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Sample records for cellulose pour applications

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

    PubMed

    George, Johnsy; Sabapathi, S N

    2015-01-01

    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. PMID:26604715

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

    PubMed Central

    George, Johnsy; Sabapathi, SN

    2015-01-01

    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. PMID:26604715

  3. Cellulose-binding domains: biotechnological applications.

    PubMed

    Levy, Ilan; Shoseyov, Oded

    2002-11-01

    Many researchers have acknowledged the fact that there exists an immense potential for the application of the cellulose-binding domains (CBDs) in the field of biotechnology. This becomes apparent when the phrase "cellulose-binding domain" is used as the key word for a computerized patent search; more then 150 hits are retrieved. Cellulose is an ideal matrix for large-scale affinity purification procedures. This chemically inert matrix has excellent physical properties as well as low affinity for nonspecific protein binding. It is available in a diverse range of forms and sizes, is pharmaceutically safe, and relatively inexpensive. Present studies into the application of CBDs in industry have established that they can be applied in the modification of physical and chemical properties of composite materials and the development of modified materials with improved properties. In agro-biotechnology, CBDs can be used to modify polysaccharide materials both in vivo and in vitro. The CBDs exert nonhydrolytic fiber disruption on cellulose-containing materials. The potential applications of "CBD technology" range from modulating the architecture of individual cells to the modification of an entire organism. Expressing these genes under specific promoters and using appropriate trafficking signals, can be used to alter the nutritional value and texture of agricultural crops and their final products. PMID:14550028

  4. Cellulose Modifications and Their Future Application

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this poster, we will describe the synthesis and structural characterizations of a benzyl-, nitrobenzyl-, and aminobenzyl celluloses. Nitrobenzyl- and aminobenzyl cellulose derivatives are synthesized by etherification process in lithium chloride/N,N-dimethylacetamide homogeneous solution. Nitrobe...

  5. Cellulose

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  6. Cellulose-silica/gold nanomaterials for electronic applications.

    PubMed

    Kim, Gwang-Hoon; Ramesh, Sivalingam; Kim, Joo-Hyung; Jung, Dongsoo; Kim, Heung Soo

    2014-10-01

    Cellulose and one dimensional nano-material composite has been investigated for various industrial applications due to their optical, mechanical and electrical properties. In present investigation, cellulose/silica and silica-gold hybrid biomaterials were prepared by sol-gel covalent cross-linking process. The tetraethoxysiliane (TEOS) and gold precursors and γ-aminopropyltriethoxysilane (γ-APTES) as coupling agent were used for sol-gel cross-linking process. The chemical and morphological properties of cellulose/silica and cellulose/silica-gold nano-materials via covalent cross-linking hybrids were confirmed by FTIR, XRD, SEM, and TEM analysis. In the sol-gel process, the inorganic particles were dispersed in the cellulose host matrix at the nanometer scale, bonding to the cellulose through the covalent bonds. PMID:25942815

  7. Review on biomedical and bioengineering applications of cellulose sulfate.

    PubMed

    Zhang, Qilei; Lin, Dongqiang; Yao, Shanjing

    2015-11-01

    Polysaccharide sulfates are naturally existing chemicals that show important biological activities in living organisms. Cellulose sulfate is a semi-synthesized polysaccharide sulfate with a relatively simple chain structure and unique biological properties and its biological applications have been explored in research and clinical trials. With the advance of cellulose derivatization and characterization, cellulose sulfate molecules with tailored structures have been developed to fulfill individual requirements. This review aims to provide a summary of recent development of cellulose sulfate in biomedical applications. Its synthesis pathways were discussed with structure-property relationship elucidated. The application of cellulose sulfate in drug delivery and microbe/cell immobilization were summarized with emphasis given on its polyelectrolyte complex formation processes. PMID:26256354

  8. Overview of Cellulose Nanomaterials, Their Capabilities and Applications

    NASA Astrophysics Data System (ADS)

    Moon, Robert J.; Schueneman, Gregory T.; Simonsen, John

    2016-07-01

    Cellulose nanomaterials (CNs) are a new class of cellulose particles with properties and functionalities distinct from molecular cellulose and wood pulp, and as a result, they are being developed for applications that were once thought impossible for cellulosic materials. Momentum is growing in CN research and development, and commercialization in this field is happening because of the unique combination of characteristics (e.g., high mechanical properties, sustainability, and large-scale production potential) and utility across a broad spectrum of material applications (e.g. as an additive, self-sustaining structures, and template structures) that CNs offer. Despite the challenges typical for materials development, CN and near-CN production is ramping up with pilot scale to industry demonstration trials, and the first commercial products are starting to hit the marketplace. This review provides a broad overview of CNs and their capabilities that are enabling new application areas for cellulose-based materials.

  9. Applications of bacterial cellulose and its composites in biomedicine.

    PubMed

    Rajwade, J M; Paknikar, K M; Kumbhar, J V

    2015-03-01

    Bacterial cellulose produced by few but specific microbial genera is an extremely pure natural exopolysaccharide. Besides providing adhesive properties and a competitive advantage to the cellulose over-producer, bacterial cellulose confers UV protection, ensures maintenance of an aerobic environment, retains moisture, protects against heavy metal stress, etc. This unique nanostructured matrix is being widely explored for various medical and nonmedical applications. It can be produced in various shapes and forms because of which it finds varied uses in biomedicine. The attributes of bacterial cellulose such as biocompatibility, haemocompatibility, mechanical strength, microporosity and biodegradability with its unique surface chemistry make it ideally suited for a plethora of biomedical applications. This review highlights these qualities of bacterial cellulose in detail with emphasis on reports that prove its utility in biomedicine. It also gives an in-depth account of various biomedical applications ranging from implants and scaffolds for tissue engineering, carriers for drug delivery, wound-dressing materials, etc. that are reported until date. Besides, perspectives on limitations of commercialisation of bacterial cellulose have been presented. This review is also an update on the variety of low-cost substrates used for production of bacterial cellulose and its nonmedical applications and includes patents and commercial products based on bacterial cellulose. PMID:25666681

  10. Cellulose Electro-Active Paper: From Discovery to Technology Applications

    NASA Astrophysics Data System (ADS)

    Abas, Zafar; Kim, Heung Soo; Kim, Jaehwan; Kim, Joo-Hyung

    2014-09-01

    Cellulose electro-active paper (EAPap) is an attractive material of electro-active polymers (EAPs) family due to its smart characteristics. EAPap is thin cellulose film coated with metal electrodes on both sides. Its large displacement output, low actuation voltage and low power consumption can be used for biomimetic sensors/actuators and electromechanical system. Because cellulose EAPap is ultra-lightweight, easy to manufacture, inexpensive, biocompatible, and biodegradable, it has been employed for many applications such as bending actuator, vibration sensor, artificial muscle, flexible speaker, and can be advantageous in areas such as micro-insect robots, micro-flying objects, microelectromechanical systems, biosensors, and flexible displays.

  11. All-cellulose nanocomposite film made from bagasse cellulose nanofibers for food packaging application.

    PubMed

    Ghaderi, Moein; Mousavi, Mohammad; Yousefi, Hossein; Labbafi, Mohsen

    2014-04-15

    All-cellulose nanocomposite (ACNC) film was produced from sugarcane bagasse nanofibers using N,N-dimethylacetamide/lithium chloride solvent. The average diameter of bagasse fibers (14 μm) was downsized to 39 nm after disk grinding process. X-ray diffraction showed that apparent crystallinity and crystallite size decreased relatively to an increased duration of dissolution time. Thermogravimetric analysis confirmed that thermal stability of the ACNC was slightly less than that of the pure cellulose nanofiber sheet. Tensile strength of the fiber sheet, nanofiber sheet and ACNC prepared with 10 min dissolution time were 8, 101 and 140 MPa, respectively. Water vapor permeability (WVP) of the ACNC film increased relatively to an increased duration of dissolution time. ACNC can be considered as a multi-performance material with potential for application in cellulose-based food packaging owing to its promising properties (tough, bio-based, biodegradable and acceptable levels of WVP). PMID:24607160

  12. The future prospects of microbial cellulose in biomedical applications.

    PubMed

    Czaja, Wojciech K; Young, David J; Kawecki, Marek; Brown, R Malcolm

    2007-01-01

    Microbial cellulose has proven to be a remarkably versatile biomaterial and can be used in wide variety of applied scientific endeavors, such as paper products, electronics, acoustics, and biomedical devices. In fact, biomedical devices recently have gained a significant amount of attention because of an increased interest in tissue-engineered products for both wound care and the regeneration of damaged or diseased organs. Due to its unique nanostructure and properties, microbial cellulose is a natural candidate for numerous medical and tissue-engineered applications. For example, a microbial cellulose membrane has been successfully used as a wound-healing device for severely damaged skin and as a small-diameter blood vessel replacement. The nonwoven ribbons of microbial cellulose microfibrils closely resemble the structure of native extracellular matrices, suggesting that it could function as a scaffold for the production of many tissue-engineered constructs. In addition, microbial cellulose membranes, having a unique nanostructure, could have many other uses in wound healing and regenerative medicine, such as guided tissue regeneration (GTR), periodontal treatments, or as a replacement for dura mater (a membrane that surrounds brain tissue). In effect, microbial cellulose could function as a scaffold material for the regeneration of a wide variety of tissues, showing that it could eventually become an excellent platform technology for medicine. If microbial cellulose can be successfully mass produced, it will eventually become a vital biomaterial and will be used in the creation of a wide variety of medical devices and consumer products. PMID:17206781

  13. Cellulose nanowhiskers and nanofibers from biomass for composite applications

    NASA Astrophysics Data System (ADS)

    Wang, Tao

    2011-12-01

    Biological nanocomposites such as plant cell wall exhibit high mechanical properties at a light weight. The secret of the rigidity and strength of the cell wall lies in its main structural component -- cellulose. Native cellulose exists as highly-ordered microfibrils, which are just a few nanometers wide and have been found to be stiffer than many synthetic fibers. In the quest for sustainable development around the world, using cellulose microfibrils from plant materials as renewable alternatives to conventional reinforcement materials such as glass fibers and carbon fibers is generating particular interest. In this research, by mechanical disintegration and by controlled chemical hydrolysis, both cellulose nanofibers and nanowhiskers were extracted from the cell wall of an agricultural waste, wheat straw. The reinforcement performances of the two nanofillers were then studied and compared using the water-soluble polyvinyl alcohol (PVOH) as a matrix material. It was found that while both of these nanofillers could impart higher stiffness to the polymer, the nanofibers from biomass were more effective in composite reinforcement than the cellulose crystals thanks to their large aspect ratio and their ability to form interconnected network structures through hydrogen bonding. One of the biggest challenges in the development of cellulose nanocomposites is achieving good dispersion. Because of the high density of hydroxyl groups on the surface of cellulose, it remains a difficult task to disperse cellulose nanofibers in many commonly used polymer matrices. The present work addresses this issue by developing a water-based route taking advantage of polymer colloidal suspensions. Combining cellulose nanofibers with one of the most important biopolymers, poly(lactic acid) (PLA), we have prepared nanocomposites with excellent fiber dispersion and improved modulus and strength. The bio-based nanocomposites have a great potential to serve as light-weight structural materials

  14. Zinc impregnated cellulose nanocomposites: Synthesis, characterization and applications

    NASA Astrophysics Data System (ADS)

    Ali, Attarad; Ambreen, Sidra; Maqbool, Qaisar; Naz, Sania; Shams, Muhammad Fahad; Ahmad, Madiha; Phull, Abdul Rehman; Zia, Muhammad

    2016-11-01

    Nanocomposite materials have broad applicability due to synergistic effect of combined components. In present investigation, cellulose isolated from citrus peel waste is used as a supporting material; impregnation of zinc oxide nanoparticles via co-precipitation method. The characterization of nano composite is carried out through Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) and Thermo-gravimetric analysis (TGA) resulting less than 10 μm cellulose fiber and approx. 50 nm ZnO NPs. Zinc oxide impregnated cellulose (ZnO-Cel) exhibited significant bacterial devastation property when compared to ZnO NPs or Cellulose via disc diffusion and colony forming unit methods. In addition, the ZnO-Cel exhibited significant total antioxidant, and minor DPPH free radical scavenging and total reducing power activities. The nano composite also showed time dependent increase in photocatalytic by effectively degrading methylene blue dye up to 69.5% under sunlight irradiation within 90 min. The results suggest effective utilization of cellulose obtained from citrus waste and synthesis of pharmacologically important nano-composites that can be exploited in wound dressing; defence against microbial attack and healing due to antioxidative property, furthermore can also be used for waste water treatment.

  15. Conception et calibration d'un sonoreacteur pour l'oxydation de la cellulose par le systeme TEMPO/NaOCl/NaBr

    NASA Astrophysics Data System (ADS)

    Paquin, Michel

    Avec le contexte economique actuel dans le domaine des pates et papiers au Canada, l'industrie se doit de diversifier ses produits mis en marche. La fermeture de plus de 20 usines depuis 2005, une baisse du PIB de l'industrie de 1,4 milliard CAD entre 1999--2008, une baisse de la demande de 2,4 %, une diminution du prix de la pate de 20,9 % depuis juillet 2009. La delocalisation du secteur vers l'Asie et l'hemisphere sud sont autant de raisons pour laquelle l'industrie se doit d'etre a l'avant plan de nouvelle technologie a base de fibre de bois. Pour augmenter leur rentabilite, l'industrie se doit de diversifier ses produits dans d'autres secteurs que le simple fabricant de papier impression-ecriture. Sa diversification passe par l'elaboration de nouveaux papiers a valeur ajoutee (papier conducteur, papier bioactif, etc.), par l'utilisation de la biomasse forestiere pour la production d'energie, par l'utilisation de la biomasse forestiere pour l'elaboration d'une plateforme de chimie verte, par l'utilisation de la lignine pour le developpement de polymeres et par l'utilisation de la fibre cellulosique pour la fabrication de nanomateriaux. La fabrication de nanofibrille de cellulose peut devenir un des produits qui servira a diversifier la production des usines de pates et papiers. Les nanofibrilles de cellulose possedent des proprietes mecaniques et chimiques exceptionnelles. Les nanofibrilles de cellulose sont fabriquees a partir d'une oxydation selective de la pate kraft de feuillu avec le systeme TEMPO-NaOCl-NaBr. L'oxydation selective de l'alcool primaire en C6 du monomere de glucose sous forme de carboxylates engendre une modification chimique de la cellulose qui accroit l'hydrophilicite des fibrilles. Suite a cette oxydation, nous devons effectuer une desintegration mecanique de la fibre kraft de feuillu oxydee pour separer les fibrilles. Le processus d'oxydation de la fibre par le systeme TEMPO-NaOCl-NaBr et sa defibrillation par la suite engendre une

  16. New application of crystalline cellulose in rubber composites

    NASA Astrophysics Data System (ADS)

    Bai, Wen

    Rubber without reinforcement has limited applications. The strength of reinforced rubber composites can be ten times stronger than that of unreinforced rubbers. Therefore, rubber composites are widely used in various applications ranging from automobile tires to seals, valves, and gaskets because of their excellent mechanical elastic properties. Silica and carbon black are the two most commonly used reinforcing materials in rubber tires. They are derived from non-renewable materials and are expensive. Silica also contributes to a large amount of ash when used tires are disposed of by incineration. There is a need for a new reinforcing filler that is inexpensive, renewable and easily disposable. Cellulose is the most abundant natural polymer. Native cellulose includes crystalline regions and amorphous regions. Crystalline cellulose can be obtained by removing the amorphous regions with the acid hydrolysis of cellulose because the amorphous cellulose can be hydrolyzed faster than crystalline cellulose. We recently discovered that the partial replacement of silica with microcrystalline cellulose (MCC) provided numerous benefits: (1) low energy consumption for compounding, (2) good processability, (3) strong tensile properties, (4) good heat resistance, and (5) potential for good fuel efficiency in the application of rubber tires. Strong bonding between fillers and a rubber matrix is essential for imparting rubber composites with the desired properties for many specific applications. The bonding between hydrophilic MCC and the hydrophobic rubber matrix is weak and can be improved by addition of a coupling agent or surface modifications of MCC. In this study, MCC was surface-modified with acryloyl chloride or alkenyl ketene dimer (AnKD) to form acrylated MCC (A-MCC) and AnKD-modified MCC (AnKD-MCC). The surface modifications of MCC did not change the integrity and mechanical properties of MCC, but provided functional groups that were able to form covalent linkages with

  17. New applications for cellulose nanofibers: Rheological challenges

    NASA Astrophysics Data System (ADS)

    Nazari-Nasrabad, Behzad

    Cellulose nanofibers (CNF) are an exciting new renewable material produced from wood fibers. Even at low solids content, CNF-water suspensions have a complex rheology that includes extreme shear-thinning as well as viscoelastic properties and a yield stress. In the rheology of CNF suspensions, the measurement method may influence the results due to wall-slippage, but it is unclear how the behavior near walls influences the measurement method and what process equipment can manipulate this material. Parallel-plate and vane geometries were utilized to compare yielding and flow of CNF suspensions obtained by steady-state shear and oscillatory rheological measurements. Four different methods were compared as techniques to obtain a yield stress. The results are compared to pressure driven flow in a tube. Cone and plate geometries were found to lead to sample ejection at low shear rates: floc-floc interactions can explain this ejection. The suspensions violated the Cox-Merz rule in a significant manner as a sign of containing weak gel structures and the formation of a water-rich layer near the solid boundaries. For suspensions lower than 3% solids, the yield stress measured with different procedures were within 20% of each other, but for high solids suspensions, differences among the methods could be as large as 100%; the water-rich layer formation likely is the cause of these results. Oscillatory methods are suggested as a technique to obtain yield stress values. The pressure driven flow results were consistent with the power-law line fitted to the parallel-plate geometry data from steady shear. The capability of the extrusion process was investigated for pumping CNF suspensions through different dies. The extrusion process resulted in acceptable pumping rates which was in good agreement with the mathematical model. However, attributable to the extreme shear-thinning behavior of CNF, the pressure counter-flow dominates the drag flow along the screw channel and does not

  18. A review on chitosan-cellulose blends and nanocellulose reinforced chitosan biocomposites: Properties and their applications.

    PubMed

    H P S, Abdul Khalil; Saurabh, Chaturbhuj K; A S, Adnan; Nurul Fazita, M R; Syakir, M I; Davoudpour, Y; Rafatullah, M; Abdullah, C K; M Haafiz, M K; Dungani, R

    2016-10-01

    Chitin is one of the most abundant natural polymers in world and it is used for the production of chitosan by deacetylation. Chitosan is antibacterial in nature, non-toxic, and biodegradable thus it can be used for the production of biodegradable film which is a green alternative to commercially available synthetic counterparts. However, their poor mechanical and thermal properties restricted its wide spread applications. Chitosan is highly compatible with other biopolymers thus its blending with cellulose and/or incorporation of nanofiber isolated from cellulose namely cellulose nanofiber and cellulose nanowhiskers are generally useful. Cellulosic fibers in nano scale are attractive reinforcement in chitosan to produce environmental friendly composite films with improved physical properties. Thus chitosan based composites have wide applicability and potential in the field of biomedical, packaging and water treatment. This review summarises properties and preparation procedure of chitosan-cellulose blends and nano size cellulose reinforcement in chitosan bionanocomposites for different applications. PMID:27312632

  19. Recent Progress on Cellulose-Based Electro-Active Paper, Its Hybrid Nanocomposites and Applications.

    PubMed

    Khan, Asif; Abas, Zafar; Kim, Heung Soo; Kim, Jaehwan

    2016-01-01

    We report on the recent progress and development of research into cellulose-based electro-active paper for bending actuators, bioelectronics devices, and electromechanical transducers. The cellulose electro-active paper is characterized in terms of its biodegradability, chirality, ample chemically modifying capacity, light weight, actuation capability, and ability to form hybrid nanocomposites. The mechanical, electrical, and chemical characterizations of the cellulose-based electro-active paper and its hybrid composites such as blends or coatings with synthetic polymers, biopolymers, carbon nanotubes, chitosan, and metal oxides, are explained. In addition, the integration of cellulose electro-active paper is highlighted to form various functional devices including but not limited to bending actuators, flexible speaker, strain sensors, energy harvesting transducers, biosensors, chemical sensors and transistors for electronic applications. The frontiers in cellulose paper devices are reviewed together with the strategies and perspectives of cellulose electro-active paper and cellulose nanocomposite research and applications. PMID:27472335

  20. Nanocrystalline cellulose from coir fiber: preparation, properties, and applications

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nanocrystalline cellulose derived from various botanical sources offers unique and potentially useful characteristics. In principle, any cellulosic material can be considered as a potential source of a nanocrystalline material, including crops, crop residues, and agroindustrial wastes. Because of t...

  1. Development of carboxymethyl cellulose acrylate for various biomedical applications.

    PubMed

    Pal, Kunal; Banthia, A K; Majumdar, D K

    2006-06-01

    The purpose of this work is to prepare a pH-sensitive hydrogel membrane of sodium carboxymethyl cellulose acrylate for drug delivery and other biomedical applications. The hydrogel was made by esterification of sodium carboxymethyl cellulose (SCMC) and acryloyl chloride (ACl). The esterified product was characterized by FTIR spectroscopy and XRD. Swelling, hemocompatibility, water vapor transmission rate, contact angle and diffusional studies were also done. Biocompatibility of the membrane was established by quantification of cell growth of L929 cells and mice splenocytes. The FTIR spectrum of the hydrogel suggested the formation of ester bonds between the hydroxyl groups of sodium carboxymethyl cellulose and the carbonyl group of acryloyl chloride. Water vapor transmission rate, hemocompatibility, contact angle and swelling studies indicated that the hydrogel can be tried as a wound dressing material. The hydrogel showed pH-dependent swelling behavior arising from the acidic pendant group in the polymer network. The permeability of the hydrogel membrane produced, as shown by salicylic acid diffusion, increased in response to an increase in pH of the external medium. The hydrogel membrane was permeable to salicylic acid at pH 7.2 but not at pH 2.0 (0.01N HCl). The effect of changes of pH on the hydrogel's permeability was found to be reversible. The hydrogel membrane was found to be compatible with the L929 mice fibroblast cell line and mice splenocytes. The esterified product of SCMC and ACl swells on increase of pH indicating its possible use in a pH-sensitive drug delivery system and as a wound dressing material. PMID:18460761

  2. Development of carboxymethyl cellulose acrylate for various biomedical applications

    NASA Astrophysics Data System (ADS)

    Pal, Kunal; Banthia, A. K.; Majumdar, D. K.

    2006-06-01

    The purpose of this work is to prepare a pH-sensitive hydrogel membrane of sodium carboxymethyl cellulose acrylate for drug delivery and other biomedical applications. The hydrogel was made by esterification of sodium carboxymethyl cellulose (SCMC) and acryloyl chloride (ACl). The esterified product was characterized by FTIR spectroscopy and XRD. Swelling, hemocompatibility, water vapor transmission rate, contact angle and diffusional studies were also done. Biocompatibility of the membrane was established by quantification of cell growth of L929 cells and mice splenocytes. The FTIR spectrum of the hydrogel suggested the formation of ester bonds between the hydroxyl groups of sodium carboxymethyl cellulose and the carbonyl group of acryloyl chloride. Water vapor transmission rate, hemocompatibility, contact angle and swelling studies indicated that the hydrogel can be tried as a wound dressing material. The hydrogel showed pH-dependent swelling behavior arising from the acidic pendant group in the polymer network. The permeability of the hydrogel membrane produced, as shown by salicylic acid diffusion, increased in response to an increase in pH of the external medium. The hydrogel membrane was permeable to salicylic acid at pH 7.2 but not at pH 2.0 (0.01N HCl). The effect of changes of pH on the hydrogel's permeability was found to be reversible. The hydrogel membrane was found to be compatible with the L929 mice fibroblast cell line and mice splenocytes. The esterified product of SCMC and ACl swells on increase of pH indicating its possible use in a pH-sensitive drug delivery system and as a wound dressing material.

  3. Cationic-cellulose nanofibers: preparation and dyeability with anionic reactive dyes for apparel application.

    PubMed

    Khatri, Zeeshan; Mayakrishnan, Gopiraman; Hirata, Yuichi; Wei, Kai; Kim, Ick-Soo

    2013-01-01

    Continuous effort in research and development of nanofibers for apparel usage has been focused within their functional properties only. We investigated esthetic properties by producing colored cationic-cellulose nanofibers for the very first time for the potential application of apparel use. The cellulose acetate nanofibers were electrospun followed by deacetylation and cationization to produce functional cationic-cellulose nanofibers and then dyed with anionic reactive dyes. The spectrophotometric measurement of dyed samples was carried out to determine color coordinates and color yield values. The cationic-cellulose nanofibers showed enhanced color yield and dye fixation without addition of an electrolyte in comparison to cellulose nanofibers. The cationization of cellulose nanofibers significantly enhanced the color yield values of around 76% at dye concentrations of 5%. Excellent color fastness results demonstrate that these new colored and breathable materials can potentially be considered as future apparel for casual or fashion. PMID:23044154

  4. Application of ethyl cellulose, microcrystalline cellulose and octadecanol for wax based floating solid dispersion pellets.

    PubMed

    Yan, Hong-Xiang; Zhang, Shuang-Shuang; He, Jian-Hua; Liu, Jian-Ping

    2016-09-01

    The present study aimed to develop and optimize the wax based floating sustained-release dispersion pellets for a weakly acidic hydrophilic drug protocatechuic acid to achieve prolonged gastric residence time and improved bioavailability. This low-density drug delivery system consisted of octadecanol/microcrystalline cellulose mixture matrix pellet cores prepared by extrusion-spheronization technique, coated with drug/ethyl cellulose 100cp solid dispersion using single-step fluid-bed coating method. The formulation-optimized pellets could maintain excellent floating state without lag time and sustain the drug release efficiently for 12h based on non-Fickian transport mechanism. Observed by SEM, the optimized pellet was the dispersion-layered spherical structure containing a compact inner core. DSC, XRD and FTIR analysis revealed drug was uniformly dispersed in the amorphous molecule form and had no significant physicochemical interactions with the polymer dispersion carrier. The stability study of the resultant pellets further proved the rationality and integrity of the developed formulation. PMID:27185125

  5. Application of a water jet system to the pretreatment of cellulose.

    PubMed

    Watanabe, Yuka; Kitamura, Shinichi; Kawasaki, Kazunori; Kato, Tomoki; Uegaki, Koichi; Ogura, Kota; Ishikawa, Kazuhiko

    2011-12-01

    Plant cellulose is the most abundant organic compound on earth. Technologies for producing cellulose fiber or improving the enzymatic saccharification of cellulose hold the key to biomass applications. A technology for atomizing biomass without strong acid catalysis remains to be developed. The water jet is a well-known device used in machines (e.g., washing machines, cutters, and mills) that use high-pressure water. In this study, we examined whether a water jet system could be used to atomize crystalline cellulose, which comprises approximately 50% of plant biomass. The Star Burst System manufactured by Sugino Machine Limited (Sugino Machine; Toyama, Japan) is a unique atomization machine that uses a water jet to atomize materials and thereby places lower stress on the environment. After treatment with this system, the crystalline cellulose was converted into a gel-like form. High-angular annular dark-field scanning transmission electron microscopy showed that the cellulose fibers had been converted from a solid crystalline into a matrix of cellulose nanofibers. In addition, our results show that this system can improve the saccharification efficiency of cellulases by more than three-fold. Hence, the Star Burst System provides a new and mild pretreatment system for processing biomass materials. PMID:21698594

  6. A Strategy to Develop Bioactive Nanoarchitecture Cellulose: Sustained Release and Multifarious Applications.

    PubMed

    Karuppusamy, Sembanadar; Pratheepkumar, Annamalai; Dhandapani, Perumal; Maruthamuthu, Sundaram; Kulandainathan, Manickam Anbu

    2015-09-01

    Cellulose membranes were engineered to produce hydrophobic surfaces via a simple and soft chemical process to introduce multifunctional properties of an otherwise hydrophilic cellulose surface with polymer-grafted nanosilver to form a core-shell nanostructure. A superhydrophobic domain of the polymer on cellulose was created through the amide bond formation between the anhydride units of the polymer and the aminosiloxane-functionalized cellulose through layer-over-layer formulation. This formulation was confirmed through XPS, XRD, 29Si-NMR, and FTIR studies. Further, SEM and TEM analysis revealed that short linear silver nanowires were uniformly obtained with an average diameter of 60 nm and length of 288 nm, using a mild reducing agent at 60 degrees C, which resulted in a hierarchical cellulose surface. The nanosilver colloids released from the hierarchical cellulose surface were stabilized by the polymer matrix in solution, which led to a decrease in the rate of formation of Ag+ enhancing the material's killing efficacy against microbes. This biodegradable nanocomposite-based cellulose hierarchical surface development has potential for application as superhydrophobic membranes for oil-water separation, antimicrobial activity, and pH-triggered sustained release of colloidal silver for wound healing, which could possibly be applied for use as smart bandages. PMID:26485925

  7. Synthesis of cellulose nanofiber composites for mechanical reinforcement and other advanced applications

    NASA Astrophysics Data System (ADS)

    Xu, Xuezhu

    Cellulose nanofibers from bioresources have attracted intensive research interest in recent years due to their unique combination of properties including high strength and modulus, low density, biocompatibility/biodegradability and rich surface chemistry for functionalization. The nanofibers have been widely studied as nanoreinforcements in polymer nanocomposites; while the nanocomposite research is still very active, new research directions of using the nanofibers for hydrogels/aerogels, template for nanoparticle synthesis, scaffold, carbon materials, nanopaper, etc. have emerged. In this Ph.D. thesis, fundamental studies and application developments are performed on three types of cellulose nanofibers, i.e. cellulose nanocrystals (CNCs), cellulose nanofibrils (CNFs) and bacterial cellulose (BC). First CNCs and CNFs are systematically compared in terms of their effects on the mechanical properties, crystallization and failure behavior of the nanocomposites, which provides a guideline for the design of cellulose nanofiber reinforced composites. Second, CNFs and BC are used to develop core-shell carbon fibers and flexible carbon aerogels for energy storage applications. This part is focused on developing nanocarbon materials with multi-scale features. Lastly, hybrid CNC/CNF nanopaper with superior optical, mechanical, and electrical properties is developed and its application is demonstrated on a LED device.

