT-WDFs. A typical "core-shell" structure was created in CNC/BT-WDFs due to the strong surface interactions among BT layers, CNCs, and immobilized water molecules. However, a similar structure was not formed in MFC/BT-WDFs. As a result, CNC/BT-WDFs had superior rheological properties, higher temperature stability, less fluid loss volume, and thinner filter cakes than BT and MFC/BT-WDFs. Moreover, the presence of polyanionic cellulose (PAC) further improved the rheological and filtration performances of CNC/BT-WDFs, suggesting a synergistic effect between PAC and CNCs. PMID:25679499

  5. The effect of chemical composition on microfibrillar cellulose films from wood pulps: mechanical processing and physical properties.

    Science.gov (United States)

    Spence, Kelley L; Venditti, Richard A; Habibi, Youssef; Rojas, Orlando J; Pawlak, Joel J

    2010-08-01

    Films of microfibrillated celluloses (MFCs) from pulps of different yields, containing varying amounts of extractives, lignin, and hemicelluloses, were produced by combining refining and high-pressure homogenization techniques. MFC films were produced using a casting-evaporation technique and the physical and mechanical properties (including density, roughness, fold endurance and tensile properties) were determined. Homogenization of bleached and unbleached Kraft pulps gave rise to highly individualized MFCs, but not for thermo-mechanical pulp (TMP). The resulting MFC films had a roughness equivalent to the surface upon which the films were cast. Interestingly, after homogenization, the presence of lignin significantly increased film toughness, tensile index, and elastic modulus. The hornification of fibers through a drying and rewetting cycle prior to refining and homogenization did not produce any significant effect compared to films from never-dried fibers, indicating that MFC films can potentially be made from low-cost recycled cellulosic materials. PMID:20335025

  6. Exploration of a Chemo-Mechanical Technique for the Isolation of Nanofibrillated Cellulosic Fiber from Oil Palm Empty Fruit Bunch as a Reinforcing Agent in Composites Materials

    Directory of Open Access Journals (Sweden)

    Ireana Yusra A. Fatah

    2014-10-01

    Full Text Available The aim of the present study was to determine the influence of sulphuric acid hydrolysis and high-pressure homogenization as an effective chemo-mechanical process for the isolation of quality nanofibrillated cellulose (NFC. The cellulosic fiber was isolated from oil palm empty fruit bunch (OPEFB using acid hydrolysis methods and, subsequently, homogenized using a high-pressure homogenizer to produce NFC. The structural analysis and the crystallinity of the raw fiber and extracted cellulose were carried out by Fourier transform infrared spectroscopy (FT-IR and X-ray diffraction (XRD. The morphology and thermal stability were investigated by scanning electron microscopy (SEM, transmission electron microscopy (TEM and thermogravimetric (TGA analyses, respectively. The FTIR results showed that lignin and hemicellulose were removed effectively from the extracted cellulose nanofibrils. XRD analysis revealed that the percentage of crystallinity was increased from raw EFB to microfibrillated cellulose (MFC, but the decrease for NFC might due to a break down the hydrogen bond. The size of the NFC was determined within the 5 to 10 nm. The TGA analysis showed that the isolated NFC had high thermal stability. The finding of present study reveals that combination of sulphuric acid hydrolysis and high-pressure homogenization could be an effective chemo-mechanical process to isolate cellulose nanofibers from cellulosic plant fiber for reinforced composite materials.

  7. Multiscale approach including microfibril scale to assess elastic constants of cortical bone based on neural network computation and homogenization method

    CERN Document Server

    Barkaoui, Abdelwahed; Tarek, Merzouki; Hambli, Ridha; Ali, Mkaddem

    2014-01-01

    The complexity and heterogeneity of bone tissue require a multiscale modelling to understand its mechanical behaviour and its remodelling mechanisms. In this paper, a novel multiscale hierarchical approach including microfibril scale based on hybrid neural network computation and homogenisation equations was developed to link nanoscopic and macroscopic scales to estimate the elastic properties of human cortical bone. The multiscale model is divided into three main phases: (i) in step 0, the elastic constants of collagen-water and mineral-water composites are calculated by averaging the upper and lower Hill bounds; (ii) in step 1, the elastic properties of the collagen microfibril are computed using a trained neural network simulation. Finite element (FE) calculation is performed at nanoscopic levels to provide a database to train an in-house neural network program; (iii) in steps 2 to 10 from fibril to continuum cortical bone tissue, homogenisation equations are used to perform the computation at the higher s...

  8. A 3D Multiscale Modelling of Cortical Bone Structure, Using the Inverse Identification Method: Microfibril Scale Study

    CERN Document Server

    Barkaoui, Abdelwahed

    2011-01-01

    Complexity and heterogeneity of bone tissue require a multiscale modelling to understand their mechanical behaviour and their remodelling mechanism. Human cortical bone structure consists of six structural scale levels which are the (macroscopic) cortical bone, osteonal, lamellar, fibrous, fibril and microfibril. In this paper, a 3D model based on finite elements method was achieved to study the nanomechanical behaviour of collagen Microfibril. The mechanical properties and the geometry (gap, overlap and diameter) of both tropocollagen and mineral were taken into consideration as well as the effects of cross-links. An inverse identification method has been applied to determine equivalent averaged properties in order to link up these nanoscopic characteristics to the macroscopic mechanical behaviour of bone tissue. Results of nanostructure modelling of the nanomechanical properties of strain deformation under varying cross-links were investigated in this work.

  9. Two active forms of Zymomonas mobilis levansucrase. An ordered microfibril structure of the enzyme promotes levan polymerization.

    Science.gov (United States)

    Goldman, Dan; Lavid, Noa; Schwartz, Alon; Shoham, Gil; Danino, Dganit; Shoham, Yuval

    2008-11-21

    Fructansucrases, members of glycoside hydrolase family 68, catalyze both sucrose hydrolysis and the polymerization of fructose to beta-d-fructofuranose polymers. The resulting fructan polymers are distinguished by the nature of the glycosidic bond: inulin (beta-(2-1)-fructofuranose) and levan (beta-(2-6)-fructofuranose). In this study we demonstrate that Zymomonas mobilis levansucrase exists in two active forms, depending on the pH and ionic strength. At pH values above 7.0, the enzyme is mainly a dimer, whereas at pH values below 6.0, the protein forms well ordered microfibrils that precipitate out of the solution. These two forms are readily interchangeable simply by changing the pH. Surprisingly the manner in which the enzyme is arranged strongly affects its product specificity and kinetic properties. At pH values above 7.0, the activity of the enzyme as a dimer is mainly sucrose hydrolysis and the synthesis of short fructosaccharides (degree of polymerization, 3). At pH values below 6.0, in its microfibril form, the enzyme catalyzes almost exclusively the synthesis of levan (a degree of polymerization greater than 20,000). This difference in product specificity appears to depend on the form of the enzyme, dimer versus microfibril, and not directly on the pH. Images made by negative stain transmission electron microscopy reveal that the enzyme forms a very ordered structure of long fibrils that appear to be composed of repeating rings of six to eight protein units. A single amino acid replacement of H296R abolished the ability of the enzyme to form microfibrils with organized fibril networks and to synthesize levan at pH 6.0. PMID:18809687

  10. Fulton Cellulosic Ethanol Biorefinery

    Energy Technology Data Exchange (ETDEWEB)

    Sumait, Necy [BlueFire Ethanol, Irvine, CA (United States); Cuzens, John [BlueFire Ethanol, Irvine, CA (United States); Klann, Richard [BlueFire Ethanol, Irvine, CA (United States)

    2015-07-24

    Final report on work performed by BlueFire on the deployment of acid hydrolysis technology to convert cellulosic waste materials into renewable fuels, power and chemicals in a production facility to be located in Fulton, Mississippi.

  11. Biosynthesis of bacterial cellulose in the presence of different nanoparticles to create novel hybrid materials.

    Science.gov (United States)

    Erbas Kiziltas, Esra; Kiziltas, Alper; Blumentritt, Melanie; Gardner, Douglas J

    2015-09-20

    The unique micro-nano porous three-dimensional network of bacterial cellulose (BC) can facilitate the incorporation of nanoparticles (NPs) into the BC matrix to create advanced BC-based functional nanomaterials for diverse applications. In this study, novel nanomaterials comprised of bacterial cellulose (BC) synthesized in the presence of different NPs (cellulose nanofibrils (CNF), exfoliated graphite nanoplatelets (xGnP), and nanoclay (NC)) were prepared using an in situ approach. NPs at 0.5 wt.% loading were added into the BC culture medium and their effect on the resulting nanocomposite structure was studied by field emission scanning electron microscopy (FE-SEM), X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and thermogravimetric analysis (TGA). All BC-based nanomaterials produced, exhibited good dispersion of the NPs within the BC matrix and the NPs were found embedded among the voids and microfibrils. The thermal stability and residual mass of BC-xGnP and BC-NC nanomaterials was significantly increased compared with the neat BC. CNF incorporation into the BC matrix did not change the thermal stability and residual mass of the BC matrix. This study also provides novel insights into the properties of the hybrid materials, and shows the approach used to make these materials which results in increased performance for chosen applications. PMID:26050900

  12. Self-organized films from cellulose I Nanofibrils using the layer-by-layer technique.

    Science.gov (United States)

    Aulin, Christian; Johansson, Erik; Wågberg, Lars; Lindström, Tom

    2010-04-12

    The possibility of forming self-organized films using only charge-stabilized dispersions of cellulose I nanofibrils with opposite charges is presented, that is, the multilayers were composed solely of anionically and cationically modified microfibrillated cellulose (MFC) with a low degree of substitution. The build-up behavior and the properties of the layer-by-layer (LbL)-constructed films were studied using a quartz crystal microbalance with dissipation (QCM-D) and stagnation point adsorption reflectometry (SPAR). The adsorption behavior of cationic/anionic MFC was compared with that of polyethyleneimine (PEI)/anionic MFC. The water contents of five bilayers of cationic/anionic MFC and PEI/anionic MFC were approximately 70 and 50%, respectively. The MFC surface coverage was studied by atomic force microscopy (AFM) measurements, which clearly showed a more dense fibrillar structure in the five bilayer PEI/anionic MFC than in the five bilayer cationic/anionic MFC. The forces between the cellulose-based multilayers were examined using the AFM colloidal probe technique. The forces on approach were characterized by a combination of electrostatic and steric repulsion. The wet adhesive forces were very long-range and were characterized by multiple adhesive events. Surfaces covered by PEI/anionic MFC multilayers required more energy to be separated than surfaces covered by cationic/anionic MFC multilayers. PMID:20196583

  13. Colloidal ionic assembly between anionic native cellulose nanofibrils and cationic block copolymer micelles into biomimetic nanocomposites.

    Science.gov (United States)

    Wang, Miao; Olszewska, Anna; Walther, Andreas; Malho, Jani-Markus; Schacher, Felix H; Ruokolainen, Janne; Ankerfors, Mikael; Laine, Janne; Berglund, Lars A; Osterberg, Monika; Ikkala, Olli

    2011-06-13

    We present a facile ionic assembly between fibrillar and spherical colloidal objects toward biomimetic nanocomposites with majority hard and minority soft domains based on anionic reinforcing native cellulose nanofibrils and cationic amphiphilic block copolymer micelles with rubbery core. The concept is based on ionic complexation of carboxymethylated nanofibrillated cellulose (NFC, or also denoted as microfibrillated cellulose, MFC) and micelles formed by aqueous self-assembly of quaternized poly(1,2-butadiene)-block-poly(dimethylaminoethyl methacrylate) with high fraction of the NFC reinforcement. The adsorption of block copolymer micelles onto nanocellulose is shown by quartz crystal microbalance measurements, atomic force microscopy imaging, and fluorescent optical microscopy. The physical properties are elucidated using electron microscopy, thermal analysis, and mechanical testing. The cationic part of the block copolymer serves as a binder to NFC, whereas the hydrophobic rubbery micellar cores are designed to facilitate energy dissipation and nanoscale lubrication between the NFC domains under deformation. We show that the mechanical properties do not follow the rule of mixtures, and synergistic effects are observed with promoted work of fracture in one composition. As the concept allows wide possibilities for tuning, the work suggests pathways for nanocellulose-based biomimetic nanocomposites combining high toughness with stiffness and strength. PMID:21517114

  14. Loosenin, a novel protein with cellulose-disrupting activity from Bjerkandera adusta

    Directory of Open Access Journals (Sweden)

    Segovia Lorenzo

    2011-02-01

    Full Text Available Abstract Background Expansins and expansin-like proteins loosen cellulose microfibrils, possibly through the rupture of intramolecular hydrogen bonds. Together with the use of lignocellulolytic enzymes, these proteins are potential molecular tools to treat plant biomass to improve saccharification yields. Results Here we describe a new type of expansin-related fungal protein that we have called loosenin. Its corresponding gene, loos1, from the basidiomycete Bjerkandera adusta, was cloned and heterologously expressed in Saccharomyces cerevisiae. LOOS1 is distantly related to plant expansins through the shared presence of a DPBB domain, however domain II found in plant expansins is absent. LOOS1 binds tightly to cellulose and chitin, and we demonstrate that cotton fibers become susceptible to the action of a commercial cellulase following treatment with LOOS1. Natural fibers of Agave tequilana also become susceptible to hydrolysis by cellulases after loosenin treatment. Conclusions LOOS1 is a new type of protein with disrupting activity on cellulose. LOOS1 binds polysaccharides, and given its enhancing properties on the action of hydrolytic enzymes, LOOS1 represents a potential additive in the production of fermentable sugars from lignocellulose.

  15. Photoresponsive Cellulose Nanocrystals

    Directory of Open Access Journals (Sweden)

    Dimitris S Argyropoulos

    2011-07-01

    Full Text Available In this communication a method for the creation of fluorescent cellulose nanoparticles using click chemistry and subsequent photodimerization of the installed side‐ chains is demonstrated. In the first step, the primary hydroxyl groups on the surface of the CNCs were converted to carboxylic acids by using TEMPO‐mediated hypohalite oxidation. The alkyne groups, essential for the click reaction, were introduced into the surface of TEMPO‐ oxidized CNCs via carbodiimide‐mediated formation of an amide linkage between monomers carrying an amine functionality and carboxylic acid groups on the surface of the TEMPO‐oxidized CNCs. Finally, the reaction of surface‐modified TEMPO‐oxidized cellulose nanocrystals and azido‐bearing coumarin and anthracene monomers were carried out by means of a click chemistry, i.e., Copper(I‐catalyzed Azide‐Alkyne Cycloaddition (CuAAC to produce highly photo‐responsive and fluorescent cellulose nanoparticles. Most significantly, the installed coumarin and/or anthracene side‐chains were shown to undergo UV‐induced [2+2] and [4+4] cycloaddition reactions, bringing and locking the cellulose nanocrystals together. This effort paves the way towards creating, cellulosic photo responsive nano‐arrays with the potential of photo reversibility since these reactions are known to be reversible at varying wavelengths.

  16. Pretreatment Methods of Ligno - Cellulosic Biomass: A Review

    Directory of Open Access Journals (Sweden)

    Aritra Das

    2015-12-01

    Full Text Available Present work primarily deals with the exhaustive investigations of rapid de-lignification processes from source-sorted organic fractions that are recalcitrant in nature. Organic solid wastes (OSW belongs to the organic fraction of municipal solid wastes (MSW and they act as enormous potential substrate for alternative source of energy in the form of bio-fuels. Nevertheless, these substrates are not easily biodegradable and the degree of biodegradability is solely dependent on the composition & characteristic of organic solid wastes in municipal solid wastes. The component responsible for recalcitrance of organic solid wastes is lignin that occurs in variable amounts in different plant residues. In order to remove the recalcitrance from organic fraction municipal solid wastes and to make it more easily degradable by microbial consortia, certain pretreatment techniques have been adopted and they are applied either individually or in combined way for enhancement of bio-methanation i.e anaerobic digestion (AD process. The goal of pretreatment method is to make the cellulose in micro-fibrils available for hydrolysis and improve the rate of hydrolysis. This paper reviews pretreatment techniques including physical, physico-chemical, chemical, biological methods respectively. The various effects of pretreatment on organic solid wastes are discussed separately and pretreatment methods have been compared on the basis of cost, efficiency and suitability to substrate.

  17. Apo- and Cellopentaose-bound Structures of the Bacterial Cellulose Synthase Subunit BcsZ

    Energy Technology Data Exchange (ETDEWEB)

    Mazur, Olga; Zimmer, Jochen (UV)

    2012-10-25

    Cellulose, a very abundant extracellular polysaccharide, is synthesized in a finely tuned process that involves the activity of glycosyl-transferases and hydrolases. The cellulose microfibril consists of bundles of linear {beta}-1,4-glucan chains that are synthesized inside the cell; however, the mechanism by which these polymers traverse the cell membrane is currently unknown. In Gram-negative bacteria, the cellulose synthase complex forms a trans-envelope complex consisting of at least four subunits. Although three of these subunits account for the synthesis and translocation of the polysaccharide, the fourth subunit, BcsZ, is a periplasmic protein with endo-{beta}-1,4-glucanase activity. BcsZ belongs to family eight of glycosyl-hydrolases, and its activity is required for optimal synthesis and membrane translocation of cellulose. In this study we report two crystal structures of BcsZ from Escherichia coli. One structure shows the wild-type enzyme in its apo form, and the second structure is for a catalytically inactive mutant of BcsZ in complex with the substrate cellopentaose. The structures demonstrate that BcsZ adopts an ({alpha}/{alpha}){sub 6}-barrel fold and that it binds four glucan moieties of cellopentaose via highly conserved residues exclusively on the nonreducing side of its catalytic center. Thus, the BcsZ-cellopentaose structure most likely represents a posthydrolysis state in which the newly formed nonreducing end has already left the substrate binding pocket while the enzyme remains attached to the truncated polysaccharide chain. We further show that BcsZ efficiently degrades {beta}-1,4-glucans in in vitro cellulase assays with carboxymethyl-cellulose as substrate.

  18. The cellulose resource matrix.

    Science.gov (United States)

    Keijsers, Edwin R P; Yılmaz, Gülden; van Dam, Jan E G

    2013-03-01

    The emerging biobased economy is causing shifts from mineral fossil oil based resources towards renewable resources. Because of market mechanisms, current and new industries utilising renewable commodities, will attempt to secure their supply of resources. Cellulose is among these commodities, where large scale competition can be expected and already is observed for the traditional industries such as the paper industry. Cellulose and lignocellulosic raw materials (like wood and non-wood fibre crops) are being utilised in many industrial sectors. Due to the initiated transition towards biobased economy, these raw materials are intensively investigated also for new applications such as 2nd generation biofuels and 'green' chemicals and materials production (Clark, 2007; Lange, 2007; Petrus & Noordermeer, 2006; Ragauskas et al., 2006; Regalbuto, 2009). As lignocellulosic raw materials are available in variable quantities and qualities, unnecessary competition can be avoided via the choice of suitable raw materials for a target application. For example, utilisation of cellulose as carbohydrate source for ethanol production (Kabir Kazi et al., 2010) avoids the discussed competition with easier digestible carbohydrates (sugars, starch) deprived from the food supply chain. Also for cellulose use as a biopolymer several different competing markets can be distinguished. It is clear that these applications and markets will be influenced by large volume shifts. The world will have to reckon with the increase of competition and feedstock shortage (land use/biodiversity) (van Dam, de Klerk-Engels, Struik, & Rabbinge, 2005). It is of interest - in the context of sustainable development of the bioeconomy - to categorize the already available and emerging lignocellulosic resources in a matrix structure. When composing such "cellulose resource matrix" attention should be given to the quality aspects as well as to the available quantities and practical possibilities of processing the

  19. Electrochemical synthesis of cellulose mesylate

    Science.gov (United States)

    Khidirov, Sh Sh; Akhmedov, M. A.; Khibiev, H. S.

    2016-04-01

    The article deal with the possibility anode modification of cellulose to form its ester - mesylate by voltametric measurement method and preparative electrosynthesis on a platinum electrode in the system cellulose - dimethyl sulfoxide - methanesulfonic

  20. Conductive nano composites based on cellulose nano fiber coated poly aniline via in situ polymerization; Nanocompositos condutores de nanofibras de celulose recobertas com polianilina via polimerizacao in situ

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Michael J. da; Sanches, Alex O.; Malmonge, Luiz F.; Malmonge, Jose A. [Grupo de Polimero, Depto de Fisica e Quimica, Faculdade de Engenharia de Ilha Solteira, Universidade Estadual Paulista, Ilha Solteira, SP (Brazil); Medeiros, Eliton S. de [Depto de Engenharia de Materiais, Universidade Federal da Paraiba, Joao Pessoa, PB (Brazil); Rosa, Morsyleide F. [Embrapa Agroindustria Tropical, Fortaleza, CE (Brazil)

    2011-07-01

    Cellulose nano fiber (CNF) was extracted by acid hydrolysis from cotton microfibril and nano composites of CNF/PANI-DBSA were obtained by in situ polymerization of aniline onto CNF. The ratios between DBSA/aniline and aniline/oxidant were varied and the nano composites were characterized by four probes direct current (dc) electrical conductivity, ultraviolet-visible (UV-Vis-NIR) and FTIR spectroscopy and X-ray diffraction (XRD). Electrical conductive about {approx}10{sup -1}S/cm was research and was independent of DBSA/aniline molar ratio between 2-4 and the aniline/oxidant molar ratio between 1-5. X-ray patterns of the samples show crystalline peaks characteristic of cellulose I. The FTIR spectra confirmed the presence of PANI and CNF in all samples. (author)

  1. Structure of cellulose acetobacter xylinum

    International Nuclear Information System (INIS)

    The data are presented on optimization of cellulose synthesis by Acetobacter xylinum (strain VKM V-880) and the structural characteristics of A. xylinum cellulose gel film synthesized during static cultivation. The structural changes caused by the removal of water from gel films are established and the structural organization of macromolecular chains in cellulose A. xylinum is studied

  2. CARS and SHG microscopy for the characterization of bacterial cellulose

    Science.gov (United States)

    Enejder, Annika; Brackmann, Christian; Bodin, Aase; Åkeson, Madeleine; Gatenholm, Paul

    2009-02-01

    We have developed a protocol employing dual-mode non-linear microscopy for the monitoring of the biosynthesis of bacterial cellulose at a single-fiber level, with the fundamental aim to achieve a product with material properties similar to those of human blood vessels. Grown in a tubular geometry it could then be used as a natural and biocompatible source of replacement tissue in conjunction with cardiovascular surgery. The bacteria (Acetobacter xylinum) were selectively visualized based on the CH2 vibration of its organic macromolecular contents by the Coherent Anti-Stokes Raman Scattering (CARS) process and, simultaneously, the non-centrosymmetrically ordered, birefringent cellulose fibers were depicted by the Second Harmonic Generation (SHG) process. This dual-channel detection approach allows the monitoring of cellulose-fiber formation in vivo and to determine the influence of e.g. different growth conditions on fiber thickness and orientation, their assembling into higher-order structures and overall network density. The bacterial and fiber distributions were monitored in a simple microscope cultivation chamber, as well as in samples harvested during the actual fermentation process of tubular cellulose grafts. The CARS and SHG co-localization images reveal that highest bacterial population densities can be observed in the surface regions of the cellulose tissue, where the primary growth presumably takes place. The cellulose network morphology was also compared with that of human arteries and veins, from which we conclude that the cellulose matrix is comparatively homogeneous in contrast to the wavy band-like supra-formations of collagen in the native tissue. This prompts for sophisticated fermentation methods by which tunnels and pores of appropriate sizes and shapes can be introduced in the cellulose network in a controllable way. With this protocol we hope to contribute to the fundamental knowledge required for optimal production of bioengineered cellulose

  3. CHARACTERIZATION OF REGENERATED CELLULOSE MEMBRANES HYDROLYZED FROM CELLULOSE ACETATE

    Institute of Scientific and Technical Information of China (English)

    Yun Chen; Xiao-peng Xiong; Guang Yang; Li-na Zhang; Sen-lin Lei; Hui Lianga

    2002-01-01

    A series of cellulose acetate membranes were prepared by using formamide as additive, and then were hydrolyzedin 4 wt% aqueous NaOH solution for 8 h to obtain regenerated cellulose membranes. The dependence of degree ofsubstitution, structure, porous properties, solubility and thermal stability on hydrolysis time was studied by chemical titration,Fourier transform infrared spectroscopy, scanning electron microscopy, wide-angle X-ray diffraction, and differentialscanning calorimetry, respectively. The results indicated that the pore size of the regenerated cellulose membranes wasslightly smaller than that of cellulose acetate membrane, while solvent-resistance, crystallinity and thermostability weresignificantly improved. This work provides a simple way to prepare the porous cellulose membranes, which not only kept thegood pore characteristics of cellulose acetate membranes, but also possessed solvent-resistance, high crystallinity andthermostability. Therefore, the application range of cellulose acetate membranes can be expanded.

  4. Degradation of cellulose in irradiated wood and purified celluloses

    International Nuclear Information System (INIS)

    The degradation of cellulose chains in Pinus radiata and Eucalyptus regnans given small gamma-radiation doses has been studied. Scission yields showed marked dose-dependency effects, of which some appear to be due to an inherent dose-dependency exhibited by cellulose itself, and others indicate a protective action of some natural wood constituents. A uniform treatment of viscometry data reported by various workers who have studied radiation-induced degradation of purified cellulose materials, has been used to enable their scission results to be compared with each other and with those for natural wood cellulose of various dose levels. Generally, cellulose in wood is less degraded by radiation than is purified cellulose. However, with Eucalyptus regnans remarkably high scission yields, significantly higher than expected for purified cellulose, were observed at dose levels of 0.5-1.0 x 104Gy. The relevance of these results to changes in pulp yield following irradiation of wood chips, is briefly discussed. (author)

  5. Multiscale approach including microfibril scale to assess elastic constants of cortical bone based on neural network computation and homogenization method.

    Science.gov (United States)

    Barkaoui, Abdelwahed; Chamekh, Abdessalem; Merzouki, Tarek; Hambli, Ridha; Mkaddem, Ali

    2014-03-01

    The complexity and heterogeneity of bone tissue require a multiscale modeling to understand its mechanical behavior and its remodeling mechanisms. In this paper, a novel multiscale hierarchical approach including microfibril scale based on hybrid neural network (NN) computation and homogenization equations was developed to link nanoscopic and macroscopic scales to estimate the elastic properties of human cortical bone. The multiscale model is divided into three main phases: (i) in step 0, the elastic constants of collagen-water and mineral-water composites are calculated by averaging the upper and lower Hill bounds; (ii) in step 1, the elastic properties of the collagen microfibril are computed using a trained NN simulation. Finite element calculation is performed at nanoscopic levels to provide a database to train an in-house NN program; and (iii) in steps 2-10 from fibril to continuum cortical bone tissue, homogenization equations are used to perform the computation at the higher scales. The NN outputs (elastic properties of the microfibril) are used as inputs for the homogenization computation to determine the properties of mineralized collagen fibril. The mechanical and geometrical properties of bone constituents (mineral, collagen, and cross-links) as well as the porosity were taken in consideration. This paper aims to predict analytically the effective elastic constants of cortical bone by modeling its elastic response at these different scales, ranging from the nanostructural to mesostructural levels. Our findings of the lowest scale's output were well integrated with the other higher levels and serve as inputs for the next higher scale modeling. Good agreement was obtained between our predicted results and literature data. PMID:24123969

  6. The cellulose resource matrix

    NARCIS (Netherlands)

    Keijsers, E.R.P.; Yilmaz, G.; Dam, van J.E.G.

    2013-01-01

    The emerging biobased economy is causing shifts from mineral fossil oil based resources towards renewable resources. Because of market mechanisms, current and new industries utilising renewable commodities, will attempt to secure their supply of resources. Cellulose is among these commodities, where

  7. Cysticercosis cellulose cutis

    Directory of Open Access Journals (Sweden)

    Inamadar Arun

    2001-01-01

    Full Text Available A woman aged 30 years with solitary lesion of cysticercosis cellulose cutis is reported. Cutaneous cysticerci are often a pointer to the involvement of internal organs. Our patient was a pure vegetarian so, probable mode of infection may be ingestion of contaminated vegetables, where the practice of using pig feces as manure is prevalent.

  8. Derivatives of Oxidized Cellulose

    Czech Academy of Sciences Publication Activity Database

    Taubner, T.; Sobek, Jiří; Havelka, P.; Kvasnička, F.; Synytsya, A.; Čopíková, J.

    Praha : Česká společnost chemická, 2009, s. 777. ISSN 0009-2770. [International Conference on Polysaccharides-Glycoscience 2009 /5./. Praha (CZ), 11.11.2009-13.11.2009] Institutional research plan: CEZ:AV0Z40720504 Keywords : cellulose * reaction progress * chromatography Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  9. The Influence of S_2 Microfibril Angle on Longitudinal and Tangential Shrinkage in China-fir (Cunninghamia lanceolata) Plantation

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The first objective of this study was to investigate the variation of microfibril angle (Mfa), tracheid morphology and shrinkage within China-fir (Cunninghamia lanceolata) plantation tree. The second objective was to discuss the relationship between Mfa and tracheid morphology, and the influence of Mfa on longitudinal and tangential shrinkage. The results showed that the mean value of Mfa decreased from the 2nd (30.8°) to 26th growth ring (7.7°); the radial variation of latewood tracheid length ranged f...

  10. Enzymatic hydrolysis combined with mechanical shearing and high-pressure homogenization for nanoscale cellulose fibrils and strong gels.

    Science.gov (United States)

    Pääkkö, M; Ankerfors, M; Kosonen, H; Nykänen, A; Ahola, S; Osterberg, M; Ruokolainen, J; Laine, J; Larsson, P T; Ikkala, O; Lindström, T

    2007-06-01

    Toward exploiting the attractive mechanical properties of cellulose I nanoelements, a novel route is demonstrated, which combines enzymatic hydrolysis and mechanical shearing. Previously, an aggressive acid hydrolysis and sonication of cellulose I containing fibers was shown to lead to a network of weakly hydrogen-bonded rodlike cellulose elements typically with a low aspect ratio. On the other hand, high mechanical shearing resulted in longer and entangled nanoscale cellulose elements leading to stronger networks and gels. Nevertheless, a widespread use of the latter concept has been hindered because of lack of feasible methods of preparation, suggesting a combination of mild hydrolysis and shearing to disintegrate cellulose I containing fibers into high aspect ratio cellulose I nanoscale elements. In this work, mild enzymatic hydrolysis has been introduced and combined with mechanical shearing and a high-pressure homogenization, leading to a controlled fibrillation down to nanoscale and a network of long and highly entangled cellulose I elements. The resulting strong aqueous gels exhibit more than 5 orders of magnitude tunable storage modulus G' upon changing the concentration. Cryotransmission electron microscopy, atomic force microscopy, and cross-polarization/magic-angle spinning (CP/MAS) 13C NMR suggest that the cellulose I structural elements obtained are dominated by two fractions, one with lateral dimension of 5-6 nm and one with lateral dimensions of about 10-20 nm. The thicker diameter regions may act as the junction zones for the networks. The resulting material will herein be referred to as MFC (microfibrillated cellulose). Dynamical rheology showed that the aqueous suspensions behaved as gels in the whole investigated concentration range 0.125-5.9% w/w, G' ranging from 1.5 Pa to 105 Pa. The maximum G' was high, about 2 orders of magnitude larger than typically observed for the corresponding nonentangled low aspect ratio cellulose I gels, and G' scales

  11. Characterization of the viscoelastic behavior of a simplified collagen micro-fibril based on molecular dynamics simulations.

    Science.gov (United States)

    Ghodsi, Hossein; Darvish, Kurosh

    2016-10-01

    Collagen fibril is a major component of connective tissues such as bone, tendon, blood vessels, and skin. The mechanical properties of this highly hierarchical structure are greatly influenced by the presence of covalent cross-links between individual collagen molecules. This study investigates the viscoelastic behavior of a collagen lysine-lysine cross-link based on creep simulations with applied forces in the range or 10 to 2000pN using steered molecular dynamics (SMD). The viscoelastic model of the cross-link was combined with a system composed by two segments of adjacent collagen molecules hence representing a reduced viscoelastic model for a simplified micro-fibril. It was found that the collagen micro-fibril assembly had a steady-state Young׳s modulus ranging from 2.24 to 3.27GPa, which is in agreement with reported experimental measurements. The propagation of longitudinal force wave along the molecule was implemented by adding a delay element to the model. The force wave speed was found to be correlated with the speed of one-dimensional elastic waves in rods. The presented reduced model with three degrees of freedom can serve as a building block for developing models of the next level of hierarchy, i.e., a collagen fibril. PMID:27341288

  12. Synthesis and characterization of cellulose derivatives obtained from bacterial cellulose

    International Nuclear Information System (INIS)

    The chemical modification of cellulose leads to production of derivatives with different properties from those observed for the original cellulose, for example, increased solubility in more traditional solvents. In this work we synthesized four derivatives of cellulose: microcrystalline cellulose, cellulose acetate, methylcellulose and carboxymethylcellulose using bacterial cellulose as a source. These were characterized in terms of chemical and structural changes by examining the degree of substitution (DS), infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy - NMR 13C. The molecular weight and degree of polymerization were evaluated by viscometry. The characterization of the morphology of materials and thermal properties were performed with the techniques of X-ray diffraction, electron microscopy images, differential scanning calorimetry (DSC) and thermogravimetric analysis. (author)

  13. Bacterial cellulose: the ultimate nano-scalar cellulose morphology for the production of high-strength composites

    Science.gov (United States)

    Nakagaito, A. N.; Iwamoto, S.; Yano, H.

    2005-01-01

    High-strength composites were produced using bacterial cellulose (BC) sheets impregnated with phenolic resin and compressed at 100 MPa. By utilizing this unique material synthesized by bacteria, it was possible to improve the mechanical properties over the previously reported high-strength composites based on fibrillated kraft pulp of plant origin. BC-based composites were stronger, and in particular the Young’s modulus was significantly higher, attaining 28 GPa versus 19 GPa of fibrillated pulp composites. The superior modulus value was attributed to the uniform, continuous, and straight nano-scalar network of cellulosic elements oriented in-plane via the compression of BC pellicles.

  14. Novel oil resistant cellulosic materials

    OpenAIRE

    Aulin, Christian

    2009-01-01

    The aim of this study has been to prepare and characterise oil resistant cellulosic materials, ranging from model surfaces to papers and aerogels. The cellulosic materials were made oil resistant by chemical and topographic modifications, based on surface energy, surface roughness and barrier approaches. Detailed wetting studies of the prepared cellulosic materials were made using contact angle measurements and standardised penetration tests with different alkanes and oil mixtures. A signific...

  15. Adamtsl2 deletion results in bronchial fibrillin microfibril accumulation and bronchial epithelial dysplasia – a novel mouse model providing insights into geleophysic dysplasia

    Directory of Open Access Journals (Sweden)

    Dirk Hubmacher

    2015-05-01

    Full Text Available Mutations in the secreted glycoprotein ADAMTSL2 cause recessive geleophysic dysplasia (GD in humans and Musladin–Lueke syndrome (MLS in dogs. GD is a severe, often lethal, condition presenting with short stature, brachydactyly, stiff skin, joint contractures, tracheal-bronchial stenosis and cardiac valve anomalies, whereas MLS is non-lethal and characterized by short stature and severe skin fibrosis. Although most mutations in fibrillin-1 (FBN1 cause Marfan syndrome (MFS, a microfibril disorder leading to transforming growth factor-β (TGFβ dysregulation, domain-specific FBN1 mutations result in dominant GD. ADAMTSL2 has been previously shown to bind FBN1 and latent TGFβ-binding protein-1 (LTBP1. Here, we investigated mice with targeted Adamtsl2 inactivation as a new model for GD (Adamtsl2−/− mice. An intragenic lacZ reporter in these mice showed that ADAMTSL2 was produced exclusively by bronchial smooth muscle cells during embryonic lung development. Adamtsl2−/− mice, which died at birth, had severe bronchial epithelial dysplasia with abnormal glycogen-rich inclusions in bronchial epithelium resembling the cellular anomalies described previously in GD. An increase in microfibrils in the bronchial wall was associated with increased FBN2 and microfibril-associated glycoprotein-1 (MAGP1 staining, whereas LTBP1 staining was increased in bronchial epithelium. ADAMTSL2 was shown to bind directly to FBN2 with an affinity comparable to FBN1. The observed extracellular matrix (ECM alterations were associated with increased bronchial epithelial TGFβ signaling at 17.5 days of gestation; however, treatment with TGFβ-neutralizing antibody did not correct the epithelial dysplasia. These investigations reveal a new function of ADAMTSL2 in modulating microfibril formation, and a previously unsuspected association with FBN2. Our studies suggest that the bronchial epithelial dysplasia accompanying microfibril dysregulation in Adamtsl2−/− mice

  16. Fatigue damage evaluation of plain woven carbon fiber reinforced plastic (CFRP) modified with MFC (micro-fibrillated cellulose) by thermo-elastic damage analysis (TDA)

    Science.gov (United States)

    Aoyama, Ryohei; Okubo, Kazuya; Fujii, Toru

    2013-04-01

    The aim of this study is to investigate characteristics of fatigue damage of CFRP modified with MFC by TDA under tensile cyclic loading. In this paper, fatigue life of CFRP modified with MFC was investigated under cyclic loading. Characteristics of fatigue damage of CFRP modified with MFC were evaluated by thermo-elastic damage analysis. Maximum improvement in fatigue life was also obtained under cyclic loading when epoxy matrix was enhanced with 0.3wt% of MFC as well as under static loading. Result of TDA showed same tendency as the result of fatigue test, and the result of TDA well expressed the fatigue damage behavior of plain woven CFRP plate. Eventually, TDA was effective for clear understanding the degree of fatigue damage progression of CFRP modified with MFC.

  17. ACCESSIBILITY AND CRYSTALLINITY OF CELLULOSE

    Directory of Open Access Journals (Sweden)

    Michael Ioelovich

    2009-08-01

    Full Text Available The accessibility of cellulose samples having various degrees of crystallinity was studied with respect to molecules of water, lower primary alcohols, and lower organic acids. It was found that small water molecules have full access to non-crystalline domains of cellulose (accessibility coefficient α = 1. Molecules of the lowest polar organic liquids (methanol, ethanol, and formic acid have partial access into the non-crystalline domains (α<1, and with increasing diameter of the organic molecules their accessibility to cellulose structure decreases. Accessibility of cellulose samples to molecules of various substances is a linear function of the coefficient α and the content of non-crystalline domains. The relationship between crystallinity (X and accessibility (A of cellulose to molecules of some liquids has been established as A = α (1-X. The water molecules were found to have greater access to cellulose samples than the molecules of the investigated organic liquids. The obtained results permit use of accessibility data to estimate the crystallinity of cellulose, to examine the structural state of non-crystalline domains, and to predict the reactivity of cellulose samples toward some reagents.

  18. Cellulose Synthesis in Agrobacterium tumefaciens

    Energy Technology Data Exchange (ETDEWEB)

    Alan R. White; Ann G. Matthysse

    2004-07-31

    We have cloned the celC gene and its homologue from E. coli, yhjM, in an expression vector and expressed the both genes in E. coli; we have determined that the YhjM protein is able to complement in vitro cellulose synthesis by extracts of A. tumefaciens celC mutants, we have purified the YhjM protein product and are currently examining its enzymatic activity; we have examined whole cell extracts of CelC and various other cellulose mutants and wild type bacteria for the presence of cellulose oligomers and cellulose; we have examined the ability of extracts of wild type and cellulose mutants including CelC to incorporate UDP-14C-glucose into cellulose and into water-soluble, ethanol-insoluble oligosaccharides; we have made mutants which synthesize greater amounts of cellulose than the wild type; and we have examined the role of cellulose in the formation of biofilms by A. tumefaciens. In addition we have examined the ability of a putative cellulose synthase gene from the tunicate Ciona savignyi to complement an A. tumefaciens celA mutant. The greatest difference between our knowledge of bacterial cellulose synthesis when we started this project and current knowledge is that in 1999 when we wrote the original grant very few bacteria were known to synthesize cellulose and genes involved in this synthesis were sequenced only from Acetobacter species, A. tumefaciens and Rhizobium leguminosarum. Currently many bacteria are known to synthesize cellulose and genes that may be involved have been sequenced from more than 10 species of bacteria. This additional information has raised the possibility of attempting to use genes from one bacterium to complement mutants in another bacterium. This will enable us to examine the question of which genes are responsible for the three dimensional structure of cellulose (since this differs among bacterial species) and also to examine the interactions between the various proteins required for cellulose synthesis. We have carried out one

  19. Ultrasonic dyeing of cellulose nanofibers.

    Science.gov (United States)

    Khatri, Muzamil; Ahmed, Farooq; Jatoi, Abdul Wahab; Mahar, Rasool Bux; Khatri, Zeeshan; Kim, Ick Soo

    2016-07-01

    Textile dyeing assisted by ultrasonic energy has attained a greater interest in recent years. We report ultrasonic dyeing of nanofibers for the very first time. We chose cellulose nanofibers and dyed with two reactive dyes, CI reactive black 5 and CI reactive red 195. The cellulose nanofibers were prepared by electrospinning of cellulose acetate (CA) followed by deacetylation. The FTIR results confirmed complete conversion of CA into cellulose nanofibers. Dyeing parameters optimized were dyeing temperature, dyeing time and dye concentrations for each class of the dye used. Results revealed that the ultrasonic dyeing produced higher color yield (K/S values) than the conventional dyeing. The color fastness test results depicted good dye fixation. SEM analysis evidenced that ultrasonic energy during dyeing do not affect surface morphology of nanofibers. The results conclude successful dyeing of cellulose nanofibers using ultrasonic energy with better color yield and color fastness results than conventional dyeing. PMID:26964959

  20. Surfactant-free emulsions stabilized by tempo-oxidized bacterial cellulose.

    Science.gov (United States)

    Jia, Yuanyuan; Zhai, Xiaoli; Fu, Wei; Liu, Yang; Li, Fei; Zhong, Cheng

    2016-10-20

    In order to seek a safe, biodegradable, and sustainable solid stabilizer for food, topical and pharmaceutical emulsions, individualized cellulose nanofibers were prepared by oxidizing bacterial cellulose (BC) in a Tempo-mediated system; their ability to stabilize oil/water interface was investigated. Significant amounts of C6 carboxylate groups were selectively formed on each cellulose microfibril surface, so that the hydrophilicity was strengthened, leading to lower contact angles. Meanwhile, both the length and width of fibrils were decreased significantly, by partial cleavage of numerous numbers of inter- and intra-fibrillar hydrogen bonds. Tempo-oxidized BC (TOBC) was more effective than BC in stabilizing oil-water interface, attributing to the much smaller size. Fibril dosage and oxidation degree exerted a great influence on the stability and particle size distribution of emulsion samples. When the fibril dosage was 0.7wt.%, the sample was so stable that it did not experience creaming and coalescence over 8 months. The 2-TOBC coated droplets showed the greatest stability, although both the zeta potential and the electric repulsion were the largest for the 10-TOBC analogue, which was manipulated by the wettability of fibrils. In addition, the stability of samples was analyzed from the viewpoint of particle size distribution. Consequently, fibril size and wettability are two counterbalanced factors influencing the stability of TOBC-stabilized emulsions; a combination of suitable wettability and size imparts TOBC-stabilized emulsion high stability. As a kind of biomass-based particle stabilizer, TOBC showed great potential applications in food, topical and pharmaceutical formulations. PMID:27474639

  1. Cellulose Derivatives for Water Repellent Properties

    Science.gov (United States)

    In this poster presentation, we will discuss the synthesis and structural characterizations of nitro-benzyl cellulose (1), amino-benzyl cellulose (2) and pentafluoro –benzyl cellulose (3). All cellulose derivatives are synthesized by etherification process in lithium chloride/N,N-dimethylacetamide h...

  2. Cellulose nanocrystals: synthesis, functional properties, and applications

    OpenAIRE

    George J.; Sabapathi SN

    2015-01-01

    Johnsy George, SN Sabapathi Food Engineering and Packaging Division, Defence Food Research Laboratory, Siddarthanagar, Mysore, Karnataka, India Abstract: Cellulose nanocrystals are unique nanomaterials derived from the most abundant and almost inexhaustible natural polymer, cellulose. These nanomaterials have received significant interest due to their mechanical, optical, chemical, and rheological properties. Cellulose nanocrystals primarily obtained from naturally occurring cellulose fibers...

  3. Cellulose synthase complexes: structure and regulation

    Directory of Open Access Journals (Sweden)

    Lei eLei

    2012-04-01

    Full Text Available This review is to update the most recent progress on characterization of the composition, regulation, and trafficking of cellulose synthase complexes. We will highlight proteins that interact with cellulose synthases, e.g. cellulose synthase-interactive protein 1 (CSI1. The potential regulation mechanisms by which cellulose synthase interact with cortical microtubules in primary cell walls will be discussed.

  4. Pharmaceutical significance of cellulose: A review

    Directory of Open Access Journals (Sweden)

    2008-11-01

    Full Text Available The amalgamation of polymer and pharmaceutical sciences led to the introduction of polymer in the design and development of drug delivery systems. Polymeric delivery systems are mainly intended to achieve controlled or sustained drug delivery. Polysaccharides fabricated into hydrophilic matrices remain popular biomaterials for controlled-release dosage forms and the most abundant naturally occurring biopolymer is cellulose; so hdroxypropylmethyl cellulose, hydroxypropyl cellulose, microcrystalline cellulose and hydroxyethyl cellulose can be used for production of time controlled delivery systems. Additionally microcrystalline cellulose, sodium carboxymethyl cellulose, hydroxypropylmethyl cellulose, hydroxyethyl cellulose as well as hydroxypropyl cellulose are used to coat tablets. Cellulose acetate phthalate and hydroxymethyl cellulose phthalate are also used for enteric coating of tablets. Targeting of drugs to the colon following oral administration has also been accomplished by using polysaccharides such as hdroxypropylmethyl cellulose and hydroxypropyl cellulose in hydrated form; also they act as binders that swell when hydrated by gastric media and delay absorption. This paper assembles the current knowledge on the structure and chemistry of cellulose, and in the development of innovative cellulose esters and ethers for pharmaceuticals.

  5. Radiation degradation of cellulose

    International Nuclear Information System (INIS)

    The application of straw and other cellulose polymers as feedstuff for ruminants is limited by its low digestibility. During recent decades it was attempted to increase the digestibility of straw by several chemical and physical methods. In this work some results of the degradation of gamma and electron treated wheat straw are reported. Complex methods of treatment (e.g. radiation influence and influence of lyes) are taken into consideration. In vitro-experiments with radiation treated straw show that the digestibility can be increased from 20% up to about 80%. A high pressure liquid chromatography method was used to analyze the hydrolysates. The contents of certain species of carbohydrates in the hydrolysates in dependence on the applied dose are given

  6. Thermophilic degradation of cellulosic biomass

    Science.gov (United States)

    Ng, T.; Zeikus, J. G.

    1982-12-01

    The conversion of cellulosic biomass to chemical feedstocks and fuel by microbial fermentation is an important objective of developing biotechnology. Direct fermentation of cellulosic derivatives to ethanol by thermophilic bacteria offers a promising approach to this goal. Fermentations at elevated temperatures lowers the energy demand for cooling and also facilitates the recovery of volatile products. In addition, thermophilic microorganisms possess enzymes with greater stability than those from mesophilic microorganisms. Three anaerobic thermophilic cocultures that ferment cellulosic substrate mainly to ethanol have been described: Clostridium thermocellum/Clostriidium thermohydrosulfuricum, C. thermocellum/Clostridium thermosaccharolyticum, and C. thermocellum/Thermoanaerobacter ethanolicus sp. nov. The growth characteristics and metabolic features of these cocultures are reviewed.

  7. Atomic force microscopy characterization of cellulose nanocrystals.

    Science.gov (United States)

    Lahiji, Roya R; Xu, Xin; Reifenberger, Ronald; Raman, Arvind; Rudie, Alan; Moon, Robert J

    2010-03-16

    Cellulose nanocrystals (CNCs) are gaining interest as a "green" nanomaterial with superior mechanical and chemical properties for high-performance nanocomposite materials; however, there is a lack of accurate material property characterization of individual CNCs. Here, a detailed study of the topography, elastic and adhesive properties of individual wood-derived CNCs is performed using atomic force microscopy (AFM). AFM experiments involving high-resolution dynamic mode imaging and jump-mode measurements were performed on individual CNCs under ambient conditions with 30% relative humidity (RH) and under a N(2) atmosphere with 0.1% RH. A procedure was also developed to calculate the CNC transverse elastic modulus (E(T)) by comparing the experimental force-distance curves measured on the CNCs with 3D finite element calculations of tip indentation on the CNC. The E(T) of an isolated CNC was estimated to be between 18 and 50 GPa at 0.1% RH; however, the associated crystallographic orientation of the CNC could not be determined. CNC properties were reasonably uniform along the entire CNC length, despite variations along the axis of 3-8 nm in CNC height. The range of RH used in this study was found to have a minimal effect on the CNC geometry, confirming the resistance of the cellulose crystals to water penetration. CNC flexibility was also investigated by using the AFM tip as a nanomanipulator. PMID:20055370

  8. Chromophores in lignin-free cellulosic materials belong to three compound classes. Chromophores in cellulosics, XII

    Science.gov (United States)

    The CRI (chromophore release and identification) method isolates well-defined chromophoric substances from different cellulosic matrices, such as highly bleached pulps, cotton linters, bacterial cellulose, viscose or lyocell fibers, and cellulose acetates. The chromophores are present only in extrem...

  9. Bacterial cellulose/boehmite composites

    Energy Technology Data Exchange (ETDEWEB)

    Salvi, Denise T.B. de; Barud, Hernane S.; Messaddeq, Younes; Ribeiro, Sidney J.L. [Universidade Estadual Paulista Julio de Mesquita Filho. UNESP. Instituto de Quimica de Araraquara, SP (Brazil); Caiut, Jose Mauricio A. [Universidade de Sao Paulo. Departamento de Quimica - FFCLRP/USP, Ribeirao Preto, SP (Brazil)

    2011-07-01

    Composites based on bacterial cellulose membranes and boehmite were obtained. SEM results indicate that the bacterial cellulose (BC) membranes are totally covered by boehmite and obtained XRD patterns suggest structural changes due to this boehmite addition. Thermal stability is accessed through TG curves and is dependent on boehmite content. Transparency is high comparing to pure BC as can be seen through UV-vis absorption spectroscopy. (author)

  10. Bacterial cellulose/boehmite composites

    International Nuclear Information System (INIS)

    Composites based on bacterial cellulose membranes and boehmite were obtained. SEM results indicate that the bacterial cellulose (BC) membranes are totally covered by boehmite and obtained XRD patterns suggest structural changes due to this boehmite addition. Thermal stability is accessed through TG curves and is dependent on boehmite content. Transparency is high comparing to pure BC as can be seen through UV-vis absorption spectroscopy. (author)

  11. Cellulose biosynthesis in Acetobacter xylinum

    International Nuclear Information System (INIS)

    Time-lapse video microscopy has shown periodic reversals during the synthesis of cellulose. In the presence of Congo Red, Acetobacter produces a band of fine fibrils. The direction of cell movement is perpendicular to the longitudinal axis of cell, and the rate of movement was decreased. A linear row of particles, presumably the cellulose synthesizing complexes, was found on the outer membrane by freeze-fracture technique. During the cell cycle, the increase of particles in linear row, the differentiation to four linear rows and the separation of the linear rows have been observed. A digitonin-solubilized cellulose synthase was prepared from A. xylinum, and incubated under conditions known to lead to active in vitro synthesis of 1,4-β-D-glucan polymer. Electron microscopy revealed that clusters of fibrils were assembled within minutes. Individual fibrils are 17 ± 2 angstroms in diameter. Evidence for the cellulosic composition of newly synthesized fibrils was based on incorporation of tritium from UDP-[3H] glucose binding of gold-labeled cellobiohydrolase, and an electron diffraction pattern identified as cellulose II polymorph instead of cellulose I

  12. Opportunity for profitable investments in cellulosic biofuels

    International Nuclear Information System (INIS)

    Research efforts to allow large-scale conversion of cellulose into biofuels are being undertaken in the US and EU. These efforts are designed to increase logistic and conversion efficiencies, enhancing the economic competitiveness of cellulosic biofuels. However, not enough attention has been paid to the future market conditions for cellulosic biofuels, which will determine whether the necessary private investment will be available to allow a cellulosic biofuels industry to emerge. We examine the future market for cellulosic biofuels, differentiating between cellulosic ethanol and 'drop-in' cellulosic biofuels that can be transported with petroleum fuels and have equivalent energy values. We show that emergence of a cellulosic ethanol industry is unlikely without costly government subsidies, in part because of strong competition from conventional ethanol and limits on ethanol blending. If production costs of drop-in cellulosic biofuels fall enough to become competitive, then their expansion will not necessarily cause feedstock prices to rise. As long as local supplies of feedstocks that have no or low-valued alternative uses exist, then expansion will not cause prices to rise significantly. If cellulosic feedstocks come from dedicated biomass crops, then the supply curves will have a steeper slope because of competition for land. - Research highlights: → The likelihood of a significant cellulosic ethanol industry in the US looks dim. → Drop-in biofuels made from cellulosic feedstocks have a more promising future. → The spatial dimension of markets for cellulosic feedstocks will be limited. → Corn ethanol will be a tough competitor for cellulosic ethanol.

  13. A thermodynamic investigation of the cellulose allomorphs: Cellulose(am), cellulose Iβ(cr), cellulose II(cr), and cellulose III(cr)

    International Nuclear Information System (INIS)

    Highlights: • Cellulose allomorphs were prepared and carefully characterized. • Measurements by oxygen bomb calorimetry, solution calorimetry, and by PPMS. • Thermodynamic properties for interconversion reactions of the cellulose allomorphs. • Review of the earlier literature with recalculation of property values. • Standard thermodynamic formation properties. - Abstract: The thermochemistry of samples of amorphous cellulose, cellulose I, cellulose II, and cellulose III was studied by using oxygen bomb calorimetry, solution calorimetry in which the solvent was cadoxen (a cadmium ethylenediamine solvent), and with a Physical Property Measurement System (PPMS) in zero magnetic field to measure standard massic heat capacities Cp,w∘ over the temperature range T = (2 to 302) K. The samples used in this study were prepared so as to have different values of crystallinity indexes CI and were characterized by X-ray diffraction, by Karl Fischer moisture determination, and by using gel permeation chromatography to determine the weight average degree of polymerization DPw. NMR measurements on solutions containing the samples dissolved in cadoxen were also performed in an attempt to resolve the issue of the equivalency or non-equivalency of the nuclei in the different forms of cellulose that were dissolved in cadoxen. While large differences in the NMR spectra for the various cellulose samples in cadoxen were not observed, one cannot be absolutely certain that these cellulose samples are chemically equivalent in cadoxen. Equations were derived which allow one to adjust measured property values of cellulose samples having a mass fraction of water wH2O to a reference value of the mass fraction of water wref. The measured thermodynamic properties (standard massic enthalpy of combustion ΔcHw∘, standard massic enthalpy of solution ΔsolHw∘, and Cp,w∘) were used in conjunction with the measured CI values to calculate values of the changes in the standard massic

  14. Visualization of particle complexes in the plasma membrane of Micrasterias denticulata associated with the formation of cellulose fibrils in primary and secondary cell walls.

    Science.gov (United States)

    Giddings, T H; Brower, D L; Staehelin, L A

    1980-02-01

    Highly ordered arrays of intramembrane particles are observed in freeze-fractured plasma membranes of the green alga Micrasterias denticulata during the synthesis of the secondary cell wall. The observable architecture of the complex consists primarily of a precise hexagonal array of from 3 to 175 rosettes, consisting of 6 particles each, which fracture with the P-face. The complexes are observed at the ends of impressions of cellulose fibrils. The distance between rows of rosettes is equal to the center-to-center distance between parallel cellulose fibrils of the secondary wall. Correlation of the structure of the complex with the pattern of deposition indicates that the size of a given fibril is proportional to the number of rosettes engaged in its formation. Vesicles containing hexagonal arrays of rosettes are found in the cytoplasm and can be observed in the process of fusing with the plasma membrane, suggesting that the complexes are first assembled in the cytoplasm and then incorporated into the plasma membrane, where they become active in fibril formation. Single rosettes appear to be responsible for the synthesis of microfibrils during primary wall growth. Similar rosettes have now been detected in a green alga, in fern protonemata, and in higher plant cells. This structure, therefore, probably represents a significant component of the cellulose synthesizing mechanism in a large variety of plant cells. PMID:7189756

  15. Nano-structural study of microfibrils in acacia mangium wood using small- angle x-ray scattering (SAXS)

    International Nuclear Information System (INIS)

    Small-angle X-ray scattering (SAXS) was used to investigate the nanostructure of the microfibrils of cell wall in Acacia Mangium wood. Parameters, such as the fibre length (L), surface area of the single fibre (S), the correspondence distance from the center of the fibre to the center of its neighbor and the shape of the fibre were determined as a function to the distance from pith towards the bark The results indicate that the fibre length ranged from 53.44 mm to 13.72 mm from pith to bark. Surface area of the single fibre varied from 0.65 nm?2 to 4.36 nm?2, the highest being found at the end of bark region. The mean value of the correspondence distance is 13.95 nm. Surface structure analysis from scattering graph showed a rod shape off fibre in the pith region of Acacia Mangium wood. The use of SAXS technique and scanning electron microscope (SEM) micrographs gives the most reliable dimensions values. (Author)

  16. Synchrotron SAXS and WAXD Studies of Cellulose Nascent Crystals: Experiment and Structure Analysis

    Science.gov (United States)

    Su, Ying; Burger, Christian; Hsiao, Benjamin S.; Chu, Benjamin

    2012-02-01

    Cellulose nascent crystals extracted from biomass (wood pulp, jute and cotton)by combined chemical and mechanical treatments are low cost, environmentally friendly and high performance materials to form the barrier layer in ultrafiltration membranes. This research project is aimed at using the synchrotron X-ray scattering methods to characterize the nascent crystalline nanofibers in different formats. The SAXS (Small Angle X-ray Scattering) data of cellulose nanofiber suspensions was analyzed and the polydisperse ribbon model with rectangular cross section fit the data well. The 2D and 3D simulations of WAXD (Wide Angle X-ray Diffraction) pattern of jute cellulose fibers solved the contents ratio of cellulose I-alpha and I-beta and Hermans' orientation parameter P2.

  17. Mechanical properties of cellulose electro-active paper under different environmental conditions

    International Nuclear Information System (INIS)

    The mechanical properties of cellulose-based electro-active paper (EAPap) are investigated under various environmental conditions. Cellulose EAPap has been discovered as a smart material that can be used as both sensor and actuator. Its advantages include low voltage operation, light weight, low power consumption, biodegradability and low cost. EAPap is made with cellulose paper coated with thin electrodes. EAPap shows a reversible and reproducible bending movement as well as longitudinal displacement under an electric field. However, EAPap is a complex anisotropic material which has not been fully characterized. This study investigates the mechanical properties of cellulose-based EAPap, including Young's modulus, yield strength, ultimate strength and creep, along with orientation directions, humidity and temperature levels. To test the materials in different humidity and temperature levels, a special material testing system was made that can control the testing environmental conditions. The initial Young's modulus of EAPap is in the range of 4–9 GPa, which was higher than that of other polymer materials. Also, the Young's modulus is orientation dependent, which may be associated with the piezoelectricity of EAPap materials. The elastic strength and stiffness gradually decreased when the humidity and temperature were increased. Creep and relaxation were observed under constant stress and strain, respectively. Through scanning electron microscopy, EAPap is shown to exhibit both layered and oriented cellulose macromolecular structures that impact both the elastic and plastic behavior

  18. INFLUENCE OF ADSORBED AND DISSOLVED CARBOXYMETHYL CELLULOSE ON FIBRE SUSPENSION DISPERSING, DEWATERABILITY, AND FINES RETENTION

    Directory of Open Access Journals (Sweden)

    Henrikki Liimatainen

    2009-02-01

    Full Text Available The effect of adsorbed and soluble carboxymethyl cellulose (CMC on dispersing, dewaterability, and fines retention of pulp fibre suspensions was investigated. CMC was added to a suspension in the presence of electrolytes, causing its adsorption to the fibre surfaces, or to a suspension without electrolytes, so that it stayed in the liquid phase. Both the CMC adsorbed on fibre surfaces and that in the liquid phase were able to disperse the fibre suspension due to the ability of CMC to reduce fibre-to-fibre friction in both phases. Adsorbed CMC promoted the formation of a water-rich microfibrillar gel on the fibre surfaces through the spreading out of microfibrils, leading to a decrease in friction at the fibre-fibre contact points and to the increased dispersion of fibres. CMC in the liquid phase of the suspension was in turn thought to prevent fibre-to-fibre contacts due to the large physical size of the CMC molecules. CMC in both phases had detrimental effects on dewatering of the pulp suspension, but adsorbed CMC caused more plugging of the filter cake, and this was attributed to its ability to disperse fibre fines, in particular. Thus, adsorbed CMC also reduced fines retention considerably more than did CMC in the liquid phase of a suspension.

  19. Superporous thermo-responsive hydrogels by combination of cellulose fibers and aligned micropores.

    Science.gov (United States)

    Halake, Kantappa S; Lee, Jonghwi

    2014-05-25

    In the area of artificial hydrogels, simultaneous engineering of the volume transition characteristics and mechanical properties of stimuli-responsive hydrogels is an important subject. By unrestricted architecting of hierarchical structures, natural hydrogels are able to provide a wide range of swelling and mechanical properties, beyond the limits of artificial hydrogels. Herein, a combination of nanostructures and microstructures was developed to construct superporous hydrogels. Fibers of microfibrillated cellulose (MFC), an eco-friendly reinforcing material, were used as nanostructures, aligned micropores were used as microstructures, and in situ photopolymerization was used to immobilize the two structures together within the gel networks of poly(N-isopropyl acrylamide) (PNIPAm). The introduction of MFC distinctly enhanced volume transition, mainly by decreasing the swelling ratios above the transition. The introduction of directional micropores increased the swelling ratio below the transition and decreased the swelling ratio above the transition, thereby also enhancing the volume transition. Additionally, the formation of aligned micropores achieved fast water infiltration, which is beneficial for superabsorbent applications. The introduction of aligned micropores reduced the elastic modulus, but this could partially be compensated for by reinforcement with MFC. This combination of crystalline nanofibers and aligned micropores has great potential for the development of stimuli-responsive superporous hydrogels outperforming current artificial hydrogels. PMID:24708968

  20. Adsorption of hydrogen sulphide from aqueous solutions using modified nano/micro fibrillated cellulose.

    Science.gov (United States)

    Hokkanen, Sanna; Repo, Eveliina; Bhatnagar, Amit; Tang, Walter Zhonghong; Sillanpää, Mika

    2014-01-01

    In the present study, microfibrillated cellulose (MFC) was modified by aminopropyltriethoxysilane (APS), hydroxy-carbonated apatite (HAP), or epoxy in order to produce novel nanostructured adsorbents for the removal of hydrogen sulphide (H2S) from the aqueous solutions. Structural properties of the modified MFC materials were examined using a scanning electron microscope, Fourier transform infrared spectroscopy and acid/base titration. These methods were used to verify the presence of nanostructures on the adsorbents surfaces as well as functionalities suitable for H2S adsorption. Adsorption of H2S by prepared adsorbents was investigated in batch mode under different experimental conditions, i.e., varying pH and H2S concentrations. H2S uptake was found to be 103.95, 13.38 and 12.73 mg/g by APS/MFC, HAP/MFC and epoxy/MFC, respectively from 80 mg/L H2S solution. The equilibrium data were best described by the Langmuir isotherm for HAP/MFC and APS/MFC and the Sips isotherm for epoxy/MFC. PMID:25145187

  1. Rheological properties of micro-/nanofibrillated cellulose suspensions: wall-slip and shear banding phenomena.

    Science.gov (United States)

    Nechyporchuk, Oleksandr; Belgacem, Mohamed Naceur; Pignon, Frédéric

    2014-11-01

    The rheological properties of enzymatically hydrolyzed and TEMPO-oxidized microfibrillated/nanofibrillated cellulose (MFC/NFC) aqueous suspensions were investigated in oscillation and steady-flow modes and were compared with the morphology of the studied materials. The flow instabilities, which introduce an error in the rheological measurements, were discovered during flow measurements. A wall-slip (interfacial slippage on the edge of geometry tools and suspension) was detected at low shear rates for two types of NFC suspensions while applying cone-plate geometry. A roughening of the tool surfaces was performed to overcome the aforementioned problem. Applying to TEMPO-oxidized NFC, a stronger suspension response was detected at low shear rates with higher values of measured shear stress. However, a shear banding (localization of shear within a sample volume) became more pronounced. The use of serrated tools for enzymatically hydrolyzed NFC produced lower shear stress at the moderate shear rates, which was influenced by water release from the suspension. PMID:25129764

  2. The cellulose synthase companion proteins act non-redundantly with CELLULOSE SYNTHASE INTERACTING1/POM2 and CELLULOSE SYNTHASE 6

    OpenAIRE

    Endler, Anne; Schneider, Rene; Kesten, Christopher; Edwin R Lampugnani; Persson, Staffan

    2016-01-01

    ABSTRACT Cellulose is a cell wall constituent that is essential for plant growth and development, and an important raw material for a range of industrial applications. Cellulose is synthesized at the plasma membrane by massive cellulose synthase (CesA) complexes that track along cortical microtubules in elongating cells of Arabidopsis through the activity of the protein CELLULOSE SYNTHASE INTERACTING1 (CSI1). In a recent study we identified another family of proteins that also are associated ...

  3. Microbial Cellulose Assembly in Microgravity

    Science.gov (United States)

    Brown, R. Malcolm, Jr.

    1998-01-01

    Based on evidence indicating a possible correlation between hypo-gravity conditions and alteration of cellulose production by the gram negative bacterium, Acetobacter xylinum, a ground-based study for a possible long term Space Shuttle flight has been conducted. The proposed experiment for A. xylinum aboard the Shuttle is the BRIC (Biological Research in a Canister), a metal container containing spaces for nine Petri plates. Using a common experimental design, the cellulose production capability as well as the survivability of the A. xylinum strains NQ5 and AY201 have been described. It should now be possible to use the BRIC for the first long term microgravity experiments involving the biosynthesis of cellulose.

  4. Chemical modification of cellulose for electrospinning applications

    OpenAIRE

    Martín Ferrer, Elena

    2013-01-01

    The aim of the thesis is to develop technology for producing cellulose fatty acid esters that later will be used to produce fibrous materials by means of electrospinning. Main material of the study is cellulose-stearate which is a polymer synthesised by reaction between stearoyl chloride and cellulose. The experimental part consists of synthesis of it by chemical modification of cellulose using ionic liquid as a reaction media. In addition, ionic liquid is also synthesised from the beginning....

  5. Filtration properties of bacterial cellulose membranes

    OpenAIRE

    Lehtonen, Janika

    2015-01-01

    Bacterial cellulose has the same molecular formula as cellulose from plant origin, but it is characterized by several unique properties including high purity, crystallinity and mechanical strength. These properties are dependent on parameters such as the bacterial strain used, the cultivation conditions and post-growth processing. The possibility to achieve bacterial cellulose membranes with different properties by varying these parameters could make bacterial cellulose an interesting materi...

  6. Biocompatibility of Bacterial Cellulose Based Biomaterials

    OpenAIRE

    Omar P. Troncoso; Solene Commeaux; Torres, Fernando G.