  8. Potential applications of cellulose and chitosan nanoparticles/composites in wastewater treatment: A review.

    PubMed

    Olivera, Sharon; Muralidhara, Handanahally Basavarajaiah; Venkatesh, Krishna; Guna, Vijay Kumar; Gopalakrishna, Keshavanarayana; Kumar K, Yogesh

    2016-11-20

    This work concerns the investigation of potential candidature of cellulose and chitosan-based nano-sized materials for heavy metals and dyes removal. Cellulose and chitosan being the first two abundant biopolymers in nature offer wide opportunities to be utilized for high-end applications such as water purification. The nano-sized cellulose and nano-sized chitosan present superior adsorption behavior compared to their micro-sized counterparts. This area of research which explores the possible usage of nano-biopolymers is relatively new. The present review article outlines the development history of research in the field of cellulose and chitosan, various methods employed for the functionalization of the biopolymers, current stage of research, and mechanisms involved in adsorption of heavy metals and dyes using nanocellulose and nanochitosan. The significance of research using nano-biopolymers and future prospects are also identified. PMID:27561533

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

    PubMed

    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

  10. Graphene oxide/cellulose aerogels nanocomposite: Preparation, pyrolysis, and application for electromagnetic interference shielding.

    PubMed

    Wan, Caichao; Li, Jian

    2016-10-01

    Hybrid aerogels consisting of graphene oxide (GO) and cellulose were prepared via a solution mixing-regeneration-freeze drying process. The presence of GO affected the micromorphology of the hybrid aerogels, and a self-assembly behavior of cellulose was observed after the incorporation of GO. Moreover, there is no remarkable modification in the crystallinity index and thermal stability after the insertion of GO. After the reduction of GO in the hybrid aerogels by l-ascorbic acid and the subsequent pyrolysis of the aerogels, the resultant displays some interesting characteristics, including good electromagnetic interference (EMI) shielding capacity (SEtotal=58.4dB), high electrical conductivity (19.1Sm(-1)), hydrophobicity, and fire resistance, which provide an opportunity for some advanced applications such as EMI protection, electrochemical devices, water-proofing agents, and fire retardants. Moreover, this work possibly helps to facilitate the development of both cellulose and GO-based materials and expand their application scope. PMID:27312627

  11. Feasibility Investigation of Cellulose Polymers for Mucoadhesive Nasal Drug Delivery Applications.

    PubMed

    Hansen, Kellisa; Kim, Gwangseong; Desai, Kashappa-Goud H; Patel, Hiren; Olsen, Karl F; Curtis-Fisk, Jaime; Tocce, Elizabeth; Jordan, Susan; Schwendeman, Steven P

    2015-08-01

    The feasibility of various cellulose polymer derivatives, including methylcellulose (MC), hydroxypropyl methylcellulose (HPMC), sodium-carboxymethylcellulose (sodium-CMC), and cationic-hydroxyethylcellulose (cationic-HEC), for use as an excipient to enhance drug delivery in nasal spray formulations was investigated. Three main parameters for evaluating the polymers in nasal drug delivery applications include rheology, ciliary beat frequency (CBF), and permeation across nasal tissue. Reversible thermally induced viscosity enhancement was observed at near nasal physiological temperature when cellulose derivatives were combined with an additional excipient, poly(vinyl caprolactam)-poly(vinyl acetate)-poly(ethylene glycol) graft copolymer (PVCL-PVA-PEG). Cationic-HEC was shown to enhance acyclovir permeation across the nasal mucosa. None of the tested cellulosic polymers caused any adverse effects on porcine nasal tissues and cells, as assessed by alterations in CBF. Upon an increase in polymer concentration, a reduction in CBF was observed when ciliated cells were immersed in the polymer solution, and this decrease returned to baseline when the polymer was removed. While each cellulose derivative exhibited unique advantages for nasal drug delivery applications, none stood out on their own to improve more than one of the performance characteristics examined. Hence, these data may be useful for the development of new cellulose derivatives in nasal drug formulations. PMID:26097994

  12. Noble metal/functionalized cellulose nanofiber composites for catalytic applications.

    PubMed

    Gopiraman, Mayakrishnan; Bang, Hyunsik; Yuan, Guohao; Yin, Chuan; Song, Kyung-Hun; Lee, Jung Soon; Chung, Ill Min; Karvembu, Ramasamy; Kim, Ick Soo

    2015-11-01

    In this study, cellulose acetate nanofibers (CANFs) with a mean diameter of 325 ± 2.0 nm were electrospun followed by deacetylation and functionalization to produce anionic cellulose nanofibers (f-CNFs). The noble metal nanoparticles (RuNPs and AgNPs) were successfully decorated on the f-CNFs by a simple wet reduction method using NaBH4 as a reducing agent. TEM and SEM images of the nanocomposites (RuNPs/CNFs and AgNPs/CNFs) confirmed that the very fine RuNPs or AgNPs were homogeneously dispersed on the surface of f-CNFs. The weight percentage of the Ru and Ag in the nanocomposites was found to be 13.29 wt% and 22.60 wt% respectively; as confirmed by SEM-EDS analysis. The metallic state of the Ru and Ag in the nanocomposites was confirmed by XPS and XRD analyses. The usefulness of these nanocomposites was realized from their superior catalytic activity. In the aerobic oxidation of benzyl alcohol to benzaldehyde, the RuNPs/CNFs system gave a better yield of 89% with 100% selectivity. Similarly, the AgNPs/CNFs produced an excellent yield of 99% (100% selectivity) in the aza-Michael reaction of 1-phenylpiperazine with acrylonitrile. Mechanism has been proposed for the catalytic systems. PMID:26256382

  13. Micro-Nanostructured Polyaniline Assembled in Cellulose Matrix via Interfacial Polymerization for Applications in Nerve Regeneration.

    PubMed

    Xu, Dingfeng; Fan, Lin; Gao, Lingfeng; Xiong, Yan; Wang, Yanfeng; Ye, Qifa; Yu, Aixi; Dai, Honglian; Yin, Yixia; Cai, Jie; Zhang, Lina

    2016-07-13

    Conducting polymers have emerged as frontrunners to be alternatives for nerve regeneration, showing a possibility of the application of polyaniline (PANI) as the nerve guidance conduit. In the present work, the cellulose hydrogel was used as template to in situ synthesize PANI via the limited interfacial polymerization method, leading to one conductive side in the polymer. PANI sub-micrometer dendritic particles with mean diameter of ∼300 nm consisting of the PANI nanofibers and nanoparticles were uniformly assembled into the cellulose matrix. The hydrophobic PANI nanoparticles were immobilized in the hydrophilic cellulose via the phytic acid as "bridge" at presence of water through hydrogen bonding interaction. The PANI/cellulose composite hydrogels exhibited good mechanical properties and biocompatibility as well as excellent guiding capacity for the sciatic nerve regeneration of adult Sprague-Dawley rats without any extra treatment. On the basis of the fact that the pure cellulose hydrogel was an inert material for the neural repair, PANI played an indispensable role on the peripheral nerve regeneration. The hierarchical micro-nanostructure and electrical conductivity of PANI could remarkably induce the adhesion and guiding extension of neurons, showing its great potential in biomedical materials. PMID:27314673

  14. Production, characterization, and biogas application of magnetic hydrochar from cellulose.

    PubMed

    Reza, M Toufiq; Rottler, Erwin; Tölle, Rainer; Werner, Maja; Ramm, Patrice; Mumme, Jan

    2015-06-01

    Hydrothermal carbonization (HTC) produces carbon-rich nano-micro size particles. In this study, magnetic hydrochar (MHC) was prepared from model compound cellulose by simply adding ferrites during HTC. The effects of ferrites on HTC were evaluated by characterizing solid MHC and corresponding process liquid. Additionally, magnetic stability of MHC was tested by magnetic susceptibility method. Finally, MHC was used as support media for anaerobic films in anaerobic digestion (AD). Ash-free mass yield was around 50% less in MHC than hydrochar produced without ferrites at any certain HTC reaction condition, where organic part of MHC is mainly carbon. In fact, amorphous hydrochar was growing on the surface of inorganic ferrites. MHC maintained magnetic susceptibility regardless of reaction time at reaction temperature 250°C. Pronounced inhibitory effects of magnetic hydrochar occurred during start-up of AD but diminished with prolong AD times. Visible biofilms were observed on the MHC by laser scanning microscope after AD. PMID:25804500

  15. Application of cellulose acetate for controlled release of thymol.

    PubMed

    Milovanovic, Stoja; Markovic, Darka; Aksentijevic, Ksenija; Stojanovic, Dusica B; Ivanovic, Jasna; Zizovic, Irena

    2016-08-20

    Cellulose acetate (CA) was investigated as a carrier towards development of material with controlled release of thymol as a natural substance with strong antibacterial properties using high pressure techniques. Effect of thymol content on CA was confirmed by SEM, FTIR and DSC methods. Kinetic of thymol release from CA was tested using simulated gastric and intestinal fluids (hydrochloric acid and phosphate buffer saline). Results were correlated with Korsmeyer-Peppas and Weibull model. Depending on the thymol content and chemical nature of the release medium, the time of thymol release varied from one to three days indicating CA as a promising carrier of thymol with potential uses from medicine to agriculture. The impregnated CA showed antibacterial activity against 23 tested bacterial strains including methicillin-resistant Staphylococcus aureus (MRSA) which is particularly important bearing in mind that this strain causes fatal infections in humans and animals. PMID:27178940

  16. Progress in bacterial cellulose matrices for biotechnological applications.

    PubMed

    Cacicedo, Maximiliano L; Castro, M Cristina; Servetas, Ioannis; Bosnea, Loulouda; Boura, Konstantina; Tsafrakidou, Panagiota; Dima, Agapi; Terpou, Antonia; Koutinas, Athanasios; Castro, Guillermo R

    2016-08-01

    Bacterial cellulose (BC) is an extracellular polymer produced by many microorganisms. The Komagataeibacter genus is the best producer using semi-synthetic media and agricultural wastes. The main advantages of BC are the nanoporous structure, high water content and free hydroxyl groups. Modification of BC can be made by two strategies: in-situ, during the BC production, and ex-situ after BC purification. In bioprocesses, multilayer BC nanocomposites can contain biocatalysts designed to be suitable for outside to inside cell activities. These nanocomposites biocatalysts can (i) increase productivity in bioreactors and bioprocessing, (ii) provide cell activities does not possess without DNA cloning and (iii) provide novel nano-carriers for cell inside activity and bioprocessing. In nanomedicine, BC matrices containing therapeutic molecules can be used for pathologies like skin burns, and implantable therapeutic devices. In nanoelectronics, semiconductors BC-based using salts and synthetic polymers brings novel films showing excellent optical and photochemical properties. PMID:26927233

  17. A multipurpose natural and renewable polymer in medical applications: Bacterial cellulose.

    PubMed

    de Oliveira Barud, Hélida Gomes; da Silva, Robson Rosa; da Silva Barud, Hernane; Tercjak, Agnieszka; Gutierrez, Junkal; Lustri, Wilton Rogério; de Oliveira, Osmir Batista; Ribeiro, Sidney J L

    2016-11-20

    Bacterial cellulose (BC) produced by some bacteria, among them Gluconacetobacter xylinum, which secrets an abundant 3D networks fibrils, represents an interesting emerging biocompatible nanomaterial. Since its discovery BC has shown tremendous potential in a wide range of biomedical applications, such as artificial skin, artificial blood vessels and microvessels, wound dressing, among others. BC can be easily manipulated to improve its properties and/or functionalities resulting in several BC based nanocomposites. As example BC/collagen, BC/gelatin, BC/Fibroin, BC/Chitosan, etc. Thus, the aim of this review is to discuss about the applicability in biomedicine by demonstrating a variety of forms of this biopolymer highlighting in detail some qualities of bacterial cellulose. Therefore, various biomedical applications ranging from implants and scaffolds, carriers for drug delivery, wound-dressing materials, etc. that were reported until date will be presented. PMID:27561512

  18. Chitosan/titanium dioxide nanocomposite coatings: Rheological behavior and surface application to cellulosic paper.

    PubMed

    Tang, Yanjun; Hu, Xiulan; Zhang, Xinqi; Guo, Daliang; Zhang, Junhua; Kong, Fangong

    2016-10-20

    Incorporation of nanofillers into a polymeric matrix has received much attention as a route to reinforced polymer nanocomposites. In the present work, an environmentally friendly chitosan (CTS)/titanium dioxide (TiO2) nanocomposite coating was designed/prepared and subsequently employed for imparting antibacterium and improved mechanical properties to cellulosic paper via surface coating. Effect of TiO2 nanoparticle loadings on the rheological behavior of nanocomposite coatings was investigated. Surface application of CTS/TiO2 nanocomposite coatings to cellulosic paper was performed, and the antibacterial activity and mechanical properties of surface-coated cellulosic paper were examined. Results showed that the increased TiO2 nanoparticle loadings decreased the viscosity and dynamic viscoelasticity of the as-prepared coatings, and improved the antibacterial activity and mechanical properties of surface-coated cellulosic paper. The optimum loading of TiO2 nanoparticles was identified at 10%. This work suggested that CTS/TiO2 nanocomposite coatings may have the potential to be used as a promising antibacterial protective coating for paper packaging. PMID:27474622

  19. More than meets the eye in bacterial cellulose: biosynthesis, bioprocessing, and applications in advanced fiber composites.

    PubMed

    Lee, Koon-Yang; Buldum, Gizem; Mantalaris, Athanasios; Bismarck, Alexander

    2014-01-01

    Bacterial cellulose (BC) nanofibers are one of the stiffest organic materials produced by nature. It consists of pure cellulose without the impurities that are commonly found in plant-based cellulose. This review discusses the metabolic pathways of cellulose-producing bacteria and the genetic pathways of Acetobacter xylinum. The fermentative production of BC and the bioprocess parameters for the cultivation of bacteria are also discussed. The influence of the composition of the culture medium, pH, temperature, and oxygen content on the morphology and yield of BC are reviewed. In addition, the progress made to date on the genetic modification of bacteria to increase the yield of BC and the large-scale production of BC using various bioreactors, namely static and agitated cultures, stirred tank, airlift, aerosol, rotary, and membrane reactors, is reviewed. The challenges in commercial scale production of BC are thoroughly discussed and the efficiency of various bioreactors is compared. In terms of the application of BC, particular emphasis is placed on the utilization of BC in advanced fiber composites to manufacture the next generation truly green, sustainable and renewable hierarchical composites. PMID:23897676

  20. Novel cellulosic gel preparation for using in electro-responsive applications

    NASA Astrophysics Data System (ADS)

    Kunchornsup, Wissawin; Sirivat, Anuvat

    2010-04-01

    Electroactive-papers (EAPaps) are paper that used in the field of electro-responsive applications, consisting primarily of a cellulose. 1-butyl-3-methylimidazolium chloride (BMIMCl) is an interesting ionic liquid that acts as an effective cellulose solvent for EAPap due to its high solubility without chain derivatization, less chain degradation, and stability in electro-responsive applications. In our work, physical and chemical cellulose gels were fabricated and studied for the effects of varying crosslinking ratio (CR) with glutaraldehyde (GA) as the crosslinking agent. The crosslinking reaction conversion could be increased by increasing the CR; the reaction products are ketone linkages and by-product water molecules. A difference in optical properties could be observed and related to the differing amounts of ketone linkages, as confirmed by Fourier transform infrared spectroscopy: Attenuated total reflectance (FTIR-ATR), and the degradation temperature (Td). All of the prepared gels show no significant differences in electrical conductivity; however they can be classified in the level of semiconductors. Our paper-gels showed potential characteristics towards electro-responsive applications as the ionic migration is a promising mechanism and with less preparation time (< 14 hours).

  1. Highly Porous Regenerated Cellulose Fiber Mats via the Co-Forcespinning of Cellulose Acetate for Separator Applications

    NASA Astrophysics Data System (ADS)

    Castillo, Alejandro; Mao, Yuanbing

    2015-03-01

    Improvements in battery technology are necessary for the transition away from a fossil fuel based economy. An important bottle-neck in battery efficiency is the quality of the separator, which separates the cathode and anode to prevent a short-circuit while still allowing the ions in solution to flow as close to unabated as possible. In this work solutions of cellulose acetate, polyvinyldiflourine (pvdf), and polyvinylpyrrolidone (pvp) dissolved in a 2:1 v/v acetone/dimethylacetamide solvent mixture were Forcespun to create nonwoven fiber mats of nanoscale diameter. These mats were then soaked in a NaOH solution so as to both strip the pvp from the fiber as well as regenerate cellulose from its acetate derivative for the purpose of creating high surface area, nanoporous, hydrophilic, and ioniclly conductive cellulose/pvdf nonwoven mats for the purposes of testing their suitability as battery separators

  2. Agarose particle-templated porous bacterial cellulose and its application in cartilage growth in vitro.

    PubMed

    Yin, Na; Stilwell, Matthew D; Santos, Thiago M A; Wang, Huaping; Weibel, Douglas B

    2015-01-01

    Bacterial cellulose (BC) is a biocompatible hydrogel with a three-dimensional (3-D) structure formed by a dense network of cellulose nanofibers. A limitation of using BC for applications in tissue engineering is that the pore size of the material (∼0.02-10μm) is smaller than the dimensions of mammalian cells and prevents cells from penetrating into the material and growing into 3-D structures that mimic tissues. This paper describes a new route to porous bacterial cellulose (pBC) scaffolds by cultivating Acetobacter xylinum in the presence of agarose microparticles deposited on the surface of a growing BC pellicle. Monodisperse agarose microparticles with a diameter of 300-500μm were created using a microfluidic technique, layered on growing BC pellicles and incorporated into the polymer as A. xylinum cells moved upward through the growing pellicle. Removing the agarose microparticles by autoclaving produced BC gels containing a continuous, interconnected network of pores with diameters ranging from 300 to 500μm. Human P1 chondrocytes seeded on the scaffolds, replicated, invaded the 3-D porous network and distributed evenly throughout the substrate. Chondrocytes grown on pBC substrates displayed a higher viability compared to growth on the surface of unmodified BC substrates. The approach described in this paper introduces a new method for creating pBC substrates with user-defined control over the physical dimensions of the pore network, and demonstrates the application of these materials for tissue engineering. PMID:25449918

  3. Advances in biomedical and pharmaceutical applications of functional bacterial cellulose-based nanocomposites.

    PubMed

    Ullah, Hanif; Wahid, Fazli; Santos, Hélder A; Khan, Taous

    2016-10-01

    Bacterial cellulose (BC) synthesized by certain species of bacteria, is a fascinating biopolymer with unique physical and mechanical properties. BC's applications range from traditional dessert, gelling, stabilizing and thickening agent in the food industry to advanced high-tech applications, such as immobilization of enzymes, bacteria and fungi, tissue engineering, heart valve prosthesis, artificial blood vessels, bone, cartilage, cornea and skin, and dental root treatment. Various BC-composites have been designed and investigated in order to enhance its biological applicability. This review focuses on the application of BC-based composites for microbial control, wound dressing, cardiovascular, ophthalmic, skeletal, and endodontics systems. Moreover, applications in controlled drug delivery, biosensors/bioanalysis, immobilization of enzymes and cells, stem cell therapy and skin tissue repair are also highlighted. This review will provide new insights for academia and industry to further assess the BC-based composites in terms of practical applications and future commercialization for biomedical and pharmaceutical purposes. PMID:27312644

  4. Applicability of bacterial cellulose as an alternative to paper points in endodontic treatment.

    PubMed

    Yoshino, Aya; Tabuchi, Mari; Uo, Motohiro; Tatsumi, Hiroto; Hideshima, Katsumi; Kondo, Seiji; Sekine, Joji

    2013-04-01

    Dental root canal treatment is required when dental caries progress to infection of the dental pulp. A major goal of this treatment is to provide complete decontamination of the dental root canal system. However, the morphology of dental root canal systems is complex, and many human dental roots have inaccessible areas. In addition, dental reinfection is fairly common. In conventional treatment, a cotton pellet and paper point made from plant cellulose is used to dry and sterilize the dental root canal. Such sterilization requires a treatment material with high absorbency to remove any residue, the ability to improve the efficacy of intracanal medication and high biocompatibility. Bacterial cellulose (BC) is produced by certain strains of bacteria. In this study, we developed BC in a pointed form and evaluated its applicability as a novel material for dental canal treatment with regard to solution absorption, expansion, tensile strength, drug release and biocompatibility. We found that BC has excellent material and biological characteristics compared with conventional materials, such as paper points (plant cellulose). BC showed noticeably higher absorption and expansion than paper points, and maintained a high tensile strength even when wet. The cumulative release of a model drug was significantly greater from BC than from paper points, and BC showed greater compatibility than paper points. Taken together, BC has great potential for use in dental root canal treatment. PMID:23268234

  5. Application of GPC/LALLS to cellulose research. [Gel permeation chromatography/low-angle laser light scattering

    SciTech Connect

    Cael, J.J.; Cietek, D.J.; Kolpak, F.J.

    1983-01-01

    The techniques of gel permeation chromatography and low-angle laser light scattering (GPC/LALLS) have been combined for absolute determination of cellulose molecular weights and molecular weight distributions (MWD). The GPC/LALLS technique has been applied to tetrahydrofuran (THF) solutions of cellulose tricarbanilate (CTC) derivatives prepared from celluloses having a wide range of molecular weights. The molecular weight data obtained are consistent with values determined by intrinsic viscosity methods; and as a consequence of the absolute nature of this technique, Mark-Houswink coefficients can be predicted from a single, broad-distribution, linear homopolymer without recourse to tedious and time-consuming fractional precipitation methods. A unique application of the technique has been in correlating GPC/LALLS molecular weight data with the viscosity of nonderivatized celluloses dissolved in 0.5 M cupiethylenediamine hydroxide (CuEn). The procedure yields an absolute viscosity-molecular weight relationship which is comparable with a similar relationship originally derived from cellulose nitrates. The results indicate that the weight-average degree of polymerization (DP/sub w/) for CTC preparations is considerably greater than that obtained from cellulose nitrates, and this discrepancy, in DP/sub w/ has been attributed to errors in the Mark-Houwink coefficients for the cellulose nitrate-acetone system. 25 references, 9 figures, 7 tables.

  6. Cellulosic carbon fibers with branching carbon nanotubes for enhanced electrochemical activities for bioprocessing applications.

    PubMed

    Zhao, Xueyan; Lu, Xin; Tze, William Tai Yin; Kim, Jungbae; Wang, Ping

    2013-09-25

    Renewable biobased carbon fibers are promising materials for large-scale electrochemical applications including chemical processing, energy storage, and biofuel cells. Their performance is, however, often limited by low activity. Herein we report that branching carbon nanotubes can enhance the activity of carbonized cellulosic fibers, such that the oxidation potential of NAD(H) was reduced to 0.55 V from 0.9 V when applied for bioprocessing. Coordinating with enzyme catalysts, such hierarchical carbon materials effectively facilitated the biotransformation of glycerol, with the total turnover number of NAD(H) over 3500 within 5 h of reaction. PMID:24020801

  7. Electrospun cellulose acetate nanofibers: the present status and gamut of biotechnological applications.

    PubMed

    Konwarh, Rocktotpal; Karak, Niranjan; Misra, Manjusri

    2013-01-01

    Cellulose acetate (CA) has been a material of choice for spectrum of utilities across different domains ranging from high absorbing diapers to membrane filters. Electrospinning has conferred a whole new perspective to polymeric materials including CA in the context of multifarious applications across myriad of niches. In the present review, we try to bring out the recent trend (focused over last five years' progress) of research on electrospun CA fibers of nanoscale regime in the context of developmental strategies of their blends and nanocomposites for advanced applications. In the realm of biotechnology, electrospun CA fibers have found applications in biomolecule immobilization, tissue engineering, bio-sensing, nutraceutical delivery, bioseparation, crop protection, bioremediation and in the development of anti-counterfeiting and pH sensitive material, photocatalytic self-cleaning textile, temperature-adaptable fabric, and antimicrobial mats, amongst others. The present review discusses these diverse applications of electrospun CA nanofibers. PMID:23318668

  8. Cotton-based Cellulose Nanomaterials for Applications in Composites and Electronics

    NASA Astrophysics Data System (ADS)

    Farahbakhsh, Nasim

    A modern society demands development of highly valued and sustainable products via innovative process technologies and utilizing bio-based alternatives for petroleum based materials. Systematic comparative study of nanocellulose particles as a biodegradable and renewable reinforcing agent can help to develop criteria for selecting an appropriate candidate to be incorporated in polymer nanocomposites. Of particular interest has been nanocellulosic materials including cellulose nanocrystal (CNC) and micro/nanofibrilated cellulose (MFC/NFC) which possess a hierarchical structure that permits an ordered structure with unique properties that has served as building blocks for the design of green and novel materials composites for applications in flexible electronics, medicine and composites. Key differences exist in nanocellulosic materials as a result the process by which the material is produced. This research demonstrates the applicability for the use of recycled cotton as promising sustainable material to be utilized as a substrate for electronic application and a reinforcing agent choice that can be produced without any intensive purification process and be applied to synthetic-based polymer nanocomposites in melt-processing. (Abstract shortened by ProQuest.).

  9. Bacterial cellulose-kaolin nanocomposites for application as biomedical wound healing materials

    NASA Astrophysics Data System (ADS)

    Wanna, Dwi; Alam, Catharina; Toivola, Diana M.; Alam, Parvez

    2013-12-01

    This short communication provides preliminary experimental details on the structure-property relationships of novel biomedical kaolin-bacterial cellulose nanocomposites. Bacterial cellulose is an effective binding agent for kaolin particles forming reticulated structures at kaolin-cellulose interfaces and entanglements when the cellulose fraction is sufficiently high. The mechanical performance of these materials hence improves with an increased fraction of bacterial cellulose, though this also causes the rate of blood clotting to decrease. These composites have combined potential as both short-term (kaolin) and long-term (bacterial cellulose) wound healing materials.

  10. Application of tetra-n-methylammonium hydroxide on cellulose dissolution and isolation from sugarcane bagasse.

    PubMed

    Zhong, Chao; Wang, Chunming; Wang, Fengxue; Jia, Honghua; Wei, Ping; Zhao, Yin

    2016-01-20

    Cellulose isolation, a promising way for lignocellulosic biomass utilization, is always restricted by the poor solubility of cellulose. In this paper, tetra-n-methylammonium hydroxide (TMAH) was confirmed to be capable of readily dissolving/regenerating cellulose without chemical modification at room temperature. Meanwhile, cellulose isolation from lignocellulosic biomass by initially dissolving the biomass in TMAH followed by cellulose precipitation was proposed, and the isolated substance with average cellulose purity of 92.1 ± 0.3% could be obtained throughout this process under the optimum conditions: temperature 52 °C, time 60 min, and loading ratio of TMAH/biomass (w/w) 7.2:1. Besides, high efficiency cellulose isolation (i.e. >70% cellulose purity) could be continuously remained during 4-round cycles by using the recycled TMAH solvent without distinct activity loss. PMID:26572437

  11. Physically and chemically cross-linked cellulose cryogels: Structure, properties and application for controlled release.

    PubMed

    Ciolacu, Diana; Rudaz, Cyrielle; Vasilescu, Mihai; Budtova, Tatiana

    2016-10-20

    Porous cellulose matrices were prepared via cellulose dissolution in 8wt% NaOH-water, physical gelation and chemical cross-linking with epichlorohydrin (ECH), coagulation in water and lyophilisation. Cellulose and cross-linker concentration were varied. The behaviour of gels upon coagulation and the swelling of cryogels in water were analysed. An anomalous high swelling at cross-linker concentration around stoichiometric molar ratio with cellulose was observed. Cellulose cryogel morphology, crystallinity and density were studied. The influence of chemical cross-linking on cellulose swelling was explained by suggesting that ECH acts as a spacer preventing cellulose chains tight packing during coagulation. Cellulose was loaded with a model drug, procaine hydrochloride, and the kinetics of its release was investigated. PMID:27474581

  12. Cellulose binding domain assisted immobilization of lipase (GSlip-CBD) onto cellulosic nanogel: characterization and application in organic medium.