    2012-01-01

    Some bacteria can synthesize cellulose when they are cultivated under adequate conditions. These bacteria produce a mat of cellulose on the top of the culture medium, which is formed by a three-dimensional coherent network of pure cellulose nanofibers. Bacterial cellulose (BC) has been widely used in different fields, such as the paper industry, electronics and tissue engineering due to its remarkable mechanical properties, conformability and porosity. Nanocomposites based on BC have received...

  7. A Molecular Description of Cellulose Biosynthesis

    OpenAIRE

    McNamara, Joshua T.; Morgan, Jacob L.W.; Zimmer, Jochen

    2015-01-01

    Cellulose is the most abundant biopolymer on Earth, and certain organisms from bacteria to plants and animals synthesize cellulose as an extracellular polymer for various biological functions. Humans have used cellulose for millennia as a material and an energy source, and the advent of a lignocellulosic fuel industry will elevate it to the primary carbon source for the burgeoning renewable energy sector. Despite the biological and societal importance of cellulose, the molecular mechanism by ...

  8. The trafficking and behavior of cellulose synthase and a glimpse of potential cellulose synthesis regulators

    Institute of Scientific and Technical Information of China (English)

    Logan BASHLINE; Juan DU; Ying GU

    2011-01-01

    Cellulose biosynthesis is a topic of intensive research not only due to the significance of cellulose in the integrity of plant cell walls,but also due to the potential of using cellulose,a natural carbon source,in the production ot biofuels.Characterization of the composition,regulation,and trafficking of cellulose synthase complexes (CSCs) is critical to an understanding of cellulose biosynthesis as well as the characterization of additional proteins that contribute to the production of cellulose either through direct interactions with CSCs or through indirect mechanisms.In this review,a highlight of a few proteins that appear to affect cellulose biosynthesis,which includes:KORRIGAN (KOR),Cellulose Synthase-Interactive Protein 1 (CSI1),and the poplar microtubule-associated protein,PttMAP20,will accompany a description of cellulose synthase (CESA) behavior and a discussion of CESA trafficking compartments that might act in the regulation of cellulose biosynthesis.

  9. Preparation of Nanocomposite Plasmonic Films Made from Cellulose Nanocrystals or Mesoporous Silica Decorated with Unidirectionally Aligned Gold Nanorods

    Directory of Open Access Journals (Sweden)

    Michael G. Campbell

    2014-04-01

    Full Text Available Using liquid crystalline self-assembly of cellulose nanocrystals, we achieve long-range alignment of anisotropic metal nanoparticles in colloidal nanocrystal dispersions that are then used to deposit thin structured films with ordering features highly dependent on the deposition method. These hybrid films are comprised of gold nanorods unidirectionally aligned in a matrix that can be made of ordered cellulose nanocrystals or silica nanostructures obtained by using cellulose-based nanostructures as a replica. The ensuing long-range alignment of gold nanorods in both cellulose-based and nanoporous silica films results in a polarization-sensitive surface plasmon resonance. The demonstrated device-scale bulk nanoparticle alignment may enable engineering of new material properties arising from combining the orientational ordering of host nanostructures and properties of the anisotropic plasmonic metal nanoparticles. Our approach may also allow for scalable fabrication of plasmonic polarizers and nanoporous silica structures with orientationally ordered anisotropic plasmonic nanoinclusions.

  10. Adsorption and desorption of cellulose derivatives.

    NARCIS (Netherlands)

    Hoogendam, C.W.

    1998-01-01

    Cellulose derivatives, in particular carboxymethyl cellulose (CMC) are used in many (industrial) applications. The aim of this work is to obtain insight into the adsorption mechanism of cellulose derivatives on solid-liquid interfaces.In chapter 1 of this thesis we discuss some appl

  11. Iodine catalyzed acetylation of starch and cellulose

    Science.gov (United States)

    Starch and cellulose, earth's most abundant biopolymers, are of tremendous economic importance. Over 90% of cotton and 50% of wood are made of cellulose. Wood and cotton are the major resources for all cellulose products such as paper, textiles, construction materials, cardboard, as well as such c...

  12. Bioengineering cellulose-hemicellulose networks in plants

    NARCIS (Netherlands)

    Obembe, O.

    2006-01-01

    The interactions between cellulose and hemicellulose in the cell walls are important in the industrial application of the cellulose (natural) fibres. We strive to modify these interactions (i) by interfering with cellulose biosynthesis and (ii) by direct interference of the

  13. Ionic Liquids and Cellulose: Dissolution, Chemical Modification and Preparation of New Cellulosic Materials

    Directory of Open Access Journals (Sweden)

    Mehmet Isik

    2014-07-01

    Full Text Available Due to its abundance and a wide range of beneficial physical and chemical properties, cellulose has become very popular in order to produce materials for various applications. This review summarizes the recent advances in the development of new cellulose materials and technologies using ionic liquids. Dissolution of cellulose in ionic liquids has been used to develop new processing technologies, cellulose functionalization methods and new cellulose materials including blends, composites, fibers and ion gels.

  14. Impact of Biofield Treatment on Chemical and Thermal Properties of Cellulose and Cellulose Acetate

    OpenAIRE

    Trivedi, Mahendra Kumar

    2015-01-01

    Cellulose being an excellent biopolymer has cemented its place firmly in many industries as a coating material, textile, composites, and biomaterial applications. In the present study, we have investigated the effect of biofield treatment on physicochemical properties of cellulose and cellulose acetate. The cellulose and cellulose acetate were exposed to biofield and further the chemical and thermal properties were investigated. X-ray diffraction study asserted that the biofield treatment did...

  15. Strength and Water Interactions of Cellulose I Filaments Wet-Spun from Cellulose Nanofibril Hydrogels.

    Science.gov (United States)

    Lundahl, Meri J; Cunha, A Gisela; Rojo, Ester; Papageorgiou, Anastassios C; Rautkari, Lauri; Arboleda, Julio C; Rojas, Orlando J

    2016-01-01

    Hydrogels comprising cellulose nanofibrils (CNF) were used in the synthesis of continuous filaments via wet-spinning. Hydrogel viscosity and spinnability, as well as orientation and strength of the spun filaments, were found to be strongly affected by the osmotic pressure as determined by CNF surface charge and solid fraction in the spinning dope. The tensile strength, Young's modulus and degree of orientation (wide-angle X-ray scattering, WAXS) of filaments produced without drawing were 297 MPa, 21 GPa and 83%, respectively, which are remarkable values. A thorough investigation of the interactions with water using dynamic vapour sorption (DVS) experiments revealed the role of sorption sites in the stability of the filaments in wet conditions. DVS analysis during cycles of relative humidity (RH) between 0 and 95% revealed major differences in water uptake by the filaments spun from hydrogels of different charge density (CNF and TEMPO-oxidised CNF). It is concluded that the mechanical performance of filaments in the presence of water deteriorates drastically by the same factors that facilitate fibril alignment and, consequently, enhance dry strength. For the most oriented filaments, the maximum water vapour sorption at 95% RH was 39% based on dry weight. PMID:27465828

  16. High performance cellulose nanocomposites: comparing the reinforcing ability of bacterial cellulose and nanofibrillated cellulose

    OpenAIRE

    Lee, K. Y.; Tammelin, T.; Schulfter, K.; Kiiskinen, H.; Samela, J.; Bismarck, A.

    2012-01-01

    This work investigates the surface and bulk properties of nanofibrillated cellulose (NFC) and bacterial cellulose (BC), as well as their reinforcing ability in polymer nanocomposites. BC possesses higher critical surface tension of 57 mN m(-1) compared to NFC (41 mN m(-1)). The thermal degradation temperature in both nitrogen and air atmosphere of BC was also found to be higher than that of NFC. These results are in good agreement with the higher crystallinity of BC as determined by XRD, meas...

  17. Conductivity of microfibrillar polymer-polymer composites with CNT-loaded microfibrils or compatibilizer: A comparative study

    Directory of Open Access Journals (Sweden)

    S. Fakirov

    2013-07-01

    Full Text Available Conductive polymer composites have wide ranging applications, but when they are produced by conventional melt blending, high conductive filler loadings are normally required, hindering their processability and reducing mechanical properties. In this study, two types of polymer-polymer composites were studied: i microfibrillar composites (MFC of polypropylene (PP and 5 wt% carbon nanotube (CNT loaded poly(butylene terephthalate (PBT as reinforcement, and ii maleic anhydride-grafted polypropylene (PP-g-MA compatibilizer, loaded with 5 wt% CNTs introduced into an MFC of PP and poly(ethylene terephthalate (PET in concentrations of 5 and 10 wt%. For the compatibilized composite type, PP and PET were melt-blended, cold-drawn and pelletized, followed by dry-mixing with PP-g-MA/CNT, re-extrusion at 200°C, and cold-drawing. The drawn blends produced were compression moulded to produce sheets with MFC structure. Using scanning electron microscopy, CNTs coated with PP-g-MA could be observed at the interface between PP matrix and PET microfibrils in the compatibilized blends. The volume resistivities tested by four-point test method were: 2.87•108 and 9.93•107 Ω•cm for the 66.5/28.5/5 and 63/27/10 (by wt% PP/PET/(PP-g-MA/CNT blends, corresponding to total CNT loadings (in the composites of 0.07 vol% (0.24 wt% and 0.14 vol% (0.46 wt%, respectively. For the non-compatibilized MFC types based on PP/(PBT/CNT with higher and lower melt flow grades of PP, the resistivities of 70/(95/5 blends were 1.9•106 and 1.5•107 Ω•cm, respectively, corresponding to a total filler loading (in the composite of 0.44 vol% (1.5 wt% in both MFCs.

  18. Production of bacterial cellulose from alternate feedstocks

    Energy Technology Data Exchange (ETDEWEB)

    D. N. Thompson; M. A. Hamilton

    2000-05-07

    Production of bacterial cellulose by Acetobacter xylinum ATCC 10821 and 23770 in static cultures was tested from unamended food process effluents. Effluents included low- and high-solids potato effluents (LS and HS), cheese whey permeate (CW), and sugar beet raffinate (CSB). Strain 23770 produced 10% less cellulose from glucose than did 10821, and diverted more glucose to gluconate. Unamended HS, CW, and CSB were unsuitable for cellulose production by either strain, while LS was unsuitable for production by 10821. However, 23770 produced 17% more cellulose from LS than from glucose, indicating unamended LS could serve as a feedstock for bacterial cellulose.

  19. Production of Bacterial Cellulose from Alternate Feedstocks

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, David Neil; Hamilton, Melinda Ann

    2000-05-01

    Production of bacterial cellulose by Acetobacter xylinum ATCC 10821 and 23770 in static cultures was tested from unamended food process effluents. Effluents included low- and high-solids potato effluents (LS & HS), cheese whey permeate (CW), and sugar beet raffinate (CSB). Strain 23770 produced 10% less cellulose from glucose than did 10821, and diverted more glucose to gluconate. Unamended HS, CW, and CSB were unsuitable for cellulose production by either strain, while LS was unsuitable for production by 10821. However, 23770 produced 17% more cellulose from LS than from glucose, indicating unamended LS could serve as a feedstock for bacterial cellulose.

  20. Effect of amino-terminated substrates onto surface properties of cellulose esters and their interaction with lectins

    International Nuclear Information System (INIS)

    Films of cellulose acetate butyrate (CAB) and carboxymethylcellulose acetate butyrate (CMCAB) were deposited from ethyl acetate solutions onto bare silicon wafers (Si/SiO2) or amino-terminated surfaces (APS) by means of equilibrium adsorption. All surfaces were characterized by means of ellipsometry, atomic force microscopy (AFM) and contact angle measurements. The presence of amino groups on the support surface favored the adsorption of CAB and CMCAB, inducing the orientation of most polar groups to the surface and the exposition of alkyl group to the air. Such molecular orientation caused increase of the dispersive component of surface energy (γsd) and decrease of the polar component of surface energy (γsp) of cellulose esters in comparison to those values determined for films deposited onto bare Si/SiO2 wafers. Adsorption behavior of jacalin or concanavalin A onto CAB and CMCAB films was also investigated. The adsorbed amounts of lectins were more pronounced on cellulose esters with high (γsp) and total surface energy (γst) values. - Highlights: ► Amino groups on the substrate induce the orientation of cellulose esters polar groups. ► Amino terminated substrate caused decrease of surface energy of cellulose ester films. ► Lectins adsorbed preferentially onto cellulose esters with high surface energy.

  1. Effect of amino-terminated substrates onto surface properties of cellulose esters and their interaction with lectins

    Energy Technology Data Exchange (ETDEWEB)

    Amim, Jorge [Instituto de Quimica, Universidade de Sao Paulo, Av. Prof. Lineu Prestes 748, 05508-000 Sao Paulo (Brazil); Instituto de Quimica, Universidade Federal do Rio de Janeiro, Campus Macae, Av. Aluizio Gomes da Silva 50, 27930-560, Macae (Brazil); Petri, Denise F.S., E-mail: dfsp@usp.br [Instituto de Quimica, Universidade de Sao Paulo, Av. Prof. Lineu Prestes 748, 05508-000 Sao Paulo (Brazil)

    2012-02-01

    Films of cellulose acetate butyrate (CAB) and carboxymethylcellulose acetate butyrate (CMCAB) were deposited from ethyl acetate solutions onto bare silicon wafers (Si/SiO{sub 2}) or amino-terminated surfaces (APS) by means of equilibrium adsorption. All surfaces were characterized by means of ellipsometry, atomic force microscopy (AFM) and contact angle measurements. The presence of amino groups on the support surface favored the adsorption of CAB and CMCAB, inducing the orientation of most polar groups to the surface and the exposition of alkyl group to the air. Such molecular orientation caused increase of the dispersive component of surface energy ({gamma}{sub s}{sup d}) and decrease of the polar component of surface energy ({gamma}{sub s}{sup p}) of cellulose esters in comparison to those values determined for films deposited onto bare Si/SiO{sub 2} wafers. Adsorption behavior of jacalin or concanavalin A onto CAB and CMCAB films was also investigated. The adsorbed amounts of lectins were more pronounced on cellulose esters with high ({gamma}{sub s}{sup p}) and total surface energy ({gamma}{sub s}{sup t}) values. - Highlights: Black-Right-Pointing-Pointer Amino groups on the substrate induce the orientation of cellulose esters polar groups. Black-Right-Pointing-Pointer Amino terminated substrate caused decrease of surface energy of cellulose ester films. Black-Right-Pointing-Pointer Lectins adsorbed preferentially onto cellulose esters with high surface energy.

  2. Cellulose nanomaterials in water treatment technologies.

    Science.gov (United States)

    Carpenter, Alexis Wells; de Lannoy, Charles-François; Wiesner, Mark R

    2015-05-01

    Cellulose nanomaterials are naturally occurring with unique structural, mechanical and optical properties. While the paper and packaging, automotive, personal care, construction, and textiles industries have recognized cellulose nanomaterials' potential, we suggest cellulose nanomaterials have great untapped potential in water treatment technologies. In this review, we gather evidence of cellulose nanomaterials' beneficial role in environmental remediation and membranes for water filtration, including their high surface area-to-volume ratio, low environmental impact, high strength, functionalizability, and sustainability. We make direct comparison between cellulose nanomaterials and carbon nanotubes (CNTs) in terms of physical and chemical properties, production costs, use and disposal in order to show the potential of cellulose nanomaterials as a sustainable replacement for CNTs in water treatment technologies. Finally, we comment on the need for improved communication and collaboration across the myriad industries invested in cellulose nanomaterials production and development to achieve an efficient means to commercialization. PMID:25837659

  3. Polymorphy in native cellulose: recent developments

    International Nuclear Information System (INIS)

    In a number of earlier studies, the authors developed a model of cellulose structure based on the existence of two stable, linearly ordered conformations of the cellulose chain that are dominant in celluloses I and II, respectively. The model rests on extensive Raman spectral observations together with conformational considerations and solid-state 13C-NMR studies. More recently, they have proposed, on the basis of high resolution solid-state 13C-NMR observations, that native celluloses are composites of two distinct crystalline forms that coexist in different proportions in all native celluloses. In the present work, they examine the Raman spectra of the native celluloses, and reconcile their view of conformational differences with the new level of crystalline polymorphy of native celluloses revealed in the solid-state 13C-NMR investigations

  4. Structure and properties of highly oriented polyoxymethylene produced by hot stretching

    International Nuclear Information System (INIS)

    Research highlights: → Highly oriented POM was fabricated through solid hot stretching technology → Tensile strength and modulus of POM increased remarkably with draw ratio. → The crystal structure of POM changed from spherulite to mat texture by drawing. → Crystallinity and orientation factor of POM increased remarkably by drawing. → The mechanical structure model of microfibril of POM was established. - Abstract: Highly oriented self-reinforced polyoxymethylene (POM) was successfully fabricated through solid phase hot stretching technology. The tensile strength and modulus increased with draw ratio, which reached 900 MPa and 12 GPa, respectively at a high draw ratio of 900% without remarkable drop of the elongation at break. The structure and morphology of the drawn products were studied and the mechanical structure model of microfibril of POM was established. Raman spectral exhibited a low-frequency shift, which indicated two types of molecular chains with different response to the stress. During drawing, the spherulitic structure of POM was broken up and the mat texture crystals were formed. With the increase of draw ratio, the melting peak moved to high temperature and an additional shoulder peak ascribed to melting of highly chain-extended and oriented crystalline blocks was observed. X-ray diffraction showed that the crystallinity and orientation factor increased, while the grain size perpendicular to (1 0 0) crystal plane of POM decreased by drawing. The α relaxation peak corresponding to the glass transition temperature of POM (Tg) moved to high temperature with draw ratio. The section morphology of drawn POM exhibited a fibrillar structure which contributed to the significantly high tensile strength and modulus of the product.

  5. In vivo determination of fibril orientation in plant cell walls with polarization CSLM

    International Nuclear Information System (INIS)

    Congo Red fluorescence is used to detect cellulose in the wall of plant cells. The orientation of the cellulose fibrils is determined by using polarized light for excitation. The absorption characteristics of Congo Red make this approach a method of choice for applications with any standard confocal scanning laser microscope (CSLM). The semiquantitative character of CSLM observations combined with the non-toxicity of the stain allow a very fast and reliable assessment of cellulose orientation in the wall of living plant cells. (author)

  6. From Cellulosic Based Liquid Crystalline Sheared Solutions to 1D and 2D Soft Materials

    Directory of Open Access Journals (Sweden)

    Maria Helena Godinho

    2014-06-01

    Full Text Available Liquid crystalline cellulosic-based solutions described by distinctive properties are at the origin of different kinds of multifunctional materials with unique characteristics. These solutions can form chiral nematic phases at rest, with tuneable photonic behavior, and exhibit a complex behavior associated with the onset of a network of director field defects under shear. Techniques, such as Nuclear Magnetic Resonance (NMR, Rheology coupled with NMR (Rheo-NMR, rheology, optical methods, Magnetic Resonance Imaging (MRI, Wide Angle X-rays Scattering (WAXS, were extensively used to enlighten the liquid crystalline characteristics of these cellulosic solutions. Cellulosic films produced by shear casting and fibers by electrospinning, from these liquid crystalline solutions, have regained wider attention due to recognition of their innovative properties associated to their biocompatibility. Electrospun membranes composed by helical and spiral shape fibers allow the achievement of large surface areas, leading to the improvement of the performance of this kind of systems. The moisture response, light modulated, wettability and the capability of orienting protein and cellulose crystals, opened a wide range of new applications to the shear casted films. Characterization by NMR, X-rays, tensile tests, AFM, and optical methods allowed detailed characterization of those soft cellulosic materials. In this work, special attention will be given to recent developments, including, among others, a moisture driven cellulosic motor and electro-optical devices.

  7. Surface modification of cellulose fibres

    Directory of Open Access Journals (Sweden)

    Mohamed Naceur Belgacem

    2005-06-01

    Full Text Available Several approaches to the modification of cellulose fibres are described, namely: (i physical treatments such as corona or plasma treatments under different atmospheres; (ii grafting with hydrophobic molecules using well-known sizing compounds; (iii grafting with bi-functional molecules, leaving one of the functions available for further exploitation; and (iv grafting with organometallic compounds. The modified surfaces were characterized by elemental analysis, contact angle measurements, inverse gas chromatography, X-ray photoelectron and infrared spectroscopy, wettability, etc. These different tools provided clear-cut evidence of the occurrence of chemical reactions between the grafting agent used and the hydroxy functions of the cellulose surface, as well as of the existence of covalent bonding in the ensuing composite materials between the matrix and the fibres through the use of doubly reactive coupling agents.

  8. Cellulose degradation by oxidative enzymes

    Directory of Open Access Journals (Sweden)

    Maria Dimarogona

    2012-09-01

    Full Text Available Enzymatic degradation of plant biomass has attracted intensive research interest for the production of economically viable biofuels. Here we present an overview of the recent findings on biocatalysts implicated in the oxidative cleavage of cellulose, including polysaccharide monooxygenases (PMOs or LPMOs which stands for lytic PMOs, cellobiose dehydrogenases (CDHs and members of carbohydrate-binding module family 33 (CBM33. PMOs, a novel class of enzymes previously termed GH61s, boost the efficiency of common cellulases resulting in increased hydrolysis yields while lowering the protein loading needed. They act on the crystalline part of cellulose by generating oxidized and non-oxidized chain ends. An external electron donor is required for boosting the activity of PMOs. We discuss recent findings concerning their mechanism of action and identify issues and questions to be addressed in the future.

  9. Cell adhesion on cellulose nanofibrils

    OpenAIRE

    Liljeström, Anna

    2016-01-01

    Cellulose nanofibrils (CNF) is an emerging biomaterial suitable for medical research. CNF hydrogel has been used as a three dimensional platforms for cell culture. This thesis aims to understand how human liver carcinoma (HepG2) cells interact with CNF. Measurements were performed with Quartz crystal microbalance with dissipation in order to quantify cell adsorption on CNF. Furthermore, the effect of the cell medium on the viscoelastic properties of CNF and on cell-CNF interactions were ...

  10. Lowering costs of microbial cellulose

    OpenAIRE

    Pajuelo, María González; Bungay, Henry; Hogg, Tim; Vasconcelos, Isabel

    1997-01-01

    We have been conducting research with Acetobacter xylinium for microbial conversion of sugars to cellulose. A rotating disk biological contactor should lower costs considerably because its production rates are greater than for the usual method of surface culture. Another major cost saving comes from replacing expensive sugars in the medium with sugars derived from wastes. Extracts of spent grapes from wastes of Portuguese wine factories supply suitable sugars for good production of micr...

  11. Transcriptomic analysis of Clostridium thermocellum ATCC 27405 cellulose fermentation

    Energy Technology Data Exchange (ETDEWEB)

    McKeown, Catherine K [ORNL; Brown, Steven D [ORNL

    2011-01-01

    The ability of Clostridium thermocellum ATCC 27405 wild-type strain to hydrolyze cellulose and ferment the degradation products directly to ethanol and other metabolic byproducts makes it an attractive candidate for consolidated bioprocessing of cellulosic biomass to biofuels. In this study, whole-genome microarrays were used to investigate the expression of C. thermocellum mRNA during growth on crystalline cellulose in controlled replicate batch fermentations. A time-series analysis of gene expression revealed changes in transcript levels of {approx}40% of genes ({approx}1300 out of 3198 ORFs encoded in the genome) during transition from early-exponential to late-stationary phase. K-means clustering of genes with statistically significant changes in transcript levels identified six distinct clusters of temporal expression. Broadly, genes involved in energy production, translation, glycolysis and amino acid, nucleotide and coenzyme metabolism displayed a decreasing trend in gene expression as cells entered stationary phase. In comparison, genes involved in cell structure and motility, chemotaxis, signal transduction and transcription showed an increasing trend in gene expression. Hierarchical clustering of cellulosome-related genes highlighted temporal changes in composition of this multi-enzyme complex during batch growth on crystalline cellulose, with increased expression of several genes encoding hydrolytic enzymes involved in degradation of non-cellulosic substrates in stationary phase. Overall, the results suggest that under low substrate availability, growth slows due to decreased metabolic potential and C. thermocellum alters its gene expression to (i) modulate the composition of cellulosomes that are released into the environment with an increased proportion of enzymes than can efficiently degrade plant polysaccharides other than cellulose, (ii) enhance signal transduction and chemotaxis mechanisms perhaps to sense the oligosaccharide hydrolysis products

  12. Cellulose-binding domains: tools for innovation in cellulosic fibre production and modification

    NARCIS (Netherlands)

    Quentin, M.G.E.; Valk, van der H.C.P.M.; Dam, van J.E.G.; Jong, de E.

    2003-01-01

    Plant cell walls are composed of cellulose, nature's most abundant macromolecule, and therefore represent a renewable resource of special technical importance. Cellulose degrading enzymes involved in plant cell wall loosening (expansins), or produced by plant pathogenic microorganisms (cellulases),

  13. Engineering of a novel cellulose-adherent cellulolytic Saccharomyces cerevisiae for cellulosic biofuel production.

    Science.gov (United States)

    Liu, Zhuo; Ho, Shih-Hsin; Sasaki, Kengo; den Haan, Riaan; Inokuma, Kentaro; Ogino, Chiaki; van Zyl, Willem H; Hasunuma, Tomohisa; Kondo, Akihiko

    2016-01-01

    Cellulosic biofuel is the subject of increasing attention. The main obstacle toward its economic feasibility is the recalcitrance of lignocellulose requiring large amount of enzyme to break. Several engineered yeast strains have been developed with cellulolytic activities to reduce the need for enzyme addition, but exhibiting limited effect. Here, we report the successful engineering of a cellulose-adherent Saccharomyces cerevisiae displaying four different synergistic cellulases on the cell surface. The cellulase-displaying yeast strain exhibited clear cell-to-cellulose adhesion and a "tearing" cellulose degradation pattern; the adhesion ability correlated with enhanced surface area and roughness of the target cellulose fibers, resulting in higher hydrolysis efficiency. The engineered yeast directly produced ethanol from rice straw despite a more than 40% decrease in the required enzyme dosage for high-density fermentation. Thus, improved cell-to-cellulose interactions provided a novel strategy for increasing cellulose hydrolysis, suggesting a mechanism for promoting the feasibility of cellulosic biofuel production. PMID:27079382

  14. Effects of reaction conditions on cellulose structures synthesized in vitro by bacterial cellulose synthases.

    Science.gov (United States)

    Penttilä, Paavo A; Sugiyama, Junji; Imai, Tomoya

    2016-01-20

    Cellulose was synthesized by cellulose synthases extracted from the Komagataeibacter xylinus (formerly known as Gluconacetobacter xylinus). The effects of temperature and centrifugation of the reaction solution on the synthesis products were investigated. Cellulose with number-average degree of polymerization (DPn) roughly in the range 60-80 and cellulose II crystal structure was produced under all conditions. The amount of cellulose varied with temperature and centrifugation, and the centrifugation at 2000 × g also slightly reduced the DPn. Cellulose production was maximal around the temperature 35 °C and without centrifugation. At higher temperatures and during centrifugation at 2000 × g the proteins started to denature, causing differences also in the morphology of the cellulosic aggregates, as seen with electron microscopy. These observations serve as a basis for discussions about the factors affecting the structure formation and chain length of in vitro synthesized cellulose. PMID:26572398

  15. Micromechanics and poroelasticity of hydrated cellulose networks.

    Science.gov (United States)

    Lopez-Sanchez, P; Rincon, Mauricio; Wang, D; Brulhart, S; Stokes, J R; Gidley, M J

    2014-06-01

    The micromechanics of cellulose hydrogels have been investigated using a new rheological experimental approach, combined with simulation using a poroelastic constitutive model. A series of mechanical compression steps at different strain rates were performed as a function of cellulose hydrogel thickness, combined with small amplitude oscillatory shear after each step to monitor the viscoelasticity of the sample. During compression, bacterial cellulose hydrogels behaved as anisotropic materials with near zero Poisson's ratio. The micromechanics of the hydrogels altered with each compression as water was squeezed out of the structure, and microstructural changes were strain rate-dependent, with increased densification of the cellulose network and increased cellulose fiber aggregation observed for slower compressive strain rates. A transversely isotropic poroelastic model was used to explain the observed micromechanical behavior, showing that the mechanical properties of cellulose networks in aqueous environments are mainly controlled by the rate of water movement within the structure. PMID:24784575

  16. CELLULOSE POWDER FROM OLIVE INDUSTRY SOLID WASTE

    Directory of Open Access Journals (Sweden)

    Othman A. Hamed,

    2012-07-01

    Full Text Available In the present work, a method for extracting cellulose from olive industry solid waste has been developed. The method involves subjecting solid olive waste to kraft pulping, followed by multistep bleaching processes. The totally free chlorine chemical bleaching sequence APEP was the most effective and gave an average cellulose yield of about 35%. The extracted cellulose was extensively characterized using FTIR, EMS, HPLC, and viscometry. Our key finding in this study is that the extracted cellulose was found to have physio-chemical properties that are similar to those of conventional microcrystalline cellulose (MCC. This is important, as our results show how lignocellulosic agricultural wastes can be utilized to produce high value cellulose powder.

  17. Size Effects of Nano-crystalline Cellulose

    Institute of Scientific and Technical Information of China (English)

    Guo Kang LI; Xiao Fang LI; Yong JIANG; Mei Zhen ZENG; En Yong DING

    2003-01-01

    Natural cellulose with the crystal form of cellulose Ⅰ, when treated with condensed lye(e.g. 18%NaOH), can change into new crystal form of cellulose Ⅱ. But the nano-crystallinecellulose(NCC) can do it when only treated with dilute lye (e.g. 1%NaOH) at room temperatureand even can dissolve into slightly concentrated lye (e.g. 4%NaOH).

  18. Bulk and interfacial properties of cellulose ethers

    OpenAIRE

    Bodvik, Rasmus

    2012-01-01

    This work summarizes several studies that all concern cellulose ethers of the types methylcellulose (MC) hydroxypropylmethylcellulose (HPMC) and ethyl(hydroxyethyl)cellulose (EHEC). They share the feature of negative temperature response, as they are soluble in water at room temperature but phase separate and sometimes form gels at high temperatures. The different types of viscosity transitions occurring in these three cellulose ethers are well-known. However, earlier studies have not solved ...

  19. Drag Reduction of Bacterial Cellulose Suspensions

    OpenAIRE

    Ogata, Satoshi; Numakawa, Tetsuya; Kubo, Takuya

    2010-01-01

    Drag reduction due to bacterial cellulose suspensions with small environmental loading was investigated. Experiments were carried out by measuring the pressure drop in pipe flow. It was found that bacterial cellulose suspensions give rise to drag reduction in the turbulent flow range. We observed a maximum drag reduction ratio of 11% and found that it increased with the concentration of the bacterial cellulose suspension. However, the drag reduction effect decreased in the presence of mechani...

  20. Drag Reduction of Bacterial Cellulose Suspensions

    OpenAIRE

    Satoshi Ogata; Tetsuya Numakawa; Takuya Kubo

    2011-01-01

    Drag reduction due to bacterial cellulose suspensions with small environmental loading was investigated. Experiments were carried out by measuring the pressure drop in pipe flow. It was found that bacterial cellulose suspensions give rise to drag reduction in the turbulent flow range. We observed a maximum drag reduction ratio of 11% and found that it increased with the concentration of the bacterial cellulose suspension. However, the drag reduction effect decreased in the presence of mechani...

  1. Cellulose biosynthesis and function in bacteria.

    OpenAIRE

    Ross, P; Mayer, R; Benziman, M

    1991-01-01

    The current model of cellulose biogenesis in plants, as well as bacteria, holds that the membranous cellulose synthase complex polymerizes glucose moieties from UDP-Glc into beta-1,4-glucan chains which give rise to rigid crystalline fibrils upon extrusion at the outer surface of the cell. The distinct arrangement and degree of association of the polymerizing enzyme units presumably govern extracellular chain assembly in addition to the pattern and width of cellulose fibril deposition. Most e...

  2. Liquid crystalline cellulose derivatives for mirrorless lasing

    OpenAIRE

    Wenzlik, Daniel

    2013-01-01

    In this thesis cholesteric films made of liquid crystalline cellulose derivatives with improved optical properties were prepared. The choice of the solvent, hydrogen bond influencing additives, the synthetic realization of a very high degree of substitution on the cellulosic polymer and the use of mechanical stirring at the upper concentration limit of the liquid crystalline range were the basis for an improved alignment of the applied cellulose tricarbamates. In combination with a tuned subs...

  3. Lyocell, The New Generation of Regenerated Cellulose

    OpenAIRE

    Éva Borbély

    2008-01-01

    For the majority of the last century, commercial routes to regenerated cellulosefibres have coped with the difficulties of making a good cellulose solution by using an easyto dissolve derivative (e.g. xanthane in the case of viscose rayon) or complex (e.g.cuprammonium rayon). For the purposes of this paper, advanced cellulosic fibres aredefined as those made from a process involving direct dissolution of cellulose. The firstexamples of such fibres have now been generically designaed as lyocel...

  4. Alexa Fluor-labeled Fluorescent Cellulose Nanocrystals for Bioimaging Solid Cellulose in Spatially Structured Microenvironments

    Energy Technology Data Exchange (ETDEWEB)

    Grate, Jay W.; Mo, Kai-For; Shin, Yongsoon; Vasdekis, Andreas; Warner, Marvin G.; Kelly, Ryan T.; Orr, Galya; Hu, Dehong; Dehoff, Karl J.; Brockman, Fred J.; Wilkins, Michael J.

    2015-03-18

    Cellulose nanocrystal materials have been labeled with modern Alexa Fluor dyes in a process that first links the dye to a cyanuric chloride molecule. Subsequent reaction with cellulose nanocrystals provides dyed solid microcrystalline cellulose material that can be used for bioimaging and suitable for deposition in films and spatially structured microenvironments. It is demonstrated with single molecular fluorescence microscopy that these films are subject to hydrolysis by cellulose enzymes.