    PubMed

    Kumar, Ashok; Zhang, Shaowei; Wu, Gaobing; Wu, Cheng Chao; Chen, JunPeng; Baskaran, R; Liu, Ziduo

    2015-12-01

    A cbd gene was cloned into the C-terminal region of a lip gene from Geobacillus stearothermophilus. The native lipase (43.5 kDa) and CBD-Lip fusion protein (60.2 kDa) were purified to homogeneity by SDS-PAGE. A highly stable cellulosic nanogel was prepared by controlled hydrolysis of microcrystalline cellulose onto which the CBD-lip fusion protein was immobilized through bio-affinity based binding. The nanogel-bound lipase showed optimum activity at 55 °C, and it remains stable and active at pH 10-10.5. Furthermore, the immobilized lipase showed an over two-fold increase of relative activity in the presence of DMSO, isopropanol, isoamyl alcohol and n-butanol, but a mild activity decrease at a low concentration of methanol and ethanol. The immobilized biocatalyst retained ~50% activity after eight repetitive hydrolytic cycles. Enzyme kinetic studies of the immobilized lipase showed a 1.24 fold increase in Vmax and 5.25 fold increase in kcat towards p-NPP hydrolysis. Additionally, the nanogel bound lipase was tested to synthesize a biodiesel ester, ethyl oleate in DMSO. Kinetic analysis showed the km 100.5 ± 4.3 mmol and Vmax 0.19 ± 0.015 mmolmin(-1) at varied oleic acid concentration. Also, the values of km and Vmax at varying concentration of ethanol were observed to be 95.9 ± 13.9 mmol and 0.22 ± 0.013 mmolmin(-1) respectively. The maximum yield of ethyl oleate 111.2 ± 1.24 mM was obtained under optimized reaction conditions in organic medium. These results suggest that this immobilized biocatalyst can be used as an efficient tool for the biotransformation reactions on an industrial scale. PMID:26590897

  13. Potential of nanocrystalline cellulose-fibrin nanocomposites for artificial vascular graft applications.

    PubMed

    Brown, Elvie E; Hu, Dehong; Abu Lail, Nehal; Zhang, Xiao

    2013-04-01

    The potential of synthesizing new nanocomposites from nanocrystalline cellulose (NCC) and fibrin for small-diameter replacement vascular graft (SDRVG) application was demonstrated. Periodate oxidation of NCC can augment reactive carbonyl groups on NCC and facilitate its cross-linking with fibrin. NCC-fibrin nanocomposites were synthesized, composed of homogeneously dispersed oxidized NCC (ONCC) in a fibrin matrix, with fibrin providing elasticity and ONCC providing strength. The maximum strength and elongation of the nanocomposites were determined by Atomic Force Microscopy (AFM) and compared with a native blood vessel. The manipulation of degree of oxidation of NCC and the NCC-to-fibrin ratio resulted in the variation of strength and elongation of the nanocomposites, indicating that the nanocomposites can be tailored to conform to the diverse mechanical properties of native blood vessels. A mechanistic understanding of the molecular interactions of ONCC and fibrin was illustrated. This study established fundamental information to utilizing NCC for SDRVG applications. PMID:23421631

  14. Potential of nanocrystalline cellulose-fibrin nanocomposites for artificial vascular graft applications

    SciTech Connect

    Brown, Elvie; Hu, Dehong; Abu-Lail, Nehal; Zhang, Xiao

    2013-02-19

    Nanocrystalline cellulose, a new bio-nanomaterial is utilized as a reinforcing material for biocompatible fibrin matrix to form into a nanocomposite for small-diameter replacement vascular graft application (SDRVG). The periodate oxidation of NCC, which provided it with a reactive carbonyl group, allowed molecular interaction between NCC and fibrin. Such interaction resulted into an effective mechanical reinforcement indicated by the improvement of max. force, elongation at break and modulus when oxidized NCC (ONCC) was incorporated into fibrin. The nanocomposite’s mechanical properties can be manipulated to conform to the native blood vessel by varying the ONCC to fibrin ratio and/or by controlling the degree of oxidation of NCC. Using atomic force microscopy had provided fundamental information on the effects of molecular interactions to the nanolevel mechanical properties of NCC/fibrin nanocomposites. This fundamental information established the positive feasibility and commenced continuing investigation for the practical SDRVG application of NCC/fibrin nanocomposite.

  15. Thermo-responsive hydrogels from cellulose-based polyelectrolytes and catanionic vesicles for biomedical application.

    PubMed

    Milcovich, Gesmi; Antunes, Filipe; Golob, Samuel; Farra, Rossella; Grassi, Mario; Voinovich, Dario; Grassi, Gabriele; Asaro, Fioretta

    2016-07-01

    In this study, negatively charged catanionic vesicles/hydrophobically modified hydroxyethylcellulose polymers thermo-responsive hydrogels have been fabricated. Vesicular aggregates were found to act as multifunctional junctions for networking of modified-cellulose water solutions. The contributions of the electrostatic and hydrophobic interactions were evaluated by changing either vesicles composition or the polymer hydrophobic substitution. Thermal-induced size and lamellarity of hydrogel-enclosed vesicles were detected, with further polygonal shape changes induced by cellulose-based polymer addition. The thermal transition was also found to tune hydrogel mechanical behaviour. The network formation was further assessed through molecular insights, which allow to determine the arrangement of the polymer chains on the vesicles' surface. The examined systems exhibited interesting thermo-responsive characteristics. Thus, vesicularly cross-linked hydrogels herein presented can offer a wide variety of applications, i.e. in biomedical field, as multi-drug delivery systems, thanks to their ability to provide for different environments to guest molecules, comprising bulk water, vesicles' interior and bilayers, sites on polymeric chains. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1668-1679, 2016. PMID:26939864

  16. Fabrication of bacterial cellulose-ZnO composite via solution plasma process for antibacterial applications.

    PubMed

    Janpetch, Nattakammala; Saito, Nagahiro; Rujiravanit, Ratana

    2016-09-01

    Zinc oxide (ZnO) was successfully synthesized by applying a solution plasma, a plasma discharge in a liquid phase, without the addition of a reducing agent and simultaneously deposited into a bacterial cellulose pellicle that functioned as a template. By the reasons of its nano-sized structure as well as favorable porous configuration, the BC pellicle has been proved to be a splendid upholding template for the coordination of ZnO. In addition, the ZnO-deposited BC composites demonstrated strong antibacterial activity without a photocatalytic reaction against both Staphylococcus aureus and Escherichia coli. Hence, the ZnO-deposited BC composites can be used as an antibacterial material in wound dressing and water disinfection applications. PMID:27185147

  17. Carboxymethyl Cellulose Acetate Butyrate: A Review of the Preparations, Properties, and Applications

    PubMed Central

    Kamel, Samir; Salama, Ahmed; Sarhan, Hebat-Allah

    2014-01-01

    Carboxymethyl cellulose acetate butyrate (CMCAB) has gained increasing importance in several fields, particularly in coating technologies and pharmaceutical research. CMCAB is synthesized by esterification of CMC sodium salt with acetic and butyric anhydrides. CMCAB mixed esters are relatively high molecular weight (MW) thermoplastic polymers with high glass transition temperatures (Tg). CMCAB ester is dispersible in water and soluble in a wide range of organic solvents, allowing varied opportunity to the solvent choice. It makes application of coatings more consistent and defect-free. Its ability to slow down the release rate of highly water-soluble compounds and to increase the dissolution of poorly soluble compounds makes CMCAB a unique and potentially valuable tool in pharmaceutical and amorphous solid dispersions (ASD) formulations. PMID:25548679

  18. Guides d'ondes infrarouges pour applications en télécommunications, capteurs chimiques et biochimiques

    NASA Astrophysics Data System (ADS)

    Smektala, F.; Bureau, B.; Adam, J. L.; Lucas, J.

    2002-06-01

    Les énergies de phonons élevés des verres à base de silice limitent leurs applications dans l'infrarouge. Il devient donc incontournable de créer des verres à plus faible énergie de phonons pour développer une optique passive guidée opérationnelle dans l'IR moyen et pour réaliser de nouveaux guide d'ondes optiques activés par des lanthanides pouvant jouer le rôle soit d'amplificateurs optiques soit de fibres lasers. Les compositions de verres stables répondant à ces critères sont exceptionnelles et appartiennent aux familles chimiques des fluorures et des chalcogénures. Les verres de fluorures, convenablement dopés par des terres rares, ont permis la réalisation d'amplificateurs optiques opérant dans la fenêtre télecom de la silice (1.3 μm avec le praséodyme, 1.45 μm avec le thulium et 1.55 μm avec l'erbium. Les verres de chalcogénures permettent la réalisation de fibres opérationnelles jusqu'à 12 μm mais seulement pour des applications courtes distances telles que le transport d'énergie moyenne, la radiométrie à l'ambiante et la spectrométrie IR déportée par fibre optique de molécules chimiques ou de tissus biologiques.

  19. Synthesis of polymer electrolyte membranes from cellulose acetate/poly(ethylene oxide)/LiClO4 for lithium ion battery application

    NASA Astrophysics Data System (ADS)

    Nurhadini, Arcana, I. Made

    2015-09-01

    This study was conducted to determine the effect of cellulose acetate on poly(ethylene oxide)-LiClO4 membranes as the polymer electrolyte. Cellulose acetate is used as an additive to increase ionic conductivity and mechanical property of polymer electrolyte membranes. The increase the percentage of cellulose acetate in membranes do not directly effect on the ionic conductivity, and the highest ionic conductivity of membranes about 5,7 × 10-4 S/cm was observed in SA/PEO/LiClO4 membrane with cellulose ratio of 10-25% (w/w). Cellulose acetate in membranes increases mechanical strength of polymer electrolyte membranes. Based on TGA analysis, this polymer electrolyte thermally is stable until 270 °C. The polymer electrolyte membrane prepared by blending the cellulose acetate, poly(ethylene oxide), and lithium chlorate could be potentially used as a polymer electrolyte for lithium ion battery application.

  20. Synthesis of polymer electrolyte membranes from cellulose acetate/poly(ethylene oxide)/LiClO{sub 4} for lithium ion battery application

    SciTech Connect

    Nurhadini, Arcana, I Made

    2015-09-30

    This study was conducted to determine the effect of cellulose acetate on poly(ethylene oxide)-LiClO{sub 4} membranes as the polymer electrolyte. Cellulose acetate is used as an additive to increase ionic conductivity and mechanical property of polymer electrolyte membranes. The increase the percentage of cellulose acetate in membranes do not directly effect on the ionic conductivity, and the highest ionic conductivity of membranes about 5,7 × 10{sup −4} S/cm was observed in SA/PEO/LiClO{sub 4} membrane with cellulose ratio of 10-25% (w/w). Cellulose acetate in membranes increases mechanical strength of polymer electrolyte membranes. Based on TGA analysis, this polymer electrolyte thermally is stable until 270 °C. The polymer electrolyte membrane prepared by blending the cellulose acetate, poly(ethylene oxide), and lithium chlorate could be potentially used as a polymer electrolyte for lithium ion battery application.

  1. A versatile method for producing functionalized cellulose nanofibers and their application

    NASA Astrophysics Data System (ADS)

    Huang, Pei; Zhao, Yang; Kuga, Shigenori; Wu, Min; Huang, Yong

    2016-02-01

    A facile method was developed to produce functionalized cellulose nanofibers in one step by ball milling. Through the synergy of mechanical and chemical actions, the produced cellulose nanofibers are ca. 20 nm wide and several micrometers long, with surface properties tailored by choice of modifying reagent. Modified by succinic anhydride, a cellulose nanofiber shows enhanced hydrophilicity, can be readily dispersed in water or DMSO, and gives a zeta potential of -38.7 mV due to carboxyl groups on the surface. Modified by dodecyl succinic anhydride, a cellulose nanofiber has excellent dispersibility in o-xylene and good compatibility with polyethylene. The polyethylene-cellulose nanofiber composite presents overall enhancement of mechanical properties. This method opens a new way to the production of functionalized cellulose nanofibers.A facile method was developed to produce functionalized cellulose nanofibers in one step by ball milling. Through the synergy of mechanical and chemical actions, the produced cellulose nanofibers are ca. 20 nm wide and several micrometers long, with surface properties tailored by choice of modifying reagent. Modified by succinic anhydride, a cellulose nanofiber shows enhanced hydrophilicity, can be readily dispersed in water or DMSO, and gives a zeta potential of -38.7 mV due to carboxyl groups on the surface. Modified by dodecyl succinic anhydride, a cellulose nanofiber has excellent dispersibility in o-xylene and good compatibility with polyethylene. The polyethylene-cellulose nanofiber composite presents overall enhancement of mechanical properties. This method opens a new way to the production of functionalized cellulose nanofibers. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr08179c

  2. Efficient application of boron fire retardant to cellulosic loose-fill insulation

    SciTech Connect

    Wegner, T.H.; Holmes, C.A.

    1983-01-01

    Different methods of applying boron fire-retardant chemicals were investigated for their effectiveness in improving the fire performance of cellulose insulation. Loose-fill insulation derived from newsprint was treated with boric acid/borax (1:1) applied as either a dry powder or an aqueous solution; vapor deposition treatment was also evaluated for applying boric acid. Insulation produced by direct conversion from wood chips was treated with an aqueous solution and by vapor deposition. Nominal fire retardant application levels of 10, 18, and 25% (based on newsprint or wood fiber weight) were employed. The aqueous method gave better flame-spread resistance than dry powder or vapor application. Wavelength dispersive spectroscopy showed more uniform distribution of fire retardant on the fiber surface and penetration into the fiber when applied by the aqueous method. Smoldering resistance showed little dependence on application method but did depend on fire retardant level, insulation density, and particle size. Thermal conductivity was independent of fire-retardant application method, fire retardant level, and insulation density. Overall, wood fiber and newsprint insulation gave very comparable results.

  3. Cellobiose dehydrogenase in cellulose degradation

    SciTech Connect

    Eriksson, L.; Igarashi, Kiyohiko; Samejima, Masahiro

    1996-10-01

    Cellobiose dehydrogenase is produced by a variety of fungi. Although it was already discovered during the 70`s, it`s role in cellulose and lignin degradation is yet ambiguous. The enzyme contains both heme and FAD as prosthetic groups, and seems to have a domain specifically designed to bind the enzyme to cellulose. It`s affinity to amorphous cellulose is higher than to crystalline cellulose. We will report on the binding behavior of the enzyme, its usefulness in elucidation of cellulose structures and also, possibilities for applications such as its use in measuring individual and synergistic mechanisms for cellulose degradation by endo- and exo-glucanases.

  4. Cellulose binding domain proteins

    DOEpatents

    Shoseyov, O.; Shpiegl, I.; Goldstein, M.; Doi, R.

    1998-11-17

    A cellulose binding domain (CBD) having a high affinity for crystalline cellulose and chitin is disclosed, along with methods for the molecular cloning and recombinant production. Fusion products comprising the CBD and a second protein are likewise described. A wide range of applications are contemplated for both the CBD and the fusion products, including drug delivery, affinity separations, and diagnostic techniques. 16 figs.

  5. Cellulose binding domain proteins

    DOEpatents

    Shoseyov, Oded; Shpiegl, Itai; Goldstein, Marc; Doi, Roy

    1998-01-01

    A cellulose binding domain (CBD) having a high affinity for crystalline cellulose and chitin is disclosed, along with methods for the molecular cloning and recombinant production thereof. Fusion products comprising the CBD and a second protein are likewise described. A wide range of applications are contemplated for both the CBD and the fusion products, including drug delivery, affinity separations, and diagnostic techniques.

  6. Cellulose nanocrystals in nanocomposite approach: Green and high-performance materials for industrial, biomedical and agricultural applications

    NASA Astrophysics Data System (ADS)

    Fortunati, E.; Torre, L.

    2016-05-01

    The need to both avoid wastes and find new renewable resources has led to a new and promising research based on the possibility to revalorize the biomass producing sustainable chemicals and/or materials which may play a major role in replacing systems traditionally obtained from non-renewable sources. Most of the low-value biomass is termed lignocellulosic, referring to its main constituent biopolymers: cellulose, hemicelluloses and lignin. In this context, nanocellulose, and in particular cellulose nanocrystals (CNC), have gain considerable attention as nanoreinforcement for polymer matrices, mainly biodegradable. Derived from the most abundant polymeric resource in nature and with inherent biodegradability, nanocellulose is an interesting nanofiller for the development of nanocomposites for industrial, biomedical and agricultural applications. Due to the high amount of hydroxyl groups on their surface, cellulose nanocrystals are easy to functionalize. Well dispersed CNC are able, in fact, to enhance several properties of polymers, i.e.: thermal, mechanical, barrier, surface wettability, controlled of active compound and/or drug release. The main objective here is to give a general overview of CNC applications, summarizing our recent developments of bio-based nanocomposite formulations reinforced with cellulose nanocrystals extracted from different natural sources and/or wastes for food packaging, medical and agricultural sectors.

  7. Exploring biosensor applications with cotton cellulose nanocrystalline protein and peptide conjugates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sensor I: Nano-crystalline preparations were produced through acid hydrolysis and mechanical breakage of the cotton fibers from a scoured and bleached cotton fabric and a scoured and bleached, mercerized fabric, which was shown to produce cellulose I (NCI) and cellulose II (NCII) crystals respective...

  8. A versatile pathway to end-functionalized cellulose ethers for click chemistry applications.

    PubMed

    Kamitakahara, Hiroshi; Suhara, Ryo; Yamagami, Mao; Kawano, Haruko; Okanishi, Ryoko; Asahi, Tomoyuki; Takano, Toshiyuki

    2016-10-20

    This paper describes a versatile pathway to heterobifunctional/telechelic cellulose ethers, such as tri-O-methyl cellulosyl azide and propargyl tri-O-methyl celluloside, having one free C-4 hydroxyl group attached to the glucosyl residue at the non-reducing end for the use in Huisgen 1,3-dipolar cycloaddition and copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC). The one-step end-functionalization of cellulose ethers for molecular rod synthesis involves the introduction of two reactive groups at both ends of the cellulose molecule, and can afford linear triblock copolymers via CuAAC and further reactions. We were able to tailor the degree of polymerization of end-functionalized cellulose ethers with controlled amounts of a Lewis acid, namely SnCl4. Chemical structures of the above cellulose ethers and the reaction conditions for controlling molecular length are discussed. PMID:27474546

  9. Carboxymethyl cellulose enables silk fibroin nanofibrous scaffold with enhanced biomimetic potential for bone tissue engineering application.

    PubMed

    Singh, B N; Panda, N N; Mund, R; Pramanik, K

    2016-10-20

    Novel silk fibroin (SF) and carboxymethyl cellulose (CMC) composite nanofibrous scaffold (SFC) were developed to investigate their ability to nucleate bioactive nanosized calcium phosphate (Ca/P) by biomineralization for bone tissue engineering application. The composite nanofibrous scaffold was prepared by free liquid surface electrospinning method. The developed composite nanofibrous scaffold was observed to control the size of Ca/P particle (≤100nm) as well as uniform nucleation of Ca/P over the surface. The obtained nanofibrous scaffolds were fully characterized for their functional, structural and mechanical property. The XRD and EDX analysis depicted the development of apatite like crystals over SFC scaffolds of nanospherical in morphology and distributed uniformly throughout the surface of scaffold. Additionally, hydrophilicity as a measure of contact angle and water uptake capacity is higher than pure SF scaffold representing the superior cell supporting property of the SF/CMC scaffold. The effect of biomimetic Ca/P on osteogenic differentiation of umbilical cord blood derived human mesenchymal stem cells (hMSCs) studied in early and late stage of differentiation shows the improved osteoblastic differentiation capability as compared to pure silk fibroin. The obtained result confirms the positive correlation of alkaline phosphatase activity, alizarin staining and expression of runt-related transcription factor 2, osteocalcin and type1 collagen representing the biomimetic property of the scaffolds. Thus, the developed composite has been demonstrated to be a potential scaffold for bone tissue engineering application. PMID:27474575

  10. Development of nanofibrous cellulose acetate/gelatin skin substitutes for variety wound treatment applications.

    PubMed

    Vatankhah, Elham; Prabhakaran, Molamma P; Jin, Guorui; Mobarakeh, Laleh Ghasemi; Ramakrishna, Seeram

    2014-02-01

    The major component of fibrous extracellular matrix of dermis is composed of a complex combination of proteins and polysaccharides. Electrospun cellulose acetate/gelatin might be an effective simulator of the structure and composition of native skin and during this study, we electrospun cellulose acetate/gelatin membranes in various compositions and their performance as a scaffold for either skin tissue engineering or as a wound dressing was evaluated. Skin treatment products, whether tissue-engineered scaffolds or wound dressings, should be sufficiently hydrophilic to allow for gas and fluid exchange and absorb excess exudates while controlling the fluid loss. However, a wound dressing should be easily removable without causing tissue damage and a tissue-engineered scaffold should be able to adhere to the wound, and support cell proliferation during skin regeneration. We showed that these distinct adherency features are feasible just by changing the composition of cellulose acetate and gelatin in composite cellulose acetate/gelatin scaffolds. High proliferation of human dermal fibroblasts on electrospun cellulose acetate/gelatin 25:75 confirmed the capability of cellulose acetate/gelatin 25:75 nanofibers as a tissue-engineered scaffold, while the electrospun cellulose acetate/gelatin 75:25 can be a potential low-adherent wound dressing. PMID:23640859

  11. Aerogels from unaltered bacterial cellulose: application of scCO2 drying for the preparation of shaped, ultra-lightweight cellulosic aerogels.

    PubMed

    Liebner, Falk; Haimer, Emmerich; Wendland, Martin; Neouze, Marie-Alexandra; Schlufter, Kerstin; Miethe, Peter; Heinze, Thomas; Potthast, Antje; Rosenau, Thomas

    2010-04-01

    Bacterial cellulose produced by the gram-negative bacterium Gluconacetobacter xylinum was found to be an excellent native starting material for preparing shaped ultra-lightweight cellulose aerogels. The procedure comprises thorough washing and sterilization of the aquogel, quantitative solvent exchange and subsequent drying with supercritical carbon dioxide at 40 degrees C and 100 bar. The average density of the obtained dry cellulose aerogels is only about 8 mg x cm(-3) which is comparable to the most lightweight silica aerogels and distinctly lower than all values for cellulosic aerogels obtained from plant cellulose so far. SEM, ESEM and nitrogen adsorption experiments at 77 K reveal an open-porous network structure that consists of a comparatively high percentage of large mesopores and smaller macropores. PMID:20166232

  12. Development of Injectable Hyaluronic Acid/Cellulose Nanocrystals Bionanocomposite Hydrogels for Tissue Engineering Applications.

    PubMed

    Domingues, Rui M A; Silva, Marta; Gershovich, Pavel; Betta, Sefano; Babo, Pedro; Caridade, Sofia G; Mano, João F; Motta, Antonella; Reis, Rui L; Gomes, Manuela E

    2015-08-19

    Injectable hyaluronic acid (HA)-based hydrogels compose a promising class of materials for tissue engineering and regenerative medicine applications. However, their limited mechanical properties restrict the potential range of application. In this study, cellulose nanocrystals (CNCs) were employed as nanofillers in a fully biobased strategy for the production of reinforced HA nanocomposite hydrogels. Herein we report the development of a new class of injectable hydrogels composed of adipic acid dihydrazide-modified HA (ADH-HA) and aldehyde-modified HA (a-HA) reinforced with varying contents of aldehyde-modified CNCs (a-CNCs). The obtained hydrogels were characterized in terms of internal morphology, mechanical properties, swelling, and degradation behavior in the presence of hyaluronidase. Our findings suggest that the incorporation of a-CNCs in the hydrogel resulted in a more organized and compact network structure and led to stiffer hydrogels (maximum storage modulus, E', of 152.4 kPa for 0.25 wt % a-CNCs content) with improvements of E' up to 135% in comparison to unfilled hydrogels. In general, increased amounts of a-CNCs led to lower equilibrium swelling ratios and higher resistance to degradation. The biological performance of the developed nanocomposites was assessed toward human adipose derived stem cells (hASCs). HA-CNCs nanocomposite hydrogels exhibited preferential cell supportive properties in in vitro culture conditions due to higher structural integrity and potential interaction of microenvironmental cues with CNC's sulfate groups. hASCs encapsulated in HA-CNCs hydrogels demonstrated the ability to spread within the volume of gels and exhibited pronounced proliferative activity. Together, these results demonstrate that the proposed strategy is a valuable toolbox for fine-tuning the structural, biomechanical, and biochemical properties of injectable HA hydrogels, expanding their potential range of application in the biomedical field. PMID:26106949

  13. Cellulose acetate based 3-dimensional electrospun scaffolds for skin tissue engineering applications.

    PubMed

    Atila, Deniz; Keskin, Dilek; Tezcaner, Ayşen

    2015-11-20

    Skin defects that are not able to regenerate by themselves are among the major problems faced. Tissue engineering approach holds promise for treating such defects. Development of tissue-mimicking-scaffolds that can promote healing process receives an increasing interest in recent years. In this study, 3-dimensional electrospun cellulose acetate (CA) pullulan (PULL) scaffolds were developed for the first time. PULL was intentionally used to obtain 3D structures with adjustable height. It was removed from the electrospun mesh to increase the porosity and biostability. Different ratios of the polymers were electrospun and analyzed with respect to degradation, porosity, and mechanical properties. It has been observed that fiber diameter, thickness and porosity of scaffolds increased with increased PULL content, on the other hand this resulted with higher degradation of scaffolds. Mechanical strength of scaffolds was improved after PULL removal suggesting their suitability as cell carriers. Cell culture studies were performed with the selected scaffold group (CA/PULL: 50/50) using mouse fibroblastic cell line (L929). In vitro cell culture tests showed that cells adhered, proliferated and populated CA/PULL (50/50) scaffolds showing that they are cytocompatible. Results suggest that uncrosslinked CA/PULL (50/50) electrospun scaffolds hold potential for skin tissue engineering applications. PMID:26344279

  14. The association effect of quaternary ammonium salt on carboxymethyl cellulose and its analytical applications.

    PubMed

    Wang, Yanhua; Gao, Chanjuan; Yang, Shengke

    2015-01-01

    Sodium carboxymethyl cellulose (CMC) has been extensively used in petroleum, geology, common household chemicals, food, medicine and other industries, owing to its excellent water-soluble, emulsifying, water retention and film forming properties. It is known as 'industrial monosodium glutamate'. However, the research of the test method on CMC is far behind the research of its actual application value. This study showed that, weak acid or weak basic medium, the carboxyl groups dissociated from CMC, existing as a big negative ion, which can form ion-association complexes with some quaternary ammonium cations through electrostatic and hydrophobic interactions. The absorption spectrum changes and Triton-X100 can increase the sensitivity of the system. The maximum absorption wavelengths are, respectively, about 256 nm for dodecyl trimethyl ammonium bromide (LTAB), 244 nm for tetradecyltrimethyl ammonium bromide (TTAB) and 240 nm for cetyltrimethyl ammonium bromide (CTAB) with CMC. The reactions show very high sensitivities and the maximum molar absorption coefficients are 1.10 × 10(4) L/(mol·cm) for LTAB system, 1.24 × 10(6) L/(mol·cm) for TTAB system and 1.78 × 10(6) L/(mol·cm) for CTAB system. This method is simple and rapid, and can be applied for the spectrophotometric determination of trace CMC in the supernatant of centrifuged drilling mud. PMID:26360741

  15. Chimeric proteins combining phosphatase and cellulose-binding activities: proof-of-concept and application in the hydrolysis of paraoxon.

    PubMed

    Gonçalves, Larissa M; Chaimovich, Hernan; Cuccovia, Iolanda M; Marana, Sandro R

    2014-05-01

    Phosphatases for organophosphate degradation and carbohydrate-binding domains (CBMs) have potential biotechnological applications. As a proof-of-concept, a soluble chimeric protein that combines acid phosphatase (AppA) from Escherichia coli and a CBM from Xanthomonas axonopodis pv. citri (AppA-CBM) was produced in E.coli. AppACBM adsorbed in microcrystalline cellulose Avicel PH101 catalyzed the hydrolysis of p-nitrophenyl phosphate (PNPP). The binding to microcrystalline cellulose displayed saturation behavior with an apparent binding constant (Kb) of 22 ± 5 mg and a maximum binding (Bmax) of 1.500 ± 0.001 enzyme units. Binding was highest at pH 2.5 and decreased above pH 6.5, as previously observed for family 2 CBMs. The Km values for PNPP of AppA-CBM and native AppA were identical (2.7 mM). To demonstrate that this strategy for protein engineering has practical applications and is largely functional, even for phosphatases exhibiting diverse folds, a chimeric protein combining human paraoxonase 1 (hPON1) and the CBM was produced. Both PON1-CBM and hPON1 had identical Km values for paraoxon (1.3 mM). Additionally, hPON1 bound to microcrystalline cellulose with a Kb of 27 ± 3 mg, the same as that observed for AppA-CBM. These data show that the phosphatase domains are as functional in both of the chimeric proteins as they are in the native enzymes and that the CBM domain maintains the same cellulose affinity. Therefore, the engineering of chimeric proteins combining domains of phosphatases and CBMs is fully feasible, resulting in chimeric enzymes that exhibit potential for OP detoxification. PMID:24555432

  16. Bacterial cellulose membrane produced by Acetobacter sp. A10 for burn wound dressing applications.

    PubMed

    Kwak, Moon Hwa; Kim, Ji Eun; Go, Jun; Koh, Eun Kyoung; Song, Sung Hwa; Son, Hong Joo; Kim, Hye Sung; Yun, Young Hyun; Jung, Young Jin; Hwang, Dae Youn

    2015-05-20

    Bacteria cellulose membranes (BCM) are used for wound dressings, bone grafts, tissue engineering, artificial vessels, and dental implants because of their high tensile strength, crystallinity and water holding ability. In this study, the effects of BCM application for 15 days on healing of burn wounds were investigated based on evaluation of skin regeneration and angiogenesis in burn injury skin of Sprague-Dawley (SD) rats. BCM showed a randomly organized fibrils network, 12.13 MPa tensile strength, 12.53% strain, 17.63% crystallinity, 90.2% gel fraction and 112.14 g × m(2)/h highest water vapor transmission rate (WVTR) although their swelling ratio was enhanced to 350% within 24h. In SD rats with burned skin, the skin severity score was lower in the BCM treated group than the gauze (GZ) group at all time points, while the epidermis and dermis thickness and number of blood vessels was greater in the BCM treated group. Furthermore, a significant decrease in the number of infiltrated mast cells and in vascular endothelial growth factor (VEGF) and angiopoietin-1 (Ang-1) expression was observed in the BCM treated group at day 10 and 15. Moreover, a significant high level in collagen expression was observed in the BCM treated group at day 5 compared with GZ treated group, while low level was detected in the same group at day 10 and 15. However, the level of metabolic enzymes representing liver and kidney toxicity in the serum of BCM treated rats was maintained at levels consistent with GZ treated rats. Overall, BCM may accelerate the process of wound healing in burn injury skin of SD rats through regulation of angiogenesis and connective tissue formation as well as not induce any specific toxicity against the liver and kidney. PMID:25817683

  17. THERMAL INSULATION PROPERTIES OF BIODEGRADABLE, CELLULOSIC-BASED NONWOVEN COMPOSITES FOR AUTOMOTIVE APPLICATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Moldable, cellulosic-based nonwoven composites with excellent thermal insulation properties were fabricated from kenaf, jute, flax, and waste cotton using recycled polyester and substandard polypropylene. The composites of these fibers have excellent shape stability and high tensile and flexural pro...