  5. Cytocompatible cellulose hydrogels containing trace lignin.

    Science.gov (United States)

    Nakasone, Kazuki; Kobayashi, Takaomi

    2016-07-01

    Sugarcane bagasse was used as a cellulose resource to prepare transparent and flexible cellulose hydrogel films. On the purification process from bagasse to cellulose, the effect of lignin residues in the cellulose was examined for the properties and cytocompatibility of the resultant hydrogel films. The cellulose was dissolved in lithium chloride/N,N-dimethylacetamide solution and converted to hydrogel films by phase inversion. In the purification process, sodium hydroxide (NaOH) treatment time was changed from 1 to 12h. This resulted in cellulose hydrogel films having small amounts of lignin from 1.62 to 0.68%. The remaining lignin greatly affected hydrogel properties. Water content of the hydrogel films was increased from 1153 to 1525% with a decrease of lignin content. Moreover, lower lignin content caused weakening of tensile strength from 0.80 to 0.43N/mm(2) and elongation from 45.2 to 26.5%. Also, similar tendency was observed in viscoelastic behavior of the cellulose hydrogel films. Evidence was shown that the lignin residue was effective for the high strength of the hydrogel films. In addition, scanning probe microscopy in the morphological observation was suggested that the trace lignin in the cellulose hydrogel affected the cellulose fiber aggregation in the hydrogel network. The trace of lignin in the hydrogels also influenced fibroblast cell culture on the hydrogel films. The hydrogel film containing 1.68% lignin showed better fibroblast compatibility as compared to cell culture polystyrene dish used as reference. PMID:27127053

  6. Carboxymethylation of Cellulose by Microwave irradiation

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ Cellulose may be readily converted into ethers involving primary and secondary alcohol groups in each monomer unit and the glycosidic bonds. However, these reactions are rather more complicated than with simple substances, because the stereochemistry of the cellulose molecule is such that the vast majority of its hydroxyl groups form intra-chain hydrogen bonds or inter-chain hydrogen bonds with contiguous molecules. Carboxymethylcellulose (CMC) has played an important part in the commercial uses of cellulose derivatives. CMC becomes alkali and water soluble. The polarity can, in fact, be increased by introduction of ionizing groups, ie carboxymethyl group. CMC is generally produced by the reaction of alkali cellulose with chloroacetic acid.

  7. Chemo-catalytic valorization of cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Palkovits, R. [RWTH Aachen Univ. (Germany). Inst. fuer Technische und Makromolekulare Chemie

    2012-07-01

    Cellulose can be utilized as carbon source for the production of novel platform molecules as well as fuel motifs. Promising transformation strategies cover the hydrolytic hydrogenation or hydrogenolysis of cellulose to sugar alcohols, the hydrolysis of cellulose to glucose followed by dehydration to 5-hydroxymethylfurfural or levulinic acid and the further hydrogenation of levulinic acid to {gamma}-valerolactone. Main challenges result from the high degree of functionalization of cellulosic feedstocks. In line, processes are carried out in liquid phase utilizing rather polar solvents and aiming for a tailored defunctionalisation of these oxygen rich compounds. Consequently, such transformations require novel strategies concerning the development of suitable catalysts and appropriate process concepts. (orig.)

  8. Simultaneous cellulose conversion and hydrogen production assisted by cellulose decomposition under UV-light photocatalysis

    OpenAIRE

    Zhang, Guan; Ni, Chengsheng; Huang, Xiubing; Welgamage, Aakash; Lawton, Linda A.; Robertson, Peter K. J.; Irvine, John T. S.

    2016-01-01

    Photocatalytic conversion of cellulose to sugars and carbon dioxide with simultaneous production of hydrogen assisted by cellulose decomposition under UV or solar light irradiation was achieved upon immobilization of cellulose onto a TiO2 photocatalyst. This approach enables production of hydrogen from water without using valuable sacrificial agents, and provides the possibility for recovering sugars as liquid fuels.

  9. Simultaneous cellulose conversion and hydrogen production assisted by cellulose decomposition under UV-light photocatalysis.

    Science.gov (United States)

    Zhang, Guan; Ni, Chengsheng; Huang, Xiubing; Welgamage, Aakash; Lawton, Linda A; Robertson, Peter K J; Irvine, John T S

    2016-01-28

    Photocatalytic conversion of cellulose to sugars and carbon dioxide with simultaneous production of hydrogen assisted by cellulose decomposition under UV or solar light irradiation was achieved upon immobilization of cellulose onto a TiO2 photocatalyst. This approach enables production of hydrogen from water without using valuable sacrificial agents, and provides the possibility for recovering sugars as liquid fuels. PMID:26661296

  10. High Performance Regenerated Cellulose Membranes from Trimethylsilyl Cellulose

    KAUST Repository

    Ali, Ola

    2013-05-01

    Regenerated cellulose (RC) membranes are extensively used in medical and pharmaceutical separation processes due to their biocompatibility, low fouling tendency and solvent resistant properties. They typically possess ultrafiltration and microfiltration separation characteristics, but recently, there have been attempts to widen their pool of applications in nanofiltration processes. In this work, a novel method for preparing high performance composite RC membranes was developed. These membranes reveal molecular weight cut-offs (MWCO) of less than 250 daltons, which possibly put them ahead of all commercial RC membranes and in competition with high performance nanofiltration membranes. The membranes were prepared by acidic hydrolysis of dip-coated trimethylsilyl cellulose (TMSC) films. TMSC, with a degree of silylation (DS) of 2.8, was prepared from microcrystalline cellulose by reaction with hexamethyldisilazane under the homogeneous conditions of LiCl/DMAC solvent system. Effects of parameters, such as coating solution concentration and drying rates, were investigated. It was concluded that higher TMSC concentrations as well as higher solvent evaporation rates favor better MWCOs, mainly due to increase in the selective layer thickness. Successful cross-linking of prepared membranes with glyoxal solutions, in the presence of boric acid as a catalyst, resulted in MWCOs less than 250 daltons. The suitability of this crosslinking reaction for large scale productions was already proven in the manufacturing of durable-press fabrics. For us, the inexpensive raw materials as well as the low reaction times and temperatures were of interest. Moreover, the non-toxic nature of glyoxal is a key advantage in medical and pharmaceutical applications. The membranes prepared in this work are strong candidates for separation of small organic solutes from organic solvents streams in pharmaceutical industries. Their hydrophilicity, compared to typical nanofiltration membranes, offer

  11. Structure and mechanical properties of wet-spun fibers made from natural cellulose nanofibers.

    Science.gov (United States)

    Iwamoto, Shinichiro; Isogai, Akira; Iwata, Tadahisa

    2011-03-14

    Cellulose nanofibers were prepared by TEMPO-mediated oxidation of wood pulp and tunicate cellulose. The cellulose nanofiber suspension in water was spun into an acetone coagulation bath. The spinning rate was varied from 0.1 to 100 m/min to align the nanofibers to the spun fibers. The fibers spun from the wood nanofibers had a hollow structure at spinning rates of >10 m/min, whereas the fibers spun from tunicate nanofibers were porous. Wide-angle X-ray diffraction analysis revealed that the wood and tunicate nanofibers were aligned to the fiber direction of the spun fibers at higher spinning rates. The wood spun fibers at 100 m/min had a Young's modulus of 23.6 GPa, tensile strength of 321 MPa, and elongation at break of 2.2%. The Young's modulus of the wood spun fibers increased with an increase in the spinning rate because of the nanofiber orientation effect. PMID:21302950

  12. Present status and applications of bacterial cellulose-based materials for skin tissue repair.

    Science.gov (United States)

    Fu, Lina; Zhang, Jin; Yang, Guang

    2013-02-15

    Bacterial cellulose (BC, also known as microbial cellulose, MC) is a promising natural polymer which is biosynthesized by certain bacteria. This review focused on BC-based materials which can be utilized for skin tissue repair. Firstly, it is illustrated that BC has unique structural and mechanical properties as compared with higher plant cellulose, and is thus expected to become a commodity material. Secondly, we summarized the basic properties and different types of BC, including self-assembled, oriented BC, and multiform BC. Thirdly, composites prepared by using BC in conjunction with other polymers are explored, and the research on BC for application in skin tissue engineering is addressed. Finally, experimental results and clinical treatments assessing the performance of wound healing materials based on BC were examined. With its superior mechanical properties, as well as its excellent biocompatibility, BC was shown to have great potential for biomedical application and very high clinical value for skin tissue repair. PMID:23399174

  13. Over-expression of the cucumber expansin gene (Cs-EXPA1) in transgenic maize seed for cellulose deconstruction.

    Science.gov (United States)

    Yoon, Sangwoong; Devaiah, Shivakumar P; Choi, Seo-Eun; Bray, Jeff; Love, Robert; Lane, Jeffrey; Drees, Carol; Howard, John H; Hood, Elizabeth E

    2016-04-01

    Plant cell wall degradation into fermentable sugars by cellulases is one of the greatest barriers to biofuel production. Expansin protein loosens the plant cell wall by opening up the complex of cellulose microfibrils and polysaccharide matrix components thereby increasing its accessibility to cellulases. We over-expressed cucumber expansin in maize kernels to produce enough protein to assess its potential to serve as an industrial enzyme for applications particularly in biomass conversion. We used the globulin-1 embryo-preferred promoter to express the cucumber expansin gene in maize seed. Expansin protein was targeted to one of three sub-cellular locations: the cell wall, the vacuole, or the endoplasmic reticulum (ER). To assess the level of expansin accumulation in seeds of transgenic kernels, a high throughput expansin assay was developed. The highest expressing plants were chosen and enriched crude expansin extract from those plants was tested for synergistic effects with cellulase on several lignocellulosic substrates. Activity of recombinant cucumber expansin from transgenic kernels was confirmed on these pretreated substrates. The best transgenic lines (ER-targeted) can now be used for breeding to increase expansin expression for use in the biomass conversion industry. Results of these experiments show the success of expansin over-expression and accumulation in transgenic maize seed without negative impact on growth and development and confirm its synergistic effect with cellulase on deconstruction of complex cell wall substrates. PMID:26712321

  14. Pyrolytic sugars from cellulosic biomass

    Science.gov (United States)

    Kuzhiyil, Najeeb

    Sugars are the feedstocks for many promising advanced cellulosic biofuels. Traditional sugars derived from starch and sugar crops are limited in their availability. In principle, more plentiful supply of sugars can be obtained from depolymerization of cellulose, the most abundant form of biomass in the world. Breaking the glycosidic bonds between the pyranose rings in the cellulose chain to liberate glucose has usually been pursued by enzymatic hydrolysis although a purely thermal depolymerization route to sugars is also possible. Fast pyrolysis of pure cellulose yields primarily levoglucosan, an anhydrosugar that can be hydrolyzed to glucose. However, naturally occurring alkali and alkaline earth metals (AAEM) in biomass are strongly catalytic toward ring-breaking reactions that favor formation of light oxygenates over anhydrosugars. Removing the AAEM by washing was shown to be effective in increasing the yield of anhydrosugars; but this process involves removal of large amount of water from biomass that renders it energy intensive and thereby impractical. In this work passivation of the AAEM (making them less active or inactive) using mineral acid infusion was explored that will increase the yield of anhydrosugars from fast pyrolysis of biomass. Mineral acid infusion was tried by previous researchers, but the possibility of chemical reactions between infused acid and AAEM in the biomass appears to have been overlooked, possibly because metal cations might be expected to already be substantially complexed to chlorine or other strong anions that are found in biomass. Likewise, it appears that previous researchers assumed that as long as AAEM cations were in the biomass, they would be catalytically active regardless of the nature of their complexion with anions. On the contrary, we hypothesized that AAEM can be converted to inactive or less active salts using mineral acids. Various biomass feedstocks were infused with mineral (hydrochloric, nitric, sulfuric and

  15. Plants flex their skeletons

    DEFF Research Database (Denmark)

    Foster, Randy; Mattsson, Ole; Mundy, John

    2003-01-01

    Recent work on the fragile fiber mutants of Arabidopsis has identified microtubule-associated proteins that affect the orientation of cellulose microfibrils in cell walls, a major determinant of plant elongation growth. These same proteins are implicated in responses to gibberellin, provoking fresh...

  16. Orienteering club

    CERN Multimedia

    Club d'orientation

    2015-01-01

    Course d'orientation La reprise des courses d’orientation était attendue dans la région puisque près de 150 coureurs ont participé à la première épreuve automnale organisée par le club d’orientation du CERN sur le site de La Faucille. Les circuits ont été remportés par Yann Locatelli du club d’Orientation Coeur de Savoie avec 56 secondes d’avance sur Damien Berguerre du club SOS Sallanches pour le parcours technique long, Marie Vuitton du club CO CERN (membre également de l’Equipe de France Jeune) pour le parcours technique moyen avec presque 4 minutes d’avance sur Jeremy Wichoud du club Lausanne-Jorat, Victor Dannecker pour le circuit technique court devant Alina Niggli, Elliot Dannecker pour le facile moyen et Alice Merat sur le facile court, tous membres du club O’Jura. Les résultats comp...

  17. [Audiometry in the cellulose industry].

    Science.gov (United States)

    Corrao, C R; Milano, L; Pedulla, P; Carlesi, G; Bacaloni, A; Monaco, E

    1993-01-01

    A noise level dosimetry and audiometric testing were conducted in a cellulose factory to determine the hazardous noise level and the prevalence of noise induced hearing loss among the exposed workers. The noise level was recorded up to 90 db (A) in several working areas. 18 workers, potentially exposed to noise injury, evidenced a significant hearing loss. While no evidence of noise injury was recorded in a control group of 100 subjects. This finding suggest a strict relationship between audiometric tests, the noise level recorded in the working place and the working seniority of exposed employers. PMID:7720969

  18. Rheological characterization of microcrystalline cellulose and silicified microcrystalline cellulose wet masses using a mixer torque rheometer.

    Science.gov (United States)

    Luukkonen, P; Schaefer, T; Hellén, L; Juppo, A M; Yliruusi, J

    1999-10-25

    The rheological properties of silicified microcrystalline cellulose (Prosolv 50) were compared with those of standard grades of microcrystalline cellulose (Emcocel 50 and Avicel PH 101). Cellulose samples were analyzed using nitrogen adsorption together with particle size, flowability, density and swelling volume studies. The rheological behaviour of the wet powder masses was studied as a function of mixing time using a mixer torque rheometer (MTR). Silicified microcrystalline cellulose exhibited improved flow characteristics and increased specific surface area compared to standard microcrystalline cellulose grades. Although the silicification process affected the swelling properties and, furthermore, the mixing kinetics of microcrystalline cellulose, the source of the microcrystalline cellulose had a stronger influence than silicification on the liquid requirement at peak torque. PMID:10518674

  19. Cellulose nanocrystals: synthesis, functional properties, and applications

    Directory of Open Access Journals (Sweden)

    George J

    2015-11-01

    Full Text Available Johnsy George, SN Sabapathi Food Engineering and Packaging Division, Defence Food Research Laboratory, Siddarthanagar, Mysore, Karnataka, India Abstract: Cellulose nanocrystals are unique nanomaterials derived from the most abundant and almost inexhaustible natural polymer, cellulose. These nanomaterials have received significant interest due to their mechanical, optical, chemical, and rheological properties. Cellulose nanocrystals primarily obtained from naturally occurring cellulose fibers are biodegradable and renewable in nature and hence they serve as a sustainable and environmentally friendly material for most applications. These nanocrystals are basically hydrophilic in nature; however, they can be surface functionalized to meet various challenging requirements, such as the development of high-performance nanocomposites, using hydrophobic polymer matrices. Considering the ever-increasing interdisciplinary research being carried out on cellulose nanocrystals, this review aims to collate the knowledge available about the sources, chemical structure, and physical and chemical isolation procedures, as well as describes the mechanical, optical, and rheological properties, of cellulose nanocrystals. Innovative applications in diverse fields such as biomedical engineering, material sciences, electronics, catalysis, etc, wherein these cellulose nanocrystals can be used, are highlighted. Keywords: sources of cellulose, mechanical properties, liquid crystalline nature, surface modification, nanocomposites 

  20. Radiation pretreatment of cellulose for energy production

    Science.gov (United States)

    Dela Rosa, A. M.; Dela Mines, A. S.; Banzon, R. B.; Simbul-Nuguid, Z. F.

    The effect of radiation pretreatment of agricultural cellulosic wastes was investigated through hydrolytic reactions of cellulose. Gamma irradiation significantly increased the acid hydrolysis of rice straw, rice hull and corn husk. The yields of reducing sugar were higher with increasing radiation dose in these materials. The observed radiation effect varied with the cellulosic material but it correlated with neither the cellulose content nor the lignin content. Likewise, the radiation pretreatment accelerated the subsequent enzymatic hydrolysis of rice straw and rice hull by cellulase. The irradiated rice straw appeared to be a better growth medium for the cellulolytic microorganism, Myrothecium verrucaria, than the non-irradiated material. This was attributed to increased digestibility of the cellulose by the microorganism.

  1. Radiation pretreatment of cellulose for energy production

    International Nuclear Information System (INIS)

    The effect of radiation pretreatment of agricultural cellulosic wastes was investigated through hydrolytic reactions of cellulose. Gamma irradiation significantly increased the acid hydrolysis of rice straw, rice hull and corn husk. The yields of reducing sugar were higher with increasing radiation dose in these materials. The observed radiation effect varied with the cellulose material but it correlated with neither the cellulose content nor the lignin content. Likewise, the radiation pretreatment accelerated the subsequent enzymatic hydrolysis of rice straw and rice hull by cellulase. The irradiated rice straw appeared to be a better growth medium for the cellulolytic microorganism, Myrothecium verrucaria, than the non-irradiated material. This was attributed to increased digestibility of the cellulose by the microorganism. (author)

  2. Single-cell protein from waste cellulose

    Science.gov (United States)

    Dunlap, C. E.; Callihan, C. D.

    1973-01-01

    The recycle, reuse, or reclamation of single cell protein from liquid and solid agricultural waste fibers by a fermentation process is reported. It is shown that cellulose comprises the bulk of the fibers at 50% to 55% of the dry weight of the refuse and that its biodegradability is of prime importance in the choice of a substrate. The application of sodium hydroxide followed by heat and pressure serves to de-polymerize and disrupt lignin structure while swelling the cellulose to increase water uptake and pore volume. Some of the lignin, hemi-celluloses, ash, and cellulose of the material is hydrolized and solubilized. Introduction of microorganisms to the substrate fibers mixed with nutrients produces continuous fermentation of cellulose for further protein extraction and purification.

  3. Photophysics of alloxazines on cellulose.

    Science.gov (United States)

    Sikorski, Marek; Sikorska, Ewa; Khmelinskii, Igor V; Gonzalez-Moreno, Rafael; Bourdelande, José L; Siemiarczuk, Aleksander

    2002-09-01

    We report the UV-Vis absorption, fluorescence and transient absorption spectra of selected methylalloxazines adsorbed on cellulose from a polar solvent. The ground-state properties of these probe molecules in the cellulose matrix are similar to those in polar protic solvents. Fluorescence decay data allowed identification of three emitting species for every molecule studied, excluding 1-methyllumichrome which lacks the capacity to rearrange into an isoalloxazinic form. The short-lived emission component was attributed to the neutral form of the molecule, and the two longer-lived components were assigned to the two distinct deprotonated monoanionic forms resulting from dissociation at the respective N(3) and N(1) nitrogen atoms. The two monoanions coexist due to their very similar pKa, values. Transient absorption experiments detected two species created by the laser pulse in these systems. The short-lived species was identified as the triplet excited state, and the long-lived species as the semireduced radical, formed by hydrogen atom or proton transfer from the glycosidic unit to the alloxazine carbonyl group. PMID:12665311

  4. Anaerobic digestion of cellulosic wastes

    International Nuclear Information System (INIS)

    Anaerobic digestion is a potentially attractive technology for volume reduction of low-level radioactive cellulosic wastes. A substantial fraction of the waste is converted to off-gas and a relatively small volume of biologically stabilized sludge is produced. Process development work has been completed using a 75-L digester to verify rates and conversions obtained at the bench scale. Start-up and operating procedures have been developed, and effluent was generated for characterization and disposal studies. Three runs using batch and fed-batch conditions were made lasting 36, 90, and 423 d. Solids solubilization rates and gas production rates averaged approximately 1.8 g cellulose per L of reactor per d and 1.2 L of off-gas per L reactor per d. Greater than 80% destruction of the volatile suspended solids was obtained. A simple dynamic process model was constructed to aid in process design and for use in process monitoring and control of a large-scale digester

  5. Anaerobic digestion of cellulosic wastes

    International Nuclear Information System (INIS)

    Anaerobic digestion is a potentially attractive technology for volume reduction of cellulosic wastes. A substantial fraction of the waste is converted to off-gas and a relatively small volume of biologically stabilized sludge is produced. Process development work is underway using a 75-L digester to verify rates and conversions obtained at the bench scale, to develop start-up and operating procedures, and to generate effluent for characterization and disposal studies. Three runs using batch and batch-fed conditions have been made lasting 36, 90, and over 200 days. Solids solubilization and gas production rates and total solids destruction have met or exceeded the target values of 0.6 g cellulose per L of reactor per day, 0.5 L off-gas per L of reactor per day, and 80% destruction of solids, respectively. Successful start-up procedures have been developed, and preliminary effluent characterization and disposal studies have been done. A simple dynamic process model has been constructed to aid in further process development and for use in process monitoring and control of a large-scale digester. 7 references, 5 figures, 1 table

  6. Orienteering Club

    CERN Multimedia

    Club d'orientation

    2013-01-01

    Courses d’orientation Une bonne dizaine de clubs étaient représentés samedi dernier à La Faucille pour participer à la  2e manche de la coupe genevoise organisée par le club du CERN. Les 120 coureurs ont pu découvrir des parcours classés "technique". Ceux du Haut-Jura familiarisés à ce type de terrain ont pu sortir leur épingle du jeu et se sont octroyé la victoire sur 4 des 5 circuits. Samedi 21 septembre, la montagne du Haut-Jura était encore plébiscitée puisque les coureurs étaient attendus à Saint Cergue sur la carte des Pralies. Pour les résultats complets de La Faucille et les informations sur la prochaine étape, consultez le site du club http://cern.ch/club-orientation.

  7. Orienteering Club

    CERN Multimedia

    Club d'orientation

    2013-01-01

    Courses d’orientation ce printemps Le Club d’orientation du CERN vous invite à venir découvrir la course d’orientation et vous propose, en partenariat avec d’autres clubs de la région, une dizaine de courses populaires. Celles-ci ont lieu les samedis après-midi, elles sont ouvertes à tous, quel que soit le niveau, du débutant au sportif confirmé, en famille ou en individuel, en promenade ou en course. Si vous êtes débutant vous pouvez profiter d’une petite initiation offerte par l’organisateur avant de vous lancer sur un parcours. Divers types de parcours sont à votre choix lors de chaque épreuve : facile court (2-3 km), facile moyen (3-5 km), technique court (3-4 km), technique moyen (4-5 km) et technique long (5-7 km). Les dates à retenir sont les suivantes : Samedi 23 mars: Pully (Vd) Samedi 13 avril: Pougny...

  8. Orientation Club

    CERN Multimedia

    Club d'orientation

    2014-01-01

    COURSE ORIENTATION Résultats de samedi 10 mai    C’est sur une carte entièrement réactualisée dans les bois de Versoix, que plus de 100 coureurs sont venus participer à la course d’orientation, type longue distance, préparée par des membres du club du CERN. Le terrain plutôt plat nécessitait une orientation à grande vitesse, ce qui a donné les podiums suivants :  Technique long avec 17 postes : 1er Jurg Niggli, O’Jura en 52:48, 2e Beat Muller, COLJ Lausanne-Jorat en 58:02, 3e Christophe Vuitton, CO CERN en 58:19 Technique moyen avec 13 postes : 1er Jean-Bernard Zosso, CO CERN, en 46:05 ; 2e Yves Rousselot, Balise 25 Besançon, en 55:11 ; 3e Laurent Merat, O'Jura, en 55:13 Technique court avec 13 postes : 1er Julien Vuitton, CO CERN en 40:59, 2e Marc Baumgartner, CO CERN en 43:18, 3e Yaelle Mathieu en 51:42 Su...

  9. The valine and lysine residues in the conserved FxVTxK motif are important for the function of phylogenetically distant plant cellulose synthases.

    Science.gov (United States)

    Slabaugh, Erin; Scavuzzo-Duggan, Tess; Chaves, Arielle; Wilson, Liza; Wilson, Carmen; Davis, Jonathan K; Cosgrove, Daniel J; Anderson, Charles T; Roberts, Alison W; Haigler, Candace H

    2016-05-01

    Cellulose synthases (CESAs) synthesize the β-1,4-glucan chains that coalesce to form cellulose microfibrils in plant cell walls. In addition to a large cytosolic (catalytic) domain, CESAs have eight predicted transmembrane helices (TMHs). However, analogous to the structure of BcsA, a bacterial CESA, predicted TMH5 in CESA may instead be an interfacial helix. This would place the conserved FxVTxK motif in the plant cell cytosol where it could function as a substrate-gating loop as occurs in BcsA. To define the functional importance of the CESA region containing FxVTxK, we tested five parallel mutations in Arabidopsis thaliana CESA1 and Physcomitrella patens CESA5 in complementation assays of the relevant cesa mutants. In both organisms, the substitution of the valine or lysine residues in FxVTxK severely affected CESA function. In Arabidopsis roots, both changes were correlated with lower cellulose anisotropy, as revealed by Pontamine Fast Scarlet. Analysis of hypocotyl inner cell wall layers by atomic force microscopy showed that two altered versions of Atcesa1 could rescue cell wall phenotypes observed in the mutant background line. Overall, the data show that the FxVTxK motif is functionally important in two phylogenetically distant plant CESAs. The results show that Physcomitrella provides an efficient model for assessing the effects of engineered CESA mutations affecting primary cell wall synthesis and that diverse testing systems can lead to nuanced insights into CESA structure-function relationships. Although CESA membrane topology needs to be experimentally determined, the results support the possibility that the FxVTxK region functions similarly in CESA and BcsA. PMID:26646446

  10. Pharmacopoeial and physicochemical properties of α-cellulose and microcrystalline cellulose powders derived from cornstalks

    Directory of Open Access Journals (Sweden)

    Chukwuemeka P Azubuike

    2012-01-01

    Full Text Available Background: Suitable α-cellulose and microcrystalline cellulose powders for use in the pharmaceutical industry can be derived from agricultural wastes. Aims: The pharmacopoeial and physicochemical properties of cornstalk α-cellulose (CCC and cornstalk microcrystalline cellulose powders (MCCC were compared to a commercial brand of microcrystalline cellulose (Avicel PH101 to evaluate their usefulness as pharmaceutical excipients. Settings and Design: Physicochemical properties of an excipient play a very crucial role in the functions of the excipient; hence, these properties were evaluated and compared with a commercial brand. Materials and Methods: α-cellulose was extracted from cornstalks. Modification of this α-cellulose powder was carried out by its partial hydrolysis with hydrochloric acid (HCl to obtain a microcrystalline cellulose powder. Their pharmacopoeial, physicochemical and microbiological properties were evaluated using standard methods. Statistical Analysis: OriginPro 8 SR2 v. 0891 (B891 software (OriginLab Corporation USA was used for statistical evaluation. One-way analysis of variance was used to differentiate between samples and decide where significant differences were established. Results: The yield of α-cellulose from the cornstalks was 32.5%w/w and that of microcrystalline cellulose 26%w/w. All the cellulose samples met all the pharmacopoeial parameters that were carried out. The comparison of physicochemical properties of the CCC, MCCC and Avicel PH101 suggests that the microcrystalline celluloses might have better flow and compression properties than the CCC sample. The three cellulose powders were of high microbial excipient quality. For almost all parameters evaluated, it was generally observed that the MCCC has similar characteristics to Avicel PH101. Conclusions: MCCC can be a suitable alternative to the expensive Avicel PH101as pharmaceutical excipients.

  11. Degradation of cellulose by basidiomycetous fungi.

    Science.gov (United States)

    Baldrian, Petr; Valásková, Vendula

    2008-05-01

    Cellulose is the main polymeric component of the plant cell wall, the most abundant polysaccharide on Earth, and an important renewable resource. Basidiomycetous fungi belong to its most potent degraders because many species grow on dead wood or litter, in environment rich in cellulose. Fungal cellulolytic systems differ from the complex cellulolytic systems of bacteria. For the degradation of cellulose, basidiomycetes utilize a set of hydrolytic enzymes typically composed of endoglucanase, cellobiohydrolase and beta-glucosidase. In some species, the absence of cellobiohydrolase is substituted by the production of processive endoglucanases combining the properties of both of these enzymes. In addition, systems producing hydroxyl radicals based on cellobiose dehydrogenase, quinone redox cycling or glycopeptide-based Fenton reaction are involved in the degradation of several plant cell wall components, including cellulose. The complete cellulolytic complex used by a single fungal species is typically composed of more than one of the above mechanisms that contribute to the utilization of cellulose as a source of carbon or energy or degrade it to ensure fast substrate colonization. The efficiency and regulation of cellulose degradation differs among wood-rotting, litter-decomposing, mycorrhizal or plant pathogenic fungi and yeasts due to the different roles of cellulose degradation in the physiology and ecology of the individual groups. PMID:18371173

  12. Recycling of cellulosic fibers by enzymatic process.

    Science.gov (United States)

    Shojaei, K M; Dadashian, F; Montazer, M

    2012-02-01

    In this research, enzymatic treatment as an environmental friendly process has been used for recycling process of old cellulosic wastes such as cotton, viscose, and lyocell. Cellulase hydrolyses cellulosic chains and shortens cellulosic fibers. This study investigates to detect the optimum enzyme concentration and time of treatments for suitable changes of length and weight loss. The main purposes of this article are shortening of cellulosic fibers and evaluating of enzymatic treatment in different kind of cellulosic fibers. According to the data of experiments, with the increase of enzyme concentration and the treatment time, the length and weight loss percentage of the cellulosic fibers has been decreased. The length and weight loss percentage of treated viscose is more than that of lyocell and cotton fibers. Optimized condition, reaction time, and enzyme concentration have been determined by mean length of treated cellulosic samples. Suitable longitudinal distribution of fiber for papermaking industries is in the range of 0 to 4 mm. Optimum enzyme concentration and treatment time for recycling cotton, lyocell, and viscose fibers are 2% and 48 h for cotton and lyocell and 0.5% and 48 h for viscose, respectively. According to the data of experiment, the length of treated fibers is appropriate for its usage as a raw material in papermaking industries. PMID:22161212

  13. A novel cellulose hydrogel prepared from its ionic liquid solution

    Institute of Scientific and Technical Information of China (English)

    LI Lu; LIN ZhangBi; YANG Xiao; WAN ZhenZhen; CUI ShuXun

    2009-01-01

    A novel cellulose hydrogel is prepared by regenerating cellulose from its ionic liquid solution. The transparency cellulose hydrogel presents a good chemical stability and an acceptable mechanical property. This non-toxic cellulose hydrogel should be biocompatibie and may be useful in the future as a biomaterial.

  14. Colonization of Crystalline Cellulose by Clostridium cellulolyticum ATCC 35319

    OpenAIRE

    Gelhaye, E.; Gehin, A; Petitdemange, H.

    1993-01-01

    Cellulose colonization by Clostridium cellulolyticum was studied by using [methyl-3H]thymidine incorporation. The colonization process indicated that a part of the bacterial population was released from cellulose to the liquid phase before binding and colonizing another adhesion site of the cellulose. We postulate that cellulose colonization occurs according to the following process: adhesion, colonization, release, and readhesion.

  15. Surface modification of cellulose nanocrystals

    Institute of Scientific and Technical Information of China (English)

    WANG Neng; DING Enyong; CHENG Rongshi

    2007-01-01

    In order to improve the dispersibility of cellulose nanocrystal(CNC) particles,three difierent grafted reactions of acetylation,hydroxyethylation and hydroxypropylation were introduced to modify the CNC surface.The main advantages of these methods were the simple and easily controlled reaction conditions,and the dispersibility of the resulting products was distinctly improved.The properties of the modified CNC were characterized by means of Fourier transform infrared spectroscopy(FT-IR),13 C nuclear magnetic resonance(NMR),transmission electron microscopy(TEM)and thermogravimetric analyses(TGA).The results indicated mat after desiccation,the modification products could be dispersed again in the proper solvents by ultrasonic treatments,and the diameter of their particles had no obvious changes.However,their thermal degradation behaviors were quite different.The initial decomposition temperature of the modified products via hydroxyethylation or hydroxypropylation was lower than that of modified products via acetylation.

  16. Lyocell, The New Generation of Regenerated Cellulose

    Directory of Open Access Journals (Sweden)

    Éva Borbély

    2008-06-01

    Full Text Available For the majority of the last century, commercial routes to regenerated cellulosefibres have coped with the difficulties of making a good cellulose solution by using an easyto dissolve derivative (e.g. xanthane in the case of viscose rayon or complex (e.g.cuprammonium rayon. For the purposes of this paper, advanced cellulosic fibres aredefined as those made from a process involving direct dissolution of cellulose. The firstexamples of such fibres have now been generically designaed as lyocell fibres todistinguish them from rayons, and the first commercial lyocell fibre is Courtaulds’ Tencel.

  17. Preparation of membranes from cellulose obtained of sugarcane bagasse

    International Nuclear Information System (INIS)

    In this work, cellulose obtained from sugarcane bagasse to produce both cellulose and acetylated cellulose to prepare asymmetric membranes. Membranes was procedure used a mixture of materials of DMAc/ LiCl systemic in different conditions. Cellulose and acetylated cellulose were characterized by thermogravimetric (TG), Xray diffraction (XRD) and scanning Electron Microscopy (SEM). Observed less stability thermal of acetylated cellulose when compared of cellulose. All membranes procedure were asymmetric, characterized by presence of a dense skin and porous support can be observed. SEM showed that the morphology of the superficial of membranes depends on the method preparation. (author)

  18. Hydrolyzability of xylan after adsorption on cellulose: Exploration of xylan limitation on enzymatic hydrolysis of cellulose.

    Science.gov (United States)

    Wang, Xiao; Li, Kena; Yang, Ming; Zhang, Junhua

    2016-09-01

    During pretreatment of lignocellulosic materials, the dissolved xylan would re-adsorb on cellulose, and then inhibits the cellulose hydrolysis by cellulases. However, the hydrolyzability of xylan adsorbed on cellulose is not clear. In this work, the adsorption behavior of xylans on celluloses and the hydrolysis of adsorbed xylan by xylanase (XYL) were investigated. The results indicated that the adsorption of beechwood xylan (BWX) and oat spelt xylan (OSX) on Avicel was conformed to Langmuir-type adsorption isotherm. Higher ion strength increased the adsorption of BWX on Avicel, but not that of OSX. Both BWX and OSX adsorbed on Avicel and corn stover after dilute acid pretreatment (CS-DA) could be hydrolyzed by XYL. Compared to OSX, BWX adsorbed on cellulosic materials could be more easily hydrolyzed by XYL. Thus, supplementation of XYL could hydrolyze the xylan adsorbed on cellulose and potentially improved hydrolysis efficiency of lignocelluloses. PMID:27185150

  19. Chiral Nematic Structure of Cellulose Nanocrystal Suspensions and Films; Polarized Light and Atomic Force Microscopy

    Directory of Open Access Journals (Sweden)

    Derek G. Gray

    2015-11-01

    Full Text Available Cellulosic liquid crystalline solutions and suspensions form chiral nematic phases that show a rich variety of optical textures in the liquid crystalline state. These ordered structures may be preserved in solid films prepared by evaporation of solvent or suspending medium. Film formation from aqueous suspensions of cellulose nanocrystals (CNC was investigated by polarized light microscopy, optical profilometry and atomic force microscopy (AFM. An attempt is made to interpret qualitatively the observed textures in terms of the orientation of the cellulose nanocrystals in the suspensions and films, and the changes in orientation caused by the evaporative process. Mass transfer within the evaporating droplet resulted in the formation of raised rings whose magnitude depended on the degree of pinning of the receding contact line. AFM of dry films at short length scales showed a radial orientation of the CNC at the free surface of the film, along with a radial height variation with a period of approximately P/2, ascribed to the anisotropic shrinkage of the chiral nematic structure.

  20. Homogeneous preparation of cellulose acetate propionate (CAP) and cellulose acetate butyrate (CAB) from sugarcane bagasse cellulose in ionic liquid.

    Science.gov (United States)

    Huang, Kelin; Wang, Ben; Cao, Yan; Li, Huiquan; Wang, Jinshu; Lin, Weijiang; Mu, Chaoshi; Liao, Dankui

    2011-05-25

    Cellulose acetate butyrate (CAB) and cellulose acetate propionate (CAP) were prepared homogeneously in a 1-allyl-3-methylimidazolium chloride (AmimCl) ionic liquid system from sugarcane bagasse (SB). The reaction temperature, reaction time, and molar ratio of butyric (propionic) anhydride/anhydroglucose units in the cellulose affect the butyryl (B) or propionyl (P) content of CAB or CAP samples. The (13)C NMR data revealed the distribution of the substituents of CAB and CAP. The thermal stability of sugar cane bagasse cellulose was found by thermogravimetric analysis to have decreased after chemical modification. After reaction, the ionic liquid was effectively recycled and reused. This study provides a new way for high-value-added utilization of SB and realizing the objective of turning waste into wealth. PMID:21452895

  1. Orienteering club

    CERN Document Server

    Club d’Orientation du CERN

    2015-01-01

    Courses d’orientation Nouvelle saison nouveau programme Le Club d’orientation du CERN, en partenariat avec d’autres clubs de la région, vous propose une dizaine de courses populaires comptant pour la coupe Genevoise de printemps: samedi 28 mars: Vernand Dessus samedi 18 avril: Pougny/Challex samedi 25 avril: Chancy/Valleiry samedi 2 mai: Mauvernay samedi 9 mai: Longchaumois samedi 16 mai: Genolier samedi 30 mai: Prevondavaux samedi 6 juin: Biere-Ballens samedi 13 juin: Haut-Jura samedi 20 juin: Bonmont - Finale Ces courses sont ouvertes à tous, quel que soit le niveau, du débutant au sportif confirmé, en famille ou en individuel, en promenade ou en course. Les inscriptions se font sur place le jour de l’épreuve. Si vous êtes débutant, vous pouvez profiter d’une initiation offerte par l’organisateur avant de vous lancer sur un parcours. Le club propose aussi...

  2. Orienteering club

    CERN Multimedia

    Orienteering Club

    2016-01-01

    Course d'orientation Calendrier des courses d’orientation Coupe genevoise d’automne 2016 Samedi 3 septembre : La Faucille (01) Samedi 10 septembre : Prémanon (39) Samedi 17 septembre : Saint-Cergue (VD) Samedi 24 septembre : Jorat / Corcelles (VD) Samedi 1 octobre: Bière - Ballens (VD) -relais Vendredi 14 octobre : Parc Mon Repos (GE) - nocturne Samedi 15 octobre : Terrasse de Genève (74) Samedi 29 octobre : Bonmont (VD) Samedi 5 novembre : Pomier (74) – one-man-relay - Finale   Courses ouvertes à toutes et à tous, sportifs, familles, débutants ou confirmés, du CERN ou d’ailleurs. Cinq circuits disponibles, ceci va du facile court (2 km) adapté aux débutants et aux enfants jusqu’au parcours technique long de 6 km pour les chevronnés en passant par les parcours facile moyen (4&am...

  3. Orienteering Club

    CERN Multimedia

    Club d'Orientation

    2013-01-01

    Course d’orientation Face aux Championnats de France des Clubs à Poitiers, et à une météo hivernale (vent glaciale et pluie), il ne restait qu’une cinquantaine d’orienteurs pour participer à l’épreuve organisée le samedi 25 mai à Grange-Malval. Les participants ont tout de même bien apprécié les 5 circuits proposés par le Satus Genève. Les résultats sont disponibles sur notre site http://cern.ch/club-orientation. En plus des résultats, vous pourrez noter des informations sur la nouvelle école de CO encadrée par B. Barge, Prof. EPS à Ferney-Voltaire pour les jeunes à partir de 6 ans. La prochaine étape de la coupe genevoise se déroulera samedi 1er juin à Morez (39). Epreuve organisée par le club O’Jura&nb...

  4. Orienteering Club

    CERN Document Server

    Club d'Orientation

    2012-01-01

     Course d’orientation C’est sous un magnifique soleil que s’est tenue la 7e épreuve de la coupe genevoise organisée par le club d’orientation du CERN. Les organisateurs avaient concocté des parcours assez techniques sur le site de La Faucille. Sur le parcours technique long, beau podium avec la victoire de Domenico Lepori (double médaillés aux championnats du monde en 2010 en vétéran) du club Care Vevey en 1:00:23, juste devant Jürg Niggli du club O’Jura en 1:00:56 puis Beat Mueller du club Lausanne-Jorat en 1:04:28. Sur le parcours technique moyen, Franck Longchampt s’est octroyé la première place, sur le parcours technique court, le jeune Julien Vuitton, qui n’a pas tout à fait 11 ans, a remporté son circuit. Coté parcours facile moyen, Victor Kuznetsov a une fois de plus gagn&eacut...

  5. COURSE ORIENTATION

    CERN Document Server

    Club d'orientation du CERN

    2015-01-01

      Les coureurs d’orientation de la région se sont donné rendez-vous samedi dernier dans les bois de Pougny/Challex lors de l’épreuve organisée par le club d’orientation du CERN. La carte proposée pour les 5 circuits offrait aussi bien un coté très technique avec un relief pentu qu’un coté avec de grandes zones plates à forêt claire. Le parcours technique long comportant 20 postes a été remporté par Beat Muller du COLJ Lausanne en 56:26 devançant Denis Komarov, CO CERN en 57:30 et Yvan Balliot, ASO Annecy en 57:46. Pour les autres circuits les résultats sont les suivants: Technique moyen (13 postes): 1er Joël Mathieu en 52:32 à une seconde du 2e Vladimir Kuznetsov, COLJ Lausanne-Jorat, 3e Jean-Bernard Zosso, CO CERN, en 54:01 Technique court (12 postes): 1er Lennart Jirden, ...

  6. Orienteering Club

    CERN Multimedia

    Club d'Orientation

    2015-01-01

    Course orientation C’est au pied du Salève, proche du Golf de Bosset, que le club d’orientation du CERN (CO CERN) a organisé samedi 19 septembre une nouvelle épreuve comptant pour la Coupe Genevoise d’automne. La zone « des Terrasses de Genève » avait été cartographiée et mise en service l’année dernière. Les participants ont pu apprécier un terrain ludique avec beaucoup de microreliefs, de points d’eau et de gros rochers, le tout au milieu d’une forêt assez claire et agréable à courir. Sur le parcours technique long, le résultat a été très serré puisque Pierrick Merino du club d’Annecy a gagné avec seulement 9 secondes d’avance sur Gaëtan Vuitton (CO CERN) qui confiait avoir perdu beaucoup du te...

  7. Club Orientation

    CERN Multimedia

    Club d'orientation

    2014-01-01

      COURSE ORIENTATION   Pas moins de 100 concurrents sont venus s’affronter sur les parcours proposés par le club d’orientation du CERN ce samedi 26 avril lors de la 4e étape de la coupe genevoise de printemps. Les podiums ont été attribués à :  Technique long avec 19 postes : 1er Yvan Balliot, ASO Annecy en 1:01:39 ; 2e Dominique Fleurent, ASO Annecy, en 1:05:12 ; 3e Rémi Fournier, SOS Sallanches, en 1:05:40. Technique moyen avec 14 postes : 1er Jean-Bernard Zosso, CO CERN, en 46:42 ; 2e Céline Zosso, CO CERN, en 50:51 ; 3e Clément Poncet, O’Jura Prémanon, en 51:27. Technique court avec 13 postes : 1er Jaakko Murtomaki, YKV Seinaejoki, en 36:04 ; 2e Marc Baumgartner en 41:27 ; 3e Natalia Niggli, O’Jura Prémanon, en 52:43. Sur les parcours facile moyen et facile court, victoire respectivement de Stéphanie...

  8. Orienteering club

    CERN Multimedia

    Club d'orientation

    2013-01-01

    Courses d’orientation Le soleil enfin de retour a incité nombre de sportifs et promeneurs à nous rejoindre dans la belle forêt de Challex /Pougny pour la deuxième étape de notre coupe de printemps 2013. Certains sont revenus crottés et fourbus alors que d’autres avaient les joues bien roses après un grand bol d’air frais. Mais tous avaient passé un agréable moment dans la nature. Nous rappelons que nos activités sont ouvertes à tous, jeunes, moins jeunes, sportifs, familles, du CERN ou d’ailleurs, et que le seul inconvénient est que si vous goûtez à la course d’orientation, il vous sera difficile de ne pas y revenir ! Samedi 20 avril 2013, nous serons sur le Mont Mourex (entre Gex et Divonne) pour notre prochaine épreuve et vous y serez les bienvenus. Les inscriptions et les départ...

  9. Orienteering Club

    CERN Multimedia

    Club d'orientation

    2010-01-01

    COURSE D’ORIENTATION La finale de la coupe de printemps Après avoir remporté le challenge club, samedi 29 juin lors du relais inter-club à Lausanne, le Club d’orientation du CERN organisait la dernière étape de la coupe genevoise de printemps samedi 5 juin à Saint-Cergue dans les bois de Monteret (Canton de Vaud). Plus de 100 participants se sont déplacés pour venir participer à la finale et découvrir une toute nouvelle carte dans une forêt vallonnée. Les résultats pour chaque circuit de cette étape sont : Technique long : 1. Jurg Niggli du club O’Jura, 2. Clément Poncet, 3. Oystein Midttun. Technique moyen : 1. Zoltan Trocsanyi CO CERN, 2. Christophe Ingold, 3. Christina Falga. Technique court : 1. Pierre-Andre Baum, CARE Vevey, 2. Emese Szunyog, 3. Solène Balay. Facile moyen : 1. Elisa P...

  10. Reaction mechanisms in cellulose pyrolysis: a literature review

    Energy Technology Data Exchange (ETDEWEB)

    Molton, P.M.; Demmitt, T.F.

    1977-08-01

    A bibliographic review of 195 references is presented outlining the history of the research into the mechanisms of cellulose pyrolysis. Topics discussed are: initial product identification, mechanism of initial formation of levoglucosan, from cellulose and from related compounds, decomposition of cellulose to other compounds, formation of aromatics, pyrolysis of levoglucosan, crosslinking of cellulose, pyrolytic reactions of cellulose derivatives, and the effects of inorganic salts on the pyrolysis mechanism. (JSR)

  11. Hydrolytic and Oxidative Mechanisms Involved in Cellulose Degradation

    OpenAIRE

    Nutt, Anu

    2006-01-01

    The enzymatic degradation of cellulose is an important process in nature. This thesis has focused on the degradation of cellulose by enzymes from two cellulose-degrading fungi, Hypocrea jecorina and Phanerochaete chrysosporium, including both the action of the individual enzymes and their synergistic interplay. The end-preference of cellobiohydrolases on crystalline cellulose was studied. Cellobiohydrolases belonging to glycosyl hydrolase (GH) family 7 were found to hydrolyse cellulose proce...

  12. Role of bacterial cellulose fibrils in Agrobacterium tumefaciens infection.

    OpenAIRE

    Matthysse, A G

    1983-01-01

    During the attachment of Agrobacterium tumefaciens to carrot tissue culture cells, the bacteria synthesize cellulose fibrils. We examined the role of these cellulose fibrils in the attachment process by determining the properties of bacterial mutants unable to synthesize cellulose. Such cellulose-minus bacteria attached to the carrot cell surface, but, in contrast to the parent strain, with which larger clusters of bacteria were seen on the plant cell, cellulose-minus mutant bacteria were att...

  13. Fabrication of polyaniline/carboxymethyl cellulose/cellulose nanofibrous mats and their biosensing application

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • PANI nanorods have been grown onto the surface of CMC/cellulose nanofibers for the fabrication of biosensor substrate material. • The proposed laccase biosensor exhibited a low detection limit and high sensitivity in the detection of catechol. • Hierarchical PANI/CMC/cellulose nanofibers are the promising material in the design of high-efficient biosensors. - Abstract: We report a facile approach to synthesizing and immobilizing polyaniline nanorods onto carboxymethyl cellulose (CMC)-modified cellulose nanofibers for their biosensing application. Firstly, the hierarchical PANI/CMC/cellulose nanofibers were fabricated by in situ polymerization of aniline on the CMC-modified cellulose nanofiber. Subsequently, the PANI/CMC/cellulose nanofibrous mat modified with laccase (Lac) was used as biosensor substrate material for the detection of catechol. PANI/CMC/cellulose nanofibers with highly conductive and three dimensional nanostructure were characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), Fourier transform infrared spectra (FT-IR), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Under optimum conditions, the Lac/PANI/CMC/cellulose/glassy carbon electrode (GCE) exhibited a fast response time (within 8 s), a linear response range from 0.497 μM to 2.27 mM with a high sensitivity and low detection limit of 0.374 μM (3σ). The developed biosensor also displayed good repeatability, reproducibility as well as selectivity. The results indicated that the composite mat has potential application in enzyme biosensors

  14. Fabrication of polyaniline/carboxymethyl cellulose/cellulose nanofibrous mats and their biosensing application

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Jiapeng, E-mail: firgexiao@sina.cn; Pang, Zengyuan, E-mail: pangzengyuan1212@163.com; Yang, Jie, E-mail: young1993@126.com; Huang, Fenglin, E-mail: flhuang@jiangnan.edu.cn; Cai, Yibing, E-mail: yibingcai@jiangnan.edu.cn; Wei, Qufu, E-mail: qfwei@jiangnan.edu.cn

    2015-09-15

    Graphical abstract: - Highlights: • PANI nanorods have been grown onto the surface of CMC/cellulose nanofibers for the fabrication of biosensor substrate material. • The proposed laccase biosensor exhibited a low detection limit and high sensitivity in the detection of catechol. • Hierarchical PANI/CMC/cellulose nanofibers are the promising material in the design of high-efficient biosensors. - Abstract: We report a facile approach to synthesizing and immobilizing polyaniline nanorods onto carboxymethyl cellulose (CMC)-modified cellulose nanofibers for their biosensing application. Firstly, the hierarchical PANI/CMC/cellulose nanofibers were fabricated by in situ polymerization of aniline on the CMC-modified cellulose nanofiber. Subsequently, the PANI/CMC/cellulose nanofibrous mat modified with laccase (Lac) was used as biosensor substrate material for the detection of catechol. PANI/CMC/cellulose nanofibers with highly conductive and three dimensional nanostructure were characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), Fourier transform infrared spectra (FT-IR), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Under optimum conditions, the Lac/PANI/CMC/cellulose/glassy carbon electrode (GCE) exhibited a fast response time (within 8 s), a linear response range from 0.497 μM to 2.27 mM with a high sensitivity and low detection limit of 0.374 μM (3σ). The developed biosensor also displayed good repeatability, reproducibility as well as selectivity. The results indicated that the composite mat has potential application in enzyme biosensors.

  15. Rapid saccharification for production of cellulosic biofuels.

    Science.gov (United States)

    Lee, Dae-Seok; Wi, Seung Gon; Lee, Soo Jung; Lee, Yoon-Gyo; Kim, Yeong-Suk; Bae, Hyeun-Jong

    2014-04-01

    The economical production of biofuels is hindered by the recalcitrance of lignocellulose to processing, causing high consumption of processing enzymes and impeding hydrolysis of pretreated lignocellulosic biomass. We determined the major rate-limiting factor in the hydrolysis of popping pre-treated rice straw (PPRS) by examining cellulase adsorption to lignin and cellulose, amorphogenesis of PPRS, and re-hydrolysis. Based on the results, equivalence between enzyme loading and the open structural area of cellulose was required to significantly increase productive adsorption of cellulase and to accelerate enzymatic saccharification of PPRS. Amorphogenesis of PPRS by phosphoric acid treatment to expand open structural area of the cellulose fibers resulted in twofold higher cellulase adsorption and increased the yield of the first re-hydrolysis step from 13% to 46%. The total yield from PPRS was increased to 84% after 3h. These results provide evidence that cellulose structure is one of major effects on the enzymatic hydrolysis. PMID:24607460

  16. Carboxymethylation of Cellulose by Microwave irradiation

    Institute of Scientific and Technical Information of China (English)

    YE; Jun

    2001-01-01

    Cellulose may be readily converted into ethers involving primary and secondary alcohol groups in each monomer unit and the glycosidic bonds. However, these reactions are rather more complicated than with simple substances, because the stereochemistry of the cellulose molecule is such that the vast majority of its hydroxyl groups form intra-chain hydrogen bonds or inter-chain hydrogen bonds with contiguous molecules. Carboxymethylcellulose (CMC) has played an important part in the commercial uses of cellulose derivatives. CMC becomes alkali and water soluble. The polarity can, in fact, be increased by introduction of ionizing groups, ie carboxymethyl group. CMC is generally produced by the reaction of alkali cellulose with chloroacetic acid.……

  17. Cellulosic ethanol is ready to go

    Energy Technology Data Exchange (ETDEWEB)

    Burke, M. [SunOpta BioProcess Group, Brampton, ON (Canada)

    2006-07-01

    A corporate overview of the SunOpta organization was presented. The organization includes three divisions, notably organic food, industrial minerals, and a bioprocess group. It is a Canadian organization that has experienced over 60 per cent growth per year since 1999. The presentation provided a history of the bioprocess group from 1973 to 2003. The presentation also illustrated the biomass process from wood, straw or corn stover to cellulosic ethanol and acetone and butanol. Several images were presented. The production of xylitol from oat hulls and birch and from ryegrass straw to linerboard was also illustrated. Last, the presentation illustrated the biomass production of cellulose, hemicellulose and lignin extraction as well as the ammonia pretreatment of cellulosics. The presentation also listed several current and future developments such as an expansion plan and implementation of cellulosic ethanol. Economic success was defined as requiring proximity to market; high percentage concentration to distillation; and co-located within existing infrastructure. figs.

  18. Cellulose whisker/epoxy resin nanocomposites

    OpenAIRE

    Tang, Liming; Weder, Christoph

    2010-01-01

    New nanocomposites composed of cellulose nanofibers or “whiskers” and an epoxy resin were prepared. Cellulose whiskers with aspect ratios of ∼10 and ∼84 were isolated from cotton and sea animals called tunicates, respectively. Suspensions of these whiskers in dimethylformamide were combined with an oligomeric difunctional diglycidyl ether of bisphenol A with an epoxide equivalent weight of 185−192 and a diethyl toluenediamine-based curing agent. Thin films were produced by casting these mixtu...

  19. Nanopores Structure in Electrospun Bacterial Cellulose

    OpenAIRE

    Pierre Basmaji; Gabriel Molina de Olyveira; Ligia Maria Manzine Costa; Lauro Xavier Filho

    2011-01-01

    Bacterial cellulose (BC) has established to be a remarkably versatile biomaterial and can be used in wide variety of applied scientific endeavours, especially for medical devices, lately, bacterial cellulose mats are used in the treatment of skin conditions such as burns and ulcers, because of the morphology of fibrous biopolymers serving as a support for cell proliferation, its pores allow gas exchange between the organism and the environment. Moreover, the nanostructure and morphological si...

  20. Cellulose composite structures – by design

    OpenAIRE

    Winkworth-Smith, Charles G.

    2015-01-01

    The aim of the work presented in this thesis was to investigate different mechanical and chemical pre-treatments which can dramatically change the properties of native cellulose and add alternative routes to structure formation. Ball milled cellulose, which had a reduced crystallinity, degree of polymerisation and degradation temperature, was rehydrated in excess water resulting in recrystallisation. Fully amorphous samples recrystallised to the more thermodynamically stable type II polymorph...

  1. Nanosized Cellulose Fibrils as Stabilizer of Emulsions

    OpenAIRE

    Xhanari, Klodian

    2011-01-01

    Pickering emulsions have been a subject of research for many years due to their practical applications not only in everyday life products but also in industry. The stability of these emulsions is due to the irreversible adsorption of colloid particles at the oil/water interface which prevents droplet coalescence. Cellulose materials are among the different types of particles used as stabilizers. Most of the studies report the use of native cellulose as stabilizer of oil-in-water emulsions due...

  2. Production of Cellulosic Polymers from Agricultural Wastes

    OpenAIRE

    Israel, A. U.; I. B. Obot; Umoren, S. A.; Mkpenie, V.; Asuquo, J. E.

    2008-01-01

    Cellulosic polymers namely cellulose, di-and triacetate were produced from fourteen agricultural wastes; Branch and fiber after oil extraction from oil palm (Elais guineensis), raffia, piassava, bamboo pulp, bamboo bark from raphia palm (Raphia hookeri), stem and cob of maize plant (Zea mays), fruit fiber from coconut fruit (Cocos nucifera), sawdusts from cotton tree (Cossypium hirsutum), pear wood (Manilkara obovata), stem of Southern gamba green (Andropogon tectorus), sugarcane baggase (Sac...

  3. Orienteering club

    CERN Multimedia

    Club d'orientation

    2011-01-01

    Reprise fin août Le Club d’orientation, en partenariat avec d’autres clubs de la région, vous propose une nouvelle série de courses pour cet automne. Le calendrier à retenir est le suivant : Samedi 27 août : Granges Malval (GE) – type classique Samedi 10 septembre : Lamoura (39) – type classique Samedi 17 septembre : La Dôle (F/VD) – type classique Samedi 24 septembre : Monteret (VD) – relais Samedi 8 octobre : Saint Cergue (VD) – type classique Vendredi 14 octobre : Les Evaux (GE) – nocturne Samedi 15 octobre : Grand Jorat (VD) – type classique Samedi 22 octobre : Pomier (74) – type classique Samedi 5 novembre : Echallens (VD) – type classique Samedi 12 novembre : CERN (GE) - sprint - Finale Généralement cinq circuits sont disponibles : ceci va du facile court (2 km) adapt&eacu...

  4. Orientation games in kindergarten

    OpenAIRE

    Pišek, Anja

    2012-01-01

    The thesis presents the area of general orientation and orientation of the child. The focus is placed on orientation games for preschool children. The first part outlines different definitions of orientation, types of orientation, accessories for orientation and major errors in orientation. It also presents the development of spatial orientation of preschool children, the development of the concept of space according to the level of cognitive development in line with the theory by Piaget,...

  5. Utilization of biocatalysts in cellulose waste minimization

    Energy Technology Data Exchange (ETDEWEB)

    Woodward, J.; Evans, B.R.

    1996-09-01

    Cellulose, a polymer of glucose, is the principal component of biomass and, therefore, a major source of waste that is either buried or burned. Examples of biomass waste include agricultural crop residues, forestry products, and municipal wastes. Recycling of this waste is important for energy conservation as well as waste minimization and there is some probability that in the future biomass could become a major energy source and replace fossil fuels that are currently used for fuels and chemicals production. It has been estimated that in the United States, between 100-450 million dry tons of agricultural waste are produced annually, approximately 6 million dry tons of animal waste, and of the 190 million tons of municipal solid waste (MSW) generated annually, approximately two-thirds is cellulosic in nature and over one-third is paper waste. Interestingly, more than 70% of MSW is landfilled or burned, however landfill space is becoming increasingly scarce. On a smaller scale, important cellulosic products such as cellulose acetate also present waste problems; an estimated 43 thousand tons of cellulose ester waste are generated annually in the United States. Biocatalysts could be used in cellulose waste minimization and this chapter describes their characteristics and potential in bioconversion and bioremediation processes.

  6. Biohydrogen, bioelectricity and bioalcohols from cellulosic materials

    Energy Technology Data Exchange (ETDEWEB)

    Nissila, M.

    2013-03-01

    The demand for renewable energy is increasing due to increasing energy demand and global warming associated with increasing use of fossil fuels. Renewable energy can be derived from biological production of energy carriers from cellulosic biomass. These biochemical processes include biomass fermentation to hydrogen, methane and alcohols, and bioelectricity production in microbial fuel cells (MFCs). The objective of this study was to investigate the production of different energy carriers (hydrogen, methane, ethanol, butanol, bioelectricity) through biochemical processes. Hydrogen production potential of a hot spring enrichment culture from different sugars was determined, and hydrogen was produced continuously from xylose. Cellulolytic and hydrogenic cultures were enriched on cellulose, cellulosic pulp materials, and on silage at different process conditions. The enrichment cultures were further characterized. The effect of acid pretreatment on hydrogen production from pulp materials was studied and compared to direct pulp fermentation to hydrogen. Electricity and alcohol(s) were simultaneously produced from xylose in MFCs and the exoelectrogenic and alcohologenic enrichment cultures were characterized. In the end, the energy yields obtained from different biochemical processes were determined and compared. In this study, cultures carrying out simultaneous cellulose hydrolysis and hydrogen fermentation were enriched from different sources at different operational conditions. These cultures were successfully utilized for cellulose to hydrogen fermentation in batch systems. Based on these results further research should be conducted on continuous hydrogen production from cellulosic materials.

  7. Cellulose fractionation with IONCELL-P.

    Science.gov (United States)

    Stepan, A M; Monshizadeh, A; Hummel, M; Roselli, A; Sixta, H

    2016-10-01

    IONCELL-P is a solvent fractionation process, which can separate pulps almost quantitatively into pure cellulose and hemicellulose fractions using IL-water mixtures. In this work the role of the molecular weight of cellulose on its solubility in ionic liquid-water mixtures is studied. The aim of this study was to understand and identify the determining factors of this IONCELL-P fractionation. Cotton linters (CL) served as model cellulose substrate and was degraded by ozone treatment to adjust the molecular weight to that of hemicelluloses and low molar mass cellulose in commercial pulps. The ozone treated CLs were subjected to the IONCELL-P process using 1-ethyl-3-methylimidazolium acetate ([emim][OAc]) and water mixtures with a water content between 13.5 and 19wt%. Based on the molar mass distributions of dissolved and undissolved cellulose the effect of the molecular weight of cellulose in IL-water mixture appears to be a key factor in the fractionation process. PMID:27312618

  8. EDITORIAL: Optical orientation Optical orientation

    Science.gov (United States)

    SAME ADDRESS *, Yuri; Landwehr, Gottfried

    2008-11-01

    priority of the discovery in the literature, which was partly caused by the existence of the Iron Curtain. I had already enjoyed contact with Boris in the 1980s when the two volumes of Landau Level Spectroscopy were being prepared [2]. He was one of the pioneers of magneto-optics in semiconductors. In the 1950s the band structure of germanium and silicon was investigated by magneto-optical methods, mainly in the United States. No excitonic effects were observed and the band structure parameters were determined without taking account of excitons. However, working with cuprous oxide, which is a direct semiconductor with a relative large energy gap, Zakharchenya and his co-worker Seysan showed that in order to obtain correct band structure parameters, it is necessary to take excitons into account [3]. About 1970 Boris started work on optical orientation. Early work by Hanle in Germany in the 1920s on the depolarization of luminescence in mercury vapour by a transverse magnetic field was not appreciated for a long time. Only in the late 1940s did Kastler and co-workers in Paris begin a systematic study of optical pumping, which led to the award of a Nobel prize. The ideas of optical pumping were first applied by Georges Lampel to solid state physics in 1968. He demonstrated optical orientation of free carriers in silicon. The detection method was nuclear magnetic resonance; optically oriented free electrons dynamically polarized the 29Si nuclei of the host lattice. The first optical detection of spin orientation was demonstrated by with the III-V semiconductor GaSb by Parsons. Due to the various interaction mechanisms of spins with their environment, the effects occurring in semiconductors are naturally more complex than those in atoms. Optical detection is now the preferred method to detect spin alignment in semiconductors. The orientation of spins in crystals pumped with circularly polarized light is deduced from the degree of circular polarization of the recombination

  9. Cellulose nanofibers from Curaua fibers

    International Nuclear Information System (INIS)

    Curaua is a plant from Amazon region whose leaves were used by the indians of the region to make nets, ropes, fishing wires, etc., due to their high mechanical resistance. Nowadays, some industries, mainly textile and automobile, have increased their interest on these fibers to prepare polymer composites, because their properties could be compared to composites with glass fibers. In this work, cellulose nanofibers were obtained from curaua fibers, which were submitted to alkaline treatment with a solution of NaOH 5%. Nanofibers, in watery suspension, were characterized morphologically by TEM and AFM, and they show needle like format and the ratio L/D of 14. The suspension was dried by freeze dried process, in vacuum and air circulation oven, and these nanofibers were analyzed by x-ray diffraction, presenting high crystalline index, and by thermogravimetric analysis (TGA), which showed that nanofibers have poorer thermal stability than the treated fiber, but they can reach values next to the ones of the original fibers, depending on the drying process of the suspension. (author)

  10. EDITORIAL: Optical orientation Optical orientation

    Science.gov (United States)

    SAME ADDRESS *, Yuri; Landwehr, Gottfried

    2008-11-01

    priority of the discovery in the literature, which was partly caused by the existence of the Iron Curtain. I had already enjoyed contact with Boris in the 1980s when the two volumes of Landau Level Spectroscopy were being prepared [2]. He was one of the pioneers of magneto-optics in semiconductors. In the 1950s the band structure of germanium and silicon was investigated by magneto-optical methods, mainly in the United States. No excitonic effects were observed and the band structure parameters were determined without taking account of excitons. However, working with cuprous oxide, which is a direct semiconductor with a relative large energy gap, Zakharchenya and his co-worker Seysan showed that in order to obtain correct band structure parameters, it is necessary to take excitons into account [3]. About 1970 Boris started work on optical orientation. Early work by Hanle in Germany in the 1920s on the depolarization of luminescence in mercury vapour by a transverse magnetic field was not appreciated for a long time. Only in the late 1940s did Kastler and co-workers in Paris begin a systematic study of optical pumping, which led to the award of a Nobel prize. The ideas of optical pumping were first applied by Georges Lampel to solid state physics in 1968. He demonstrated optical orientation of free carriers in silicon. The detection method was nuclear magnetic resonance; optically oriented free electrons dynamically polarized the 29Si nuclei of the host lattice. The first optical detection of spin orientation was demonstrated by with the III-V semiconductor GaSb by Parsons. Due to the various interaction mechanisms of spins with their environment, the effects occurring in semiconductors are naturally more complex than those in atoms. Optical detection is now the preferred method to detect spin alignment in semiconductors. The orientation of spins in crystals pumped with circularly polarized light is deduced from the degree of circular polarization of the recombination

  11. Degradation of γ-irradiated cellulose by the accumulating culture of a cellulose bacterium

    International Nuclear Information System (INIS)

    Possibility of degradation of γ-irradiated cellulose by the accumulating culture of an anaerobic cellulose bacterium has been investigated. Cellulose irradiation by γ-quanta (Co60) has been carried out using the RKh-30 device with 35.9 Gy/min dose rate. Radiation monitoring has been carried out by the standard ferrosulfate method. Samples have been irradiated in dry state or when water presenting with MGy. It is detected that the accumulating culture with the growth on the irradiated cellulose has a lag-phase, which duration reduces when the cellulose cleaning by flushing with distillation water. The culture has higher growth and substrate consumption rate when growing by cellulose irradiated in comparison with non-irradiated one. The economical coefficient is the same in using both the irradiated and non-irradiated cellulose. The quantity of forming reducing saccharides, organic acids, methane and carbon dioxide is the same both when cultivating by irradiated cellulose and by non-irradiated. pH of the culture liquid is shifted to the acid nature in the process of growth

  12. Preparation of cellulose II and IIII films by allomorphic conversion of bacterial cellulose I pellicles

    International Nuclear Information System (INIS)

    The structural changes resulting from the conversion of native cellulose I (Cel I) into allomorphs II (Cel II) and IIII (Cel IIII) have usually been studied using powder samples from plant or algal cellulose. In this work, the conversion of Cel I into Cel II and Cel IIII was performed on bacterial cellulose films without any mechanical disruption. The surface texture of the films was observed by atomic force microscopy (AFM) and the morphology of the constituting cellulose ribbons, by transmission electron microscopy (TEM). The structural changes were characterized using solid-state NMR spectroscopy as well as X-ray and electron diffraction. The allomorphic change into Cel II and Cel IIII resulted in films with different crystallinity, roughness and hydrophobic/hydrophilicity surface and the films remained intact during all process of allomorphic conversion. - Highlights: • Description of a method to modify the allomorphic structure of bacterial cellulose films • Preparation of films with specific morphologies and hydrophobic/hydrophilic surface characters • First report on cellulose III films from bacterial cellulose under swelling conditions • Detailed characterization of cellulose II and III films with complementary techniques • Development of films with specific properties as potential support for cells, enzymes, and drugs

  13. Engineering of a novel cellulose-adherent cellulolytic Saccharomyces cerevisiae for cellulosic biofuel production

    Science.gov (United States)

    Liu, Zhuo; Ho, Shih-Hsin; Sasaki, Kengo; den Haan, Riaan; Inokuma, Kentaro; Ogino, Chiaki; van Zyl, Willem H.; Hasunuma, Tomohisa; Kondo, Akihiko

    2016-01-01

    Cellulosic biofuel is the subject of increasing attention. The main obstacle toward its economic feasibility is the recalcitrance of lignocellulose requiring large amount of enzyme to break. Several engineered yeast strains have been developed with cellulolytic activities to reduce the need for enzyme addition, but exhibiting limited effect. Here, we report the successful engineering of a cellulose-adherent Saccharomyces cerevisiae displaying four different synergistic cellulases on the cell surface. The cellulase-displaying yeast strain exhibited clear cell-to-cellulose adhesion and a “tearing” cellulose degradation pattern; the adhesion ability correlated with enhanced surface area and roughness of the target cellulose fibers, resulting in higher hydrolysis efficiency. The engineered yeast directly produced ethanol from rice straw despite a more than 40% decrease in the required enzyme dosage for high-density fermentation. Thus, improved cell-to-cellulose interactions provided a novel strategy for increasing cellulose hydrolysis, suggesting a mechanism for promoting the feasibility of cellulosic biofuel production. PMID:27079382

  14. Orienteering club

    CERN Multimedia

    Club d'orientation

    2014-01-01

    Course d'orientation C’est sous un beau soleil samedi 4 octobre que s’est déroulée la 6e étape de la Coupe genevoise d’automne organisée par le club. Plus d’une centaine de concurrents provenant de 7 clubs de CO avaient fait le déplacement pour courir sur un des cinq parcours proposés dans les bois de Trélex-Génolier (VD). Le podium est le suivant : Technique long (5,9 km, 19 postes) : 1er Jurg Niggli, O’Jura (1:00:02); 2e Berni Wehrle, CO CERN (1:06:44); 3e Konrad Ehrbar, COLJ (1:07:08) Technique moyen (4,8 km, 18 postes) : 1er Christophe Vuitton, CO CERN (54:25); 2e J.B. Zosso, CO CERN (1:01:19); 3e Jeremy Wichoud, COLJ (1:06:21) Technique court (3,8 km, 14 postes) : 1er Julien Vuitton, CO CERN (36:19); 2e Vladimir Kuznetsov, COLJ (48:47); 3e Natalia Niggli, O’Jura (50:38) Facile moyen (3,2 km, 11 postes) : 1ère Alina Niggli, O&...