  18. SYNTHESIS OF THERMALLY STABLE CARBOXYMETHYL CELLULOSE/METAL BIODEGRADABLE NANOCOMPOSITES FOR POTENTIAL BIOLOGICAL APPLICATIONS

    EPA Science Inventory

    A green approach is described that generates bulk quantities of nanocomposites containing transition metals such as Cu, Ag, In and Fe at room temperature using a biodegradable polymer carboxymethyl cellulose (CMC) by reacting respective metal salts with sodium salt of CMC in aqu...

  19. Preparation and Application as the Filler for Elastomers of Flake-Shaped Cellulose Particles and Nanofibers

    NASA Astrophysics Data System (ADS)

    Nagatani, Asahiro; Lee, Seung-Hwan; Endo, Takashi; Tanaka, Tatsuya

    Fibrous cellulose made from wood pulp was mechanically milled into flake-shaped cellulose particles(FS-CPs) using a planetary ball mill with additives under several conditions. The average particle diameter of the FS-CPs was ca. 15μm, and the particles were available in a variety of thicknesses by changing the kind of the additives used in the milling process. FS-CPs-reinforced olefinic thermoplastic elastomer composites were prepared under melt mixing and passed through an open roll to orient the particles. The tensile modulus of the composites with a compatibilizer increased with increasing the particle content. The damping properties of the composites improved, compared to the neat elastomer. On the other hand, the fibrous cellulose was suspended in water, followed by wet disk-milled to prepare cellulose nanofibers(CNFs). The wet ground products showed nanoscopic fine morphology. CNFs-reinforced natural rubber(NR) composites were prepared by mixing the water suspension of CNFs with NR latex using a homogenizer. Then, it was dried in an oven and mixed again with vulcanizing ingredients of rubber using an open roll. The tensile properties of the composites improved remarkably by the addition of small amount of CNFs.

  20. Enzymatic properties of Thermoanaerobacterium thermosaccharolyticum β-glucosidase fused to Clostridium cellulovorans cellulose binding domain and its application in hydrolysis of microcrystalline cellulose

    PubMed Central

    2013-01-01

    Background The complete degradation of the cellulose requires the synergistic action of endo-β-glucanase, exo-β-glucanase, and β-glucosidase. But endo-β-glucanase and exo-β-glucanase can be recovered by solid–liquid separation in cellulose hydrolysis by their cellulose binding domain (CBD), however, the β-glucosidases cannot be recovered because of most β-glucosidases without the CBD, so additional β-glucosidases are necessary for the next cellulose degradation. This will increase the cost of cellulose degradation. Results The glucose-tolerant β-glucosidase (BGL) from Thermoanaerobacterium thermosaccharolyticum DSM 571 was fused with cellulose binding domain (CBD) of Clostridium cellulovorans cellulosome anchoring protein by a peptide linker. The fusion enzyme (BGL-CBD) gene was overexpressed in Escherichia coli with the maximum β-glucosidase activity of 17 U/mL. Recombinant BGL-CBD was purified by heat treatment and following by Ni-NTA affinity. The enzymatic characteristics of the BGL-CBD showed optimal activities at pH 6.0 and 65°C. The fusion of CBD structure enhanced the hydrolytic efficiency of the BGL-CBD against cellobiose, which displayed a 6-fold increase in V max /K m in comparison with the BGL. A gram of cellulose was found to absorb 643 U of the fusion enzyme (BGL-CBD) in pH 6.0 at 50°C for 25 min with a high immobilization efficiency of 90%. Using the BGL-CBD as the catalyst, the yield of glucose reached a maximum of 90% from 100 g/L cellobiose and the BGL-CBD could retain over 85% activity after five batches with the yield of glucose all above 70%. The performance of the BGL-CBD on microcrystalline cellulose was also studied. The yield of the glucose was increased from 47% to 58% by adding the BGL-CBD to the cellulase, instead of adding the Novozyme 188. Conclusions The hydrolytic activity of BGL-CBD is greater than that of the Novozyme 188 in cellulose degradation. The article provides a prospect to decrease significantly the

  1. Polyethylenimine coated bacterial cellulose nanofiber membrane and application as adsorbent and catalyst.

    PubMed

    Wang, Jianqiang; Lu, Xinkun; Ng, Pui Fai; Lee, Ka I; Fei, Bin; Xin, John H; Wu, Jian-yong

    2015-02-15

    Bacterial cellulose (BC) nanofiber membranes were simply aminalized by a flush-coating and post-crosslinking method. Firstly, wet BC membranes were flushed through by an aqueous solution of polyethylenimine (PEI) and glycerol diglycidyl ether (GDE) under vacuum suction, then further heated up to 70 °C to crosslink the resultant coating on the surface of the nanofibers. The PEI coated bacterial cellulose (BC@PEI) nanofiber membrane presented excellent adsorption performance for Cu(2+) and Pb(2+) ions from aqueous solutions. Desorption of these ions was achieved using ethylene diamine tetraacetic acid treatment. This cycle of adsorption and desorption was repeated for several times with good remain adsorption performance (over 90%). Furthermore, the adsorbed Cu(2+) ions can be reduced to copper nanoparticles, and showed excellent catalytic performance for methylene blue reduction in aqueous solution. The catalytic performance can remained after several times of usage. PMID:25460686

  2. Nanofibrillated Cellulose and Copper Nanoparticles Embedded in Polyvinyl Alcohol Films for Antimicrobial Applications

    PubMed Central

    Zhong, Tuhua; Oporto, Gloria S.; Jaczynski, Jacek; Jiang, Changle

    2015-01-01

    Our long-term goal is to develop a hybrid cellulose-copper nanoparticle material as a functional nanofiller to be incorporated in thermoplastic resins for efficiently improving their antimicrobial properties. In this study, copper nanoparticles were first synthesized through chemical reduction of cupric ions on TEMPO nanofibrillated cellulose (TNFC) template using borohydride as a copper reducing agent. The resulting hybrid material was embedded into a polyvinyl alcohol (PVA) matrix using a solvent casting method. The morphology of TNFC-copper nanoparticles was analyzed by transmission electron microscopy (TEM); spherical copper nanoparticles with average size of 9.2 ± 2.0 nm were determined. Thermogravimetric analysis and antimicrobial performance of the films were evaluated. Slight variations in thermal properties between the nanocomposite films and PVA resin were observed. Antimicrobial analysis demonstrated that one-week exposure of nonpathogenic Escherichia coli DH5α to the nanocomposite films results in up to 5-log microbial reduction. PMID:26137482

  3. Flexible and monolithic zinc oxide bionanocomposite foams by a bacterial cellulose mediated approach for antibacterial applications.

    PubMed

    Wang, Peipei; Zhao, Jun; Xuan, Ruifei; Wang, Yun; Zou, Chen; Zhang, Zhiquan; Wan, Yizao; Xu, Yan

    2014-05-14

    The use of self-assembled biomacromolecules in the development of functional bionanocomposite foams is one of the best lessons learned from nature. Here, we show that monolithic, flexible and porous zinc oxide bionanocomposite foams with a hierarchical architecture can be assembled through the mediation of bacterial cellulose. The assembly is achieved by controlled hydrolysis and solvothermal crystallization using a bacterial cellulose aerogel as a template in a non-aqueous polar medium. The bionanocomposite foam with a maximum zinc oxide loading of 70 wt% is constructed of intimately packed spheres of aggregated zinc oxide nanocrystals exhibiting a BET surface area of 92 m(2) g(-1). The zinc oxide bionanocomposite foams show excellent antibacterial activity, which give them potential value as self-supporting wound dressing and water sterilization materials. PMID:24647467

  4. Synthesis of novel reactive N-halamine precursors and application in antimicrobial cellulose

    NASA Astrophysics Data System (ADS)

    Jiang, Zhiming; Ma, Kaikai; Du, Jinmei; Li, Rong; Ren, Xuehong; Huang, T. S.

    2014-01-01

    2,4,6-Trichloro-s-triazine has been used as one of the important linkers of reactive dyes for textiles such as cellulosic fibers. N-Halamine precursors could be bonded to a triazine-based linker by the chloride displacement reaction, and the synthesized compounds could attach to cotton fabrics by covalent bonds through a reactive dyeing process. In this study, two novel antimicrobial N-halamine precursors, 2,2,6,6-tetramethyl-4-piperidinol-s-trizine (TMPT) and 4-(4-(2,2,6,6-tetramethyl-4-piperidinol)-6-chloro-1,3,5-triazinylamino)-benzenesulfonate (BTMPT), were synthesized and used to coat cotton fabrics. The synthesized s-triazine-based N-halamine precursors react with cellulose to produce biocidal cellulosic fibers upon exposure to diluted household bleach. The coated fabrics were characterized by FT-IR and SEM. The chlorinated treated cotton swatches demonstrated excellent antimicrobial properties against S. aureus (Gram-positive) and E. coli O157:H7 (Gram-negative) with short contact times. Washing test and UVA light test showed that chlorinated BTMPT-coated cotton fabrics were more stable than TMPT-coated cotton fabrics. Compared to the traditional pad-dry-cure technique to produce antimicrobial textiles, the novel process in this study has advantages of saving energy and maintaining tensile strength of fabrics.

  5. Feasibility of e-paper made with cellulose

    NASA Astrophysics Data System (ADS)

    Yoo, K. H.; Han, K. J.; Chen, Yi; Kang, K. S.; Kim, Jaehwan

    2008-03-01

    Cellulose is a beneficial material that has low cost, light weight, high compatibility, and biodegradability. Recently electro-active paper (EAPap) composed with cellulose was discovered as a smart material for application to variety industrial fields such as smart wall-paper, actuator, and magic carpet. It also exhibited actuator property through ion migration and piezoelectric effect. Since cellulose acetate (CA) film has optically transparent property, we focused on optical field application, such as electronic paper, prismsheet, and polarized film. Since CA can be easily dissolved in variety of organic solvent, various weight % (from 1 to 25 wt. %) of CA solution in acetone was prepared. Polydimethylsilane (PDMS) master pattern was fabricated on the silicone wafer. CA solution was poured to the master mold and dried using spin-coating or tape casting method. Various shape and height patterns, such as circle, honeycomb, and rectangular patterns were fabricated using 12 wt. % CA solution. The resulting pattern showed uniform size in the large area without defect. These patterns can be utilized as a substrate and cell pattern for the electronic paper. To investigate saponification (SA) effect to convert CA to regenerated cellulose, CA film was immersed into the sodium methoxide solution in methanol for various times. The fabricated CA films were stretched and immersed into the sodium methoxide solution in methanol to desubstitute the acetate group. These regenerated cellulose films have larger mechanical strength than CA films. Although the UV-visible transmittance was decreased as increasing SA time, the transmittance of the further SA process and stretched film backed up near untreated CA film. Although the cross-sectional image of the saponified and unstretched CA film did not have specific directional structure, the cross-sectional FESEM image of the saponified and stretched CA film had one directional fiber structure. The fiber was aligned to the stretched

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

    PubMed Central

    Isik, Mehmet; Sardon, Haritz; Mecerreyes, David

    2014-01-01

    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. PMID:25000264

  7. Cellulose binding domain fusion proteins

    DOEpatents

    Shoseyov, O.; Yosef, K.; Shpiegl, I.; Goldstein, M.A.; Doi, R.H.

    1998-02-17

    A cellulose binding domain (CBD) having a high affinity for crystalline cellulose and chitin is disclosed, along with methods for the molecular cloning and recombinant production. Fusion products comprising the CBD and a second protein are likewise described. A wide range of applications are contemplated for both the CBD and the fusion products, including drug delivery, affinity separations, and diagnostic techniques. 16 figs.

  8. Cellulose binding domain fusion proteins

    DOEpatents

    Shoseyov, Oded; Shpiegl, Itai; Goldstein, Marc A.; Doi, Roy H.

    1998-01-01

    A cellulose binding domain (CBD) having a high affinity for crystalline cellulose and chitin is disclosed, along with methods for the molecular cloning and recombinant production thereof. Fusion products comprising the CBD and a second protein are likewise described. A wide range of applications are contemplated for both the CBD and the fusion products, including drug delivery, affinity separations, and diagnostic techniques.

  9. Reversible redox activity of ferrocene functionalized hydroxypropyl cellulose and its application to detect H2O2.

    PubMed

    Li, Pingping; Kang, Hongliang; Zhang, Chao; Li, Weiwei; Huang, Yong; Liu, Ruigang

    2016-04-20

    Novel ferrocene functionalized hydroxypropyl cellulose (HPC-Fc) were prepared by azide-alkyne cycloaddition and characterized. HPC-Fc exhibits an excellent reversible redox activity and could establish amazing electron transfer ability between enzyme and electrode. HPC-Fc and horseradish peroxidase (HRP) were coated on a platinized carbon electrode to prepare an amperometric biosensor for hydrogen peroxide (H2O2) detection. The amperometric response was measured as a function of H2O2 concentration at a fixed potential of 0.35V in 100mM phosphate buffer solution (pH 7.0). The novel biosensor exhibits a fast linear response toward H2O2 in the range of 0.1-8μM with sensitivity of 4.21nA/μM. Moreover, the enzyme assays measured by the spectrophotometer method confirm that abundant hydroxyl groups of HPC backbones are conductive for HRP to maintaining or even enhancing their activity. The redox active HPC-Fc with the unique properties of both ferrocene and cellulose is a good candidate for biosensor applications. PMID:26876825

  10. Recepteur SBAS-GNSS logiciel pour des applications temps-reel

    NASA Astrophysics Data System (ADS)

    Guay, Jean-Christophe

    Satellite positioning is at a critical point of its existence. The modernization of Global Positioning System (GPS) and GLObal Navigation Satellite System (GLONASS) and the arrival of European and Chinese systems will allow a multitude of new applications. This combination of global positioning system satellites and the GPS augmentation system will improve the integrity, availability, accuracy and electromagnetic vulnerability. To takes full advantage of these new signals, the GNSS receiver will be rethought. The objective of this thesis is to develop SBAS-GNSS receiver software for real-time applications to take advantage of these new GNSS signals. To achieve this goal, a channel architecture BPSK (Binary Phase Shift Keying) has been implemented in order to profit from the similarities between different GNSS signals considered in this work. These signals are: GPS L1 CIA, GPS L2C, SBAS L1, L5 SBAS, GLONASS L1 and L2 GLONASS. In addition, this thesis also focuses on implementing a full SBAS solution to improve the accuracy of the navigation solution. BPSK channel tracks GPS L1 CIA, SBAS L1, L5 SBAS, GLONASS L1, L2 GLONASS, COMPASS and COMPASS B1 B2 covering all the band GNSS 1176 MHz to 1602 MHz This channel does not degrade any receiver performance. In fact, the horizontal accuracy is increased from 2.3 m at 1 sigma to 1.1 m at 1 sigma with some minor adjustments. In addition, the implementation of a smoothing algorithm using the carrier improves accuracy up to 0.96 mat 1 cr. The circle of 50% probability (CEP) for the smoothed solution is 0.62 m and for 95% (R95) is 2.21 m. Finally, the implementation of the SBAS solution improves the performance to 0.73 m at 1 sigma, to a CEP of 0.44 m and to a R95 of 1.4 m. Moreover, an improvement of 70% can be observed between the previous works and the actual one when we compare the 1 sigma performance. In addition, new channels and algorithms are also tested dynamically. An improvement of 5% can be observed on the standard

  11. Pigment-cellulose nanofibril composite and its application as a separator-substrate in printed supercapacitors

    NASA Astrophysics Data System (ADS)

    Torvinen, Katariina; Lehtimäki, Suvi; Keränen, Janne T.; Sievänen, Jenni; Vartiainen, Jari; Hellén, Erkki; Lupo, Donald; Tuukkanen, Sampo

    2015-11-01

    Pigment-cellulose nanofibril (PCN) composites were manufactured in a pilot line and used as a separator-substrate in printed graphene and carbon nanotube supercapacitors. The composites consisted typically of 80% pigment and 20% cellulose nanofibrils (CNF). This composition makes them a cost-effective alternative as a substrate for printed electronics at high temperatures that only very special plastic films can nowadays stand. The properties of these substrates can be varied within a relatively large range by the selection of raw materials and their relative proportions. A semi-industrial scale pilot line was successfully used to produce smooth, flexible, and nanoporous composites, and their performance was tested in a double functional separator-substrate element in supercapacitors. The nanostructural carbon films printed on the composite worked simultaneously as high surface area active electrodes and current collectors. Low-cost supercapacitors made from environmentally friendly materials have significant potential for use in flexible, wearable, and disposable low-end products. [Figure not available: see fulltext.

  12. Application of Vat Green 1 dye on gamma ray treated cellulosic fabric

    NASA Astrophysics Data System (ADS)

    Bhatti, Ijaz Ahmad; Adeel, Shahid; Taj, Hina

    2014-09-01

    For the present study, Vat Green 1 dye has been selected for dyeing gamma irradiated cellulosic fabric. The dyeing variables such as dyeing temperature, dyeing time and dyeing pH were optimized. Concentrations of sodium hydrosulphite for reduction process and hydrogen peroxide for oxidation process were also optimized. After evaluation of dyed fabrics in a CIE Lab system using Spectraflash SF-650 it has been found that 6 kGy is the effective absorbed dose for improvement in dyeing behaviour of cellulosic fabric. Good colour strength has been obtained by dyeing optimal irradiated fabric (6 kGy, IC) at 75 °C for 1 h. by employing dyeing solution of pH 11. It has also been found that gamma ray treatment has reduced the necessary quantity of reducing (NaHSO3) and oxidizing agents (H2O2). The rating results after implementation of suggested standard methods of ISO for colourfastness showed that using irradiated textiles, the fastness to light, washing and rubbing has been significantly improved.

  13. Novel carboxymethyl cellulose based nanocomposite membrane: Synthesis, characterization and application in water treatment.

    PubMed

    Saber-Samandari, Samaneh; Saber-Samandari, Saeed; Heydaripour, Samira; Abdouss, Majid

    2016-01-15

    Significant efforts have been made to develop composite membranes with high adsorption efficiencies for water treatment. In this study, a carboxymethyl cellulose-graft-poly(acrylic acid) membrane was synthesized in the presence of silica gel, which was used as an inorganic support. Then, different amounts of bentonite were introduced to the carboxymethyl cellulose (CMC) grafted networks as a multifunctional crosslinker, and nanocomposite membranes were prepared. The nanocomposite membranes were characterized using Fourier transform infrared spectroscopy, and scanning electron microscopy, which revealed their compositions and surface morphologies. The novel synthesized nanocomposite membranes were utilized as adsorbents for the removal of crystal violet (CV) and cadmium (Cd (II)) ions, which were selected as representatives of a dye and a heavy metal, respectively. We explored the effects of various parameters, such as time, pH, temperature, initial concentration of adsorbate solution and amount of adsorbent, on membrane adsorption capacity. Furthermore, the kinetic, adsorption isotherm models and thermodynamic were employed for the description of adsorption processes. The maximum adsorption capacities of membranes for CV and Cd (II) ions were found to be 546 and 781 mg g(-1), respectively. The adsorption of adsorbate ions by all types of nanocomposite membranes followed pseudo-second-order kinetic model and was best fit with the Freundlich adsorption isotherm. The results indicated that the synthesized nanocomposite membrane is an efficient adsorbent for the removal of cationic dye and metal contaminants from aqueous solution during water treatment. PMID:26560638

  14. Characterisation of microcrystalline cellulose from oil palm fibres for food applications.

    PubMed

    Xiang, Loo Yu; P Mohammed, Mohd Afandi; Samsu Baharuddin, Azhari

    2016-09-01

    Microcrystalline cellulose (MCC) extracted from empty fruit bunches (EFB), stalk and spikelet were characterised through physicochemical and microstructure analyses. Raw stalk fibres yielded the highest cellulose content (42.43%), followed by EFB (32.33%) and spikelet (18.83%). Likewise, lowest lignin and residual oil content was reported in raw stalk fibres compared to EFB and spikelet. SEM revealed significant changes on fibres' surface morphology throughout the extraction process. FTIR analysis showed that main characteristic peaks of hemicellulose and lignin was absent on the extracted MCC. The crystallinity index for MCC extracted from EFB (82.5%), stalk (82.2%) and spikelet (86.5%) was comparable to commercial MCC (81.9%). Results suggested stalk fibres is more preferable for the production of MCC compared to EFB and spikelet. Further rheological studies showed viscoelastic behaviour with no significant differences between commercial and stalk-based MCC, while modelling work showed ability to simulate complex deformation of the MCC-hydrogel/food mixture during processing/handling stage. PMID:27185110

  15. Synthese de nanoparticules plasmoniques par laser femtoseconde en milieu liquide pour des applications biomedicales

    NASA Astrophysics Data System (ADS)

    Besner, Sebastien

    The femtosecond laser synthesis of plasmonic nanoparticles (Au, Ag, Cu, AuAg, AuCu) is described. The approach relies on the fs laser ablation of a target immersed in a liquid, followed by the laser-induced fragmentation and growth of nanoparticles in solution. This two-step methodology significantly enhances the production rate, the reproducibility and the size control of nanoparticles in comparison to the direct laser ablation based technique. For gold, the laser-induced growth of nanometric seeds initially formed by laser ablation in the presence of a stabilizing agent allows the synthesis of functionalized nanoparticles with sizes ranging from 3-76 nm and coefficients of variation (COV) varying between 15-30%. In comparison to the direct laser ablation, the size control is much simpler, as it uniquely depends on the gold to stabilizing agent molecular concentration ratio. The approach has been described for dextran and polyethylene glycol (PEG), but can be extended to all stabilizing agents and open new avenues in the formation of various novel bioconjugates. The fs laser ablation and fragmentation also allow the synthesis of stable and low dispersed Au nanoparticles in pure water. These nanoparticles are unique for sensing applications with high sensitivity based on surface enhanced Raman scattering (SERS), since they greatly reduce the noise associated with surface contaminants and byproducts found in solution. The formation of various nanospheres with predetermined size, shape and composition (AuxAg(1-x), AuxCu(1-x) ) is also reported by the use of a fs irradiation of a mixture of two pure metallic ix colloidal solutions in a very simple chemical environment, e.g. water and a stabilizing agent. From a chemical point of view, oxidation of silver nanoparticles is significantly reduced by the incorporation of a small amount of gold and is completely inhibited for a gold atomic fraction larger than 0.4-0.5. The bifunctional nature related to the partial

  16. Preparation of naproxen-ethyl cellulose microparticles by spray-drying technique and their application to textile materials.

    PubMed

    Arici, Mesut; Topbas, Ozlem; Karavana, Sinem Yaprak; Ertan, Gokhan; Sariisik, Merih; Ozturk, Cihat

    2014-01-01

    The objective of this study is to develop a new textile-based drug delivery system containing naproxen (NAP) microparticles and to evaluate the potential of the system as the carrier of NAP for topical delivery. Microparticles were prepared by spray-drying using an aqueous ethyl cellulose dispersion. The drug content and entrapment efficiency, particle size and distribution, particle morphology and in vitro drug release characteristics of microparticles were optimized for the application of microparticles onto the textile fabrics. Microparticles had spherical shape in the range of 10-15 μm and a narrow particle size distribution. NAP encapsulated in microparticles was in the amorphous or partially crystalline nature. Microparticles were tightly fixed onto the textile fabrics. In vitro drug release exhibited biphasic release profile with an initial burst followed by a very slow release. Skin permeation profiles were observed to follow near zero-order release kinetics. PMID:24861324

  17. Preparation of nano cellulose fibers and its application in kappa-carrageenan based film.

    PubMed

    Savadekar, N R; Karande, V S; Vigneshwaran, N; Bharimalla, A K; Mhaske, S T

    2012-12-01

    Bio-based nanocomposite films were successfully developed using nanofibrillated cellulose (NFC) as the reinforcing phase and kappa-carrageenan (KCRG) as the matrix. NFC was successfully synthesis from short stable cotton fibers by chemo-mechanical process. The bionanocomposites were prepared by incorporating 0.1, 0.2, 0.3, 0.4, 0.5, and 1wt% of the NFC into a KCRG matrix using a solution casting method there characterization was done in terms of thermal properties (DSC), morphology (SEM), water vapor transmission rate (WVTR), oxygen transmission rate (OTR), X-ray diffractograms (XRD), and tensile properties. The main conclusion arising from the analysis of the result is that the bionanocomposites containing 0.4wt% of NFC exhibited the highest enhancement in tensile strength it is almost 44% improvement. WVTR and OTR results showed improvement of all nanocomposite film compare to control KCRG film. PMID:22940239

  18. Use of CdS quantum dot-functionalized cellulose nanocrystal films for anti-counterfeiting applications

    NASA Astrophysics Data System (ADS)

    Chen, L.; Lai, C.; Marchewka, R.; Berry, R. M.; Tam, K. C.

    2016-07-01

    Structural colors and photoluminescence have been widely used for anti-counterfeiting and security applications. We report for the first time the use of CdS quantum dot (QD)-functionalized cellulose nanocrystals (CNCs) as building blocks to fabricate nanothin films via layer-by-layer (LBL) self-assembly for anti-counterfeiting applications. Both negatively- and positively-charged CNC/QD nanohybrids with a high colloidal stability and a narrow particle size distribution were prepared. The controllable LBL coating process was characterized by scanning electron microscopy and ellipsometry. The rigid structure of CNCs leads to nanoporous structured films on poly(ethylene terephthalate) (PET) substrates with high transmittance (above 70%) over the entire range of visible light and also resulted in increased hydrophilicity (contact angles of ~40 degrees). Nanothin films on PET substrates showed good flexibility and enhanced stability in both water and ethanol. The modified PET films with structural colors from thin-film interference and photoluminescence from QDs can be used in anti-counterfeiting applications.Structural colors and photoluminescence have been widely used for anti-counterfeiting and security applications. We report for the first time the use of CdS quantum dot (QD)-functionalized cellulose nanocrystals (CNCs) as building blocks to fabricate nanothin films via layer-by-layer (LBL) self-assembly for anti-counterfeiting applications. Both negatively- and positively-charged CNC/QD nanohybrids with a high colloidal stability and a narrow particle size distribution were prepared. The controllable LBL coating process was characterized by scanning electron microscopy and ellipsometry. The rigid structure of CNCs leads to nanoporous structured films on poly(ethylene terephthalate) (PET) substrates with high transmittance (above 70%) over the entire range of visible light and also resulted in increased hydrophilicity (contact angles of ~40 degrees). Nanothin films

  19. The cellulose resource matrix.

    PubMed

    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

  20. Use of CdS quantum dot-functionalized cellulose nanocrystal films for anti-counterfeiting applications.

    PubMed

    Chen, L; Lai, C; Marchewka, R; Berry, R M; Tam, K C

    2016-07-21

    Structural colors and photoluminescence have been widely used for anti-counterfeiting and security applications. We report for the first time the use of CdS quantum dot (QD)-functionalized cellulose nanocrystals (CNCs) as building blocks to fabricate nanothin films via layer-by-layer (LBL) self-assembly for anti-counterfeiting applications. Both negatively- and positively-charged CNC/QD nanohybrids with a high colloidal stability and a narrow particle size distribution were prepared. The controllable LBL coating process was characterized by scanning electron microscopy and ellipsometry. The rigid structure of CNCs leads to nanoporous structured films on poly(ethylene terephthalate) (PET) substrates with high transmittance (above 70%) over the entire range of visible light and also resulted in increased hydrophilicity (contact angles of ∼40 degrees). Nanothin films on PET substrates showed good flexibility and enhanced stability in both water and ethanol. The modified PET films with structural colors from thin-film interference and photoluminescence from QDs can be used in anti-counterfeiting applications. PMID:27337656

  1. Development of microporous structure and its application to optical film for cellulose triacetate containing diisodecyl adipate.

    PubMed

    Shimada, Hikaru; Nobukawa, Shogo; Yamaguchi, Masayuki

    2015-04-20

    Phase separation in plasticized cellulose triacetate (CTA) films is investigated to produce a microporous film that can be used in optical devices. Hot-stretched CTA films containing diisodecyl adipate (DIDA) show negative orientation birefringence similar to the hot-stretched pure CTA. After extracting DIDA from the stretched films by immersion into an organic solvent, however, the films exhibit positive birefringence. Moreover, the magnitude of the birefringence increases with the wavelength, known as extraordinary dispersion, which is an essential property in the preparation of an ideal quarter-wave plate. Numerous ellipsoidal pores with micro-scale were detected in the film after the immersion, indicating that DIDA were segregated and formed ellipsoidal domains in the CTA matrix during annealing and stretching. These results indicate that extraordinary wavelength dispersion is given by the combinations of orientation birefringence from CTA and form birefringence from micropores. Furthermore, it was found that annealing time and stretching condition affect the phase separation as well as the shape and size of pores. PMID:25662683

  2. CHITOSAN-CELLULOSE COMPOSITE MATERIALS: PREPARATION, CHARACTERIZATION AND APPLICATION FOR REMOVAL OF MICROCYSTIN

    PubMed Central

    Tran, Chieu D.; Duri, Simon; Delneri, Ambra; Franko, Mladen

    2013-01-01

    We developed a simple and one-step method to prepare biocompatible composites from cellulose (CEL) and chitosan (CS). [BMIm+Cl−], an ionic liquid (IL), was used as a green solvent to dissolve and prepare the [CEL+CS] composites. Since majority (>88%) of IL used was recovered for reuse by distilling the aqueous washings of [CEL+CS], the method is recyclable. XRD, FTIR, NIR, 13C CP-MAS-NMR and SEM were used to monitor the dissolution and to characterize the composites. The composite was found to have combined advantages of their components: superior mechanical strength (from CEL) and excellent adsorption capability for microcystin-LR, a deadly toxin produced by cyanobacteria (from CS). Specifically, the mechanical strength of the composites increased with CEL loading; e.g., up to 5X increase in tensile strength was achieved by adding 80% of CEL into CS. Kinetic results of adsorption confirm that unique properties of CS remain intact in the composite, i.e., it is not only a very good adsorbent for microcystin but also is better than all other available adsorbents. For example, it can adsorb 4X times more microcystin than the best reported adsorbent. Importantly, the microcystin adsorbed can be quantitatively desorbed to enable the composite to be reused with similar adsorption efficiency. PMID:23542326

  3. Cellulose nanocrystals mediated assembly of graphene in rubber composites for chemical sensing applications.

    PubMed

    Cao, Jie; Zhang, Xinxing; Wu, Xiaodong; Wang, Shuman; Lu, Canhui

    2016-04-20

    In this study, we report a green assembled approach to prepare natural rubber (NR) composites with 3D interconnected graphene-based conductive networks. Taking advantage of the water-dispersity and amphiphilicity of cellulose nanocrystals (CNC), well suspended graphene@CNC aqueous colloids could be prepared by the CNC-mediated reduction of graphene oxide. When homogenized with NR latex under ultrasonication and subsequently co-coagulation, the graphene@CNC nanohybrids selectively located in the interstitial space between the NR latex microspheres and constructed an ordered 3D conductive structure. This unique 3D conductive network endowed the NR composites with remarkably enhanced electric conductivity (the percolation threshold is twofold lower than that of the conventional NR/graphene composites), mechanical properties and more importantly resistivity response to organic liquids. Our strategy offered a novel, simple and eco-friendly route for the fabrication of liquid sensors capable of sensing and discriminating various solvent leakage in chemical industry as well as environmental monitoring. PMID:26876831

  4. TEMPO-oxidized cellulose nanofibers

    NASA Astrophysics Data System (ADS)

    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.