  15. Orienteering club

    CERN Multimedia

    Club d'orientation

    2010-01-01

    COURSE D’ORIENTATION  De La Rippe à Sauvabellin, la coupe genevoise continue ! Le rendez-vous était donné samedi 8 mai aux amateurs de course d’orientation dans les bois de La Rippe (Canton de Vaud). Cette 6e épreuve était organisée par le Club Satus Grutli de Genève. Il est dommage que les participants n’aient pas été aussi nombreux que lors des dernières courses, les Championnats de France des clubs à Dijon ayant certainement retenus plus d’un compétiteur. La première place est revenue à : – Technique long : Berni Wehrle – Technique moyen : Jean-Bernard Zosso – Technique court : Berni Wehrle – Facile moyen : Peter Troscanyi – Facile court : Claire Droz. Il ne restera plus que deux épreuves ...

  16. Orienteering Club

    CERN Multimedia

    Club d'orientation

    2011-01-01

    Coupe genevoise, suite Résultats de la course de Saint-Cergue, sur la carte Les Pralies, samedi 17 septembre. Nouvelle victoire du finlandais Ville Keskisaari, du club COLJ sur le parcours technique long avec une belle avance sur le deuxième concurrent Christophe Vuitton du CO CERN. David Cuenin a remporté le parcours technique moyen, Franck Lonchampt du club O’Jura a, lui aussi, remporté à nouveau le parcours technique court, tout comme Julien Vuitton du club CO CERN sur le facile moyen. Pour finir, Stéphane Clément devance Victor Dannecker sur le parcours facile court. Les résultats complets sont disponibles sur le site du club du CERN http://cern.ch/club-orientation. Un abonnement est pris sur le secteur de Saint-Cergue, puisque le club organise les deux prochaines étapes de la coupe genevoise dans le Haut-Jura suisse. Tout d’abord le samedi 24 septembre, un relais inter-club se courr...

  17. Orienteering Club

    CERN Document Server

    Club d'Orientation

    2012-01-01

    Course d'orientation Ces deux dernières semaines, le club a organisé la troisième puis la quatrième étape de la coupe de printemps, une dans la forêt de Collogny/Moissey près de Vulbens, l’autre vers le parcours vita de Trélex. Les résultats sont: Facile court Vulbens : 1er Léo Lonchampt, O’Jura (16:04), 2e Timothée Bazin (23:07), 3e Francesco Pieri (26:57) Trélex : 1er Noora Maurent (23:11), 2e Sarah Stuber, COLJ (26:51), 3e T. Bazin (28:17) Facile moyen Vulbens : 1er Victor Kuznetsov, CO CERN (25:36), 2e Didier Descourvières (28:03), 3e Konstantinos Haider, CO CERN (36:53) Trélex : 1er V. Kuznetsov, COLJ (38:01), 2e K. Haider, CO CERN (43:15), 3e ex aequo Olivia Nguyen et Sven Vietmeier (58:11) Technique court Vulbens : 1er Benoit Bazin (41:21), 2e Colas Gintzburger (55:12), 3e Nathan Freydoz (55:48) Trélex : 1...

  18. Orienteering Club

    CERN Document Server

    Club d'orientation

    2013-01-01

    Finale de la coupe d’automne La dernière épreuve de la coupe d’automne organisée par le club d’orientation du CERN s’est déroulée ce samedi 2 novembre avec une course au score dans le bois Tollot (GE). Les concurrents disposaient d’un temps imparti pour poinçonner le maximum de balises différemment placées selon le circuit choisi. Juerg Niggli (club O’Jura) a remporté le parcours technique long. A l’issue de cette course, le classement général de la coupe d’automne, basé sur les 6 meilleurs résultats de la saison, est le suivant : Circuit technique long : 1er Juerg Niggli (O’Jura), 2e Bruno Barge, 3e Beat Mueller. Circuit technique moyen : 1er Laurent Merat (O’Jura), 2e Jirden Lennart, 3e Daria Niggli. Circuit technique court : 1er Victor Kuznetsov (COLJ), 2e N...

  19. Orienteering club

    CERN Document Server

    Club d'orientation

    2013-01-01

    Course d'orientation Finale de la coupe genevoise Rapide et méthodique, voilà les qualités dont il fallait faire preuve pour remporter la dernière étape de la coupe organisée par le club du CERN dans les bois de Monteret. Il s’agissait d’une course au score où chaque concurrent disposait d’un temps imparti pour poinçonner le maximum de balises. Le parcours technique a été remporté par Tomas Shellman et le parcours facile par Victor Dannecker. Cette dernière étape était aussi décisive pour la désignation des lauréats de la coupe genevoise de printemps. Les résultats officiels étaient donnés par le président du club, L. Jirden : Circuit Technique Long : Berni Wehrle, Bruno Barge, Edvins Reisons Circuit Technique Moyen : J.-Bernard Zosso, ...

  20. Orienteering Club

    CERN Multimedia

    Club d'Orientation

    2012-01-01

     Finale de la coupe de printemps   La dernière course d’orientation comptant pour la Coupe de printemps a eu lieu samedi dernier dans le village des Rousses et vers le Fort. Il s’agissait d’un sprint organisé par le club O’Jura. Les temps de course ont avoisiné les 20 minutes que ce soit pour le parcours technique moyen ou technique long. Tous les habitués étaient au rendez-vous pour venir consolider ou améliorer leur place au classement. A l’issue de cette course, le classement général de la Coupe de printemps prenant en compte les 6 meilleurs résultats des 9 courses était établi et les lauréats de chaque catégorie sont les suivants: Circuit technique long : 1er Berni Wehrle, 2e Bruno Barge, 3e Edvins Reisons. Circuit technique moyen : 1er Jean-Bernard Zosso, 2e Cédric Wehrl&...

  1. Orienteering Club

    CERN Document Server

    Club d'Orientation

    2015-01-01

    Course orientation Finale de la coupe genevoise La série des courses de printemps s’est achevée samedi dernier dans les bois de Bonmont (Vaud) avec une épreuve «one-man-relay» organisée par le club. Le vainqueur du parcours technique  long, Yann Locatelli (Club de Chambéry Savoie) a réalisé les deux boucles comportant 24 balises avec presque 6 minutes d’avance sur le second concurrent Domenico Lepori (Club CARE Vevey). Cette dernière étape était aussi décisive pour la désignation des lauréats de la coupe genevoise de printemps, en comptabilisant les 6 meilleurs résultats sur les 10 épreuves. Le podium officiel était donné par le président du club, L. Jirden, qui profitait de l’occasion pour remercier tous les participants et également tous les...

  2. Orienteering Club

    CERN Multimedia

    Club d'Orientation

    2011-01-01

    Course d'orientation Avec la CO en nocturne organisée par le club du CERN vendredi 14 octobre au stade des Eveaux (Ge), et la CO à Savigny (Vd) proposée par le club de Lausanne-Jorat le lendemain, les étapes de la coupe genevoise d’automne s’enchainent rapidement. Il ne reste plus que 3 rendez-vous pour boucler la saison. Les premières places devraient certainement se jouer entre des membres du club du CERN, du O’Jura ou de Lausanne-Jorat. La prochaine course du club est programmée pour samedi 22 octobre à Pomier, près de Cruseilles. L’accueil se fera à partir de 12h30 et les départs s’échelonneront de 13h à 15h. * * * * * * * Nouvelle belle victoire samedi 8 octobre à Saint Cergue du jeune finlandais Ville Keskisaari (COLJ) en 50:56 devant Jürg Niggli (O’Jura) en 1:03:32, et Alexandre...

  3. Orienteering Club

    CERN Multimedia

    Club d'orientation

    2013-01-01

    De jour comme de nuit Les amateurs de course d’orientation ont pu s’en donner à cœur joie ce week-end puisqu’ils avaient la possibilité de courir sur deux épreuves en moins de 24 heures. En effet, le club du CERN organisait une course de nuit aux Evaux et la 7e étape de la coupe genevoise se tenait samedi après-midi dans les bois du Grand Jorat à Savigny. Les vainqueurs pour chaque course sont : Technique long CO de nuit: Julien Charlemagne, SOS Sallanches CO samedi: Philipp Khlebnikov, ANCO   Technique moyen CO de nuit: Céline Zosso, CO CERN CO samedi: Pavel Khlebnikov, ANCO Technique court CO de nuit: Colas Ginztburger, SOS Sallanches CO samedi: Victor Kuznetsov, COLJ Lausannne Facile moyen CO de nuit: Gaëtan Rickenbacher, CO CERN CO samedi: Tamas Szoke   Facile court CO de nuit:Oriane Rickenbacher, CO CERN CO samedi: Katya Kuznetsov...

  4. Orienteering Club

    CERN Multimedia

    Club d'orientation

    2012-01-01

    Finale de la coupe d’automne   La coupe d’automne organisée par le club d’orientation du CERN s’est terminée ce samedi 10 novembre avec une course sprint à Prévessins. C’était la 12e épreuve de la saison. En stage dans la région, Tanya Ryabkina, championne d’Europe en titre et médaillée de bronze en moyenne distance lors des championnats du monde à La Givrine cet été, a fait l’honneur de sa présence et termine 2e à 8 secondes de Trygve Buanes, norvégien du club de Bergen. A l’issue de cette dernière épreuve, le classement général de la coupe d’automne, basé sur les 8 meilleurs résultats de la saison, est ainsi le suivant : Circuit technique long : 1er Jurg Niggli (O&rsqu...

  5. Orienteering club

    CERN Multimedia

    Club d'orientation

    2013-01-01

    Course d'orientation Vers les dernières courses de printemps Une centaine de coureurs se sont déplacés sur le site de la Roche Fendue prés de Morez pour gouter à un des 5 parcours proposés par le club du O’Jura. Le terrain était gras mais que peut-on trouver d’autre avec cette météo! Les vainqueurs de chaque circuit sont : Alina Niggli (O’Jura) facile court, Natalja Niggli (O’Jura) facile moyen, Victor Kuznetsov (COLJ) technique court, Yves Rousselot (Balise 25) technique moyen et pour finir François Gonon (O’Jura) avec une victoire haut la main sur le technique long. Il ne reste plus que deux épreuves pour la coupe genevoise de printemps : à savoir samedi 8 juin, course de type longue distance organisée par le club de Lausanne Jorat (COLJ) dans le bois de Seyte sur Mutrux/Concise, inscription de 12h &...

  6. Orienteering Club

    CERN Multimedia

    Club d'Orientation

    2012-01-01

    Relais inter-club/Challenge Carlo Milan Samedi dernier, lors de l’épreuve de course d’orientation organisée par le club du O’Jura, le moteur de la discipline était l’esprit d’équipe, puisqu’il était question d’un relais inter-club avec le Challenge Carlo Milan. Les clubs avaient aligné leurs coureurs soit sur le relais technique (trois participants) soit sur le relais facile (deux participants). Côté O’Jura, il fallait noter la participation de François Gonon, champion du monde 2011, côté club du CERN, Marie et Gaëtan Vuitton, jeunes espoirs du club, devaient préparer la piste pour lancer le dernier relayeur. Côté Lausanne-Jorat, il fallait compter sur le très jeune Viktor Kuznetsov. Les 31 équipes engagées n’ont pas m&ea...

  7. Orienteering club

    CERN Multimedia

    Club d'orientation

    2013-01-01

    Courses d’orientation Samedi 20 avril, les organisateurs du Club de CO du CERN ont accueilli au Mont Mourex 70 participants qui n’ont pas hésité à venir malgré la forte bise. Berni Wehrle du CO CERN s’est octroyé la première place en 1:04:49 sur le parcours technique long devant Pyry Kettunen du Saynso Juankoski en 1:06:52, la 3e place revenant à Bruno Barge, CO CERN, à 7 secondes. Les autres parcours ont été remportés par : Technique moyen : 1er Jacques Moisset, Chamonix (47:44), 2e Yves Rousselot, Balise 25 Besançon (57:16), 3e Jean-Bernard Zosso, CO CERN (59:28). Technique court : 1er Victor Kuznetsov, COLJ (51:53), 2e Pierrick Collet, CO CERN (1:12:52), 3e Dominique Balay, CO CERN (1:16:04). Pour les parcours facile moyen et facile court, Ralf Nardini et Léa Nicolas, tous deux du CO CERN, terminaient respectivement premier. Voi...

  8. Orienteering Club

    CERN Multimedia

    CLUB D'ORIENTATION

    2013-01-01

    Calendrier de la coupe d’automne Le Club d’orientation du CERN, en partenariat avec d’autres clubs de la région, vous propose, pour cette nouvelle coupe d’automne genevoise, une série de 10 courses. Le club du O’Jura donnera le coup d’envoi le samedi 31 août. Les courses s’enchaîneront selon le calendrier suivant : Samedi 31 août : Prémanon (39) - longue distance Samedi 14 septembre : La Faucille (01) - longue distance Samedi 21 septembre : Saint Cergue (VD) - longue distance Samedi 28 septembre : Ballens (VD) - relais Samedi 5 octobre : La Pile (VD) - longue distance Vendredi 11 octobre : Les Evaux (GE) - nocturne Samedi 12 octobre : Grand Jorat, Savigny (VD) - longue distance Samedi 19 octobre : Terrasses de Genève (74) - longue distance Samedi 26 octobre : Prémanon (39) - longue distance Samedi 2 novembre : Bois Tollot (GE) - score - Finale Les &a...

  9. Orienteering club

    CERN Multimedia

    Club d'orientation

    2014-01-01

    Course d'orientation Finale de la coupe d’automne La dernière épreuve de la coupe d’automne organisée par le club s’est déroulée ce samedi 1er novembre avec une course type «one-man-relay» dans la forêt de Trelex (Vd). Les concurrents des circuits techniques devaient parcourir trois boucles et ceux des circuits «faciles» deux boucles, avec changements de carte. Le parcours technique long a été remporté par un membre du club, Berni Wehrle. A l’issue de cette course, le Président du club, L. Jirden annonçait le classement général de la coupe d’automne, basé sur les 6 meilleurs résultats de la saison : Circuit technique long : 1er Juerg Niggli (O’Jura), 2e Berni Wehrle, 3e Beat Mueller. Circuit technique moyen : 1er Laurent Merat (O&r...

  10. Orienteering Club

    CERN Multimedia

    Club d'orientation

    2013-01-01

    Course d'orientation Le coup d’envoi de la coupe genevoise a été donné samedi 31 août dans les bois de Combe Froide à Prémanon. Plus de 150 coureurs avaient fait le déplacement. Les parcours facile court, facile moyen et technique court ont été remportés par des coureurs du club O’Jura - Ulysse Dannecker, Léo Lonchampt, Franck Lonchampt, le technique moyen par Pekka Marti du club Ol Biel Seeland et le technique long par Térence Risse du CA Rosé – également membre de l’équipe nationale suisse des moins de 20 ans. Pour le club du CERN, les meilleures résultats ont été obtenus pas Emese Szunyog sur technique court et Marie Vuitton sur technique moyen avec une 4e place. La prochaine course aura lieu samedi 14 septembre à La Faucille. Le club propose aussi...

  11. Laser cleaning of particulates from paper: Comparison between sized ground wood cellulose and pure cellulose

    International Nuclear Information System (INIS)

    Visible laser cleaning of charcoal particulates from yellow acid mechanical ground wood cellulose paper was compared with that from bleached sulphite softwood cellulose paper. About one order of magnitude of fluence range is available for a cleaning dynamics between the cleaning threshold and the destruction threshold for two laser pulses. Wood cellulose paper exhibited a higher destruction threshold of the original paper than that of the contaminated specimen because of heat transfer from the hot or evaporating charcoal particulates. In contrast, the contaminated bleached cellulose paper exhibited a higher destruction threshold due to shading by the particulates. The graphite particles are not only detached thermo-mechanically, but also by evaporation or combustion. A cleaning effect was found also outside the illuminated areas due to lateral blasting. Infrared measurements revealed dehydration/dehydrogenation reactions and cross-links by ether bonds together with structural changes of the cellulose chain arrangement and the degree of crystallinity.

  12. Laser cleaning of particulates from paper: Comparison between sized ground wood cellulose and pure cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Arif, S.; Kautek, W., E-mail: wolfgang.kautek@univie.ac.at

    2013-07-01

    Visible laser cleaning of charcoal particulates from yellow acid mechanical ground wood cellulose paper was compared with that from bleached sulphite softwood cellulose paper. About one order of magnitude of fluence range is available for a cleaning dynamics between the cleaning threshold and the destruction threshold for two laser pulses. Wood cellulose paper exhibited a higher destruction threshold of the original paper than that of the contaminated specimen because of heat transfer from the hot or evaporating charcoal particulates. In contrast, the contaminated bleached cellulose paper exhibited a higher destruction threshold due to shading by the particulates. The graphite particles are not only detached thermo-mechanically, but also by evaporation or combustion. A cleaning effect was found also outside the illuminated areas due to lateral blasting. Infrared measurements revealed dehydration/dehydrogenation reactions and cross-links by ether bonds together with structural changes of the cellulose chain arrangement and the degree of crystallinity.

  13. Acid hydrolysis of cellulosic fibres: Comparison of bleached kraft pulp, dissolving pulps and cotton textile cellulose.

    Science.gov (United States)

    Palme, Anna; Theliander, Hans; Brelid, Harald

    2016-01-20

    The behaviour of different cellulosic fibres during acid hydrolysis has been investigated and the levelling-off degree of polymerisation (LODP) has been determined. The study included a bleached kraft pulp (both never-dried and once-dried) and two dissolving pulps (once-dried). Additionally, cotton cellulose from new cotton sheets and sheets discarded after long-time use was studied. Experimental results from the investigation, together with results found in literature, imply that ultrastructural differences between different fibres affect their susceptibility towards acid hydrolysis. Drying of a bleached kraft pulp was found to enhance the rate of acid hydrolysis and also result in a decrease in LODP. This implies that the susceptibility of cellulosic fibres towards acid hydrolysis is affected by drying-induced stresses in the cellulose chains. In cotton cellulose, it was found that use and laundering gave a substantial loss in the degree of polymerisation (DP), but that the LODP was only marginally affected. PMID:26572472

  14. Surface modification of cellulose by PCL grafts

    Energy Technology Data Exchange (ETDEWEB)

    Paquet, Olivier; Krouit, Mohammed; Bras, Julien [Laboratoire de Genie des Procedes Papetiers (UMR 5518 CNRS-CTP-INPG), Grenoble INP-Pagora, 461 Rue de la papeterie, F-38402 St Martin d' Heres (France); Thielemans, Wim [Driving Innovation in Chemistry and Chemical Engineering (DICE), School of Chemistry and Process and Environmental Research Division - Faculty of Engineering, University of Nottingham, University Park, Nottingham, NG7 2RD (United Kingdom); Belgacem, Mohamed Naceur, E-mail: Naceur.Belgacem@efpg.inpg.fr [Laboratoire de Genie des Procedes Papetiers (UMR 5518 CNRS-CTP-INPG), Grenoble INP-Pagora, 461 Rue de la papeterie, F-38402 St Martin d' Heres (France)

    2010-02-15

    Two cellulosic substrates (microcrystalline cellulose, MCC, and bleached kraft softwood pulps, BSK) were grafted by polycaprolactone (PCL) chains with different molecular weights, following a three-step procedure using non-swelling conditions in order to limit the reaction to their surface. First, one of the two OH PCL ends was blocked by phenyl isocyanate and the reaction product (adduct 1) was subsequently reacted with 2,4-toluene diisocyanate (adduct 2) to provide it with an NCO function, capable of reacting with cellulose. The ensuing PCL-grafted cellulosic materials were characterized by weight gain, elemental analysis, contact angle measurements, attenuated total reflexion-Fourier transform infrared (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and biodegradation tests. The modification was proven to occur by the presence of nitrogen atoms in the elemental analysis tests and XPS spectra of modified and soxhlet-extracted cellulose. The contact angle measurements have also shown that the surface became as hydrophobic as PCL itself. The polar component of the surface energy of cellulosic substrates before treatment was found to be about 32 and 10 mJ m{sup -2}, for MCC and BSK, respectively. This value vanished to practically zero after grafting with different PCLs. The strategy proposed in the present work is original since, to the best of our knowledge, this paper reports for the first time the chemical 'grafting onto' of the cellulose surface by PCL macromolecular structures, with the aim of obtaining fibre-matrix co-continuous fully sustainable and biodegradable composite materials.

  15. Effect of ionizing radiation on starch and cellulose

    International Nuclear Information System (INIS)

    The investigation is reported of the effects of ionizing radiation both on macromolecular systems generally and on polysaccharides, starch and cellulose. Attention is focused on changes in the physical and physico-chemical properties of starch and cellulose, such as starch swelling, gelation, viscosity, solubility, reaction with iodine, UV, IR and ESR spectra, chemical changes resulting from radiolysis and from the effect of amylases on irradiated starch, changes in cellulose fibre strength, water absorption, stain affinity, and also the degradation of cellulose by radiation and the effect of cellulases on irradiated cellulose. Practical applications of the findings concerning cellulose degradation are discussed. (author)

  16. Biocompatibility of Bacterial Cellulose Based Biomaterials

    Directory of Open Access Journals (Sweden)

    Omar P. Troncoso

    2012-12-01

    Full Text Available Some bacteria can synthesize cellulose when they are cultivated under adequate conditions. These bacteria produce a mat of cellulose on the top of the culture medium, which is formed by a three-dimensional coherent network of pure cellulose nanofibers. Bacterial cellulose (BC has been widely used in different fields, such as the paper industry, electronics and tissue engineering due to its remarkable mechanical properties, conformability and porosity. Nanocomposites based on BC have received much attention, because of the possibility of combining the good properties of BC with other materials for specific applications. BC nanocomposites can be processed either in a static or an agitated medium. The fabrication of BC nanocomposites in static media can be carried out while keeping the original mat structure obtained after the synthesis to form the final nanocomposite or by altering the culture media with other components. The present article reviews the issue of biocompatibility of BC and BC nanocomposites. Biomedical aspects, such as surface modification for improving cell adhesion, in vitro and in vivo studies are given along with details concerning the physics of network formation and the changes that occur in the cellulose networks due to the presence of a second phase. The relevance of biocompatibility studies for the development of BC-based materials in bone, skin and cardiovascular tissue engineering is also discussed.

  17. Cellulose multilayer Membranes manufacture with Ionic liquid

    KAUST Repository

    Livazovic, S.

    2015-05-09

    Membrane processes are considered energy-efficient for water desalination and treatment. However most membranes are based on polymers prepared from fossil petrochemical sources. The development of multilayer membranes for nanofiltration and ultrafiltration, with thin selective layers of naturally available cellulose has been hampered by the availability of non-aggressive solvents. We propose the manufacture of cellulose membranes based on two approaches: (i) silylation, coating from solutions in tetrahydrofuran, followed by solvent evaporation and cellulose regeneration by acid treatment; (ii) casting from solution in 1-ethyl-3-methylimidazolum acetate ([C2mim]OAc), an ionic liquid, followed by phase inversion in water. By these methods porous supports could be easily coated with semi-crystalline cellulose. The membranes were hydrophilic with contact angles as low as 22.0°, molecular weight cut-off as low as 3000 g mol-1 with corresponding water permeance of 13.8 Lm−2 h−1 bar−1. Self-standing cellulose membranes were also manufactured without porous substrate, using only ionic liquid as green solvent. This membrane was insoluble in water, tetrahydrofuran, hexane, N,N-dimethylformamide, 1-methyl-2-pyrrolidinone and N,N-dimethylacetamide.

  18. Clean conversion of cellulose into fermentable glucose.

    Science.gov (United States)

    Sun, Yong; Zhuang, Junping; Lin, Lu; Ouyang, Pingkai

    2009-01-01

    We studied the process of conversion of microcrystalline-cellulose into fermentable glucose in the formic acid reaction system using cross polarization/magic angle spinning (13)C-nuclear magnetic resonance, X-ray diffraction and Fourier transform infrared spectroscopy. The results indicated that formic acid as an active agent was able to effectively penetrate into the interior space of the cellulose molecules, thus collapsing the rigid crystalline structure and allowing hydrolysis to occur easily in the amorphous zone as well as in the crystalline zone. The microcrystalline-cellulose was hydrolyzed using formic acid and 4% hydrochloric acid under mild conditions. The effects of hydrochloric acid concentration, the ratio of solid to liquid, temperature (55-75 degrees C) and retention time (0-9 h), and the concentration of glucose were analyzed. The hydrolysis velocities of microcrystalline-cellulose were 6.14 x 10(-3) h(-1) at 55 degrees C, 2.94 x 10(-2) h(-1) at 65 degrees C, and 6.84x10(-2) h(-1) at 75 degrees C. The degradation velocities of glucose were 0.01 h(-1) at 55 degrees C, 0.14 h(-1) at 65 degrees C, 0.34 h(-1) at 75 degrees C. The activation energy of microcrystalline-cellulose hydrolysis was 105.61 kJ/mol, and the activation energy of glucose degradation was 131.37 kJ/mol. PMID:19409478

  19. Inkjet-printed silver nanoparticles on nano-engineered cellulose films for electrically conducting structures and organic transistors: concept and challenges

    Energy Technology Data Exchange (ETDEWEB)

    Chinga-Carrasco, Gary, E-mail: gary.chinga.carrasco@pfi.no [Paper and Fibre Research Institute (PFI) (Norway); Tobjoerk, Daniel; Oesterbacka, Ronald [Abo Akademi University, Physics, Department of Natural Sciences and Center for Functional Materials (Finland)

    2012-11-15

    This study explores the suitability of microfibrillated cellulose (MFC) films as a substrate for printing electrically conductive structures and multilayer electronic structures such as organic field effect transistors. Various MFC qualities were tested, including mechanically produced MFC, 2,2,6,6-tetramethylpiperidinyl-1-oxyl pre-treated MFC and carboxymethylated-MFC. The films differed significantly with respect to the surface structure. In addition, the carboxymethylated-MFC films were surface modified with hexamethyldisilazane (HMDS) to reduce the water-wettability of the films, and thus, improve the print resolution of the inkjet-printed silver (Ag) nanoparticles. The Ag-particles (diameter < 50 nm) were printed on the HMDS-modified films, which were mainly composed of nanofibrils with diameters <20 nm. The effect of surface roughness and surface chemical characteristics on the ink spreading and print resolution of the Ag-structures was explored. It was demonstrated that organic transistors operating at low voltages can be fabricated on nano-engineered MFC films.

  20. Inkjet-printed silver nanoparticles on nano-engineered cellulose films for electrically conducting structures and organic transistors: concept and challenges

    International Nuclear Information System (INIS)

    This study explores the suitability of microfibrillated cellulose (MFC) films as a substrate for printing electrically conductive structures and multilayer electronic structures such as organic field effect transistors. Various MFC qualities were tested, including mechanically produced MFC, 2,2,6,6-tetramethylpiperidinyl-1-oxyl pre-treated MFC and carboxymethylated-MFC. The films differed significantly with respect to the surface structure. In addition, the carboxymethylated-MFC films were surface modified with hexamethyldisilazane (HMDS) to reduce the water-wettability of the films, and thus, improve the print resolution of the inkjet-printed silver (Ag) nanoparticles. The Ag-particles (diameter < 50 nm) were printed on the HMDS-modified films, which were mainly composed of nanofibrils with diameters <20 nm. The effect of surface roughness and surface chemical characteristics on the ink spreading and print resolution of the Ag-structures was explored. It was demonstrated that organic transistors operating at low voltages can be fabricated on nano-engineered MFC films.

  1. POLYETHERSULFONE COMPOSITE MEMBRANE BLENDED WITH CELLULOSE FIBRILS

    Directory of Open Access Journals (Sweden)

    Ping Qu

    2010-09-01

    Full Text Available Polyethersulfone (PES is a common material used for ultrafiltration (UF membranes, which has good chemical resistance, high mechanical properties, and wide temperature tolerances. The hydrophobic property of the PES membrane seriously limits its application. Cellulose fibrils are composed of micro-sized and nano-sized elements, which have high hydrophilicity, strength, and biodegradation. A composite membrane was prepared by the phase inversion induced by an immersion process. The characteristics of the composite membrane were investigated with Fourier transform infrared spectroscopy (FTIR, X-ray diffraction (XRD, thermogravimetric analysis (TGA, and atomic force microscopy (AFM. The pure water flux of the composite membrane increased dramatically with the increase of cellulose firbils. Mean pore size and porosity were significantly increased. Both mechanical properties and hydrophilicity were enhanced due to the addition of the cellulose firbils.

  2. Prospects for Irradiation in Cellulosic Ethanol Production

    Directory of Open Access Journals (Sweden)

    Anita Saini

    2015-01-01

    Full Text Available Second generation bioethanol production technology relies on lignocellulosic biomass composed of hemicelluloses, celluloses, and lignin components. Cellulose and hemicellulose are sources of fermentable sugars. But the structural characteristics of lignocelluloses pose hindrance to the conversion of these sugar polysaccharides into ethanol. The process of ethanol production, therefore, involves an expensive and energy intensive step of pretreatment, which reduces the recalcitrance of lignocellulose and makes feedstock more susceptible to saccharification. Various physical, chemical, biological, or combined methods are employed to pretreat lignocelluloses. Irradiation is one of the common and promising physical methods of pretreatment, which involves ultrasonic waves, microwaves, γ-rays, and electron beam. Irradiation is also known to enhance the effect of saccharification. This review explains the role of different radiations in the production of cellulosic ethanol.