  5. In situ synthesis of robust conductive cellulose/polypyrrole composite aerogels and their potential application in nerve regeneration.

    PubMed

    Shi, Zhuqun; Gao, Huichang; Feng, Jiao; Ding, Beibei; Cao, Xiaodong; Kuga, Shigenori; Wang, Yingjun; Zhang, Lina; Cai, Jie

    2014-05-19

    Nanostructured conductive polymers can offer analogous environments for extracellular matrix and induce cellular responses by electric stimulation, however, such materials often lack mechanical strength and tend to collapse under small stresses. We prepared electrically conductive nanoporous materials by coating nanoporous cellulose gels (NCG) with polypyrrole (PPy) nanoparticles, which were synthesized in situ from pyrrole monomers supplied as vapor. The resulting NCG/PPy composite hydrogels were converted to aerogels by drying with supercritical CO2, giving a density of 0.41-0.53 g cm(-3), nitrogen adsorption surface areas of 264-303 m(2) g(-1), and high mechanical strength. The NCG/PPy composite hydrogels exhibited an electrical conductivity of up to 0.08 S cm(-1). In vitro studies showed that the incorporation of PPy into an NCG enhances the adhesion and proliferation of PC12 cells. Electrical stimulation demonstrated that PC12 cells attached and extended longer neurites when cultured on NCG/PPy composite gels with DBSA dopant. These materials are promising candidates for applications in nerve regeneration, carbon capture, catalyst supports, and many others. PMID:24711342

  6. From cellulose fibrils to single chains: understanding cellulose dissolution in ionic liquids.

    PubMed

    Yuan, Xueming; Cheng, Gang

    2015-12-21

    Cellulose is the most abundant and renewable organic compound on Earth, it is however not soluble in common organic solvents and aqueous solutions. Cellulose dissolution is a key aspect to promote its value-added applications. Ionic liquids (ILs) have been shown to solubilize cellulose under relatively mild conditions. The easy processability of cellulose with ILs and their environmental-friendly nature prompted research in various fields such as biomass pretreatment and conversion, cellulose fiber and composite production, and chemical conversion of cellulose in ILs. Progress has been made on understanding the mechanism of cellulose dissolution in ILs, including the structural characteristics of ILs that are cellulose solvents, however many details remain unknown. In light of rapid development and importance of cellulose dissolution in the field of IL-based cellulose and biomass processing, it is necessary to provide an overview of current understanding of cellulose dissolution in ILs and outline possible future research trends. Recent literature studies suggest that synergistic effects between the anions and the cations of ILs need to be revealed, which requires refining the structure of cellulose elementary fibrils, simulation of more realistic cellulose fibrils and detailed studies on the solution structure of cellulose in ILs. After analyzing literature studies, three interacting modules are identified, which are crucial to understand the process of cellulose dissolution in ILs: (1) the structure of elementary fibrils; (2) solvation of cellulose in ILs; and (3) solution structure of cellulose solubilized in ILs. A coherent analysis of these modules will aid in better design of more efficient ILs and processes. PMID:26562500

  7. Development of new phosphated cellulose for application as an efficient biomaterial for the incorporation/release of amitriptyline.

    PubMed

    Bezerra, Roosevelt D S; Morais, Alan I S; Osajima, Josy A; Nunes, Livio C C; Silva Filho, Edson C

    2016-05-01

    In the last years has increased the study about the using of natural biopolymers and theirs derivatives in the removal (adsorption/incorporation) of contaminats of medium aqueous, and theirs utilization in the desorption (release) de drugs. However, there not in the literature studies about the utilization of the cellulose and cellulose phosphate in the adsorption (incorporation)/desorption (release) of the drug amitriptyline (AMI). Therefore, in this study was accomplished the synthesized of the phosphated cellulose (PC) through the reaction of pure cellulose (C) with sodium trimetaphosphate (P) under-reflux, for 4h and at 393K. The efficiency of the reaction was observed by XRD, TG/DTG, (31)P NMR and EDS. The adsorption study for the AMI in aqueous medium was carried out by varying the time, pH, concentration, temperature and ionic strength. The results showed that the PC showed a greater adsorption capacity of AMI than pure cellulose, presenting an increase of about 102.72% in the adsorption capacity of the drug by cellulose after the phosphating reaction. In desorption of drug from the surface of biomaterials was performed by varying the pH and time, where it was observed that PC showed a maximum release of 40.98%±0.31% at pH 7. PMID:26812113

  8. Application of Flumethrin Pour-On on Reservoir Dogs and Its Efficacy against Sand Flies in Endemic Focus of Visceral Leishmaniasis, Meshkinshahr, Iran

    PubMed Central

    Jalilnavaz, Mohammad Reza; Abai, Mohammad Reza; Vatandoost, Hassan; Mohebali, Mehdi; Akhavan, Amir Ahmad; Zarei, Zabihollah; Rafizadeh, Sayena; Bakhshi, Hassan; Rassi, Yaver

    2016-01-01

    Background: Visceral leishmaniasis (VL) is one of the most important parasitic zoonotic diseases in the world. Domestic dogs are the main domestic reservoirs of VL in endemic foci of Iran. Various methods, including vaccination, treatment of dogs, detection and removal of infected dogs have different results around the world. General policy on control of canine visceral leishmaniasis is protection of them from sand fly bites. The aim of this study was evaluation of pour-on application of flumethrin on dogs against blood-feeding and mortality of field-caught sand flies. Methods: Once every 20 days from May untill September 2013, the treated and control dogs were exposed with field caught sandflies for 2 hours under bed net traps. After the exposure time, both alive and dead sand flies were transferred in netted cups to the laboratory. The mortality rate of them was assessed after 24 hours. The blood-fed or unfed conditions were determined 2 hours after exposure to the dogs under stereomicroscope. Results: The blood feeding index was varied from 12.0 to 25.0 % and 53.0 to 58.0 % for treated and control dogs respectively (P< 0.0001). The blood feeding inhibition was 75.0–87.0 % and 41.0–46.0 % for the control and treated dogs (P< 0.0001), respectively.The total mortality rate was 94.0–100 % and 19.0–58.0 % respectively for the treated and control groups (P< 0.001). Conclustion: Application of pour-on flumethrin on dogs caused 90–100 % mortality until 2.5 month and inhibited the blood-feeding of sand flies. PMID:27047974

  9. Cellulose synthase interacting protein

    PubMed Central

    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 recent identification of a novel component. CSI1, which encodes CESA interacting protein 1 (CSI1) in Arabidopsis. CSI1, as the first non-CESA proteins associated with cellulose synthase complexes, opens up many opportunities. PMID:21150290

  10. Water dispersible microbicidal cellulose acetate phthalate film

    PubMed Central

    Neurath, A Robert; Strick, Nathan; Li, Yun-Yao

    2003-01-01

    Background Cellulose acetate phthalate (CAP) has been used for several decades in the pharmaceutical industry for enteric film coating of oral tablets and capsules. Micronized CAP, available commercially as "Aquateric" and containing additional ingredients required for micronization, used for tablet coating from water dispersions, was shown to adsorb and inactivate the human immunodeficiency virus (HIV-1), herpesviruses (HSV) and other sexually transmitted disease (STD) pathogens. Earlier studies indicate that a gel formulation of micronized CAP has a potential as a topical microbicide for prevention of STDs including the acquired immunodeficiency syndrome (AIDS). The objective of endeavors described here was to develop a water dispersible CAP film amenable to inexpensive industrial mass production. Methods CAP and hydroxypropyl cellulose (HPC) were dissolved in different organic solvent mixtures, poured into dishes, and the solvents evaporated. Graded quantities of a resulting selected film were mixed for 5 min at 37°C with HIV-1, HSV and other STD pathogens, respectively. Residual infectivity of the treated viruses and bacteria was determined. Results The prerequisites for producing CAP films which are soft, flexible and dispersible in water, resulting in smooth gels, are combining CAP with HPC (other cellulose derivatives are unsuitable), and casting from organic solvent mixtures containing ≈50 to ≈65% ethanol (EtOH). The films are ≈100 µ thick and have a textured surface with alternating protrusions and depressions revealed by scanning electron microscopy. The films, before complete conversion into a gel, rapidly inactivated HIV-1 and HSV and reduced the infectivity of non-viral STD pathogens >1,000-fold. Conclusions Soft pliable CAP-HPC composite films can be generated by casting from organic solvent mixtures containing EtOH. The films rapidly reduce the infectivity of several STD pathogens, including HIV-1. They are converted into gels and thus do not

  11. Residues of zeta-cypermethrin in bovine tissues and milk following pour-on and spray application.

    PubMed

    Rothwell, J T; Burnett, T J; Hacket, K; Chevis, R; Lowe, L B

    2001-11-01

    The depletion of zeta-cypermethrin residues in bovine tissues and milk was studied. Beef cattle were treated three times at 3-week intervals with 1 ml 10 kg-1 body weight of a 25 g litre-1 or 50 g litre-1 pour-on formulation (2.5 and 5.0 mg zeta-cypermethrin kg-1 body weight) or 100 mg kg-1 spray to simulate a likely worst-case treatment regime. Friesian and Jersey dairy cows were treated once with 2.5 mg zeta-cypermethrin kg-1 in a pour-on formulation. Muscle, liver and kidney residue concentrations were generally less than the limit of detection (LOD = 0.01 mg kg-1). Residues in renal-fat and back-fat samples from animals treated with 2.5 mg kg-1 all exceeded the limit of quantitation (LOQ = 0.05 mg kg-1), peaking at 10 days after treatment. Only two of five kidney fat samples were above the LOQ after 34 days, but none of the back-fat samples exceeded the LOQ at 28 days after treatment. Following spray treatments, fat residues were detectable in some animals but were below the LOQ at all sampling intervals. Zeta-cypermethrin was quantifiable (LOQ = 0.01 mg kg-1) in only one whole-milk sample from the Friesian cows (0.015 mg kg-1, 2 days after treatment). In whole milk from Jersey cows, the mean concentration of zeta-cypermethrin peaked 1 day after treatment, at 0.015 mg kg-1, and the highest individual sample concentration was 0.025 mg kg-1 at 3 days after treatment. Residues in milk were not quantifiable beginning 4 days after treatment. The mean concentrations of zeta-cypermethrin in milk fat from Friesian and Jersey cows peaked two days after treatment at 0.197 mg kg-1 and 0.377 mg kg-1, respectively, and the highest individual sample concentrations were 2 days after treatment at 0.47 mg kg-1 and 0.98 mg kg-1, respectively. PMID:11721528

  12. Cellulases from Penicillium funiculosum: production, properties and application to cellulose hydrolysis.

    PubMed

    de Castro, Aline Machado; de Albuquerque de Carvalho, Marcelle Lins; Leite, Selma Gomes Ferreira; Pereira, Nei

    2010-02-01

    The objective of this work is to investigate the utilization of two abundant agricultural residues in Brazil for the production and application of cellulolytic enzymes. Different materials obtained after pretreatment of sugarcane bagasse, as well as pure synthetic substrates, were considered for cellulase production by Penicillium funiculosum. The best results for FPase (354 U L(-1)) and beta-glucosidase (1,835 U L(-1)) production were observed when sugarcane bagasse partially delignified cellulignin (PDC) was used. The crude extract obtained from PDC fermentation was then partially characterized. Optimal temperatures for cellulase action ranged from 52 to 58 degrees C and pH values of around 4.9 contributed to maximum enzyme activity. At 37 degrees C, the cellulases were highly stable, losing less than 15% of their initial activity after 23 h of incubation. There was no detection of proteases in the P. funiculosum extract, but other hydrolases, such as endoxylanases, were identified (147 U L(-1)). Finally, when compared to commercial preparations, the cellulolytic complex from P. funiculosum showed more well-balanced amounts of beta-glucosidase, endo- and exoglucanase, resulting in the desired performance in the presence of a lignocellulosic material. Cellulases from this filamentous fungus had a higher glucose production rate (470 mg L(-1) h(-1)) when incubated with corn cob than with Celluclast, GC 220 and Spezyme (312, 454 and 400 mg L(-1) h(-1), respectively). PMID:19902281

  13. Nucleic acids encoding a cellulose binding domain

    DOEpatents

    Shoseyov, Oded; Shpiegl, Itai; Goldstein, Marc A.; Doi, Roy H.

    1996-01-01

    A cellulose binding domain (CBD) having a high affinity for crystalline cellulose and chitin is disclosed, along with methods for the molecular cloning and recombinant production thereof. Fusion products comprising the CBD and a second protein are likewise described. A wide range of applications are contemplated for both the CBD and the fusion products, including drug delivery, affinity separations, and diagnostic techniques.

  14. Nucleic acids encoding a cellulose binding domain

    DOEpatents

    Shoseyov, O.; Shpiegl, I.; Goldstein, M.A.; Doi, R.H.

    1996-03-05

    A cellulose binding domain (CBD) having a high affinity for crystalline cellulose and chitin is disclosed, along with methods for the molecular cloning and recombinant production. Fusion products comprising the CBD and a second protein are likewise described. A wide range of applications are contemplated for both the CBD and the fusion products, including drug delivery, affinity separations, and diagnostic techniques. 15 figs.

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

    PubMed Central

    Endler, Anne; Schneider, Rene; Kesten, Christopher; Lampugnani, Edwin R.; 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 with the CesA complex and microtubules, and that we named COMPANIONS OF CELLULOSE SYNTHASE (CC). The CC proteins protect the cellulose synthesising capacity of Arabidopsis seedlings during exposure to adverse environmental conditions by enhancing microtubule dynamics. In this paper we provide cell biology and genetic evidence that the CSI1 and the CC proteins fulfil distinct functions during cellulose synthesis. We also show that the CC proteins are necessary to aid cellulose synthesis when components of the CesA complex are impaired. These data indicate that the CC proteins have a broad role in aiding cellulose synthesis during environmental changes and when core complex components are non-functional. PMID:26829351

  16. Developpement et application d'un systeme mobile de laser terrestre pour quantifier le bilan sedimentaire des plages

    NASA Astrophysics Data System (ADS)

    Van-Wierts, Stefanie

    Au Québec maritime, l'érosion côtière est une problématique d'envergure, notamment sur les côtes de formations meubles. Les plages ont un rôle de zone tampon ayant comme fonction naturelle d'absorber l'énergie des vagues et donc d'assurer l'équilibre de certains écosystèmes et le maintien de l'écoumène en réduisant l'érosion de la côte. Les méthodes d'acquisition conventionnelles ne permettent pas de quantifier convenablement les changements morphosédimentaires d'une plage à l'échelle des cellules hydrosédimentaires. Le manque de méthode d'acquisition fiable et de données quantitatives mène à une surestimation ou à une sous-estimation de la disponibilité sédimentaire d'un système côtier. Pour contrer ces lacunes et afin de minimiser les coûts d'acquisition, un nouveau système mobile de LiDAR terrestre a été mis en place, permettant d'acquérir des données topographiques de l'estran, de la haute plage et des falaises. Le système multicapteurs comprend un LiDAR, un système de navigation à haute précision (IMU et D-GPS) et une caméra. L'ensemble des instruments et capteurs sont montés sur un véhicule de type tout-terrain. Le système a été évalué sur la zone côtière de la péninsule de Manicouagan. La comparaison des données LiDAR avec 1 050 points de référence géopositionnés au D-GPS montre une erreur verticale moyenne de 0,1 m sur les secteurs de plage. Les résultats montrent que le volume sédimentaire moyen des plages devant les zones où la ligne de rivage présente un ouvrage de protection en enrochement (12 m 3/m) est plus de trois fois plus faible que devant les secteurs à l'état naturel (35,5 m3/m). La moyenne des secteurs en transition, constituant les segments où une zone artificielle et une zone naturelle se chevauchent présentent un volume moyen de 28 m3/m. Aussi, les plages devant les secteurs anthropisés sont en moyenne près de 2 fois plus étroites (12,7 m) que devant les secteurs naturels (25

  17. Quantitative analysis of cellulose-reducing ends.

    PubMed

    Kongruang, Sasithorn; Han, Myung Joo; Breton, Claudia Isela Gil; Penner, Michael H

    2004-01-01

    Methods for the quantification of total and accessible reducing ends on traditional cellulose substrates have been evaluated because of their relevance to enzyme-catalyzed cellulose saccharificaion. For example, quantification of accessible reducing ends is likely to be the most direct measure of substrate concentration for the exo-acting, reducing end-preferring cellobiohydrolases. Two colorimetric assays (dinitrosalicylic acid [DNS] and bicinchoninic acid [BCA] assay ) and a radioisotope approach (NaB3H4 labeling) were evaluated for this application. Cellulose substrates included microcrystalline celluloses, bacterial celluloses, and filter paper. Estimates of the number of reducing ends per unit mass cellulose were found to be dependent on the assay system (i.e. the DNS and BCA assays gave strikingly different results). DNS-based values were several-fold higher than those obtained using the BCA assay, with fold-differences being substrate specific. Sodium borohydride reduction of celluloses, using cold or radiolabeled reagent under relatively mild conditions, was used to assess the number of surface (solvent-accessible) reducing ends. The results indicate that 30-40% of the reducing ends on traditional cellulose substrates are not solvent accessible; that is, they are buried in the interior of cellulose structures and thus not available to exo-acting enzymes. PMID:15054208

  18. Tubular structured hierarchical mesoporous titania material derived from natural cellulosic substances and application as photocatalyst for degradation of methylene blue

    SciTech Connect

    Huang, Haiqing; Liu, Xiaoyan; Huang, Jianguo

    2011-11-15

    Graphical abstract: Bio-inspired, tubular structured hierarchical mesoporous titania material with high photocatalytic activity under UV light was fabricated employing natural cellulosic substance (cotton) as hard template and cetyltrimethylammonium bromide (CTAB) surfactant as soft template using a one-pot sol-gel method. Highlights: {yields} Tubular structured mesoporous titania material was fabricated by sol-gel method. {yields} The titania material faithfully recorded the hierarchical structure of the template substrate (cotton). {yields} The titania material exhibited high photocatalytic activity in decomposition of methylene blue. -- Abstract: Bio-inspired, tubular structured hierarchical mesoporous titania material was designed and fabricated employing natural cellulosic substance (cotton) as hard template and cetyltrimethylammonium bromide (CTAB) surfactant as soft template by one-pot sol-gel method. The tubular structured hierarchical mesoporous titania material processes large specific surface area (40.23 m{sup 2}/g) and shows high photocatalytic activity in the photodegradation of methylene blue under UV light irradiation.

  19. Separation of acid and sugar by ion exclusion chromatography. An application in the conversion of cellulose to ethanol

    SciTech Connect

    Hartfield, S.; Hester, R.

    1993-12-31

    The production of fuel grade alcohol by fermentation from sugars obtained by the acid hydrolysis of cellulose has been hindered by costly methods of cleansing the acid in the sugar stream. An economical and environmentally acceptable acid-sugar separation process based on ion exclusion chromatography has been developed and analyzed. This process recovers the acid for reuse in hydrolysis without producing landfill waste allowing a concentrated acid hydrolysis process to be commercially feasible.

  20. Molecular counting by photobleaching in protein complexes with many subunits: best practices and application to the cellulose synthesis complex

    PubMed Central

    Chen, Yalei; Deffenbaugh, Nathan C.; Anderson, Charles T.; Hancock, William O.

    2014-01-01

    The constituents of large, multisubunit protein complexes dictate their functions in cells, but determining their precise molecular makeup in vivo is challenging. One example of such a complex is the cellulose synthesis complex (CSC), which in plants synthesizes cellulose, the most abundant biopolymer on Earth. In growing plant cells, CSCs exist in the plasma membrane as six-lobed rosettes that contain at least three different cellulose synthase (CESA) isoforms, but the number and stoichiometry of CESAs in each CSC are unknown. To begin to address this question, we performed quantitative photobleaching of GFP-tagged AtCESA3-containing particles in living Arabidopsis thaliana cells using variable-angle epifluorescence microscopy and developed a set of information-based step detection procedures to estimate the number of GFP molecules in each particle. The step detection algorithms account for changes in signal variance due to changing numbers of fluorophores, and the subsequent analysis avoids common problems associated with fitting multiple Gaussian functions to binned histogram data. The analysis indicates that at least 10 GFP-AtCESA3 molecules can exist in each particle. These procedures can be applied to photobleaching data for any protein complex with large numbers of fluorescently tagged subunits, providing a new analytical tool with which to probe complex composition and stoichiometry. PMID:25232006

  1. Development of nonflammable cellulosic foams

    NASA Technical Reports Server (NTRS)

    Luttinger, M.

    1972-01-01

    The development of a moldable cellulosic foam for use in Skylab instrument storage cushions is considered. Requirements include density of 10 lb cu ft or less, minimal friability with normal handling, and nonflammability in an atmosphere of 70 percent oxygen and 30 percent nitrogen at 6.2 psia. A study of halogenated foam components was made, including more highly chlorinated binders, halogen-containing additives, and halogenation of the cellulose. The immediate objective was to reduce the density of the foam through reduction in inorganic phosphate without sacrificing flame-retarding properties of the foams. The use of frothing techniques was investigated, with particular emphasis on a urea-formaldehyde foam. Halogen-containing flame retardants were deemphasized in favor of inorganic salts and the preparation of phosphate and sulphate esters of cellulose. Utilization of foam products for civilian applications was also considered.

  2. Single-cell protein from waste cellulose

    NASA Technical Reports Server (NTRS)

    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. Application of silicified microcrystalline cellulose (Prosolv) as a polymer carrier of Epilobium parviflorum Schreb. extract in oral solid drug form.

    PubMed

    Marczyński, Zbigniew; Zgoda, Marian Mikołaj; Jambor, Jerzy

    2007-01-01

    Direct tableting is simpler and more cost-effective from the point of view of good manufacturing practice (GMP) than wet granulation or dry compacting. Thus, pharmaceutical industry more and more frequently uses this particular process. Only few therapeutic substances form under compression tablets meeting current requirements. Very often additional adjuvants must be used. These substances have the ability of increasing plastic deformation and tablet mass liquidity. Microcrystalline cellulose belongs to the best adjuvant substances of the type. It has binding, disintegrating and improving liquidity properties. This study aims at investigating the usefulness of selected high-molecular substances with particular consideration of silici-fled microcrystalline cellulose (Prosolv) and croscarmellose sodium (Vivasol) as a carrier of E. parviflorum Schreb. extract in oral solid drug form in the process of direct tab-leting. The manufactured tablets were subjected to morphological tests and pharmaceutical availability tests of biologically active substances from a tablet to the acceptor fluid. The investigations were based on general and detailed principles of Polish Pharmacopoeia VI. The obtained results allow to state that the applied high-molecular adjuvant substances proved to be useful in adequate proportions in the production of tablets from dry extract from Epilobium parviflo-rum Schreb. Generally, a significant shortening of the tablets disintegration time was obtained as compared to earlier produced tablets with the method of initial granulation. The tablets formed from E. parviflorum Schreb. extract with silicified microcrystalline cellulose (Prosolv SMCC 50) and croscarmellose sodium can be included into preparations of short dissolution time of the therapeutic substance. PMID:17957946

  4. Supercritical fluid assisted process for the generation of cellulose acetate loaded structures, potentially useful for tissue engineering applications.

    PubMed

    Cardea, Stefano; Scognamiglio, Mariarosa; Reverchon, Ernesto

    2016-02-01

    Supercritical CO2 phase inversion offers an alternative to obtain solvent free structures with short processing times and preservation of the morphology. We prepared cellulose acetate structures loaded with drug (ibuprofen) to perform experiments at pressures and temperatures ranging between 150 and 250 bars and 35 and 55 °C. The structures were properly characterized by SEM, EDX and DSC; drug controlled release experiments were also performed. Analyses showed that the operating conditions strongly influenced the structure morphology, porosity and drug release profiles. Indeed, connected microparticles, nanofibrous networks and cellular membranes were produced, which have generated different drug release profiles. PMID:26652399

  5. [Terahertz and Infrared Spectroscopic Investigation of Cellulose].

    PubMed

    Qiu, Guo-hua; Zhang, Le; Shentu, Nan-ying

    2016-03-01

    To investigate the Terahertz's application prospect, corn, wheat husk and reed were used to detect their Terahertz Time Domain Spectroscopy, and be compared with that of cellulose powder. The experimental results show that all of their absorption peaks exist at 1.75, 1.62, 1.1, and 0.7 THz. Absorption intensity of cellulose powder, corn, wheat husk and reed were compared in some frequencies points. It finds that corn, wheat husk and reed have higher absorption intensity than cellulose powder in early frequency domain. However, absorption intensity of cellulose powder is the strongest at 1.62 THz. Cellulose content in corn, wheat husk and reed were detected by using the method of chemical analysis. The peaks of absorption coefficient are related to their cellulose content at this frequency. It shows that plant cellulose occur lattice vibration in the frequency. Deformation, bending, flexing, and other changes appear to their functional keys. Quantum chemical calculation was carried out by using density functional theory to cellulose and the structure diagram of cellulose molecular formula was obtained. It also finds some absorption peaks exist at 0.7, 1.1, and 1.75 THz. Characterization of cellulose clusters mainly includes CH2, OH, CH, and so on. Glucose hydroxyl radical on the ring is active in the cellulose chain. Where hydroxyl related chemical reaction can occur, Hydroxyl can also be integrated into the intermolecular and intramolecular hydrogen bond. Terahertz wave can promote hydrogen bond vibration. This kind of vibration is weak in the intermolecular interaction. The vibration and rotating happen in dipole transition. The crystal lattice rotates and is absorptive in low frequency, and large molecular skeleton vibrates. All of them can show different intensity and position of the absorption peak in the terahertz band. Corn and cellulose were analyzed by infrared spectrum. The reverse and vibration mode of cellulose was discussed. The absorption peak is

  6. Electrically conductive cellulose composite

    DOEpatents

    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.

  7. Critère de fatigue polycyclique pour des matériaux anisotropes : application aux monocristaux

    NASA Astrophysics Data System (ADS)

    Cano, Florian; Constantinescu, Andrei; Maitournam, Habibou

    2004-02-01

    The high-cycle fatigue criteria based on a macroscopic-mesoscopic scale interpretation, initiated by Dang Van, were used essentially for polycrystalline materials. In the existing criteria the material isotropy at both mesoscopic and macroscopic scales plays a key role. The purpose of this paper is to revisit the macroscopic to mesoscopic fatigue approach taking into account the material anisotropy and some results obtained by Bui. The possible applications are some anisotropic steels or monocrystalline structures such as stitanium turbine blades. To cite this article: F. Cano et al., C. R. Mecanique 332 (2004).

  8. Properties of a recombinant beta-glucosidase from polycentric anaerobic fungus Orpinomyces PC-2 and its application for cellulose hydrolysis.

    PubMed

    Li, Xin-Liang; Ljungdahl, Lars G; Ximenes, Eduardo A; Chen, Huizhong; Felix, Carlos R; Cotta, Michael A; Dien, Bruce S

    2004-01-01

    A beta-glucosidase (BglA, EC 3.2.1.21) gene from the polycentric anaerobic fungus Orpinomyces PC-2 was cloned and sequenced. The enzyme containing 657 amino acid residues was homologous to certain animal, plant, and bacterial beta-glucosidases but lacked significant similarity to those from aerobic fungi. Neither cellulose- nor protein-binding domains were found in BglA. When expressed in Saccharomyces cerevisiae, the enzyme was secreted in two forms with masses of about 110 kDa and also found in two forms associated with the yeast cells. Km and Vmax values of the secreted BglA were 0.762 mM and 8.20 micromol/(min x mg), respectively, with p-nitrophenyl-beta-D-glucopyranoside (pNPG) as the substrate and 0.310 mM and 6.45 micromol/(min.mg), respectively, for the hydrolysis of cellobiose. Glucose competitively inhibited the hydrolysis of pNPG with a Ki of 3.6 mM. Beta-glucosidase significantly enhanced the conversion of cellulosic materials into glucose by Trichoderma reesei cellulase preparations, demonstrating its potential for use in biofuel and feedstock chemical production. PMID:15054209

  9. Properties and Structure of Cellulose Nanocrystal Hydrogels for Potential Applications as Three-Dimensional Artificial Extracellular Matrices

    NASA Astrophysics Data System (ADS)

    Sriskandha, Shivanthi Easwari

    This thesis describes the preparation of hydrogels of cellulose nanocrystals (CNCs) into environments that would support the growth of cells either by (i) adding Hank's Balanced Salt Solution to CNC suspensions to induce gelation or (ii) by modifying the surface of CNCs with a thermoresponsive polymer to stimulate gelation in situ. Fibroblast cells were grown within suspensions of CNCs of varying concentrations and the mechanical properties and structure of the resulting suspensions were examined. The viability of the cells cultured within the cellulose nanocrystal matrix was evaluated using two spectroscopic techniques: UV-Vis absorption and fluorescence confocal microscopy. The synthesis of thermoresponsive CNCs was conducted via an atom-transfer radical-polymerization-based living radical polymerization. The thermoresponsive polymers, poly(N-isopropylacrylamide) and poly(N -isopropylacrylamide-co-polyethylene glycol methacrylate) were polymerized from the surface of initiator-modified CNCs. The resulting polymer was characterized by attenuated total reflectance Fourier transform infrared spectroscopy, proton nuclear magnetic resonance and dynamic light scattering.

  10. Preparation of cellulose nanocrystals from asparagus (Asparagus officinalis L.) and their applications to palm oil/water Pickering emulsion.

    PubMed

    Wang, Wenhang; Du, Guanhua; Li, Cong; Zhang, Hongjie; Long, Yunduo; Ni, Yonghao

    2016-10-20

    Nano cellulosic materials as promising emulsion stabilizers have attracted great interest in food industry. In this paper, five different sized cellulose nanocrystals (CNC) samples were prepared from stem of Asparagus officinalis L. using the same sulfuric acid hydrolysis conditions but different times (1.5, 2, 2.5, 3.0, and 3.5h). The sizes of these CNC ranged from 178.2 to 261.8nm, with their crystallinity of 72.4-77.2%. The CNC aqueous dispersions showed a typical shear thinning behavior. In a palm oil/water (30/70, v/v) model solution, stable Pickering emulsions were formed with the addition of CNC, and their sizes are in the range of 1-10μm based on the optical and confocal laser scanning microscopy (CLSM) observation. The CNC sample prepared at 3h hydrolysis time, showed a relative efficient emulsion capacity for palm oil droplets, among these CNCs. Other parameters including the CNC, salt, and casein concentrations on the emulsion stability were studied. PMID:27474537

  11. Application of the central composite design to study the flocculation of an anionic azo dye using quaternized cellulose nanofibrils.

    PubMed

    Quinlan, Patrick James; Tanvir, Aafia; Tam, Kam Chiu

    2015-11-20

    Cellulose nanofibrils (CNF) grafted with glycidyltrimethylammonium chloride (GTMAC), containing quaternary ammonium contents of 0.44 (QCNF-1), 1.47 (QCNF-2), and 2.28 (QCNF-3) meqg(-1), were evaluated as flocculants for the removal of Reactive Orange 16, an anionic azo dye, from aqueous solution. A rotatable and orthogonal central composite design was used to examine the performance of QCNFs under a range of experimental conditions. Removal efficiencies at the centre point of the design space were found to be 236.9±7.8, 254.2±3.8, and 264.6±2.8mgg(-1) for QCNF-1, QCNF-2 and QCNF-3, respectively. The highest removal efficiency, 295.1mgg(-1), was observed when using QCNF-3 at a low monovalent salt concentration. The QCNF reported herein provides a sustainable and biodegradable alternative to traditional synthetic flocculants for the decolorization of dye-containing effluents. PMID:26344258

  12. Purification of aqueous cellulose ethers

    SciTech Connect

    Bartscherer, K.A.; de Pablo, J.J.; Bonnin, M.C.; Prausnitz, J.M.

    1990-07-01

    Manufacture of cellulose ethers usually involves high amounts of salt by-products. For application of the product, salt must be removed. In this work, we have studied the injection of high-pressure CO{sub 2} into an aqueous polymer-salt solution; we find that upon addition of isopropanol in addition to CO{sub 2}, the solution separates into two phases. One phase is rich in polymer and water, and the other phase contains mostly isopropanol, water and CO{sub 2}. The salt distributes between the two phases, thereby offering interesting possibilities for development of a new purification process for water-soluble polymers. This work presents experimental phase-equilibrium data for hydroxyethyl cellulose and sodium carboxymethyl cellulose with sodium acetate and potassium sulfate, respectively, in the region 40{degree}C and 30 to 80 bar. Based on these data, we suggest a process for the manufacture and purification of water-soluble cellulose ethers. 15 refs., 14 figs., 9 tabs.

  13. Radiation degradation of cellulose

    NASA Astrophysics Data System (ADS)

    Leonhardt, J.; Arnold, G.; Baer, M.; Langguth, H.; Gey, M.; Hübert, S.

    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.

  14. Cellulose-silica aerogels.

    PubMed

    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

  15. Enhancement of Cellulose Degradation by Cattle Saliva

    PubMed Central

    Seki, Yasutaka; Kikuchi, Yukiko; Kimura, Yoshihiro; Yoshimoto, Ryo; Takahashi, Masatoshi; Aburai, Kenichi; Kanai, Yoshihiro; Ruike, Tatsushi; Iwabata, Kazuki; Sugawara, Fumio; Sakai, Hideki; Abe, Masahiko; Sakaguchi, Kengo

    2015-01-01

    Saccharification of cellulose is a promising technique for producing alternative source of energy. However, the efficiency of conversion of cellulose into soluble sugar using any currently available methodology is too low for industrial application. Many additives, such as surfactants, have been shown to enhance the efficiency of cellulose-to-sugar conversion. In this study, we have examined first whether cattle saliva, as an additive, would enhance the cellulase-catalyzed hydrolysis of cellulose, and subsequently elucidated the mechanism by which cattle saliva enhanced this conversion. Although cattle saliva, by itself, did not degrade cellulose, it enhanced the cellulase-catalyzed degradation of cellulose. Thus, the amount of reducing sugar produced increased approximately 2.9-fold by the addition of cattle saliva. We also found that non-enzymatic proteins, which were present in cattle saliva, were responsible for causing the enhancement effect. Third, the mechanism of cattle saliva mediated enhancement of cellulase activity was probably similar to that of the canonical surfactants. Cattle saliva is available in large amounts easily and cheaply, and it can be used without further purification. Thus, cattle saliva could be a promising additive for efficient saccharification of cellulose on an industrial scale. PMID:26402242

  16. Cellulose nanofibrils aerogels generated from jute fibers.

    PubMed

    Lin, Jinyou; Yu, Liangbo; Tian, Feng; Zhao, Nie; Li, Xiuhong; Bian, Fenggang; Wang, Jie

    2014-08-30

    In this work, we report the cellulose nanofibrils extracted from the pristine jute fibers via the pretreatments followed by the TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical)-mediated oxidation and mechanical disintegration. The effects of pretreatments by using the NaOH solution and dimethyl sulfoxide solvent on the fiber morphology and macro/micro-structures were investigated by polarizing microscope and synchrotron radiation wide/small-angle X-ray scattering (WAXS/SAXS). The cellulose nanofibrils exhibit a diameter ranging from 5 nm to 20 nm and a length of several micrometers, which have been assembled into cellulose aerogels by the lyophilization of as-prepared nanofibrils dispersions with various concentrations. The results indicated that the hierarchical structures of as-prepared cellulose aerogels were dependent on the dispersion concentrations. The WAXS results show that the typical cellulose aerogels are coexistence of cellulose I and cellulose II, which has a great promise for many potential applications, such as pharmaceutical, liquid filtration, catalysts, bio-nanocomposites, and tissue engineering scaffolds. PMID:24815398

  17. Des ballons pour demain

    NASA Astrophysics Data System (ADS)

    Régipa, R.

    A partir d'une théorie sur la détermination des formes et des contraintes globales d'un ballon de révolution, ou s'en rapprochant, une nouvelle famille de ballons a été définie. Les ballons actuels, dits de ``forme naturelle'', sont calculés en général pour une tension circonférencielle nulle. Ainsi, pour une mission donnée, la tension longitudinale et la forme de l'enveloppe sont strictement imposées. Les ballons de la nouvelle génération sont globalement cylindriques et leurs pôles sont réunis par un câble axial, chargé de transmettre une partie des efforts depuis le crochet (pôle inférieur), directement au pôle supérieur. De plus, la zone latérale cylindrique est soumise à un faible champ de tensions circonférencielles. Ainsi, deux paramètres permettent de faire évoluer la distribution des tensions et la forme de l'enveloppe: - la tension du câble de liaison entre pôles (ou la longueur de ce câble) - la tension circonférencielle moyenne désirée (ou le rayon du ballon). On peut donc calculer et réaliser: - soit des ballons de forme adaptée, comme les ballons à fond plat pour le bon fonctionnement des montgolfières infrarouge (projet MIR); - soit des ballons optimisés pour une bonne répartition des contraintes et une meilleure utilisation des matériaux d'enveloppe, pour l'ensemble des programmes stratosphériques. Il s'ensuit une économie sensible des coûts de fabrication, une fiabilité accrue du fonctionnement de ces ballons et une rendement opérationnel bien supérieur, permettant entre autres, d'envisager des vols à très haute altitude en matériaux très légers.

  18. Highly thermostable and pH-stable cellulases from Aspergillus niger NS-2: properties and application for cellulose hydrolysis.

    PubMed

    Bansal, Namita; Janveja, Chetna; Tewari, Rupinder; Soni, Raman; Soni, Sanjeev Kumar

    2014-01-01

    Optimization of cultural conditions for enhanced cellulase production by Aspergillus niger NS-2 were studied under solid-state fermentation. Significant increase in yields (CMCase 463.9 ± 20.1 U/g, FPase 101.1 ± 3.5 U/g and β-glucosidase 99 ± 4.0 U/g) were obtained under optimized conditions. Effect of different nutritional parameters was studied to induce the maximum production of cellulase complex. Scale-up studies for enzyme production process were carried out. Characterization studies showed that enzymes produced by A. niger NS-2 were highly temperature- and pH stable. At 50 °C, the half life for CMCase, FPase, β-glucosidase were approximately 240 h. Cellulases from A. niger NS-2 were stable at 35 °C for 24 h over a broader pH range of 3.0-9.0. We examined the feasibility of using steam pretreatment to increase the saccharification yields from various lignocellulosic residues for sugar release which can potentially be used in bioethanol production. Saccharification of pretreated dry potato peels, carrot peels, composite waste mixture, orange peels, onion peels, banana peels, pineapple peels by crude enzyme extract from A. niger NS-2, resulted in very high cellulose conversion efficiencies of 92-98 %. PMID:24052336

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

    PubMed Central

    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

  20. Cellulosic nanowhiskers. Theory and application of light scattering from polydisperse spheroids in the Rayleigh-Gans-Debye regime.

    PubMed

    Braun, Birgit; Dorgan, John R; Chandler, John P

    2008-04-01

    Mathematical treatment of light scattering within the Rayleigh-Gans-Debye limit for spheroids with polydispersity in both length and diameter is developed and experimentally tested using cellulosic nanowhiskers (CNW). Polydispersity indices are obtained by fitting the theoretical formfactor to experimental data. Good agreement is achieved using a polydispersity of 2.3 for the length, independent of the type of acid used. Diameter polydispersities are 2.1 and 3.0 for sulfuric and hydrochloric acids, respectively. These polydispersities allow the determination of average dimensions from the z-average mean-square radius (z) and the weight-average molecular weight (M w) easily obtained from Berry plots. For cotton linter hydrolyzed by hydrochloric acid, the average length and diameter are 244 and 22 nm. This compares to average length and diameter of 272 and 13 nm for sulfuric acid. This study establishes a new light-scattering methodology as a quick and robust tool for size characterization of polydisperse spheroidal nanoparticles. PMID:18357993

  1. Effect of pH on cellulase production and morphology of Trichoderma reesei and the application in cellulosic material hydrolysis.

    PubMed

    Li, Chen; Yang, Zhenhua; Zhang, Ronglin He Can; Zhang, Dongyuan; Chen, Shulin; Ma, Lijuan

    2013-12-01

    A low-cost of cellulase achieved through improving fermentation technology remains a key requirement for commercialization of cellulosic biofuels and biochemicals. pH plays a very important role in the process of cellulase synthesis by Trichoderma reesei. In this work, effects of pH on the production and production rates of three cellulase components (endoglucanase, exoglucanase, β-glucosidase) and mycelial morphology were studied. Production rates of the cellulase components were kept highest and the mycelial morphology was maintained at the optimal status by developing a phased pH control strategy in order to improve cellulase production. Cellulase production in terms of filter paper activity and β-glucosidase production in batch fermentation increased 17.6% and 22%. Saccharification efficiency of the enzyme obtained by pH control was evaluated by hydrolyzing pretreated corn cob. Saccharification yield increased significantly (up to 26.2%) compared with that without pH control. These results add new knowledge on approach for improving cellulase production. PMID:24129314

  2. VIEW POURING PLATFORM SHOWING MOLD POURING JACKETS AND WEIGHTS AND, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW POURING PLATFORM SHOWING MOLD POURING JACKETS AND WEIGHTS AND, IN THE FOREGROUND, SAND RETURN FROM THE SHAKEOUT ACTUATING A SIMPLE LEVER SYSTEM THAT ADDED FRESH WATER TO THE SAND IN PREPARATION FOR ITS REUSE. - Southern Ductile Casting Company, Centerville Foundry, 101 Airport Road, Centreville, Bibb County, AL

  3. Wrinkle resistant cellulosic textiles

    SciTech Connect

    Kitchens, J.D.; Patton, R.T.; Nadar, R.S.

    1991-08-27

    This patent describes a process for treating a cellulosic textile material so as to impart wrinkle resistance and smooth drying properties. It comprises treating the cellulosic textile material with an aqueous solution comprising trans-1,2,3,4-cyclobutane tetracarboxylic acid, and a curing catalyst, and heating the treated material so as to produce esterification and crosslinking of the material with the acid.

  4. Preparation and characterization of hydroxypropyl methyl cellulose films containing stable BCS Class II drug nanoparticles for pharmaceutical applications.

    PubMed

    Sievens-Figueroa, Lucas; Bhakay, Anagha; Jerez-Rozo, Jackeline I; Pandya, Natasha; Romañach, Rodolfo J; Michniak-Kohn, Bozena; Iqbal, Zafar; Bilgili, Ecevit; Davé, Rajesh N

    2012-02-28

    The design and feasibility of a simple process of incorporating stable nanoparticles into edible polymer films is demonstrated with the goal of enhancing the dissolution rate of poorly water soluble drugs. Nanosuspensions produced from wet stirred media milling (WSMM) were transformed into polymer films containing drug nanoparticles by mixing with a low molecular weight hydroxylpropyl methyl cellulose (HPMC E15LV) solution containing glycerin followed by film casting and drying. Three different BCS Class II drugs, naproxen (NPX), fenofibrate (FNB) and griseofulvin (GF) were studied. The influence of the drug molecule on the film properties was also investigated. It was shown that film processing methodology employed has no effect on the drug crystallinity according to X-ray diffraction (XRD) and Raman spectroscopy. Differences in aggregation behavior of APIs in films were observed through SEM and NIR chemical imaging analysis. NPX exhibited the strongest aggregation compared to the other drugs. The aggregation had a direct effect on drug content uniformity in the film. Mechanical properties of the film were also affected depending on the drug-polymer interaction. Due to strong hydrogen bonding with the polymer, NPX exhibited an increase in Young's Modulus (YM) of approximately 200%, among other mechanical properties, compared to GF films. A synergistic effect between surfactant/polymer and drug/polymer interactions in the FNB film resulted in an increase of more than 600% in YM compared to the GF film. The enhancement in drug dissolution rate of films due to the large surface area and smaller drug particle size was also demonstrated. PMID:22178619

  5. Hydroxypropyl Cellulose Based Non-Volatile Gel Polymer Electrolytes for Dye-Sensitized Solar Cell Applications using 1-methyl-3-propylimidazolium iodide ionic liquid

    PubMed Central

    Khanmirzaei, Mohammad Hassan; Ramesh, S.; Ramesh, K.

    2015-01-01

    Gel polymer electrolytes using imidazolium based ionic liquids have attracted much attention in dye-sensitized solar cell applications. Hydroxypropyl cellulose (HPC), sodium iodide (NaI), 1-methyl-3-propylimidazolium iodide (MPII) as ionic liquid (IL), ethylene carbonate (EC) and propylene carbonate (PC) are used for preparation of non-volatile gel polymer electrolyte (GPE) system (HPC:EC:PC:NaI:MPII) for dye-sensitized solar cell (DSSC) applications. The highest ionic conductivity of 7.37 × 10−3 S cm−1 is achieved after introducing 100% of MPII with respect to the weight of HPC. Temperature-dependent ionic conductivity of gel polymer electrolytes is studied in this work. XRD patterns of gel polymer electrolytes are studied to confirm complexation between HPC polymer, NaI and MPII. Thermal behavior of the GPEs is studied using simultaneous thermal analyzer (STA) and differential scanning calorimetry (DSC). DSSCs are fabricated using gel polymer electrolytes and J-V centeracteristics of fabricated dye sensitized solar cells were analyzed. The gel polymer electrolyte with 100 wt.% of MPII ionic liquid shows the best performance and energy conversion efficiency of 5.79%, with short-circuit current density, open-circuit voltage and fill factor of 13.73 mA cm−2, 610 mV and 69.1%, respectively. PMID:26659087

  6. Hydroxypropyl Cellulose Based Non-Volatile Gel Polymer Electrolytes for Dye-Sensitized Solar Cell Applications using 1-methyl-3-propylimidazolium iodide ionic liquid.

    PubMed

    Khanmirzaei, Mohammad Hassan; Ramesh, S; Ramesh, K

    2015-01-01

    Gel polymer electrolytes using imidazolium based ionic liquids have attracted much attention in dye-sensitized solar cell applications. Hydroxypropyl cellulose (HPC), sodium iodide (NaI), 1-methyl-3-propylimidazolium iodide (MPII) as ionic liquid (IL), ethylene carbonate (EC) and propylene carbonate (PC) are used for preparation of non-volatile gel polymer electrolyte (GPE) system (HPC:EC:PC:NaI:MPII) for dye-sensitized solar cell (DSSC) applications. The highest ionic conductivity of 7.37 × 10(-3) S cm(-1) is achieved after introducing 100% of MPII with respect to the weight of HPC. Temperature-dependent ionic conductivity of gel polymer electrolytes is studied in this work. XRD patterns of gel polymer electrolytes are studied to confirm complexation between HPC polymer, NaI and MPII. Thermal behavior of the GPEs is studied using simultaneous thermal analyzer (STA) and differential scanning calorimetry (DSC). DSSCs are fabricated using gel polymer electrolytes and J-V centeracteristics of fabricated dye sensitized solar cells were analyzed. The gel polymer electrolyte with 100 wt.% of MPII ionic liquid shows the best performance and energy conversion efficiency of 5.79%, with short-circuit current density, open-circuit voltage and fill factor of 13.73 mA cm(-2), 610 mV and 69.1%, respectively. PMID:26659087

  7. Immobilization of Aspergillus oryzae  β-Galactosidase on Cellulose Acetate-Polymethylmethacrylate Membrane and Its Application in Hydrolysis of Lactose from Milk and Whey

    PubMed Central

    Ansari, Shakeel Ahmed; Satar, Rukhsana; Kashif Zaidi, Syed; Ahmad, Abrar

    2014-01-01

    The present study demonstrates the immobilization of Aspergillus oryzae β-galactosidase on cellulose acetate-polymethylmethacrylate (CA-PMMA) membrane and its application in hydrolyzing lactose in dairy industries. The effect of physical and chemical denaturants like pH, temperature, product inhibition by galactose, storage stability, and reuse number of the enzyme immobilized on CA-PMMA membrane has been investigated. Lactose was hydrolyzed from milk and whey in batch reactors at 50°C by free and immobilized β-galactosidase (IβG). Optimum pH for the free and immobilized enzyme was found to be the same, that is, 4.5. However, IβG retained greater fractions of catalytic activity at lower and higher pH ranges. The temperature optimum for the immobilized enzyme was increased by 10°C. Moreover, Michaelis-Menten constant was increased for IβG as compared to the native one while maximum reaction rate was reduced for the immobilized enzyme. The preserved activity of free and immobilized enzyme was found to be 45% and 83%, respectively, after five weeks of storage at 4°C. Reusability of IβG was observed to be 86% even after fifth repeated use, thereby signifying its application in lactose hydrolysis (as shown in lab-scale batch reactors) in various dairy products including milk and whey. PMID:27350979

  8. Physicochemical properties of pH-sensitive hydrogels based on hydroxyethyl cellulose-hyaluronic acid and for applications as transdermal delivery systems for skin lesions.

    PubMed

    Kwon, Soon Sik; Kong, Bong Ju; Park, Soo Nam

    2015-05-01

    We investigated the physicochemical properties of pH-sensitive hydroxyethyl cellulose (HEC)/hyaluronic acid (HA) complex hydrogels containing isoliquiritigenin (ILTG), and discussed potential applications as transdermal delivery systems for the treatment of skin lesions caused by pH imbalance. HA has skin compatibility and pH functional groups and HEC serves as scaffold to build hydrogels with varied HCE:HA mass ratio. Hydrogels were synthesized via chemical cross-linking, and three-dimensional network structures were characterized via scanning electron microscopy (SEM). The swelling properties and polymer ratios of the hydrogels were investigated at pH values in the range 1-13. HECHA13 (i.e., an HEC:HA mass ratio of 1:3) was found to have optimal rheological and adhesive properties, and was used to investigate the drug release efficiency as a function of pH; the efficiency was greater than 70% at pH 7. Antimicrobial activity assays against Propionibacterium acnes were conducted to take advantage of the pH-sensitive properties of HECHA13. At pH 7, we found that HECHA13, which contained ILTG, inhibited the growth of P. acnes. Furthermore, HECHA13 was found to exhibit excellent permeability into the skin, which penetrated mostly via the hair follicle. These results indicate that this pH-sensitive hydrogel is effective as a transdermal delivery system for antimicrobial therapeutics, with potential applications in the treatment of acne. PMID:25753198

  9. Hydroxypropyl Cellulose Based Non-Volatile Gel Polymer Electrolytes for Dye-Sensitized Solar Cell Applications using 1-methyl-3-propylimidazolium iodide ionic liquid

    NASA Astrophysics Data System (ADS)

    Khanmirzaei, Mohammad Hassan; Ramesh, S.; Ramesh, K.

    2015-12-01

    Gel polymer electrolytes using imidazolium based ionic liquids have attracted much attention in dye-sensitized solar cell applications. Hydroxypropyl cellulose (HPC), sodium iodide (NaI), 1-methyl-3-propylimidazolium iodide (MPII) as ionic liquid (IL), ethylene carbonate (EC) and propylene carbonate (PC) are used for preparation of non-volatile gel polymer electrolyte (GPE) system (HPC:EC:PC:NaI:MPII) for dye-sensitized solar cell (DSSC) applications. The highest ionic conductivity of 7.37 × 10-3 S cm-1 is achieved after introducing 100% of MPII with respect to the weight of HPC. Temperature-dependent ionic conductivity of gel polymer electrolytes is studied in this work. XRD patterns of gel polymer electrolytes are studied to confirm complexation between HPC polymer, NaI and MPII. Thermal behavior of the GPEs is studied using simultaneous thermal analyzer (STA) and differential scanning calorimetry (DSC). DSSCs are fabricated using gel polymer electrolytes and J-V centeracteristics of fabricated dye sensitized solar cells were analyzed. The gel polymer electrolyte with 100 wt.% of MPII ionic liquid shows the best performance and energy conversion efficiency of 5.79%, with short-circuit current density, open-circuit voltage and fill factor of 13.73 mA cm-2, 610 mV and 69.1%, respectively.

  10. Magnetic Mesoporous Photonic Cellulose Films.

    PubMed

    Giese, Michael; Blusch, Lina K; Schlesinger, Maik; Meseck, Georg R; Hamad, Wadood Y; Arjmand, Mohammad; Sundararaj, Uttandaraman; MacLachlan, Mark J

    2016-09-13

    Novel hybrid materials of cellulose and magnetic nanoparticles (NPs) were synthesized and characterized. The materials combine the chiral nematic structural features of mesoporous photonic cellulose (MPC) with the magnetic properties of cobalt ferrite (CoFe2O4). The photonic, magnetic, and dielectric properties of the hybrid materials were investigated during the dynamic swelling and deswelling of the MPC films. It was observed that the dielectric properties of the generated MPC films increased tremendously following swelling in water, endorsing efficient swelling ability of the generated mesoporous films. The high magnetic permeability of the developed MPC films in conjunction with their superior dielectric properties, predominantly in the swollen state, makes them interesting for electromagnetic interference shielding applications. PMID:27588561

  11. Polyimide Cellulose Nanocrystal Composite Aerogels

    NASA Technical Reports Server (NTRS)

    Nguyen, Baochau N.; Meador, Mary Ann; Rowan, Stuart; Cudjoe, Elvis; Sandberg, Anna

    2014-01-01

    Polyimide (PI) aerogels are highly porous solids having low density, high porosity and low thermal conductivity with good mechanical properties. They are ideal for various applications including use in antenna and insulation such as inflatable decelerators used in entry, decent and landing operations. Recently, attention has been focused on stimuli responsive materials such as cellulose nano crystals (CNCs). CNCs are environmentally friendly, bio-renewable, commonly found in plants and the dermis of sea tunicates, and potentially low cost. This study is to examine the effects of CNC on the polyimide aerogels. The CNC used in this project are extracted from mantle of a sea creature called tunicates. A series of polyimide cellulose nanocrystal composite aerogels has been fabricated having 0-13 wt of CNC. Results will be discussed.

  12. A facile route to prepare cellulose-based films.

    PubMed

    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

  13. Cellulose biosynthesis and function in bacteria.

    PubMed Central

    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 evident for Acetobacter xylinum, polymerization and assembly appear to be tightly coupled. To date, only bacteria have been effectively studied at the biochemical and genetic levels. In A. xylinum, the cellulose synthase, composed of at least two structurally similar but functionally distinct subunits, is subject to a multicomponent regulatory system. Regulation is based on the novel nucleotide cyclic diguanylic acid, a positive allosteric effector, and the regulatory enzymes maintaining its intracellular turnover: diguanylate cyclase and Ca2(+)-sensitive bis-(3',5')-cyclic diguanylic acid (c-di-GMP) phosphodiesterase. Four genes have been isolated from A. xylinum which constitute the operon for cellulose synthesis. The second gene encodes the catalytic subunit of cellulose synthase; the functions of the other three gene products are still unknown. Exclusively an extracellular product, bacterial cellulose appears to fulfill diverse biological roles within the natural habitat, conferring mechanical, chemical, and physiological protection in A. xylinum and Sarcina ventriculi or facilitating cell adhesion during symbiotic or infectious interactions in Rhizobium and Agrobacterium species. A. xylinum is proving to be most amenable for industrial purposes, allowing the unique features of bacterial cellulose to be exploited for novel product applications. Images PMID:2030672

  14. The effect of cellulose molar mass on the properties of palmitate esters.

    PubMed

    Willberg-Keyriläinen, Pia; Talja, Riku; Asikainen, Sari; Harlin, Ali; Ropponen, Jarmo

    2016-10-20

    Nowadays one of the growing trends is to replace oil-based products with cellulose-based materials. Currently most cellulose esters require a huge excess of chemicals and have therefore, not been broadly used in the industry. Here, we show that decreasing the molar mass of cellulose by ozone hydrolysis provides cellulose functionalization with less chemical consumption. To reveal the differences in reactivity and chemical consumption, we showed esterification of both native cellulose and ozone treated hydrolyzed cellulose. Based on the results, the molar mass of the starting cellulose has a significant effect on the end product's degree of substitution and properties. Furthermore, molar mass controlled palmitate esters form mechanically strong, flexible and optically transparent films with excellent water barrier properties. We anticipate that molar mass controlled cellulose will provide a starting point for the greater use of cellulose based materials, in various application, such as films and composites. PMID:27474646

  15. Effect of Surface Attachment on Synthesis of Bacterial Cellulose

    SciTech Connect

    Evans, Barbara R; O'Neill, Hugh Michael

    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.

  16. Structure and transformation of tactoids in cellulose nanocrystal suspensions

    NASA Astrophysics Data System (ADS)

    Wang, Pei-Xi; Hamad, Wadood Y.; MacLachlan, Mark J.

    2016-05-01

    Cellulose nanocrystals obtained from natural sources are of great interest for many applications. In water, cellulose nanocrystals form a liquid crystalline phase whose hierarchical structure is retained in solid films after drying. Although tactoids, one of the most primitive components of liquid crystals, are thought to have a significant role in the evolution of this phase, they have evaded structural study of their internal organization. Here we report the capture of cellulose nanocrystal tactoids in a polymer matrix. This method allows us to visualize, for the first time, the arrangement of cellulose nanocrystals within individual tactoids by electron microscopy. Furthermore, we can follow the structural evolution of the liquid crystalline phase from tactoids to iridescent-layered films. Our insights into the early nucleation events of cellulose nanocrystals give important information about the growth of cholesteric liquid crystalline phases, especially for cellulose nanocrystals, and are crucial for preparing photonics-quality films.

  17. Structure and transformation of tactoids in cellulose nanocrystal suspensions

    PubMed Central

    Wang, Pei-Xi; Hamad, Wadood Y.; MacLachlan, Mark J.

    2016-01-01

    Cellulose nanocrystals obtained from natural sources are of great interest for many applications. In water, cellulose nanocrystals form a liquid crystalline phase whose hierarchical structure is retained in solid films after drying. Although tactoids, one of the most primitive components of liquid crystals, are thought to have a significant role in the evolution of this phase, they have evaded structural study of their internal organization. Here we report the capture of cellulose nanocrystal tactoids in a polymer matrix. This method allows us to visualize, for the first time, the arrangement of cellulose nanocrystals within individual tactoids by electron microscopy. Furthermore, we can follow the structural evolution of the liquid crystalline phase from tactoids to iridescent-layered films. Our insights into the early nucleation events of cellulose nanocrystals give important information about the growth of cholesteric liquid crystalline phases, especially for cellulose nanocrystals, and are crucial for preparing photonics-quality films. PMID:27143197

  18. Recent developments in the catalytic conversion of cellulose

    PubMed Central

    Wang, Yan; Song, Hang; Peng, Lincai; Zhang, Qiangsheng; Yao, Shun

    2014-01-01

    The increasing demand for energy has led to the development of biomass conversion technologies. As the most abundant biomass on Earth, cellulose is generally chosen as the primary research target for biomass conversion. In this review, gasification and pyrolysis of cellulose are briefly discussed and hydrolysis is then considered in detail. Moreover, many new developments and applications are introduced in cellulose conversion in recent years. Among these technologies, heterogeneous catalysis, hydrolysis in ionic liquid and hydrolysis by hot-compressed water exhibit a promising potential in cellulose conversion. Therefore, they are well recognized as powerful, fast and efficient techniques, becoming the focus of intensive research. PMID:26019586

  19. Chapter 5: Meso-Scale Modeling of Polysaccharides in Plant Cell Walls: An Application to Translation of CBMs on Cellulose Surface

    SciTech Connect

    Bu, L.; Himmel, M. E.; Nimlos, M. R.