  3. Prospects for Irradiation in Cellulosic Ethanol Production.

    Science.gov (United States)

    Saini, Anita; Aggarwal, Neeraj K; Sharma, Anuja; Yadav, Anita

    2015-01-01

    Second generation bioethanol production technology relies on lignocellulosic biomass composed of hemicelluloses, celluloses, and lignin components. Cellulose and hemicellulose are sources of fermentable sugars. But the structural characteristics of lignocelluloses pose hindrance to the conversion of these sugar polysaccharides into ethanol. The process of ethanol production, therefore, involves an expensive and energy intensive step of pretreatment, which reduces the recalcitrance of lignocellulose and makes feedstock more susceptible to saccharification. Various physical, chemical, biological, or combined methods are employed to pretreat lignocelluloses. Irradiation is one of the common and promising physical methods of pretreatment, which involves ultrasonic waves, microwaves, γ-rays, and electron beam. Irradiation is also known to enhance the effect of saccharification. This review explains the role of different radiations in the production of cellulosic ethanol. PMID:26839707

  4. Magnetic alignment and patterning of cellulose fibers

    International Nuclear Information System (INIS)

    The alignment and patterning of cellulose fibers under magnetic fields are reported. Static and rotating magnetic fields were used to align cellulose fibers with sizes ranging from millimeter to nanometer sizes. Cellulose fibers of the millimeter order, which were prepared for papermaking, and much smaller fibers with micrometer to nanometer sizes prepared by the acid hydrolysis of larger ones underwent magnetic alignment. Under a rotating field, a uniaxial alignment of fibers was achieved. The alignment was successfully fixed by the photopolymerization of a UV-curable resin precursor used as matrix. A monodomain chiral nematic film was prepared from an aqueous suspension of nanofibers. Using a field modulator inserted in a homogeneous magnetic field, simultaneous alignment and patterning were achieved

  5. Magnetic alignment and patterning of cellulose fibers

    Directory of Open Access Journals (Sweden)

    Fumiko Kimura and Tsunehisa Kimura

    2008-01-01

    Full Text Available The alignment and patterning of cellulose fibers under magnetic fields are reported. Static and rotating magnetic fields were used to align cellulose fibers with sizes ranging from millimeter to nanometer sizes. Cellulose fibers of the millimeter order, which were prepared for papermaking, and much smaller fibers with micrometer to nanometer sizes prepared by the acid hydrolysis of larger ones underwent magnetic alignment. Under a rotating field, a uniaxial alignment of fibers was achieved. The alignment was successfully fixed by the photopolymerization of a UV-curable resin precursor used as matrix. A monodomain chiral nematic film was prepared from an aqueous suspension of nanofibers. Using a field modulator inserted in a homogeneous magnetic field, simultaneous alignment and patterning were achieved

  6. Magnetic alignment and patterning of cellulose fibers

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, Fumiko; Kimura, Tsunehisa [Division of Forest and Biomaterials Science, Graduate School of Agriculture, Kyoto University, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan)], E-mail: tkimura@kais.kyoto-u.ac.jp

    2008-04-01

    The alignment and patterning of cellulose fibers under magnetic fields are reported. Static and rotating magnetic fields were used to align cellulose fibers with sizes ranging from millimeter to nanometer sizes. Cellulose fibers of the millimeter order, which were prepared for papermaking, and much smaller fibers with micrometer to nanometer sizes prepared by the acid hydrolysis of larger ones underwent magnetic alignment. Under a rotating field, a uniaxial alignment of fibers was achieved. The alignment was successfully fixed by the photopolymerization of a UV-curable resin precursor used as matrix. A monodomain chiral nematic film was prepared from an aqueous suspension of nanofibers. Using a field modulator inserted in a homogeneous magnetic field, simultaneous alignment and patterning were achieved.

  7. Sulfated cellulose thin films with antithrombin affinity

    Directory of Open Access Journals (Sweden)

    2009-11-01

    Full Text Available Cellulose thin films were chemically modified by in situ sulfation to produce surfaces with anticoagulant characteristics. Two celluloses differing in their degree of polymerization (DP: CEL I (DP 215–240 and CEL II (DP 1300–1400 were tethered to maleic anhydride copolymer (MA layers and subsequently exposed to SO3•NMe3 solutions at elevated temperature. The impact of the resulting sulfation on the physicochemical properties of the cellulose films was investigated with respect to film thickness, atomic composition, wettability and roughness. The sulfation was optimized to gain a maximal surface concentration of sulfate groups. The scavenging of antithrombin (AT by the surfaces was determined to conclude on their potential anticoagulant properties.

  8. Cationic nanofibrillar cellulose with high antibacterial properties.

    Science.gov (United States)

    Chaker, Achraf; Boufi, Sami

    2015-10-20

    Cationic nanofibrillar cellulose (C-NFC) has been prepared via a high pressure homogenization using quaternized cellulose fibers with glycidyltrimethylammonium chloride. It has been shown that the quaternization of dried softwood pulp facilitated the defibrillation processes and prevented clogging of the homogenizer. The effects of the trimethylammonium chloride content on the fibrillation yield, the transparency degree of the gel, the rheological behavior of the NFC suspension and their electrokinetic properties were investigated. AFM observation showed that the NFC suspension consisted of individualized cellulose I nanofibrils 4-5nm in width and length in the micronic scale. In addition to their strong reinforcing potential, the inclusion of C-NFC into a polymer matrix was shown to efficiently enhance the antibacterial activity. The reinforcing potential of C-NFC, studied by dynamic mechanical analysis (DMA), was compared to anionic NFC and the difference was explained in terms of the nanofibrils capacities to build up a strong networks held by hydrogen bonding. PMID:26256179

  9. Segal crystallinity index revisited by the simulation of X-ray diffraction patterns of cotton cellulose Iβ and cellulose II.

    Science.gov (United States)

    Nam, Sunghyun; French, Alfred D; Condon, Brian D; Concha, Monica

    2016-01-01

    The Segal method estimates the amorphous fraction of cellulose Iβ materials simply based on intensity at 18° 2θ in an X-ray diffraction pattern and was extended to cellulose II using 16° 2θ intensity. To address the dependency of Segal amorphous intensity on crystal size, cellulose polymorph, and the degree of polymorphic conversion, we simulated the diffraction patterns of cotton celluloses (Iβ and II) and compared the simulated amorphous fractions with the Segal values. The diffraction patterns of control and mercerized cottons, respectively, were simulated with perfect crystals of cellulose Iβ (1.54° FWHM) and cellulose II (2.30° FWHM) as well as 10% and 35% amorphous celluloses. Their Segal amorphous fractions were 15% and 31%, respectively. The higher Segal amorphous fraction for control cotton was attributed to the peak overlap. Although the amorphous fraction was set in the simulation, the peak overlap induced by the increase of FWHM further enhanced the Segal amorphous intensity of cellulose Iβ. For cellulose II, the effect of peak overlap was smaller; however the lower reflection of the amorphous cellulose scattering in its Segal amorphous location resulted in smaller Segal amorphous fractions. Despite this underestimation, the relatively good agreement of the Segal method with the simulation for mercerized cotton was attributed to the incomplete conversion to cellulose II. The (1-10) and (110) peaks of cellulose Iβ remained near the Segal amorphous location of cellulose II for blends of control and mercerized cotton fibers. PMID:26453844

  10. Relaxation properties of natural and artificial cellulose materials

    International Nuclear Information System (INIS)

    Present article is devoted to relaxation properties of natural and artificial cellulose materials. Therefore the dielectric properties of natural and artificial cellulose materials depending on influence of frequency and temperature are studied.

  11. Preparation and evaluation of cellulose-dissolving magnetic ionic liquid

    OpenAIRE

    MURAOKA, Jin; Kamiya, Noriho; Ito, Yuji; ムラオカ, ジン; カミヤ, ノリホ; イトウ, ユウジ; 村岡, 仁; 神谷, 典穂; 伊東, 祐二

    2013-01-01

    Ionic liquids have attracted attention as potential pretreatment agents in cellulosic biomass processing. Here we report on a new magnetic ionic liquid that can dissolve crystalline cellulose and be collected by a magnet.

  12. The CELLULOSE-SYNTHASE LIKE C (CSLC) Family of Barley Includes Members that Are Integral Membrane Proteins Targeted to the Plasma Membrane

    Institute of Scientific and Technical Information of China (English)

    Fenny M. Dwivany; Dina Yuli; Rachel A. Burton; Neil J. Shirley; Sarah M. Wilson; Geoffrey B. Fincher; Antony Bacic; Ed Newbigin; Monika S. Doblin

    2009-01-01

    The CELLULOSESYNTHASE-LIKE C(CSLC) family is an ancient lineage within the CELLULOSE SYNTHASE/CEL-LULOSE SYNTHASE-LIKE (CESA/CSL) polysaccharide synthase superfamily that is thought to have arisen before the diver-gence of mosses and vascular plants. As studies in the flowering plant Arabidopsis have suggested synthesis of the (1,4)-β-glucan backbone of xyloglucan (XyG), a wall polysaccharide that tethers adjacent cellulose microfibrils to each other, as a probable function for the CSLCs, CSLC function was investigated in barley (Hordeum vulgare L.), a species with low amounts of XyG in its walls. Four barley CSLC genes were identified (designated HvCSLC1-4). Phylogenetic analysis reveals three well supported clades of CSLCs in flowering plants, with barley having representatives in two of these clades. The four barley CSLCs were expressed in various tissues, with in situ PCR detecting transcripts in all cell types of the coleoptile and root, including cells with primary and secondary cell walls. Co-expression analysis showed that HvCSLC3 was coor-dinately expressed with putative XyG xylosyltransferase genes. Both immuno-EM and membrane fractionation showed that HvCSLC2 was located in the plasma membrane of barley suspension-cultured cells and was not in internal membranes such as endoplasmic reticulum or Golgi apparatus. Based on our current knowledge of the sub-cellular locations of poly-saccharide synthesis, we conclude that the CSLC family probably contains more than one type of polysaccharide synthase.

  13. Rheological properties of aqueous suspension of bacterial cellulose%细菌纤维素水悬浮液的流变特性

    Institute of Scientific and Technical Information of China (English)

    李瑞; 杜双奎; 李志西; 程正丽; 乔艳霞; 靳玉红

    2014-01-01

    cellulose suspension. Firstly, the surface morphology of bacterial cellulose was observed by atomic force microscopy (AFM). Secondly, the rheological properties of bacterial cellulose suspension were investigated by static and dynamic methods. Specifically, consistency and index of viscosity of bacterial cellulose suspension were determined by a Texture Analyzer (TA) with AB/E35 probe under static condition, and carboxymethyl cellulose(CMC) solution was used as a control. Furthermore, consistency and indexes of viscosity of these two kinds of suspension were compared in the present study. Additionally, the dynamic method was used to study the relationship of shear stress, apparent viscosity and shear rate with a rheometer. Finally, the stability of bacterial cellulose suspension and its improvement ways by centrifugation were studied in this paper. Results showed that the width of bacterial cellulose s was between 60-80 nm. The AFM imagines showed that the microfibrils were randomly arranged with plenty of spaces among them and some s may be gathered to form a parallel or spiral bundle. From the rheology analysis, it was found that the consistency and index of viscosity of bacterial cellulose suspension were significantly higher than those of carboxymethyl cellulose solution. Additionally, when the concentration changed from 0.4% to 1.2% a positive correlation was found between the consistency and viscosity index of bacterial cellulose suspension and the concentration of bacterial cellulose (P0.95). The equation between consistency and concentration of bacterial cellulose suspension wasy=936.17x+38.166 (R2=0.9753). The equation between viscosity index and concentration of bacterial cellulose aqueous suspension wasy=61.872x-21.641 (R2=0.9988). So bacterial cellulose s can be widely applied in food as thickening agent and dietary fiber, or paper and cosmetics industries as dispersing agent and binding agent. Under the condition of a relatively low shear rate(0.02-10 s-1), the

  14. Carboxymethyl ethers of cellulose obtained from secondary products of fine-stapled cotton

    International Nuclear Information System (INIS)

    This article is devoted to synthesis and properties of carboxymethyl ethers of cellulose obtained from secondary products of fine-stapled cotton. The investigation of extraction conditions of cellulose on the quality of carboxymethyl ethers of cellulose is conducted. The qualitative characteristics of cotton cellulose are considered. The synthesis of carboxymethyl ethers of cellulose from obtained cellulose is described.

  15. Effect of γ-radiation on the saccharification of cellulose

    International Nuclear Information System (INIS)

    The effect of gamma radiation on the acid and saccharification of agricultural cellulosic wastes was investigated. Radiation doses of 200 KGy and higher significantly increased the saccharification of rice straw, rice hull and corn husk. The observed radiation effects varied with the cellulosic material. Rice straw exhibited the greatest radiosensitivity while rice hull showed the least susceptibility to gamma radiation. Possible mechanisms for the radiation-induced degradation of cellulose and agricultural cellulosic wastes are discussed. (author)

  16. The pressure-volume-temperature relationship of cellulose

    OpenAIRE

    Jallabert, Bastien; Vaca Medina, Guadalupe; Cazalbou, Sophie; Rouilly, Antoine

    2013-01-01

    Pressure–volume–temperature (PVT) mea- surements of a-cellulose with different water contents, were performed at temperatures from 25 to 180 °C and pressures from 19.6 to 196 MPa. PVT measurements allowed observation of the combined effects of pressure and temperature on the specific volume during cellulose thermo-compression. All isobars showed a decrease in cellulose specific volume with temperature. This densification is associated with a transition process of the cellulose, occurring at a...

  17. Molecular dynamics simulation study of polyelectrolyte adsorption on cellulose surfaces

    OpenAIRE

    Biermann, Oliver

    2002-01-01

    The adsorption of two polyelectrolyte ((carboxy methyl) cellulose and poly(acrylate) in water on crystalline cellulose is studied in this work. The multi-component problem has been splitted up into simulations of solutions of the polyelectrolyte (polyanions including sodium counterions) in water, into simulations of the interface of crystalline cellulose towards water. Finally polyelectrolyte-cellulose systems were studied. Molecular dynamics simulations of diluted (_ 2:5 weight percent) aque...

  18. Microbial Cellulose Production from Bacteria Isolated from Rotten Fruit

    OpenAIRE

    Rangaswamy, B.E.; Vanitha, K. P.; Hungund, Basavaraj S.

    2015-01-01

    Microbial cellulose, an exopolysaccharide produced by bacteria, has unique structural and mechanical properties and is highly pure compared to plant cellulose. Present study represents isolation, identification, and screening of cellulose producing bacteria and further process optimization. Isolation of thirty cellulose producers was carried out from natural sources like rotten fruits and rotten vegetables. The bacterial isolates obtained from rotten pomegranate, rotten sweet potato, and rott...

  19. Review: current international research into cellulose nanofibres and nanocomposites

    OpenAIRE

    Eichhorn, S. J.; Dufresne, A; Aranguren, M.; Marcovich, N. E.; Capadona, J R; Rowan, S. J.; Weder, Christoph; Thielemans, W.; Roman, M.; Renneckar, S.; Gindl, W.; Veigel, S.; Keckes, J.; Yano, H.; Abe, K.

    2010-01-01

    This paper provides an overview of recent progress made in the area of cellulose nanofibre-based nanocomposites. An introduction into the methods used to isolate cellulose nanofibres (nanowhiskers, nanofibrils) is given, with details of their structure. Following this, the article is split into sections dealing with processing and characterisation of cellulose nanocomposites and new developments in the area, with particular emphasis on applications. The types of cellulose nanofibres covered a...

  20. Continuous Cellulosic Bioethanol Fermentation by Cyclic Fed-Batch Cocultivation

    OpenAIRE

    Jiang, He-Long; He, Qiang; He, Zhili; Hemme, Christopher L.; Wu, Liyou; Zhou, Jizhong

    2013-01-01

    Cocultivation of cellulolytic and saccharolytic microbial populations is a promising strategy to improve bioethanol production from the fermentation of recalcitrant cellulosic materials. Earlier studies have demonstrated the effectiveness of cocultivation in enhancing ethanolic fermentation of cellulose in batch fermentation. To further enhance process efficiency, a semicontinuous cyclic fed-batch fermentor configuration was evaluated for its potential in enhancing the efficiency of cellulose...

  1. Characterising the cellulose synthase complexes of cell walls

    NARCIS (Netherlands)

    Mansoori Zangir, N.

    2012-01-01

    One of the characteristics of the plant kingdom is the presence of a structural cell wall. Cellulose is a major component in both the primary and secondary cell walls of plants. In higher plants cellulose is synthesized by so called rosette protein complexes with cellulose synthases (CESAs) as the c

  2. Structural differences of xylans affect their interaction with cellulose

    NARCIS (Netherlands)

    Kabel, M.A.; Borne, van den H.; Vincken, J.P.; Voragen, A.G.J.; Schols, H.A.

    2007-01-01

    The affinity of xylan to cellulose is an important aspect of many industrial processes, e.g. production of cellulose, paper making and bio-ethanol production. However, little is known about the adsorption of structurally different xylans to cellulose. Therefore, the adsorption of various xylans to b

  3. Cyanobacterial cellulose synthesis in the light of the photanol concept

    NARCIS (Netherlands)

    R.M. Schuurmans; H.C.P. Matthijs; L.J. Stal; K.J. Hellingwerf

    2014-01-01

    The detailed knowledge already available about cellulose synthases and their regulation, plus emerging insights into the process of cellulose secretion in cyanobacteria make cellulose an attractive polymer for the application of the photanol concept in an economically viable production process. By v

  4. 16 CFR 501.6 - Cellulose sponges, irregular dimensions.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Cellulose sponges, irregular dimensions. 501... REQUIREMENTS AND PROHIBITIONS UNDER PART 500 § 501.6 Cellulose sponges, irregular dimensions. Variety packages of cellulose sponges of irregular dimensions, are exempted from the requirements of § 500.25 of...

  5. Cellulose chain binding free energy drives the processive move of cellulases on the cellulose surface.

    Science.gov (United States)

    Wang, Yefei; Zhang, Shujun; Song, Xiangfei; Yao, Lishan

    2016-09-01

    Processivity is essential for cellulases in their catalysis of cellulose hydrolysis. But what drives the processive move is not well understood. In this work, we use Trichoderma reesei Cel7B as a model system and show that its processivity is directly correlated to the binding free energy difference of a cellulose chain occupying the binding sites -7 to +2 and that occupying sites -7 to -1. Several mutants that have stronger interactions with glycosyl units in sites +1 and +2 than the wild type enzyme show higher processivity. The results suggest that after the release of the product cellobiose located in sites +1 and +2, the enzyme pulls the cellulose chain to fill the vacant sites, which propels its processive move on the cellulose surface. Biotechnol. Bioeng. 2016;113: 1873-1880. © 2016 Wiley Periodicals, Inc. PMID:26928155

  6. Segal crystallinity index revisited by the simulation of X-ray diffraction patterns of cotton cellulose IB and cellulose II

    Science.gov (United States)

    The Segal method estimates the amorphous fraction of cellulose IB materials simply based on intensity at 18o 20 in an X-ray diffraction pattern and was extended to cellulose II using 16o 2O intensity. To address the dependency of Segal amorphous intensity on crystal size, cellulose polymorph, and th...

  7. Use of Cellulose and Oxidized Cellulose Nanocrystals from Olive Stones in Chitosan Bionanocomposites

    OpenAIRE

    Abou-Zeid, Ragab E.; Hassan, Enas A.; Fedia Bettaieb; Ramzi Khiari; Mohammad L. Hassan

    2015-01-01

    Cellulose nanocrystals (CNC) and 2,2,6,6-tetramethyl-1-piperidinyloxyl- (TEMPO-) oxidized cellulose nanocrystals (CNC-TEMPO) were prepared from olive stones. The prepared nanocrystals were characterized using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and carboxylic groups content determination. The prepared nanocrystals were used as reinforcing elements in chitosan nanocomposites, which were characterized using X-ray diffraction (XRD) and tensile ...

  8. Viscoelastic evaluation of topical creams containing microcrystalline cellulose/sodium carboxymethyl cellulose as stabilizer

    OpenAIRE

    Adeyeye, Moji Christianah; Jain, Ashwinkumar C.; Ghorab, Mohamed K. M.; Reilly, William J.

    2002-01-01

    The purpose of this study was to examine the viscoelastic properties of topical creams containing various concentrations of microcrystalline cellulose and sodium carboxymethyl cellulose (Avicel® CL-611) as a stabilizer. Avicel CL-611 was used at 4 different levels (1%, 2%, 4%, and 6% dispersion) to prepare topical creams, and hydrocortisone acetate was used as a model drug. The viscoelastic properties such as loss modulus (G), storage modulus (G), and loss tangent (tan δ) of these creams were...

  9. Engineering of a novel cellulose-adherent cellulolytic Saccharomyces cerevisiae for cellulosic biofuel production

    OpenAIRE

    Zhuo Liu; Shih-Hsin Ho; Kengo Sasaki; Riaan den Haan; Kentaro Inokuma; Chiaki Ogino; van Zyl, Willem H; Tomohisa Hasunuma; Akihiko Kondo

    2016-01-01

    Cellulosic biofuel is the subject of increasing attention. The main obstacle toward its economic feasibility is the recalcitrance of lignocellulose requiring large amount of enzyme to break. Several engineered yeast strains have been developed with cellulolytic activities to reduce the need for enzyme addition, but exhibiting limited effect. Here, we report the successful engineering of a cellulose-adherent Saccharomyces cerevisiae displaying four different synergistic cellulases on the cell ...

  10. Environmental sustainability of cellulosic energy cropping systems

    Science.gov (United States)

    The environmental sustainability of bioenergy production depends on both direct and indirect effects of the production systems to produce bioenergy feedstocks. This chapter evaluates what is known about the environmental sustainability of cellulosic bioenergy crop production for the types of produc...

  11. Herstellung und Beurteilung funktionalisierter Cellulose-Tiefenfilterschichten

    OpenAIRE

    Lösch, Sebastian

    2016-01-01

    Gegenstand dieser Arbeit ist die Entwicklung funktionalisierter Cellulose-Tiefenfilterschichten. Dazu werden kommerzielle Kationenaustauscher in einer Kugelmühle nass zerkleinert und bei der Herstellung in die Tiefenfilterschichten eingebettet. Die mechanischen Eigenschaften und das Filtrationsverhalten dieser Schichten sind vergleichbar mit kommerziellen Produkten. Der maximale, technisch einsetzbare Masseanteil an Ionenaustauscher beträgt dabei ca. 40 %. In Durchströmungsversuchen wird die...

  12. Formation of asymmetric cellulose acetate membranes

    NARCIS (Netherlands)

    Bokhorst, H.; Altena, F.W.; Smolders, C.A.

    1981-01-01

    Cellulose acetate membranes were prepared from casting solutions containing dioxane as a solvent and varying concentrations (up to 6%) of maleic acid as an additive. Coagulation took place in water at different temperatures. The effect of these variables on membrane structure and membrane properties

  13. Chemistry, Technology and Aplications of Oxidized Celluloses

    Czech Academy of Sciences Publication Activity Database

    Havelka, P.; Sopuch, T.; Hnatowicz, Vladimír; Suchý, P.; Masteikova, R.; Bajerová, M.; Gajdziok, J.; Milichovský, M.; Švorčík, V.

    2010-01-01

    Roč. 2010, C (2010), s. 205-245. ISBN 978-1-608-76-388-7 Institutional support: RVO:61389005 Keywords : oxidation * cellulose * in-vitro Subject RIV: BO - Biophysics https://www.novapublishers.com/catalog/product_info.php?products_id=14049

  14. Methacrylate hydrogels reinforced with bacterial cellulose

    Czech Academy of Sciences Publication Activity Database

    Hobzová, Radka; Dušková-Smrčková, Miroslava; Michálek, Jiří; Karpushkin, Evgeny; Gatenholm, P.

    2012-01-01

    Roč. 61, č. 7 (2012), s. 1193-1201. ISSN 0959-8103 R&D Projects: GA AV ČR KJB400500902 Institutional research plan: CEZ:AV0Z40500505 Keywords : bacterial cellulose * methacrylate hydrogel * composite Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.125, year: 2012

  15. HPMC reinforced with different cellulose nanoparticles

    Science.gov (United States)

    Synthetic polymers, made almost entirely from chemicals derived from crude oil, are widely used as primary packaging in the food industry causing environmental issues. Hydroxypropyl Methyl Cellulose (HPMC) can be used as bio-based packaging material. In this study, the application of nanotechnology ...

  16. [Insights into engineering of cellulosic ethanol].

    Science.gov (United States)

    Yue, Guojun; Wu, Guoqing; Lin, Xin

    2014-06-01

    For energy security, air pollution concerns, coupled with the desire to sustain the agricultural sector and revitalize the rural economy, many countries have applied ethanol as oxygenate or fuel to supplement or replace gasoline in transportation sector. Because of abundant feedstock resources and effective reduction of green-house-gas emissions, the cellulosic ethanol has attracted great attention. With a couple of pioneers beginning to produce this biofuel from biomass in commercial quantities around the world, it is necessary to solve engineering problems and complete the economic assessment in 2015-2016, gradually enter the commercialization stage. To avoid "competing for food with humans and competing for land with food", the 1st generation fuel ethanol will gradually transit to the 2nd generation cellulosic ethanol. Based on the overview of cellulosic ethanol industrialization from domestic and abroad in recent years, the main engineering application problems encountered in pretreatment, enzymes and enzymatic hydrolysis, pentose/hexose co-fermentation strains and processes, equipment were discussed from chemical engineering and biotechnology perspective. The development direction of cellulosic ethanol technology in China was addressed. PMID:25212000

  17. Nanomanufacturing metrology for cellulosic nanomaterials: an update

    Science.gov (United States)

    Postek, Michael T.

    2014-08-01

    The development of the metrology and standards for advanced manufacturing of cellulosic nanomaterials (or basically, wood-based nanotechnology) is imperative to the success of this rising economic sector. Wood-based nanotechnology is a revolutionary technology that will create new jobs and strengthen America's forest-based economy through industrial development and expansion. It allows this, previously perceived, low-tech industry to leap-frog directly into high-tech products and processes and thus improves its current economic slump. Recent global investments in nanotechnology programs have led to a deeper appreciation of the high performance nature of cellulose nanomaterials. Cellulose, manufactured to the smallest possible-size ( 2 nm x 100 nm), is a high-value material that enables products to be lighter and stronger; have less embodied energy; utilize no catalysts in the manufacturing, are biologically compatible and, come from a readily renewable resource. In addition to the potential for a dramatic impact on the national economy - estimated to be as much as $250 billion worldwide by 2020 - cellulose-based nanotechnology creates a pathway for expanded and new markets utilizing these renewable materials. The installed capacity associated with the US pulp and paper industry represents an opportunity, with investment, to rapidly move to large scale production of nano-based materials. However, effective imaging, characterization and fundamental measurement science for process control and characterization are lacking at the present time. This talk will discuss some of these needed measurements and potential solutions.

  18. African perspective on cellulosic ethanol production

    DEFF Research Database (Denmark)

    Bensah, Edem Cudjoe; Kemausuor, Francis; Miezah, Kodwo;

    2015-01-01

    A major challenge to commercial production of cellulosic ethanol pertains to the cost-effective breakdown of the complex and recalcitrant structure of lignocellulose into its components via pretreatment, the cost of enzymes for hydrolysis and fermentation, and the conversion rate of C5 sugars to ...

  19. PRODUCTION AND CHARACTERIZATION OF ECONOMICAL BACTERIAL CELLULOSE

    Directory of Open Access Journals (Sweden)

    Houssni El-Saied

    2008-11-01

    Full Text Available The present study investigates the economical production of bacterial cellulose (BC by Gluconacetobacter subsp. Xylinus (ATCC 10245 in 250 ml Erlenmeyer flasks cultivated under static conditions. The fermentation media used contained food industrial by-product liquors, such as black strap molasses solution and corn steep liquor (CSL, which represents some of the most economical carbon and nitrogen sources. However, because of the presence of undesirable components in molasses (such as coloring substances, heavy metals, and other compounds that may act as inhibitors, and in order to eliminate them, crude molasses has been treated with an acid, as an attempt to increase BC productivity. The amount of BC produced using these carbon and nitrogen sources was determined and compared to that produced using previously reported fermentation media. The characterizations of the bacterial cellulose (BC pellicles obtained using either conventional or by-product media were studied by thermal and spectral techniques and compared to those of plant-derived cellulose such as cotton linter, viscose pulp, and microcrystalline cellulose.

  20. Essays concerning the cellulosic biofuel industry

    Science.gov (United States)

    Rosburg, Alicia Sue

    Despite market-based incentives and mandated production, the U.S. cellulosic biofuel industry has been slow to develop. This dissertation explores the economic factors that have limited industry development along with important economic tradeoffs that will be encountered with commercial-scale production. The first essay provides an overview of the policies, potential, and challenges of the biofuel industry, with a focus on cellulosic biofuel. The second essay considers the economics of cellulosic biofuel production. Breakeven models of the local feedstock supply system and biofuel refining process are constructed to develop the Biofuel Breakeven (BioBreak) program, a stochastic, Excel-based program that evaluates the feasibility of local biofuel and biomass markets under various policy and market scenarios. An application of the BioBreak program is presented using expected market conditions for 14 local cellulosic biofuel markets that vary by feedstock and location. The economic costs of biofuel production identified from the BioBreak application are higher than frequently anticipated and raise questions about the potential of cellulosic ethanol as a sustainable and economical substitute for conventional fuels. Program results also are extended using life-cycle analysis to evaluate the cost of reducing GHG emissions by substituting cellulosic ethanol for conventional fuel. The third essay takes a closer look at the economic trade-offs within the biorefinery industry and feedstock production processes. A long-run biomass production through bioenergy conversion cost model is developed that incorporates heterogeneity of biomass suppliers within and between local markets. The model builds on previous literature by treating biomass as a non-commoditized feedstock and relaxes the common assumption of fixed biomass density and price within local markets. An empirical application is provided for switchgrass-based ethanol production within U.S. crop reporting districts

  1. Method of forming an electrically conductive cellulose composite

    Science.gov (United States)

    Evans, Barbara R.; O'Neill, Hugh M.; Woodward, Jonathan

    2011-11-22

    An electrically conductive cellulose composite includes a cellulose matrix and an electrically conductive carbonaceous material incorporated into the cellulose matrix. The electrical conductivity of the cellulose composite is at least 10 .mu.S/cm at 25.degree. C. The composite can be made by incorporating the electrically conductive carbonaceous material into a culture medium with a cellulose-producing organism, such as Gluconoacetobacter hansenii. The composites can be used to form electrodes, such as for use in membrane electrode assemblies for fuel cells.

  2. Rheology Behavior of Cellulose/NMMO/Water Solution

    Institute of Scientific and Technical Information of China (English)

    顾广新; 胡赛珠; 邵惠丽; 沈弋弋; 胡学超

    2001-01-01

    Rheology properties of cellulose/NMMO/water solution are important parameters for spinning. The storage and loss modulus and viscosity of the solution decrease with increasing water concentration of solvent in certain range. Flow-activation energy of two kinds of cellulose solution is quite different in view of their molecular weight. The molecular weigh distribution of cellulose samples can be characterized by the value of Gc/c Since the different cellulose samples have different MWD and DP, the relations of the first normal stress difference N1 vs. shear rate are different. Moreover, the rheology properties of cellulose solution produced by twin-screw extruder process are also investigated.

  3. The Synthesis of a Novel Cellulose Physical Gel

    Directory of Open Access Journals (Sweden)

    Jiufang Duan

    2014-01-01

    Full Text Available Cellulose possessing β-cyclodextrin (β-CD was used as a host molecule and cellulose possessing ferrocene (Fc as a guest polymer. Infrared spectra, differential scanning calorimetry (DSC, ultraviolet spectroscopy (UV, and contact angle analysis were used to characterise the material structure and the inclusion behaviour. The results showed that the β-CD-cellulose and the Fc-cellulose can form inclusion complexes. Moreover, ferrocene oxidation, and reduction of state can be adjusted by sodium hypochlorite (NaClO as an oxidant and glutathione (GSH as a reductant. In this study, a physical gel based on β-CD-cellulose/Fc-cellulose was formed under mild conditions in which autonomous healing between cut surfaces occurred after 24 hours. The physical gel can be controlled in the sol-gel transition. The compressive strength of the Fc-cellulose/β-CD-cellulose gel increased with increased cellulose concentration. The host-guest interaction between the side chains of cellulose could strengthen the gel. The cellulose physical gel may eventually be used as a stimulus-responsive, healing material in biomedical applications.

  4. Assessing nano cellulose developments using science and technology indicators

    Energy Technology Data Exchange (ETDEWEB)

    Milanez, Douglas Henrique; Amaral, Roniberto Morato do; Faria, Leandro Innocentini Lopes de; Gregolin, Jose Angelo Rodrigues, E-mail: douglasmilanez@yahoo.com.br [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil). Nucleo de Informacao Tecnologica em Materiais. Dept. de Engenharia de Materiais

    2013-11-01

    This research aims to examine scientific and technological trends of developments in nano cellulose based on scientometric and patent indicators obtained from the Science Citation Index and Derwent Innovations Index in 2001-2010. The overall nano cellulose activity indicators were compared to nanotechnology and other selected nano materials. Scientific and technological future developments in nano cellulose were forecasted using extrapolation growth curves and the main countries were also mapped. The results showed that nano cellulose publications and patent documents have increased rapidly over the last five years with an average growth rate higher than that of nanotechnology and fullerene. The USA, Japan, France, Sweden and Finland all played a significant role in nano cellulose development and the extrapolation growth curves suggested that nano cellulose scientific and technological activities are still emerging. Finally, the evidence from this study recommends monitoring nano cellulose S and T advances in the coming years. (author)

  5. Assessing nano cellulose developments using science and technology indicators

    International Nuclear Information System (INIS)

    This research aims to examine scientific and technological trends of developments in nano cellulose based on scientometric and patent indicators obtained from the Science Citation Index and Derwent Innovations Index in 2001-2010. The overall nano cellulose activity indicators were compared to nanotechnology and other selected nano materials. Scientific and technological future developments in nano cellulose were forecasted using extrapolation growth curves and the main countries were also mapped. The results showed that nano cellulose publications and patent documents have increased rapidly over the last five years with an average growth rate higher than that of nanotechnology and fullerene. The USA, Japan, France, Sweden and Finland all played a significant role in nano cellulose development and the extrapolation growth curves suggested that nano cellulose scientific and technological activities are still emerging. Finally, the evidence from this study recommends monitoring nano cellulose S and T advances in the coming years. (author)

  6. The effect of deuteration on the structure of bacterial cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Bali, Garima [Georgia Institute of Technology; Foston, Marcus [Georgia Institute of Technology; O' Neill, Hugh Michael [ORNL; Evans, Barbara R [ORNL; He, Junhong [ORNL; Ragauskas, Arthur [Georgia Institute of Technology

    2013-01-01

    ABSTRACT In vivo generated deuterated bacterial cellulose, cultivated from 100% deuterated glycerol in D2O medium, was analyzed for deuterium incorporation by ionic liquid dissolution and 2H and 1H nuclear magnetic resonance (NMR). A solution NMR method of the dissolved cellulose was used to determine that this bacterial cellulose had 85 % deuterium incorporation. Acetylation and 1H and 2H NMR of deuterated bacterial cellulose indicated near equal deuteration at all sites of the glucopyranosyl ring except C-6 which was partly deuterated. Despite the high level of deuterium incorporation there were no significant differences in the molecular and morphological properties were observed for the deuterated and protio bacterial cellulose samples. The highly deuterated bacterial cellulose presented here can be used as a model substrate for studying cellulose biopolymer properties via future small angle neutron scattering (SANS) studies.