    2010-01-01

    A coarse-grained model and force field for simulating cellulose I{beta} surface (1,0,0) was derived, in which each {beta}-D-glucose unit is represented by three beads. The coarse-grained model can reproduce a stable cellulose (1,0,0) surface with an excellent agreement with an all-atom model. When used to study the interaction of the family 1 carbohydrate-binding module (CBM1) with this cellulose surface model, the CBM 'opens' as in earlier atomistic simulations. This cellulose I{beta} surface model produces simulations in which the CBM translates along a broken cellodextrin chain. This processive motion of the exoglucanase cellobiohydrolase I has long been suggested by experimental studies, but has never before been observed in computer simulations.

  20. Preparation and application of functionalized cellulose acetate/silica composite nanofibrous membrane via electrospinning for Cr(VI) ion removal from aqueous solution.

    PubMed

    Taha, Ahmed A; Wu, Yi-na; Wang, Hongtao; Li, Fengting

    2012-12-15

    Novel NH(2)-functionalized cellulose acetate (CA)/silica composite nanofibrous membranes were successfully prepared by sol-gel combined with electrospinning technology. Tetraethoxysilane (TEOS) as a silica source, CA as precursor and 3-ureidopropyltriethoxysilane as a coupling agent were used in membrane preparation. The membrane's chemical and morphological structures were investigated by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM) images, X-ray diffraction (XRD), element analyzer, Fourier-transform infrared spectroscopy (FTIR) and N(2) adsorption-desorption isotherms. The composite nanofibrous membranes exhibited high surface area and porosity. The membranes were used for Cr(VI) ion removal from aqueous solution through static and dynamic experiments. The adsorption behavior of Cr(VI) can be well described by the Langmuir adsorption model, and the maximum adsorption capacity for Cr(VI) is estimated to be 19.46 mg/g. The membrane can be conveniently regenerated by alkalization. Thus the composite membrane prepared from biodegradable raw material has potential applications in the field of water treatment. PMID:22858801

  1. Comparison of physical properties of regenerated cellulose films fabricated with different cellulose feedstocks in ionic liquid.

    PubMed

    Pang, JinHui; Wu, Miao; Zhang, QiaoHui; Tan, Xin; Xu, Feng; Zhang, XueMing; Sun, RunCang

    2015-05-01

    With the serious "white pollution" resulted from the non-biodegradable plastic films, considerable attention has been directed toward the development of renewable and biodegradable cellulose-based film materials as substitutes of petroleum-derived materials. In this study, environmentally friendly cellulose films were successfully prepared using different celluloses (pine, cotton, bamboo, MCC) as raw materials and ionic liquid 1-ethyl-3-methylimidazolium acetate as a solvent. The SEM and AFM indicated that all cellulose films displayed a homogeneous and smooth surface. In addition, the FT-IR and XRD analysis showed the transition from cellulose I to II was occurred after the dissolution and regeneration process. Furthermore, the cellulose films prepared by cotton linters and pine possessed the most excellent thermal stability and mechanical properties, which were suggested by the highest onset temperature (285°C) and tensile stress (120 MPa), respectively. Their excellent properties of regenerated cellulose films are promising for applications in food packaging and medical materials. PMID:25659673

  2. Engineering control of bacterial cellulose production using a genetic toolkit and a new cellulose-producing strain

    PubMed Central

    Florea, Michael; Hagemann, Henrik; Santosa, Gabriella; Micklem, Chris N.; Spencer-Milnes, Xenia; de Arroyo Garcia, Laura; Paschou, Despoina; Lazenbatt, Christopher; Kong, Deze; Chughtai, Haroon; Jensen, Kirsten; Freemont, Paul S.; Kitney, Richard; Reeve, Benjamin; Ellis, Tom

    2016-01-01

    Bacterial cellulose is a strong and ultrapure form of cellulose produced naturally by several species of the Acetobacteraceae. Its high strength, purity, and biocompatibility make it of great interest to materials science; however, precise control of its biosynthesis has remained a challenge for biotechnology. Here we isolate a strain of Komagataeibacter rhaeticus (K. rhaeticus iGEM) that can produce cellulose at high yields, grow in low-nitrogen conditions, and is highly resistant to toxic chemicals. We achieved external control over its bacterial cellulose production through development of a modular genetic toolkit that enables rational reprogramming of the cell. To further its use as an organism for biotechnology, we sequenced its genome and demonstrate genetic circuits that enable functionalization and patterning of heterologous gene expression within the cellulose matrix. This work lays the foundations for using genetic engineering to produce cellulose-based materials, with numerous applications in basic science, materials engineering, and biotechnology. PMID:27247386

  3. Engineering control of bacterial cellulose production using a genetic toolkit and a new cellulose-producing strain.

    PubMed

    Florea, Michael; Hagemann, Henrik; Santosa, Gabriella; Abbott, James; Micklem, Chris N; Spencer-Milnes, Xenia; de Arroyo Garcia, Laura; Paschou, Despoina; Lazenbatt, Christopher; Kong, Deze; Chughtai, Haroon; Jensen, Kirsten; Freemont, Paul S; Kitney, Richard; Reeve, Benjamin; Ellis, Tom

    2016-06-14

    Bacterial cellulose is a strong and ultrapure form of cellulose produced naturally by several species of the Acetobacteraceae Its high strength, purity, and biocompatibility make it of great interest to materials science; however, precise control of its biosynthesis has remained a challenge for biotechnology. Here we isolate a strain of Komagataeibacter rhaeticus (K. rhaeticus iGEM) that can produce cellulose at high yields, grow in low-nitrogen conditions, and is highly resistant to toxic chemicals. We achieved external control over its bacterial cellulose production through development of a modular genetic toolkit that enables rational reprogramming of the cell. To further its use as an organism for biotechnology, we sequenced its genome and demonstrate genetic circuits that enable functionalization and patterning of heterologous gene expression within the cellulose matrix. This work lays the foundations for using genetic engineering to produce cellulose-based materials, with numerous applications in basic science, materials engineering, and biotechnology. PMID:27247386

  4. Methods of detection using a cellulose binding domain fusion product

    DOEpatents

    Shoseyov, Oded; Shpiegl, Itai; Goldstein, Marc A.; Doi, Roy H.

    1999-01-01

    A cellulose binding domain (CBD) having a high affinity for crystalline cellulose and chitin is disclosed, along with methods for the molecular cloning and recombinant production thereof. Fusion products comprising the CBD and a second protein are likewise described. A wide range of applications are contemplated for both the CBD and the fusion products, including drug delivery, affinity separations, and diagnostic techniques.

  5. Methods of use of cellulose binding domain proteins

    DOEpatents

    Shoseyov, O.; Shpiegl, I.; Goldstein, M.A.; Doi, R.H.

    1997-09-23

    A cellulose binding domain (CBD) having a high affinity for crystalline cellulose and chitin is disclosed, along with methods for the molecular cloning and recombinant production. Fusion products comprising the CBD and a second protein are likewise described. A wide range of applications are contemplated for both the CBD and the fusion products, including drug delivery, affinity separations, and diagnostic techniques. 16 figs.

  6. Methods of use of cellulose binding domain proteins

    DOEpatents

    Shoseyov, Oded; Shpiegl, Itai; Goldstein, Marc A.; Doi, Roy H.

    1997-01-01

    A cellulose binding domain (CBD) having a high affinity for crystalline cellulose and chitin is disclosed, along with methods for the molecular cloning and recombinant production thereof. Fusion products comprising the CBD and a second protein are likewise described. A wide range of applications are contemplated for both the CBD and the fusion products, including drug delivery, affinity separations, and diagnostic techniques.

  7. Methods of detection using a cellulose binding domain fusion product

    DOEpatents

    Shoseyov, O.; Shpiegl, I.; Goldstein, M.A.; Doi, R.H.

    1999-01-05

    A cellulose binding domain (CBD) having a high affinity for crystalline cellulose and chitin is disclosed, along with methods for the molecular cloning and recombinant production. Fusion products comprising the CBD and a second protein are likewise described. A wide range of applications are contemplated for both the CBD and the fusion products, including drug delivery, affinity separations, and diagnostic techniques. 34 figs.

  8. Fulton Cellulosic Ethanol Biorefinery

    SciTech Connect

    Sumait, Necy; Cuzens, John; Klann, Richard

    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.

  9. Method of saccharifying cellulose

    DOEpatents

    Johnson, Eric A.; Demain, Arnold L.; Madia, Ashwin

    1985-09-10

    A method of saccharifying cellulose by incubation with the cellulase of Clostridium thermocellum in a broth containing an efficacious amount of a reducing agent. Other incubation parameters which may be advantageously controlled to stimulate saccharification include the concentration of alkaline earth salts, pH, temperature, and duration. By the method of the invention, even native crystalline cellulose such as that found in cotton may be completely saccharified.

  10. Method of saccharifying cellulose

    DOEpatents

    Johnson, E.A.; Demain, A.L.; Madia, A.

    1983-05-13

    A method is disclosed of saccharifying cellulose by incubation with the cellulase of Clostridium thermocellum in a broth containing an efficacious amount of thiol reducing agent. Other incubation parameters which may be advantageously controlled to stimulate saccharification include the concentration of alkaline earth salts, pH, temperature, and duration. By the method of the invention, even native crystalline cellulose such as that found in cotton may be completely saccharified.

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

    PubMed

    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

  12. Elaboration d'un composite conducteur a base de polypyrrole et de nanofibres de cellulose

    NASA Astrophysics Data System (ADS)

    Bideau, Benoit

    Le projet de production de nanocellulose à grande échelle par l'équipe de recherche du professeur Claude Daneault, ne pourra se faire sans avoir démontré sa quelconque utilité sur le marché économique. C'est dans cette optique que s'est articulé mon travail afin de mettre en avant une des voix de valorisation de ces nanocelluloses. Nous avons travaillé plus précisément sur le développement d'un nanocomposite conducteur biodégradable. Nous nous sommes proposé dans ce travail de développer une technique simple et écologique permettant la conception d'un matériau composite conducteur. Nous avons étudié l'influence des nanofibres de cellulose, du pyrrole, de la température, de la durée de polymérisation et l'ajout d'additifs dans le matériau composite. L'étude de ces paramètres nous a permis de déterminer les meilleures conditions pour le développement d'un film composite conducteur avec des propriétés mécaniques acceptables. L'ajout de ce renfort (nanofibres), au sein de la matrice de polypyrrole a permis d'obtenir des films intéressants, de part leurs propriétés mécaniques, électriques et de leur caractère biodégradable. Des comparaisons ont été effectuées avec des fibres oxydées, afin d'étudier l'apport des nanofibres de cellulose au composite. Notre étude a ensuite été élargie à l'ajout d'additifs dans les matériaux conducteurs afin d'améliorer certaines propriétés du composite. L'objectif de ce travail visait l'étude de l'incorporation des nanofibres de cellulose dans une matrice de polypyrrole en vue de son utilisation en tant que matériau conducteur biodégradable pour des applications dans le domaine énergétique. Mots Clés: Nanocellulose, polypyrrole, composite, conducteur, biodégradable, propriétés mécaniques, additifs.

  13. Characterization of Bacterial Cellulose by Gluconacetobacter hansenii CGMCC 3917.

    PubMed

    Feng, Xianchao; Ullah, Niamat; Wang, Xuejiao; Sun, Xuchun; Li, Chenyi; Bai, Yun; Chen, Lin; Li, Zhixi

    2015-10-01

    In this study, comprehensive characterization and drying methods on properties of bacterial cellulose were analyzed. Bacterial cellulose was prepared by Gluconacetobacter hansenii CGMCC 3917, which was mutated by high hydrostatic pressure (HHP) treatment. Bacterial cellulose is mainly comprised of cellulose Iα with high crystallinity and purity. High-water holding and absorption capacity were examined by reticulated structure. Thermogravimetric analysis showed high thermal stability. High tensile strength and Young's modulus indicated its mechanical properties. The rheological analysis showed that bacterial cellulose had good consistency and viscosity. These results indicated that bacterial cellulose is a potential food additive and also could be used for a food packaging material. The high textural stability during freeze-thaw cycles makes bacterial cellulose an effective additive for frozen food products. In addition, the properties of bacterial cellulose can be affected by drying methods. Our results suggest that the bacterial cellulose produced from HHP-mutant strain has an effective characterization, which can be used for a wide range of applications in food industry. PMID:26352877

  14. Ethanol from municipal cellulosic wastes

    NASA Astrophysics Data System (ADS)

    Parker, A. J., Jr.; Timbario, T. J.; Mulloney, J. A., Jr.

    This paper addresses the use of municipal cellulosic wastes as a feedstock for producing ethanol fuels, and describes the application of enzymatic hydrolysis technology for their production. The concept incorporates recent process technology developments within the framework of an existing industry familiar with large-scale ethanol fermentation (the brewing industry). Preliminary indications are that the cost of producing ethanol via enzymatic hydrolysis in an existing plant with minimal facility modifications (low capital investment) can be significantly less than that of ethanol from grain fermentation.

  15. Genome sequence and plasmid transformation of the model high-yield bacterial cellulose producer Gluconacetobacter hansenii ATCC 53582

    NASA Astrophysics Data System (ADS)

    Florea, Michael; Reeve, Benjamin; Abbott, James; Freemont, Paul S.; Ellis, Tom

    2016-03-01

    Bacterial cellulose is a strong, highly pure form of cellulose that is used in a range of applications in industry, consumer goods and medicine. Gluconacetobacter hansenii ATCC 53582 is one of the highest reported bacterial cellulose producing strains and has been used as a model organism in numerous studies of bacterial cellulose production and studies aiming to increased cellulose productivity. Here we present a high-quality draft genome sequence for G. hansenii ATCC 53582 and find that in addition to the previously described cellulose synthase operon, ATCC 53582 contains two additional cellulose synthase operons and several previously undescribed genes associated with cellulose production. In parallel, we also develop optimized protocols and identify plasmid backbones suitable for transformation of ATCC 53582, albeit with low efficiencies. Together, these results provide important information for further studies into cellulose synthesis and for future studies aiming to genetically engineer G. hansenii ATCC 53582 for increased cellulose productivity.

  16. Genome sequence and plasmid transformation of the model high-yield bacterial cellulose producer Gluconacetobacter hansenii ATCC 53582.

    PubMed

    Florea, Michael; Reeve, Benjamin; Abbott, James; Freemont, Paul S; Ellis, Tom

    2016-01-01

    Bacterial cellulose is a strong, highly pure form of cellulose that is used in a range of applications in industry, consumer goods and medicine. Gluconacetobacter hansenii ATCC 53582 is one of the highest reported bacterial cellulose producing strains and has been used as a model organism in numerous studies of bacterial cellulose production and studies aiming to increased cellulose productivity. Here we present a high-quality draft genome sequence for G. hansenii ATCC 53582 and find that in addition to the previously described cellulose synthase operon, ATCC 53582 contains two additional cellulose synthase operons and several previously undescribed genes associated with cellulose production. In parallel, we also develop optimized protocols and identify plasmid backbones suitable for transformation of ATCC 53582, albeit with low efficiencies. Together, these results provide important information for further studies into cellulose synthesis and for future studies aiming to genetically engineer G. hansenii ATCC 53582 for increased cellulose productivity. PMID:27010592

  17. Genome sequence and plasmid transformation of the model high-yield bacterial cellulose producer Gluconacetobacter hansenii ATCC 53582

    PubMed Central

    Florea, Michael; Reeve, Benjamin; Abbott, James; Freemont, Paul S.; Ellis, Tom

    2016-01-01

    Bacterial cellulose is a strong, highly pure form of cellulose that is used in a range of applications in industry, consumer goods and medicine. Gluconacetobacter hansenii ATCC 53582 is one of the highest reported bacterial cellulose producing strains and has been used as a model organism in numerous studies of bacterial cellulose production and studies aiming to increased cellulose productivity. Here we present a high-quality draft genome sequence for G. hansenii ATCC 53582 and find that in addition to the previously described cellulose synthase operon, ATCC 53582 contains two additional cellulose synthase operons and several previously undescribed genes associated with cellulose production. In parallel, we also develop optimized protocols and identify plasmid backbones suitable for transformation of ATCC 53582, albeit with low efficiencies. Together, these results provide important information for further studies into cellulose synthesis and for future studies aiming to genetically engineer G. hansenii ATCC 53582 for increased cellulose productivity. PMID:27010592

  18. Synthesis and properties of cellulose functionalized -4, 4'-(propane-2, 2'-diyl) diphenol-SiO2/TiO2 hybrid nanocomposites materials for high performance applications

    NASA Astrophysics Data System (ADS)

    Ramesh, Sivalingam; Kim, Gwang-Hoon; Kim, Heung-Soo; Kim, Jaehwan; Kim, Joo-Hyung

    2013-04-01

    The general class of organic-inorganic hybrid nanocomposites materials is a fast growing area of research. The significant effort is focused on the ability to control the nanoscale structures via organic functional synthetic approaches with inorganic metal oxides. The properties of nanocomposites material depends on the properties of their individual components but also their morphological and interfacial characteristics. This rapidly expanding field is generating many exciting new materials with novel properties. Mainly, cellulose is considered as the richest renewable materials are presently among the most promising candidates for use in photonics due to their versatility, flexibility, light weight, low cost and ease of modification. Cellulose-metal oxide nanomaterials were developed the technologies to manipulate selfassembly and multifunctionallity, of new technologies to the point where industry can produce advanced and costcompetitive cellulose metal oxide hybrid materials. Therefore, the present study is focused on cellulose-functionalized - 4, 4'-(propane-2, 2'-diyl) diphenol-SiO2/TiO2 hybrid nano-composites materials by in-situ sol-gel process. The chemical and morphological properties of cellulose-functionalized SiO2/TiO2 materials via covalent crosslinking hybrids were characterized by FTIR, XRD, TGA, DSC, SEM, TEM and optical properties.

  19. Application of Molecular Techniques to Elucidate the Influence of Cellulosic Waste on the Bacterial Community Structure at a Simulated Low-Level-Radioactive-Waste Site

    SciTech Connect

    Erin K. Field; Seth D'Imperio; Amber R. Miller; Michael R. VanEngelen; Robin Gerlach; Brady D. Lee; William A. Apel; Brent M. Peyton

    2010-05-01

    Low-level radioactive waste sites, including those at various U.S. Department of Energy (DOE) sites, frequently contain cellulosic waste in the form of paper towels, cardboard boxes, or wood contaminated with heavy metals and radionuclides such as chromium and uranium. To understand how the soil microbial community is influenced by the presence of cellulosic waste products, multiple soil samples were obtained from a non-radioactive model low-level waste test pit at the Idaho National Laboratory. Samples were analyzed using 16S rDNA clone libraries and 16S rRNA gene microarray (PhyloChip) analyses. Both the clone library and PhyloChip results revealed changes in the bacterial community structure with depth. In all samples, the PhyloChip detected significantly more unique Operational Taxonomic Units (OTUs), and therefore more relative diversity, than the clone libraries. Calculated diversity indices suggest that diversity is lowest in the Fill (F) and Fill Waste (FW) layers and greater in the Wood Waste (WW) and Waste Clay (WC) layers. Principal coordinates analysis and lineage specific analysis determined that Bacteroidetes and Actinobacteria phyla account for most of the significant differences observed between the layers. The decreased diversity in the FW layer and increased members of families containing known cellulose degrading microorganisms suggests the FW layer is an enrichment environment for cellulose degradation. Overall, these results suggest that the presence of the cellulosic material significantly influences the bacterial community structure in a stratified soil system.

  20. Hybrid MPI-OpenMP Parallelism in the ONETEP Linear-Scaling Electronic Structure Code: Application to the Delamination of Cellulose Nanofibrils.

    PubMed

    Wilkinson, Karl A; Hine, Nicholas D M; Skylaris, Chris-Kriton

    2014-11-11

    We present a hybrid MPI-OpenMP implementation of Linear-Scaling Density Functional Theory within the ONETEP code. We illustrate its performance on a range of high performance computing (HPC) platforms comprising shared-memory nodes with fast interconnect. Our work has focused on applying OpenMP parallelism to the routines which dominate the computational load, attempting where possible to parallelize different loops from those already parallelized within MPI. This includes 3D FFT box operations, sparse matrix algebra operations, calculation of integrals, and Ewald summation. While the underlying numerical methods are unchanged, these developments represent significant changes to the algorithms used within ONETEP to distribute the workload across CPU cores. The new hybrid code exhibits much-improved strong scaling relative to the MPI-only code and permits calculations with a much higher ratio of cores to atoms. These developments result in a significantly shorter time to solution than was possible using MPI alone and facilitate the application of the ONETEP code to systems larger than previously feasible. We illustrate this with benchmark calculations from an amyloid fibril trimer containing 41,907 atoms. We use the code to study the mechanism of delamination of cellulose nanofibrils when undergoing sonification, a process which is controlled by a large number of interactions that collectively determine the structural properties of the fibrils. Many energy evaluations were needed for these simulations, and as these systems comprise up to 21,276 atoms this would not have been feasible without the developments described here. PMID:26584365

  1. Antioxidant films based on cross-linked methyl cellulose and native Chilean berry for food packaging applications.

    PubMed

    López de Dicastillo, Carol; Rodríguez, Francisco; Guarda, Abel; Galotto, Maria José

    2016-01-20

    Development of antioxidant and antimicrobial active food packaging materials based on biodegradable polymer and natural plant extracts has numerous advantages as reduction of synthetic additives into the food, reduction of plastic waste, and food protection against microorganisms and oxidation reactions. In this way, active films based on methylcellulose (MC) and maqui (Aristotelia chilensis) berry fruit extract, as a source of antioxidants agents, were studied. On the other hand, due to the high water affinity of MC, this polymer was firstly cross-linked with glutaraldehyde (GA) at different concentrations. The results showed that the addition of GA decreased water solubility, swelling, water vapor permeability of MC films, and the release of antioxidant substances from the active materials increased with the concentration of GA. Natural extract and active cross-linked films were characterized in order to obtain the optimal formulation with the highest antioxidant activity and the best physical properties for latter active food packaging application. PMID:26572446

  2. HPMC reinforced with different cellulose nanoparticles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 ...

  3. Electron (charge) density studies of cellulose models

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introductory material first describes electron density approaches and demonstrates visualization of electron lone pairs and bonding as concentrations of electron density. Then it focuses on the application of Bader’s Quantum Theory of Atoms-in-Molecules (AIM) to cellulose models. The purpose of the ...

  4. Biocompatibility of Bacterial Cellulose Based Biomaterials

    PubMed Central

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

    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 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. PMID:24955750

  5. Cellulose carbonates: a platform for promising biopolymer derivatives with multifunctional capabilities.

    PubMed

    Elschner, Thomas; Heinze, Thomas

    2015-06-01

    Cellulose carbonates as a platform compound open new possibilities for the design of advanced materials based on the most important renewable resource cellulose. In the present feature, the chemistry of cellulose carbonates is discussed considering own research results adequately. After a short overview about methods for activation of polysaccharides for a conversion with nucleophilic compounds in particular with amines, details about various methods for the synthesis of polysaccharide carbonates are discussed. The main issue of the feature is the synthesis and aminolysis of cellulose carbonates with low, intermediate, and high degree of substitution and the evaluation of this chemistry with respect to specific challenges. Functional cellulose carbamates, obtained from cellulose phenyl carbonate by aminolysis, show the potential use of this class of celluloses. Immunoassays and zwitterionic polymers are included as representative examples regarding properties and application of the new cellulose-based products. PMID:25677921

  6. In-situ polymerized cellulose nanocrystals (CNC)-poly(l-lactide) (PLLA) nanomaterials and applications in nanocomposite processing.

    PubMed

    Miao, Chuanwei; Hamad, Wadood Y

    2016-11-20

    CNC-PLLA nanomaterials were synthesized via in-situ ring-opening polymerization of l-lactide in the presence of CNC, resulting in hydrophobic, homogeneous mixture of PLLA-grafted-CNC and free PLLA homopolymer. The free PLLA serves two useful functions: as barrier to further prevent PLLA-g-CNC from forming aggregates, and in creating improved interfacial properties when these nanomaterials are blended with other polymers, hence enhancing their performance. CNC-PLLA nanomaterials can be used for medical or engineering applications as-they-are or by compounding with suitable biopolymers using versatile techniques, such as solution casting, co-extrusion or injection molding, to form hybrid nanocomposites of tunable mechanical properties. When compounded with commercial-grade PLA, the resulting CNC-PLA nanocomposites appear transparent and have tailored (dynamic and static) mechanical and barrier properties, approaching those of poly(ethylene terephthalate), PET. The effect of reaction conditions on the properties of CNC-PLLA nanomaterials have been carefully studied and detailed throughout the paper. PMID:27561528

  7. Acid hydrolysis of cellulose

    SciTech Connect

    Salazar, H.

    1980-12-01

    One of the alternatives to increase world production of etha nol is by the hydrolysis of cellulose content of agricultural residues. Studies have been made on the types of hydrolysis: enzimatic and acid. Data obtained from the sulphuric acid hydrolysis of cellulose showed that this process proceed in two steps, with a yield of approximately 95% glucose. Because of increases in cost of alternatives resources, the high demand of the product and the more economic production of ethanol from cellulose materials, it is certain that this technology will be implemented in the future. At the same time further studies on the disposal and reuse of the by-products of this production must be undertaken.

  8. Application of Molecular Techniques To Elucidate the Influence of Cellulosic Waste on the Bacterial Community Structure at a Simulated Low-Level-Radioactive-Waste Site▿ †

    PubMed Central

    Field, Erin K.; D'Imperio, Seth; Miller, Amber R.; VanEngelen, Michael R.; Gerlach, Robin; Lee, Brady D.; Apel, William A.; Peyton, Brent M.

    2010-01-01

    Low-level-radioactive-waste (low-level-waste) sites, including those at various U.S. Department of Energy sites, frequently contain cellulosic waste in the form of paper towels, cardboard boxes, or wood contaminated with heavy metals and radionuclides such as chromium and uranium. To understand how the soil microbial community is influenced by the presence of cellulosic waste products, multiple soil samples were obtained from a nonradioactive model low-level-waste test pit at the Idaho National Laboratory. Samples were analyzed using 16S rRNA gene clone libraries and 16S rRNA gene microarray (PhyloChip) analyses. Both methods revealed changes in the bacterial community structure with depth. In all samples, the PhyloChip detected significantly more operational taxonomic units, and therefore relative diversity, than the clone libraries. Diversity indices suggest that diversity is lowest in the fill and fill-waste interface (FW) layers and greater in the wood waste and waste-clay interface layers. Principal-coordinate analysis and lineage-specific analysis determined that the Bacteroidetes and Actinobacteria phyla account for most of the significant differences observed between the layers. The decreased diversity in the FW layer and increased members of families containing known cellulose-degrading microorganisms suggest that the FW layer is an enrichment environment for these organisms. These results suggest that the presence of the cellulosic material significantly influences the bacterial community structure in a stratified soil system. PMID:20305022

  9. Isolation and characterization of a ß-glucosidase from a Clavispora strain with potential applications in bioethanol production from cellulosic materials

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We previously reported on a new yeast strain of Clavispora sp. NRRL Y-50464 that is capable of utilizing cellobiose as sole source of carbon and energy by producing sufficient native ß-glucosidase enzyme activity without further enzyme supplementation for cellulosic ethanol production using simultan...

  10. Application of molecular techniques to elucidate the influence of cellulosic waste on the bacterial community structure at a simulated low-level-radioactive-waste site.

    PubMed

    Field, Erin K; D'Imperio, Seth; Miller, Amber R; VanEngelen, Michael R; Gerlach, Robin; Lee, Brady D; Apel, William A; Peyton, Brent M

    2010-05-01

    Low-level-radioactive-waste (low-level-waste) sites, including those at various U.S. Department of Energy sites, frequently contain cellulosic waste in the form of paper towels, cardboard boxes, or wood contaminated with heavy metals and radionuclides such as chromium and uranium. To understand how the soil microbial community is influenced by the presence of cellulosic waste products, multiple soil samples were obtained from a nonradioactive model low-level-waste test pit at the Idaho National Laboratory. Samples were analyzed using 16S rRNA gene clone libraries and 16S rRNA gene microarray (PhyloChip) analyses. Both methods revealed changes in the bacterial community structure with depth. In all samples, the PhyloChip detected significantly more operational taxonomic units, and therefore relative diversity, than the clone libraries. Diversity indices suggest that diversity is lowest in the fill and fill-waste interface (FW) layers and greater in the wood waste and waste-clay interface layers. Principal-coordinate analysis and lineage-specific analysis determined that the Bacteroidetes and Actinobacteria phyla account for most of the significant differences observed between the layers. The decreased diversity in the FW layer and increased members of families containing known cellulose-degrading microorganisms suggest that the FW layer is an enrichment environment for these organisms. These results suggest that the presence of the cellulosic material significantly influences the bacterial community structure in a stratified soil system. PMID:20305022

  11. Cellulose nanofibrils improve the properties of all-cellulose composites by the nano-reinforcement mechanism and nanofibril-induced crystallization.