  7. Method and apparatus for treating a cellulosic feedstock

    Science.gov (United States)

    Nguyen, Quang A.; Burke, Murray J.; Hillier, Sunalie N.

    2015-09-08

    Methods and apparatus for treating, pre-treating, preparing and conveying a cellulosic feedstock, such as for ethanol production, are disclosed. More specifically, the invention relates to methods and apparatus for treating a cellulosic feedstock by mixing and heating the cellulosic feedstock and/or by moistening and heating the cellulosic feedstock. The invention also relates to a holding tank, and a method of utilizing the holding tank whereby bridging may be reduced or eliminated and may result in a product stream from autohydrolysis or hydrolysis having an improved yield. The invention further relates to methods and apparatus for obtaining and conveying a cellulosic feedstock, which may be used for the subsequent production of a fermentable sugar stream from the cellulose and hemicellulose in the cellulosic feedstock wherein the fermentable sugar stream may be used for subsequent ethanol production. The invention also relates to a method and apparatus for withdrawing one or more feedstock stream from a holding tank.

  8. Characterization of cellulose extracted from oil palm empty fruit bunch

    Science.gov (United States)

    Sisak, Muhammad Asri Abdul; Daik, Rusli; Ramli, Suria

    2015-09-01

    Recently, cellulose has been studied by many researchers due to its promising properties such as biodegradability, biocompatibility, hydrophilicity and robustness. Due to that it is applied in many fields such as paper, film, drug delivery, membranes, etc. Cellulose can be extracted from various plants while oil palm empty fruit bunch (OPEFB) is the one of its sources. In this study, cellulose was extracted by chemical treatments which involved the use of formic acid and hydrogen peroxide to remove hemicellulose and lignin components. Maximum yield was 43.22%. Based on the FT-IR spectra, the peak of wax (1735 cm-1), hemicellulose (1375 cm-1) and lignin (1248 cm-1 and 1037 cm-1) were not observed in extracted cellulose. TGA analysis showed that the extracted cellulose starts to thermally degrade at 340 °C. The SEM analysis suggested that the cellulose extracted from OPEFB was not much different from commercial cellulose.

  9. Characterization of cellulose and other exopolysaccharides produced from Gluconacetobacter strains.

    Science.gov (United States)

    Fang, Lin; Catchmark, Jeffrey M

    2015-01-22

    This study characterized the cellulosic and non-cellulosic exopolysaccharides (EPS) produced by four Gluconacetobacter strains. The yields of bacterial cellulose and water-soluble polysaccharides were dependent on both carbon source and Gluconacetobacter strain. The carbon substrate also affected the composition of the free EPS. When galactose served as an exclusive carbon source, Gluconacetobacter xylinus (G. xylinus) ATCC 53524 and ATCC 700178 produced a distinct alkaline stable crystalline product, which influenced the crystallization of cellulose. Gluconacetobacter hansenii (G. hansenii) ATCC 23769 and ATCC 53582, however, did not exhibit any significant change in cellulose crystal properties when galactose was used as the carbon source. Microscopic observation further confirmed significant incorporation of EPS into the cellulose composites. The cellulosic network produced from galactose medium showed distinctive morphological and structural features compared to that from glucose medium. PMID:25439946

  10. Outer Membrane Proteins of Fibrobacter succinogenes with Potential Roles in Adhesion to Cellulose and in Cellulose Digestion▿

    OpenAIRE

    Jun, Hyun-Sik; Qi, Meng; Gong, Joshua; Egbosimba, Emmanuel E.; Forsberg, Cecil W.

    2007-01-01

    Comparative analysis of binding of intact glucose-grown Fibrobacter succinogenes strain S85 cells and adhesion-defective mutants AD1 and AD4 to crystalline and acid-swollen (amorphous) cellulose showed that strain S85 bound efficiently to both forms of cellulose while mutant Ad1 bound to acid-swollen cellulose, but not to crystalline cellulose, and mutant Ad4 did not bind to either. One- and two-dimensional electrophoresis (2-DE) of outer membrane cellulose binding proteins and of outer membr...

  11. IMPACTS OF BIOFILM FORMATION ON CELLULOSE FERMENTATION

    Energy Technology Data Exchange (ETDEWEB)

    Leschine, Susan

    2009-10-31

    This project addressed four major areas of investigation: i) characterization of formation of Cellulomonas uda biofilms on cellulose; ii) characterization of Clostridium phytofermentans biofilm development; colonization of cellulose and its regulation; iii) characterization of Thermobifida fusca biofilm development; colonization of cellulose and its regulation; and iii) description of the architecture of mature C. uda, C. phytofermentans, and T. fusca biofilms. This research is aimed at advancing understanding of biofilm formation and other complex processes involved in the degradation of the abundant cellulosic biomass, and the biology of the microbes involved. Information obtained from these studies is invaluable in the development of practical applications, such as the single-step bioconversion of cellulose-containing residues to fuels and other bioproducts. Our results have clearly shown that cellulose-decomposing microbes rapidly colonize cellulose and form complex structures typical of biofilms. Furthermore, our observations suggest that, as cells multiply on nutritive surfaces during biofilms formation, dramatic cell morphological changes occur. We speculated that morphological changes, which involve a transition from rod-shaped cells to more rounded forms, might be more apparent in a filamentous microbe. In order to test this hypothesis, we included in our research a study of biofilm formation by T. fusca, a thermophilic cellulolytic actinomycete commonly found in compost. The cellulase system of T. fusca has been extensively detailed through the work of David Wilson and colleagues at Cornell, and also, genome sequence of a T. fusca strain has been determine by the DOE Joint Genome Institute. Thus, T. fusca is an excellent subject for studies of biofilm development and its potential impacts on cellulose degradation. We also completed a study of the chitinase system of C. uda. This work provided essential background information for understanding how C. uda

  12. Purification and characterization of a cellulose-binding {beta}-glucosidase from cellulose-degrading cultures of phanerochaete chrysosporium

    Energy Technology Data Exchange (ETDEWEB)

    Lymar, E.S.; Li, B.; Renganathan, V. [Oregon Graduate Institute of Science & Technology, Portland, OR (United States)

    1995-08-01

    Extracellular {beta}-glucosidase from cellulose-degrading cultures of Phanerochaete chrysosporium was purified by DEAE-Sephadex chromatography, by Sephacryl S-200 chromatography, and by fast protein liquid chromatography (FPLC) using a Mono Q anion-exchange column. Sodium dodecyl sulfate-polyacrylamide gel electrophoretic (SDS-PAGE) analysis of FPLC-purified {beta}-glucosidase indicated the presence of three enzyme forms with molecular weights of 96,000, 98,000, and 114,000. On further fractionation with a microcrystalline cellulose column, the 114,000-molecular-weight {beta}-glucosidase, which had 82% of the {beta}-glucosidase activity, was bound to cellulose. The {beta}-glucosidases with molecular weights of 96,000 and 98,000 did not bind to cellulose. The cellulose-bound {beta}-glucosidase was eluted completely from the cellulose matrix with water. Cellulose-bound {beta}-glucosidase catalyzed p-nitrophenylglucoside hydrolysis, suggesting that the catalytic site is not involved in cellulose binding. When the cellulose-binding form was incubated with papain for 20 h, no decrease in the enzyme activity was observed; however, approximately 74% of the papain-treated glucosidase did not bind to microcrystalline cellulose. SDS-PAGE analysis of the nonbinding glucosidase produced by papain indicated the presence of three bands with molecular weights in the range of 95,000 to 97,000. On the basis of these results, we propose that the low-molecular-weight (96,000 and 98,000) non-cellulose-binding {beta}-glucosidase forms are most probably formed from the higher-molecular-weight (114,000) cellulose-binding {beta}-glucosidase via extracellular proteolytic hydrolysis. Also, it appears that the extracellular {beta}-glucosidase from P. chrysosporium might be organized into two domains, a cellulose-binding domain and a catalytic domain. Kinetic characterization of the cellulose-binding form is also presented. 31 refs., 6 figs., 1 tab.

  13. A facile route to prepare cellulose-based films.

    Science.gov (United States)

    Xu, Qin; Chen, Chen; Rosswurm, Katelyn; Yao, Tianming; Janaswamy, Srinivas

    2016-09-20

    Cellulose is the most abundant renewable and biodegradable material available in nature. Its insoluble character in water as well as common organic and inorganic liquids, however, curtails the wholesome utility. The continuous rise for biodegradable products based on cellulose coupled with its intrinsic ability to form a viable substitute for the petroleum-based materials necessitates the critical need for solubilizing the cellulose. Herein, we demonstrate the feasibility of ZnCl2 solutions, especially the 64-72% concentrations, to dissolve cellulose. FTIR results suggest that Zn(2+) ions promote Zn⋯O3H interactions, which in-turn weaken the intrinsic O3H⋯O5 hydrogen bonds that are responsible for strengthening the cellulose chains. Interestingly, Ca(2+) ions promote interactions among the Zn-cellulose chains leading to the formation of nano fibrils and yield gelling solutions. The tensile strength of the Ca(2+) added Zn-cellulose films increases by around 250% compared to the Zn-cellulose films. Overall, utilization of inorganic salt solutions to solubilize and crosslink cellulose is cost-effective, recyclable and certainly stands out tall among the other available systems. More importantly, the proposed protocol is simple and is a "green" process, and thus its large-scale adaptability is quite feasible. We strongly believe that the outcome opens up a new window of opportunities for cellulose in the biomedical, pharmaceutical, food and non-food applications. PMID:27261751

  14. Tertiary phase diagram of cellulose, ionic liquid and organic solvent

    Science.gov (United States)

    Zhang, Xin; Henderson, Doug; Tyagi, Madhusudan; Mao, Yimin; Briber, Robert M.; Wang, Howard

    Cellulose is the most abundant natural polymer on earth, and widely used in products from clothing to paper. Fundamental understanding of molecular solutions of cellulose is the key to realize advanced technologies beyond cellulose fibers. It has been reported that certain ionic liquid/organic solvent mixtures dissolve cellulose. In this study, the tertiary phase diagram of microcrystalline cellulose, 1-Ethyl-3-methylimidazolium acetate (EMIMAc), and dimethylformamide (DMF) mixtures has been determined using optical cloud point method and small angle neutron scattering (SANS). Data indicate that a molar ratio of EMIMAc to cellulose repeating unit equal or greater than 3 is necessary but not sufficient in forming one-phase homogeneous solutions. A miscibility gap exists in the dilute regime, where a minimum of 5 mol% of EMIM Ac in DMF is needed to form homogenous solutions. SANS show that cellulose chains adopt Gaussian-like conformation in homogenous solutions. The solutions exhibit the characteristics of upper critical solution temperature. Clustering of cellulose chains occurs at low EMIMAc/DMF or EMIMAc/cellulose ratio, or at low temperatures. The mechanism of cellulose dissolution in tertiary mixture is discussed.

  15. Reinforced plastics and aerogels by nanocrystalline cellulose

    International Nuclear Information System (INIS)

    Nanocrystalline cellulose (NCC), a rigid rod-like nanoscale material, can be produced from cellulosic biomass in powder, liquid, or gel forms by acid and chemical hydrolysis. Owing to its unique and exceptional physicochemical properties, the incorporation of a small amount of NCC into plastic enhances the mechanical strength of the latter by several orders of magnitudes. Carbohydrate-based NCC poses no serious environmental concerns, providing further impetus for the development and applications of this green and renewable biomaterial to fabricate lightweight and biodegradable composites and aerogels. Surface functionalization of NCC remains the main focus of NCC research to tailor its properties for dispersion in hydrophilic or hydrophobic media. It is of uttermost importance to develop tools and protocols for imaging of NCC in a complex matrix and quantify its reinforcement effect.

  16. Process Dependence of Cellulose Nanofiber Fabrication

    Science.gov (United States)

    Henderson, Doug; Zhang, Xin; Mao, Yimin; Jang, Soo-Hwan; Hu, Liangbing; Briber, Robert; Wang, Howard

    Cellulose nanofibers (CNF) are the most abundant natural nanomaterial on earth with potential applications in renewable energy, polymer nanocomposites and flexible electronics. CNF can be produced through TEMPO oxidation which separates the hierarchical structure of cellulose fibers into smaller micro- and nanofibers by altering their surface chemistry, inducing a repulsive electrostatic charge on the fibers. This work will examine the structural evolution of CNF during production. Samples were prepared by removing and quenching aliquots during the TEMPO reaction. The fibers were washed, filtered and re-dispersed into D2O for small angle neutron scattering (SANS) measurements. The SANS data was analyzed to track the changes in the CNF structure as a function of reaction time.

  17. SPECIFIC INTERACTION ACTING AT A CELLULOSE-BINDING DOMAIN/CELLULOSE INTERFACE FOR PAPERMAKING APPLICATION

    Directory of Open Access Journals (Sweden)

    Shingo Yokota

    2008-11-01

    Full Text Available Specific and strong cellulose-binding characteristics were utilized for promoting retention of additives in contaminated papermaking systems. Cellulose-binding domain (CBD of cellulase derived from Trichoderma viride was separated by digestion with papain, and then introduced into anionic polyacrylamide (A-PAM through a condensation reaction using water-soluble carbodiimide. The CBD-modified A-PAM (CBD-A-PAM showed good retention on pulp fibers, resulting in high tensile strength paper sheets. The effect remained almost unchanged in the presence of model interfering substances such as ligninsulfonate and Ca2+ ions, whereas commercial cationic paper-strengthening polymer became ineffective. The cellulose-binding force of CBD was quantitatively determined by atomic force microscopy (AFM in the liquid state. Histidine-tagged CBD protein was obtained using Escherichia coli via an expression of CBD derived from Cellulomonas fimi, and immobilized on a gold-coated AFM probe. A strong attractive force was detected only at a CBD/cellulose interface, even when Ca2+ ions were present in high concentration. Direct estimation of CBD affinity for cellulose substrate by AFM would provide significant information on the interfacial interactions useful for the functional design of papermaking additives.

  18. End-functionalization of cellulose nanocrystals

    OpenAIRE

    Lundahl, Meri

    2014-01-01

    Regioselective modification of nanocelluloses can have intriguing applications in self-assembled material synthesis. In this thesis, cellulose nanocrystals (CNC) were selectively functionalized at their reducing ends with thiol and maleimide groups. For thiol end-functionalization, a protocol was developed based on NHS/EDC-catalyzed coupling of NaClO2-oxidized CNCs with NH2 (CH2)6 SH in water. Maleimide end-functionalization was achieved by reacting end-thiolated CNCs (CNC SH) with a homobifu...

  19. Nanofibrillated Cellulose Surface Modification: A Review

    OpenAIRE

    Julien Bras,; Mohamed Naceur Belgacem; Karim Missoum

    2013-01-01

    Interest in nanofibrillated cellulose (NFC) has increased notably over recent decades. This bio-based nanomaterial has been used essentially in bionanocomposites or in paper thanks to its high mechanical reinforcement ability or barrier property respectively. Its nano-scale dimensions and its capacity to form a strong entangled nanoporous network have encouraged the emergence of new high-value applications. It is worth noting that chemical surface modification of this material can be a key fa...

  20. Cellulose nanocrystals : surface modification and advanced materials

    OpenAIRE

    Lin, Ning

    2014-01-01

    The present work focuses on the properties of cellulose nanocrystals, their surface modification and development of advanced materials. Diverse approaches are employed on these nanoscaled substrates aiming to modify their surface properties and extend their use in highly sophisticated applications, such as postsulfation and desulfation, polymer grafting and adsorption, selective oxidation, molecular grafting, and ‘host-guest' inclusion. On the basis of surface modifications, properties analys...

  1. PRODUCTION AND CHARACTERIZATION OF ECONOMICAL BACTERIAL CELLULOSE

    OpenAIRE

    Houssni El-Saied; Ahmed I. El-Diwany; Altaf H. Bast; Nagwa A. Atwa; Dina E. El-Ghwas

    2008-01-01

    The present study investigates the economical production of bacterial cellulose (BC) by Gluconacetobacter subsp. Xylinus (ATCC 10245) in 250 ml Erlenmeyer flasks cultivated under static conditions. The fermentation media used contained food industrial by-product liquors, such as black strap molasses solution and corn steep liquor (CSL), which represents some of the most economical carbon and nitrogen sources. However, because of the presence of undesirable components in molasses (such as colo...

  2. Transcriptomic and genomic analysis of cellulose fermentation by Clostridium thermocellum ATCC 27405

    Energy Technology Data Exchange (ETDEWEB)

    Raman, Babu [ORNL; McKeown, Catherine K [ORNL; Rodriguez, Jr., Miguel [ORNL; Brown, Steven D [ORNL; Mielenz, Jonathan R [ORNL

    2011-01-01

    The ability of Clostridium thermocellum ATCC 27405 wild-type strain to hydrolyze cellulose and ferment the degradation products directly to ethanol and other metabolic byproducts makes it an attractive candidate for consolidated bioprocessing of cellulosic biomass to biofuels. In this study, whole-genome microarrays were used to investigate the expression of C. thermocellum mRNA during growth on crystalline cellulose in controlled replicate batch fermentations. A time-series analysis of gene expression revealed changes in transcript levels of {approx}40% of genes ({approx}1300 out of 3198 ORFs encoded in the genome) during transition from early-exponential to late-stationary phase. K-means clustering of genes with statistically significant changes in transcript levels identified six distinct clusters of temporal expression. Broadly, genes involved in energy production, translation, glycolysis and amino acid, nucleotide and coenzyme metabolism displayed a decreasing trend in gene expression as cells entered stationary phase. In comparison, genes involved in cell structure and motility, chemotaxis, signal transduction and transcription showed an increasing trend in gene expression. Hierarchical clustering of cellulosome-related genes highlighted temporal changes in composition of this multi-enzyme complex during batch growth on crystalline cellulose, with increased expression of several genes encoding hydrolytic enzymes involved in degradation of non-cellulosic substrates in stationary phase. Overall, the results suggest that under low substrate availability, growth slows due to decreased metabolic potential and C. thermocellum alters its gene expression to (i) modulate the composition of cellulosomes that are released into the environment with an increased proportion of enzymes than can efficiently degrade plant polysaccharides other than cellulose, (ii) enhance signal transduction and chemotaxis mechanisms perhaps to sense the oligosaccharide hydrolysis products

  3. Tritium concentrations in tree ring cellulose

    International Nuclear Information System (INIS)

    Measurements of tritium (tissue bound tritium; TBT) concentration in tree rings are presented and discussed. Such measurement is expected to provide a useful means of estimating the tritium level in the environment in the past. The concentration of tritium bound in the tissue (TBT) in a tree ring considered to reflect the environmental tritium level in the area at the time of the formation of the ring, while the concentration of tritium in the free water in the tissue represents the current environmental tritium level. First, tritium concentration in tree ring cellulose sampled from a cedar tree grown in a typical environment in Fukuoka Prefecture is compared with the tritium concentration in precipitation in Tokyo. Results show that the year-to-year variations in the tritium concentration in the tree rings agree well with those in precipitation. The maximum concentration, which occurred in 1963, is attibuted to atmospheric nuclear testing which was performed frequently during the 1961 - 1963 period. Measurement is also made of the tritium concentration in tree ring cellulose sampled from a pine tree grown near the Isotope Center of Kyushu University (Fukuoka). Results indicate that the background level is higher probably due to the release of tritium from the facilities around the pine tree. Thus, measurement of tritium in tree ring cellulose clearly shows the year-to-year variation in the tritium concentration in the atmosphere. (N.K.)

  4. Drying of Pigment-Cellulose Nanofibril Substrates

    Directory of Open Access Journals (Sweden)

    Oleg Timofeev

    2014-10-01

    Full Text Available A new substrate containing cellulose nanofibrils and inorganic pigment particles has been developed for printed electronics applications. The studied composite structure contains 80% fillers and is mechanically stable and flexible. Before drying, the solids content can be as low as 20% due to the high water binding capacity of the cellulose nanofibrils. We have studied several drying methods and their effects on the substrate properties. The aim is to achieve a tight, smooth surface keeping the drying efficiency simultaneously at a high level. The methods studied include: (1 drying on a hot metal surface; (2 air impingement drying; and (3 hot pressing. Somewhat surprisingly, drying rates measured for the pigment-cellulose nanofibril substrates were quite similar to those for the reference board sheets. Very high dewatering rates were observed for the hot pressing at high moisture contents. The drying method had significant effects on the final substrate properties, especially on short-range surface smoothness. The best smoothness was obtained with a combination of impingement and contact drying. The mechanical properties of the sheets were also affected by the drying method and associated temperature.

  5. Printed optically transparent graphene cellulose electrodes

    Science.gov (United States)

    Sinar, Dogan; Knopf, George K.; Nikumb, Suwas; Andrushchenko, Anatoly

    2016-02-01

    Optically transparent electrodes are a key component in variety of products including bioelectronics, touch screens, flexible displays, low emissivity windows, and photovoltaic cells. Although highly conductive indium tin oxide (ITO) films are often used in these electrode applications, the raw material is very expensive and the electrodes often fracture when mechanically stressed. An alternative low-cost material for inkjet printing transparent electrodes on glass and flexible polymer substrates is described in this paper. The water based ink is created by using a hydrophilic cellulose derivative, carboxymethyl cellulose (CMC), to help suspend the naturally hydrophobic graphene (G) sheets in a solvent composed of 70% DI water and 30% 2-butoxyethanol. The CMC chain has hydrophobic and hydrophilic functional sites which allow adsorption on G sheets and, therefore, permit the graphene to be stabilized in water by electrostatic and steric forces. Once deposited on the functionalized substrate the electrical conductivity of the printed films can be "tuned" by decomposing the cellulose stabilizer using thermal reduction. The entire electrode can be thermally reduced in an oven or portions of the electrode thermally modified using a laser annealing process. The thermal process can reduce the sheet resistance of G-CMC films to high optical transparency.

  6. 21 CFR 177.1400 - Hydroxyethyl cellulose film, water-insoluble.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Hydroxyethyl cellulose film, water-insoluble. 177... cellulose film, water-insoluble. Water-insoluble hydroxyethyl cellulose film may be safely used for... cellulose film consists of a base sheet manufactured by the ethoxylation of cellulose under...

  7. Theories of Sexual Orientation.

    Science.gov (United States)

    Storms, Michael D.

    1980-01-01

    Results indicated homosexuals, heterosexuals, and bisexuals did not differ within each sex on measures of masculinity and femininity. Strong support was obtained for the hypothesis that sexual orientation relates primarily to erotic fantasy orientation. (Author/DB)

  8. Lateral orientation (image)

    Science.gov (United States)

    A lateral orientation is a position away from the midline of the body. For instance, the arms are lateral to the ... ears are lateral to the head. A medial orientation is a position toward the midline of the ...

  9. Biodegradation evaluation of bacterial cellulose, vegetable cellulose and poly (3-hydroxybutyrate in soil

    Directory of Open Access Journals (Sweden)

    Suellen Brasil Schröpfer

    2015-04-01

    Full Text Available In recent years, the inappropriate disposal of polymeric materials has increased due to industrial development and increase of population consumption. This problem may be minimized by using biodegradable polymers, such as bacterial cellulose and poly(hydroxybutyrate, from renewable resources. This work was aimed at monitoring and evaluating degradation of bacterial cellulose, vegetable cellulose and poly(3-hydroxybutyrate using Thermogravimetric Analysis and Scanning Electron Microscopy. Controlled mass polymer samples were buried in pots containing soil. Samples were removed in 30 day intervals up to 180 days. The results show that the mass of the polymer increased in the first month when in contact with the soil but then it was degraded as evidenced by mass loss and changes on the sample surface.

  10. Metallization of bacterial cellulose for electrical and electronic device manufacture

    Energy Technology Data Exchange (ETDEWEB)

    Evans, Barbara R [Oak Ridge, TN; O' Neill, Hugh M [Knoxville, TN; Jansen, Valerie Malyvanh [Memphis, TN; Woodward, Jonathan [Knoxville, TN

    2010-09-28

    A method for the deposition of metals in bacterial cellulose and for the employment of the metallized bacterial cellulose in the construction of fuel cells and other electronic devices is disclosed. The method for impregnating bacterial cellulose with a metal comprises placing a bacterial cellulose matrix in a solution of a metal salt such that the metal salt is reduced to metallic form and the metal precipitates in or on the matrix. The method for the construction of a fuel cell comprises placing a hydrated bacterial cellulose support structure in a solution of a metal salt such that the metal precipitates in or on the support structure, inserting contact wires into two pieces of the metal impregnated support structure, placing the two pieces of metal impregnated support structure on opposite sides of a layer of hydrated bacterial cellulose, and dehydrating the three layer structure to create a fuel cell.

  11. Metallization of bacterial cellulose for electrical and electronic device manufacture

    Energy Technology Data Exchange (ETDEWEB)

    Evans, Barbara R. (Oak Ridge, TN); O' Neill, Hugh M. (Knoxville, TN); Jansen, Valerie Malyvanh (Memphis, TN); Woodward, Jonathan (Knoxville, TN)

    2011-06-07

    A method for the deposition of metals in bacterial cellulose and for the employment of the metallized bacterial cellulose in the construction of fuel cells and other electronic devices is disclosed. The method for impregnating bacterial cellulose with a metal comprises placing a bacterial cellulose matrix in a solution of a metal salt such that the metal salt is reduced to metallic form and the metal precipitates in or on the matrix. The method for the construction of a fuel cell comprises placing a hydrated bacterial cellulose support structure in a solution of a metal salt such that the metal precipitates in or on the support structure, inserting contact wires into two pieces of the metal impregnated support structure, placing the two pieces of metal impregnated support structure on opposite sides of a layer of hydrated bacterial cellulose, and dehydrating the three layer structure to create a fuel cell.

  12. Extraction and characterization of cellulose nano whiskers from balsa wood

    International Nuclear Information System (INIS)

    In this study cellulose nano whiskers were obtained from balsa wood. For this purpose, fibers of balsa wood were subjected to hydrolysis reactions for lignin and hemi cellulose digestion and acquisition of nano-scale cellulose. Cellulose nano crystals obtained had medium length and thickness of 176 nm and 7 nm respectively. Infrared spectroscopy and x-ray diffraction showed that the process used for extracting nano whiskers could digest nearly all the lignin and hemi cellulose from the balsa fiber and still preserve the aspect ratio and crystallinity, satisfactory enough for future application in polymer nano composites. Thermogravimetry showed that the onset temperature of thermal degradation of cellulose nano crystals (226 degree C) was higher than the temperature of the balsa fiber (215 degree C), allowing its use in molding processes with many polymers from the molten state.(author)

  13. Cellulose-Based Bio- and Nanocomposites: A Review

    Directory of Open Access Journals (Sweden)

    Susheel Kalia

    2011-01-01

    Full Text Available Cellulose macro- and nanofibers have gained increasing attention due to the high strength and stiffness, biodegradability and renewability, and their production and application in development of composites. Application of cellulose nanofibers for the development of composites is a relatively new research area. Cellulose macro- and nanofibers can be used as reinforcement in composite materials because of enhanced mechanical, thermal, and biodegradation properties of composites. Cellulose fibers are hydrophilic in nature, so it becomes necessary to increase their surface roughness for the development of composites with enhanced properties. In the present paper, we have reviewed the surface modification of cellulose fibers by various methods. Processing methods, properties, and various applications of nanocellulose and cellulosic composites are also discussed in this paper.

  14. Effect of Surface Attachment on Synthesis of Bacterial Cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Evans, Barbara R [ORNL; O' Neill, Hugh Michael [ORNL

    2005-01-01

    Gluconacetobacter spp. synthesize a pure form of hydrophilic cellulose that has several industrial specialty applications. Literature reports have concentrated on intensive investigation of static and agitated culture in liquid media containing high nutrient concentrations optimized for maximal cellulose production rates. The behavior of these bacteria on semisolid and solid surfaces has not been specifically addressed. The species Gluconacetobacter hansenii was examined for cellulose synthesis and colony morphology on a range of solid supports, including cotton linters, and on media thickened with agar, methyl cellulose, or gellan. The concentration and chemical structure of the thickening agent were found to be directly related to the formation of contiguous cellulose pellicules. Viability of the bacteria following freezer storage was improved when the bacteria were frozen in their cellulose pellicules.

  15. Ductile all-cellulose nanocomposite films fabricated from core-shell structured cellulose nanofibrils.

    Science.gov (United States)

    Larsson, Per A; Berglund, Lars A; Wågberg, Lars

    2014-06-01

    Cellulosic materials have many desirable properties such as high mechanical strength and low oxygen permeability and will be an important component in a sustainable biomaterial-based society, but unfortunately they often lack the ductility and formability offered by petroleum-based materials. This paper describes the fabrication and characterization of nanocomposite films made of core-shell modified cellulose nanofibrils (CNFs) surrounded by a shell of ductile dialcohol cellulose, created by heterogeneous periodate oxidation followed by borohydride reduction of the native cellulose in the external parts of the individual fibrils. The oxidation with periodate selectively produces dialdehyde cellulose, and the process does not increase the charge density of the material. Yet the modified cellulose fibers could easily be homogenized to CNFs. Prior to film fabrication, the CNF was shown by atomic force microscopy to be 0.5-2 μm long and 4-10 nm wide. The films were fabricated by filtration, and besides uniaxial tensile testing at different relative humidities, they were characterized by scanning electron microscopy and oxygen permeability. The strength-at-break at 23 °C and 50% RH was 175 MPa, and the films could, before rupture, be strained, mainly by plastic deformation, to about 15% and 37% at 50% RH and 90% RH, respectively. This moisture plasticization was further utilized to form a demonstrator consisting of a double-curved structure with a nominal strain of 24% over the curvature. At a relative humidity of 80%, the films still acted as a good oxygen barrier, having an oxygen permeability of 5.5 mL·μL/(m(2)·24 h·kPa). These properties indicate that this new material has a potential for use as a barrier in complex-shaped structures and hence ultimately reduce the need for petroleum-based plastics. PMID:24773125

  16. Characterization of Cellulose Microfibers Isolated from Rubberwood (Hevea brasiliensis)

    OpenAIRE

    Junidah Lamaming; Nurul Hasin Sharudin; Rokiah Hashim; Othman Sulaiman

    2016-01-01

    Cellulose microfibers were isolated by chemical treatment followed by acid hydrolysis using sulphuric acid. The chemical compositions for extractive, holocellulose, cellulose and lignin were determined. The functional group of raw particles and cellulose microfibers of rubberwood were determined using fourier transform infrared spectroscopy (FT-IR). Morphological studies were viewed using Scanning Electron Microscopy (SEM) to investigate physical changes of the fibers after acid hydrolysis. T...

  17. Metallization of bacterial cellulose for electrical and electronic device manufacture

    Energy Technology Data Exchange (ETDEWEB)

    Evans, Barbara R.; O' Neill, Hugh M.; Jansen, Valerie Malyvanh; Woodward, Jonathan

    2006-01-17

    The employment of metallized bacterial cellulose in the construction of fuel cells and other electronic devices is disclosed. The fuel cell includes an electrolyte membrane comprising a membrane support structure comprising bacterial cellulose, an anode disposed on one side of the electrolyte membrane, and a cathode disposed on an opposite side of the electrolyte membrane. At least one of the anode and the cathode comprises an electrode support structure comprising bacterial cellulose, and a catalyst disposed in or on the electrode support structure.

  18. A study on paper recycling effects on cellulose properties

    OpenAIRE

    Sahin, Halil

    2013-01-01

    Cellulose is the main structural element of paper, one of the most important natural polimers that producted by plants. The water-cellulose interactions that causing swelling with water intake or shrinkage with water removal is very key issue for formation of sheet. However, during paper recycling, cellulose is undergoes some changes and swelling properties in water decreases irreversible. As a result of these modifications, plasticity and elastic properties of fibers modified. Once dried cel...

  19. Factors Involved in Hydrolysis of Microcrystalline Cellulose by Acetivibrio cellulolyticus†

    OpenAIRE

    MacKenzie, C. Roger; Girishchandra B Patel; Bilous, Doris

    1987-01-01

    Acetivibrio cellulolyticus cellulase obtained by the water elution of residual cellulose from the growth medium was compared with the cellulase activity present in culture supernatants. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis indicated that water elution released most of the protein bands which adhered to undigested cellulose from the culture medium. The enzyme in the culture supernatant and that eluted from residual cellulose had specific activities for Avicel hydr...

  20. Method for providing a nanocellulose involving modifying cellulose fibers

    OpenAIRE

    Ankerfors, Mikael; Lindström, Tom

    2009-01-01

    The present invention provides a method for the manufacturing of nanocellulose. The method includes a first modification of the cellulose material, where the cellulose fibres are treated with an aqueous electrolyte-containing solution of an amphoteric cellulose derivative. The modification is followed by a mechanical treatment. By using this method for manufacturing nanocellulose, clogging of the mechanical apparatus is avoided. Also disclosed is nanocellulose manufactured in accordance with ...