    PubMed

    Yang, Quanling; Saito, Tsuguyuki; Berglund, Lars A; Isogai, Akira

    2015-11-14

    All-cellulose nanocomposite films containing crystalline TEMPO-oxidized cellulose nanofibrils (TOCNs) of 0-1 wt% were fabricated by mixing aqueous TOCN dispersions with alkali/urea/cellulose (AUC) solutions at room temperature. The mixtures were cast on glass plates, soaked in an acid solution, and the regenerated gel-like films were washed with water and then dried. The TOCN did not form agglomerates in the composites, and had the structure of TOCN-COOH, forming hydrogen bonds with the hydroxyl groups of the regenerated cellulose molecules. X-ray diffraction analysis revealed that the matrix cellulose molecules increased the cellulose II crystal size upon incorporation of TOCN. As a result, the TOCN/AUC composite films had high Young's modulus, tensile strength, thermal stability and oxygen-barrier properties. The TOCN/AUC composite films are promising all-cellulose nanocomposites for versatile applications as new bio-based materials. PMID:26465589

  12. Preparation of food grade carboxymethyl cellulose from corn husk agrowaste.

    PubMed

    Mondal, Md Ibrahim H; Yeasmin, Mst Sarmina; Rahman, Md Saifur

    2015-08-01

    Alpha-cellulose extracted from corn husks was used as the raw material for the production of food-grade carboxymethyl cellulose (CMC). Preparation of CMC from husk cellulose was carried out by an etherification process, using sodium hydroxide and monochloroacetic acid (MCA), with ethanol as the supporting medium. Characterizations of CMC were carried out by analyzing the spectra of FTIR, XRD patterns and SEM photomicrographs. Degree of substitution (DS) was determined with respect to particle size using chemical methods. Solubility, molecular weight and DS of CMC increased with decreased cellulose particle sizes. Microbiological testing of the prepared CMC was done by the pour plate method. Concentrations of heavy metals such as arsenic, lead, cadmium and mercury in the purified CMC were measured by Atomic Absorption Spectroscopy technique and found to be within the WHO/FAO recommended value. A comparative study with CMC available in the international market was conducted. The purity of the prepared CMC was higher, at 99.99% well above the purity of 99.5% for standard CMC. High purity CMC showed a yield 2.4 g/g with DS 2.41, water holding capacity 5.11 g/g, oil holding capacity 1.59 g/g. The obtained product is well suited for pharmaceutical and food additives. PMID:25936282

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

    PubMed

    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

  14. Increased Antibiotic Release from a Bone Cement Containing Bacterial Cellulose

    PubMed Central

    Nakai, Takahisa; Enomoto, Koichi; Uchio, Yuji; Yoshino, Katsumi

    2010-01-01

    Background Major disadvantages of antibiotic bone cements include limited drug release and reduced strength resulting from the addition of high doses of antibiotics. Bacterial cellulose, a three-dimensional hydrophilic mesh, may retain antibiotics and release them gradually. We hypothesized that the addition of cellulose to antibiotic bone cement would improve mechanical strength and antibiotic release. Questions/purposes We therefore examined the mechanical strength and antibiotic release of cellulose antibiotic cement. Methods A high dose of antibiotics (5 g per 40 g cement powder) was incorporated into bacterial cellulose and then mixed with bone cement. We compared the compression strength, fracture toughness, fatigue life, and elution kinetics of this formulation with those of plain cement and a traditional antibiotic cement. Results The average values for compression strength, fracture toughness, and fatigue life of the cellulose antibiotic cement were 97%, 97%, and 78% of the values obtained for plain cement, respectively. The corresponding values for the traditional antibiotic cement were 79%, 82%, and 17%, respectively. The cumulative elution over 35 days was 129% greater from the cellulose antibiotic cement than from the traditional antibiotic cement. Conclusions With a high dose of antibiotics, incorporating cellulose into the bone cement prevented compression and fracture fragility, improved fatigue life, and increased antibiotic elution. Clinical Relevance Antibiotic cements containing cellulose may have applications in clinical situations that require high levels of antibiotic release and preservation of the mechanical properties of the cement. PMID:20945120

  15. Modeling of cellulose crystals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cotton fibers are single cells, and the substance of the fiber is the secondary cell wall that is nearly pure, microcrystalline cellulose. Normally there is about 5% moisture in cotton fiber, but variations of a few percent make differences as large as 40% in the strength, with more water resulting ...

  16. Calculating cellulose diffraction patterns

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although powder diffraction of cellulose is a common experiment, the patterns are not widely understood. The theory is mathematical, there are numerous different crystal forms, and the conventions are not standardized. Experience with IR spectroscopy is not directly transferable. An awful error, tha...

  17. Processing and characterization of natural cellulose fibers/thermoset polymer composites.

    PubMed

    Thakur, Vijay Kumar; Thakur, Manju Kumari

    2014-08-30

    Recently natural cellulose fibers from different biorenewable resources have attracted the considerable attraction of research community all around the globe owing to their unique intrinsic properties such as biodegradability, easy availability, environmental friendliness, flexibility, easy processing and impressive physico-mechanical properties. Natural cellulose fibers based materials are finding their applications in a number of fields ranging from automotive to biomedical. Natural cellulose fibers have been frequently used as the reinforcement component in polymers to add the specific properties in the final product. A variety of cellulose fibers based polymer composite materials have been developed using various synthetic strategies. Seeing the immense advantages of cellulose fibers, in this article we discuss the processing of biorenewable natural cellulose fibers; chemical functionalization of cellulose fibers; synthesis of polymer resins; different strategies to prepare cellulose based green polymer composites, and diverse applications of natural cellulose fibers/polymer composite materials. The article provides an in depth analysis and comprehensive knowledge to the beginners in the field of natural cellulose fibers/polymer composites. The prime aim of this review article is to demonstrate the recent development and emerging applications of natural cellulose fibers and their polymer materials. PMID:24815407

  18. Thin blend films of cellulose and polyacrylonitrile

    NASA Astrophysics Data System (ADS)

    Lu, Rui; Zhang, Xin; Mao, Yimin; Briber, Robert; Wang, Howard

    Cellulose is the most abundant renewable, biocompatible and biodegradable natural polymer. Cellulose exhibits excellent chemical and mechanical stability, which makes it useful for applications such as construction, filtration, bio-scaffolding and packaging. To further expand the potential applications of cellulose materials, their alloying with synthetic polymers has been investigated. In this study, thin films of cotton linter cellulose (CLC) and polyacrylonitrile (PAN) blends with various compositions spanning the entire range from neat CLC to neat PAN were spun cast on silicon wafers from common solutions in dimethyl sulfoxide / ionic liquid mixtures. The morphologies of thin films were characterized using optical microscopy, atomic force microscopy, scanning electron microscopy and X-ray reflectivity. Morphologies of as-cast films are highly sensitive to the film preparation conditions; they vary from featureless smooth films to self-organized ordered nano-patterns to hierarchical structures spanning over multiple length scales from nanometers to tens of microns. By selectively removing the PAN-rich phase, the structures of blend films were studied to gain insights in their very high stability in hot water, acid and salt solutions.

  19. Cellulose Synthesis and Its Regulation

    PubMed Central

    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 recent advances using a combination of molecular genetics, live cell imaging, and spectroscopic tools, many aspects of the cellulose synthesis remain a mystery. In this chapter, we highlight recent research progress towards understanding the mechanism of cellulose synthesis in Arabidopsis. PMID:24465174

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

    PubMed Central

    2011-01-01

    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 the swollenin

  1. Cellulose in Cyanobacteria. Origin of Vascular Plant Cellulose Synthase?

    PubMed Central

    Nobles, David R.; Romanovicz, Dwight K.; Brown, R. Malcolm

    2001-01-01

    Although cellulose biosynthesis among the cyanobacteria has been suggested previously, we present the first conclusive evidence, to our knowledge, of the presence of cellulose in these organisms. Based on the results of x-ray diffraction, electron microscopy of microfibrils, and cellobiohydrolase I-gold labeling, we report the occurrence of cellulose biosynthesis in nine species representing three of the five sections of cyanobacteria. Sequence analysis of the genomes of four cyanobacteria revealed the presence of multiple amino acid sequences bearing the DDD35QXXRW motif conserved in all cellulose synthases. Pairwise alignments demonstrated that CesAs from plants were more similar to putative cellulose synthases from Anabaena sp. Pasteur Culture Collection 7120 and Nostoc punctiforme American Type Culture Collection 29133 than any other cellulose synthases in the database. Multiple alignments of putative cellulose synthases from Anabaena sp. Pasteur Culture Collection 7120 and N. punctiforme American Type Culture Collection 29133 with the cellulose synthases of other prokaryotes, Arabidopsis, Gossypium hirsutum, Populus alba × Populus tremula, corn (Zea mays), and Dictyostelium discoideum showed that cyanobacteria share an insertion between conserved regions U1 and U2 found previously only in eukaryotic sequences. Furthermore, phylogenetic analysis indicates that the cyanobacterial cellulose synthases share a common branch with CesAs of vascular plants in a manner similar to the relationship observed with cyanobacterial and chloroplast 16s rRNAs, implying endosymbiotic transfer of CesA from cyanobacteria to plants and an ancient origin for cellulose synthase in eukaryotes. PMID:11598227

  2. Essays concerning the cellulosic biofuel industry

    NASA Astrophysics Data System (ADS)

    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

  3. When It Rains, It Pours

    ERIC Educational Resources Information Center

    Mills, Linda

    2012-01-01

    "It's raining, it's pouring, the old man is snoring!" "The itsy, bitsy spider crawled up the waterspout, down came the rain and washed the spider out. Out came the sun and dried up all the rain, and the itsy, bitsy spider went up the spout again." What do children's nursery rhymes have to do with the school library? The author begins by telling a…

  4. Applications of FT-IR spectroscopy to the studies of esterification and crosslinking of cellulose by polycarboxylic acids: Part II. The performance of the crosslinked cotton fabrics

    NASA Astrophysics Data System (ADS)

    Wei, Weishu; Yang, Charles Q.

    1998-06-01

    Durable press finishing processes are commonly used in the textile industry to produce wrinkle-free cotton fabrics and garments. A durable press finishing agent forms covalent bands with cellulosic hydroxyl groups, thus crosslinking the cellulose molecules. The crosslinking of cellulose increases wrinkle resistance of the treated cotton fabric and reduces fabric mechanical strength. Wrinkle recovery angle (WRA) and tensile strength are the two most important parameters used to evaluate the performance of the crosslinked cotton fabrics and garments. In this study, we investigated the correlation between WRA and tensile strength on one hand, and the amount of crosslinkages formed by the crosslinking agents including dimethyloldihydroxylethyleneurea (DMDHEU) and 1,2,3,4-butanetetracarboxylic acid (BTCA) determined by FT-IR spectroscopy on the other hand. Linear regression curves between the carbonyl band absorbance, and WRA and tensile strength of the treated cotton fabric were developed. The data indicated that FT-IR spectroscopy is a reliable technique for predicting the performance of durable press finished cotton fabrics, therefore can be used as a convenient instrumental method for quality control in the textile and garment industry.

  5. Electrostatic assembly and growth of gold nanoparticles in cellulosic fibres.

    PubMed

    Pinto, Ricardo J B; Marques, Paula A A P; Martins, Manuel A; Neto, Carlos Pascoal; Trindade, Tito

    2007-08-15

    Synthetic studies of nanocomposites containing gold nanoparticles attached onto wood or bacterial cellulosic fibres have been performed in situ in the presence of the fibres or by polyelectrolyte-assisted deposition. The optical properties of the final nanocomposites could be tailored not only by the starting Au nanoparticles characteristics but also by the preparative method associated to the type of cellulosic fibres used as the substrate. Thus, gold nanoparticles assembled or generated in situ within cellulosic fibres, are excellent components for long term optical and chemically stable nanocomposites, which appear particularly interesting for security paper applications. PMID:17459404

  6. Synthesis of cellulose methylcarbonate in ionic liquids using dimethylcarbonate.

    PubMed

    Labafzadeh, Sara R; Helminen, K Juhani; Kilpeläinen, Ilkka; King, Alistair W T

    2015-01-01

    Dialkylcarbonates are viewed as low-cost, low-toxicity reagents, finding application in many areas of green chemistry. Homogeneous alkoxycarbonylation of cellulose was accomplished by applying dialkycarbonates (dimethyl and diethyl carbonate) in the ionic liquid-electrolyte trioctylphosphonium acetate ([P8881 ][OAc])/DMSO or 1-ethyl-3-methylimidazolium acetate ([emim][OAc]). Cellulose dialkylcarbonates with a moderate degree of substitution (DS∼1) are accessible via this procedure and cellulose methylcarbonate was thoroughly characterized for its chemical and physical properties after regeneration. This included HSQC & HMBC NMR, ATR-IR, molecular weight distribution, morphology, thermal properties, and barrier properties after film formation. PMID:25378289

  7. Composite edible films based on hydroxypropyl methyl cellulose reinforced with microcrystalline cellulose nanoparticles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It has been stated that hydroxypropyl methyl cellulose (HPMC) based films have promising applications in the food industry because of their environmental appeal, low cost, flexibility and transparency. Nevertheless, their mechanical and moisture barrier properties should be improved. The aim of th...

  8. [Insights into engineering of cellulosic ethanol].

    PubMed

    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

  9. Hydrophobic cellulose films with excellent strength and toughness via ball milling activated acylation of microfibrillated cellulose.

    PubMed

    Deng, Sha; Huang, Rui; Zhou, Mi; Chen, Feng; Fu, Qiang

    2016-12-10

    Cellulose films with excellent mechanical strength are of interest to many researchers, but unfortunately they often lack the ductility and water resistance. This work demonstrates an efficient and easily industrialized method for hydrophobic cellulose films made of modified microfibrillated cellulose (MFC). Prior to film fabrication, the simultaneous exfoliation and acylation of MFC was achieved through the synergetic effect of mechanical and chemical actions generated from ball milling in the presence of hexanoyl chloride. Largely enhanced tensile strength and elongation at break have been achieved (4.98MPa, 4.37% for original MFC films, 140MPa, 21.3% for modified ones). Due to hydrophobicity and compact structure, modified films show excellent water resistance and decreased water vapor permeability. Moreover, optical performance of modified films is also improved compared with the original MFC films. Our work can largely expand the application of this biodegradable resource and ultimately reduce the need for petroleum-based plastics. PMID:27577904

  10. Enhanced cellulose degradation using cellulase-nanosphere complexes.

    PubMed

    Blanchette, Craig; Lacayo, Catherine I; Fischer, Nicholas O; Hwang, Mona; Thelen, Michael P

    2012-01-01

    Enzyme catalyzed conversion of plant biomass to sugars is an inherently inefficient process, and one of the major factors limiting economical biofuel production. This is due to the physical barrier presented by polymers in plant cell walls, including semi-crystalline cellulose, to soluble enzyme accessibility. In contrast to the enzymes currently used in industry, bacterial cellulosomes organize cellulases and other proteins in a scaffold structure, and are highly efficient in degrading cellulose. To mimic this clustered assembly of enzymes, we conjugated cellulase obtained from Trichoderma viride to polystyrene nanospheres (cellulase:NS) and tested the hydrolytic activity of this complex on cellulose substrates from purified and natural sources. Cellulase:NS and free cellulase were equally active on soluble carboxymethyl cellulose (CMC); however, the complexed enzyme displayed a higher affinity in its action on microcrystalline cellulose. Similarly, we found that the cellulase:NS complex was more efficient in degrading natural cellulose structures in the thickened walls of cultured wood cells. These results suggest that nanoparticle-bound enzymes can improve catalytic efficiency on physically intractable substrates. We discuss the potential for further enhancement of cellulose degradation by physically clustering combinations of different glycosyl hydrolase enzymes, and applications for using cellulase:NS complexes in biofuel production. PMID:22870287

  11. Processes for treating cellulosic material

    NASA Technical Reports Server (NTRS)

    Ladisch, Michael R. (Inventor); Kohlman, Karen L. (Inventor); Westgate, Paul L. (Inventor); Weil, Joseph R. (Inventor); Yang, Yiqi (Inventor)

    1998-01-01

    Disclosed are processes for pretreating cellulosic materials in liquid water by heating the materials in liquid water at a temperature at or above their glass transition temperature but not substantially exceeding 220.degree. C., while maintaining the pH of the reaction medium in a range that avoids substantial autohydrolysis of the cellulosic materials. Such pretreatments minimize chemical changes to the cellulose while leading to physical changes which substantially increase susceptibility to hydrolysis in the presence of cellulase.

  12. Ice formation in amorphous cellulose

    NASA Astrophysics Data System (ADS)

    Czihak, C.; Müller, M.; Schober, H.; Vogl, G.

    2000-03-01

    We investigate the formation of ice in wet amorphous cellulose in the temperature range of 190 K⩽T⩽280 K. Due to voids and pores in the cellulose film, water molecules are able to form crystalline aggregates. Beyond that, water is able to penetrate between cellulose chains where it can adsorb to hydroxyl side groups. From diffraction data we suggest an aggregation of low-density amorphous (lda) ice at cellulose surfaces. The formation of lda ice shows a clear temperature dependence which will be discussed together with recent inelastic neutron scattering results.

  13. Cellulose biogenesis in Dictyostelium discoideum

    SciTech Connect

    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.

  14. Acid hydrolysis of cellulose to yield glucose

    DOEpatents

    Tsao, George T.; Ladisch, Michael R.; Bose, Arindam

    1979-01-01

    A process to yield glucose from cellulose through acid hydrolysis. Cellulose is recovered from cellulosic materials, preferably by pretreating the cellulosic materials by dissolving the cellulosic materials in Cadoxen or a chelating metal caustic swelling solvent and then precipitating the cellulose therefrom. Hydrolysis is accomplished using an acid, preferably dilute sulfuric acid, and the glucose is yielded substantially without side products. Lignin may be removed either before or after hydrolysis.

  15. Structural and physico-mechanical characterization of bio-cellulose produced by a cell-free system.

    PubMed

    Ullah, Muhammad Wajid; Ul-Islam, Mazhar; Khan, Shaukat; Kim, Yeji; Park, Joong Kon

    2016-01-20

    This study was aimed to characterize the structural and physico-mechanical properties of bio-cellulose produced through cell-free system. Fourier transform-infrared spectrum illustrated exact matching of structural peaks with microbial cellulose, used as reference. Field-emission scanning electron microscopy revealed that fibrils of bio-cellulose were thicker and more compact than microbial cellulose. The specific positions of peaks in the X-ray diffraction and nuclear magnetic resonance spectra indicated that bio-cellulose possessed cellulose II polymorphic structure. Bio-cellulose presented superior physico-mechanical properties than microbial cellulose. The water holding capacity of bio-cellulose and microbial cellulose were found to be 188.6 ± 5.41 and 167.4 ± 4.32 times their dry-weights, respectively. Tensile strengths and degradation temperature of bio-cellulose were 17.63 MPa and 352 °C, respectively compared to 14.71 MPa and 327 °C of microbial cellulose. Overall, the results indicated successful synthesis and superior properties of bio-cellulose that advocate its effectiveness for various applications. PMID:26572428

  16. Synthesis and application of a new carboxylated cellulose derivative. Part I: Removal of Co(2+), Cu(2+) and Ni(2+) from monocomponent spiked aqueous solution.

    PubMed

    Teodoro, Filipe Simões; Ramos, Stela Nhandeyara do Carmo; Elias, Megg Madonyk Cota; Mageste, Aparecida Barbosa; Ferreira, Gabriel Max Dias; da Silva, Luis Henrique Mendes; Gil, Laurent Frédéric; Gurgel, Leandro Vinícius Alves

    2016-12-01

    A new carboxylated cellulose derivative (CTA) was prepared from the esterification of cellulose with 1,2,4-Benzenetricarboxylic anhydride. CTA was characterized by percent weight gain (pwg), amount of carboxylic acid groups (nCOOH), elemental analysis, FTIR, TGA, solid-state (13)C NMR, X-ray diffraction (DRX), specific surface area, pore size distribution, SEM and EDX. The best CTA synthesis condition yielded a pwg and nCOOH of 94.5% and 6.81mmolg(-1), respectively. CTA was used as an adsorbent material to remove Co(2+), Cu(2+) and Ni(2+) from monocomponent spiked aqueous solution. Adsorption studies were developed as a function of the solution pH, contact time and initial adsorbate concentration. Langmuir model better fitted the experimental adsorption data and the maximum adsorption capacities estimated by this model were 0.749, 1.487 and 1.001mmolg(-1) for Co(2+), Cu(2+) and Ni(2+), respectively. The adsorption mechanism was investigated by using isothermal titration calorimetry. The values of ΔadsH° were in the range from 5.36 to 8.09kJmol(-1), suggesting that the mechanism controlling the phenomenon is physisorption. Desorption and re-adsorption studies were also performed. Desorption and re-adsorption efficiencies were closer to 100%, allowing the recovery of both metal ions and CTA adsorbent. PMID:27552427

  17. Application of a two-stream radiative transfer model for leaf lignin and cellulose concentrations from spectral reflectance measurements, part 2

    NASA Technical Reports Server (NTRS)

    Conel, James E.; Vandenbosch, Jeannette; Grove, Cindy I.

    1993-01-01

    We used the Kubelka-Munk theory of diffuse spectral reflectance in layers to analyze influences of multiple chemical components in leaves. As opposed to empirical approaches to estimation of plant chemistry, the full spectral resolution of laboratory reflectance data was retained in an attempt to estimate lignin or other constituent concentrations from spectral band positions. A leaf water reflectance spectrum was derived from theoretical mixing rules, reflectance observations, and calculations from theory of intrinsic k- and s-functions. Residual reflectance bands were then isolated from spectra of fresh green leaves. These proved hard to interpret for composition in terms of simple two component mixtures such as lignin and cellulose. We next investigated spectral and dilution influences of other possible components (starch, protein). These components, among others, added to cellulose in hypothetical mixtures, produce band displacements similar to lignin, but will disguise by dilution the actual abundance of lignin present in a multicomponent system. This renders interpretation of band positions problematical. Knowledge of end-members and their spectra, and a more elaborate mixture analysis procedure may be called for. Good observational atmospheric and instrumental conditions and knowledge thereof are required for retrieval of expected subtle reflectance variations present in spectra of green vegetation.

  18. Application of a two-stream radiative transfer model for leaf lignin and cellulose concentrations from spectral reflectance measurements, part 1

    NASA Technical Reports Server (NTRS)

    Conel, James E.; Vandenbosch, Jeannette; Grove, Cindy I.

    1993-01-01

    Lignin and nitrogen contents of leaves constitute the primary rate-limiting parameters for the decomposition of forest litter, and are determinants of nutrient- and carbon-cyclic rates in forest ecosystems (Melillo et al., 1982). Wessman et al. (1988a) developed empirical multivariate relationships between forest canopy lignin amount and the (first-difference) AIS spectral response in three bands spread over the wavelength interval 1256-1555 nm. Wessman et al. (1988b) and McLellan et al. (1991) developed similar regression relationships from laboratory reflectance measurements on dried samples prepared in a standard fashion. They used four to six infrared bands for analysis of nitrogen, lignin and cellulose content of foliage in forest and prairie species. In the present article (Parts 1 and 2) the feasibility of compositional determinations is explored using positions of composite absorption bands that originate from mixtures of lignin, cellulose, and possibly other chemical constituents in the spectral reflectance of green leaves. To carry out this program, we employ full-spectral-resolution single-leaf diffuse reflectance measurements made with a laboratory spectrometer and integrating sphere. The leaf and other chemical reflectance data compiled by Elvidge (1990) have also been utilized extensively.

  19. Electro-mechanical properties of hydrogel composites with micro- and nano-cellulose fillers

    NASA Astrophysics Data System (ADS)

    N, Mohamed Shahid U.; Deshpande, Abhijit P.; Lakshmana Rao, C.

    2015-09-01

    Stimuli responsive cross-linked hydrogels are of great interest for applications in diverse fields such as sensors and biomaterials. In this study, we investigate polymer composites filled with cellulose fillers. The celluloses used in making the composites were a microcrystalline cellulose of commercial grade and cellulose nano-whiskers obtained through acid hydrolysis of microcrystalline cellulose. The filler concentration was varied and corresponding physical, mechanical and electro-mechanical characterization was carried out. The electro-mechanical properties were determined using a quasi-static method. The fillers not only enhance the mechanical properties of the composite by providing better reinforcement but also provide a quantitative electric potential in the composite. The measurements reveal that the polymer composites prepared from two different cellulose fillers possess a quantitative electric potential which can be utilized in biomedical applications. It is argued that the mechanism behind the quantitative electric potential in the composites is due to streaming potentials arising due to electrical double layer formation.

  20. Photooxidation of cellulose nitrate: new insights into degradation mechanisms.

    PubMed

    Berthumeyrie, Sebastien; Collin, Steeve; Bussiere, Pierre-Olivier; Therias, Sandrine

    2014-05-15

    Cellulose nitrate (or nitrocellulose) has received considerable interest due to its uses in various applications, such as paints, photographic films and propellants. However, it is considered as one of the primary pollutants in the energetic material industries because it can be degraded to form polluting chemical species. In this work, the UV light degradation of cellulose nitrate films was studied under conditions of artificially accelerated photooxidation. To eliminate the reactivity of nitro groups, the degradation of ethylcellulose was also investigated. Infrared spectroscopy analyses of the chemical modifications caused by the photooxidation of cellulose nitrate films and the resulting formation of volatile products revealed the occurrence of de-nitration and the formation of oxidation photoproducts exhibiting lactone and anhydride functions. The impact of these chemical modifications on the mechanical and thermal properties of cellulose nitrate films includes embrittlement and lower temperatures of ignition when used as a propellant. PMID:24685530

  1. Preparation of succinylated cellulose membranes for functionalization purposes.

    PubMed

    Ribeiro-Viana, Renato M; Faria-Tischer, Paula C S; Tischer, Cesar A

    2016-09-01

    The anhydroglucose chains of cellulose possess hydroxyls that facilitate different chemical modification strategies to expand on, or provide new applications for membranes produced by the bacteria Gluconacetobacter xylinus. Conjugation with biomolecules such as proteins, especially by the amine groups, is of great value and interest for the production of biomaterial derivatives from bacterial cellulose. To assist in these modifications, cellulose was succinylated in order to prevent steric hindrance and to create an attachment point for conjugation. Bacterial cellulose membranes were first treated in dichloromethane and reacted with succinic anhydride through a series of conditions. The membrane structure remained intact after these first processes and the product was confirmed by Infra-Red spectroscopy and solid state nuclear magnetic resonance and characterized by X-ray diffraction, thermogravimetry and atomic force microscopy. Hydrolyzed collagen was used as a model protein of interest to be conjugated to these membranes, which furnished a biomaterial functionalized over its surface. PMID:27185111

  2. Establishment of alpha-cellulose extraction method and its application using tropical tree sungkai (Peronema canescens Jack) for reliable paleoclimate reconstruction in tropical areas

    NASA Astrophysics Data System (ADS)

    Harada, M.; Watanabe, Y.; Nakatsuka, T.; Tazuru, S.; Horikawa, Y.; Sugiyama, J.; Tsuda, T.; Tagami, T.

    2012-04-01

    Tree rings are widely used to reconstruct paleoclimate in terrestrial areas in terms of high spatial / temporal resolution and great sensitivity for climatic factors (e.g., precipitation, relative humidity, air temperature, etc.). However, this is not necessarily the case for Asian tropical trees because growth rings of many tropical trees are ambiguous and also because trees that grow in dense rainforest are affected by other environmental factors, such as the existence of neighboring trees. Oxygen isotopic ratio of tree-ring alpha-cellulose can be a proxy of paleoclimate reconstruction in areas where little correlation is found between tree-ring widths and climatic factors [Waterhouse et al., 2002; Rinne et al., 2005]. Thus, continuous, alternative meteorological data in Asian tropical areas that drive the global climate system can also be provided by measuring the oxygen isotopic ratio of alpha-cellulose of tropical trees. Previous works showed that tree-ring components (mainly cellulose, hemicelluloses and lignin) have different isotopic ratios [Wilson and Grinsted, 1977; Loader et al., 2003]. In addition, the isotopic ratios of untreated samples show weaker correlations with climate signals than that of chemically treated samples [Rinne et al., 2005]. For these reasons, it is necessary to effectively extract only alpha-cellulose for reliable paleoclimatic reconstruction. Furtermore, an optimum processing time can be different between species and hence it needs to be determined for each. However, there is no report that aims at estimation of an optimum processing time using tropical hardwoods. Sungkai (Peronema canescens Jack) is one of tropical hardwood species that formed distinct growth rings and has high sensitivity species for environment [Ohashi et al., 1992]. In this study, the optimum alpha-cellulose extraction time was estimated for sungkai (SungkaiNAN7, collected at Serang, West Java, Indonesia) by measuring oxygen and carbon isotopic ratios, ATR

  3. Anomalous scaling law of strength and toughness of cellulose nanopaper

    PubMed Central

    Zhu, Hongli; Zhu, Shuze; Jia, Zheng; Parvinian, Sepideh; Li, Yuanyuan; Vaaland, Oeyvind; Hu, Liangbing; Li, Teng

    2015-01-01

    The quest for both strength and toughness is perpetual in advanced material design; unfortunately, these two mechanical properties are generally mutually exclusive. So far there exists only limited success of attaining both strength and toughness, which often needs material-specific, complicated, or expensive synthesis processes and thus can hardly be applicable to other materials. A general mechanism to address the conflict between strength and toughness still remains elusive. Here we report a first-of-its-kind study of the dependence of strength and toughness of cellulose nanopaper on the size of the constituent cellulose fibers. Surprisingly, we find that both the strength and toughness of cellulose nanopaper increase simultaneously (40 and 130 times, respectively) as the size of the constituent cellulose fibers decreases (from a mean diameter of 27 μm to 11 nm), revealing an anomalous but highly desirable scaling law of the mechanical properties of cellulose nanopaper: the smaller, the stronger and the tougher. Further fundamental mechanistic studies reveal that reduced intrinsic defect size and facile (re)formation of strong hydrogen bonding among cellulose molecular chains is the underlying key to this new scaling law of mechanical properties. These mechanistic findings are generally applicable to other material building blocks, and therefore open up abundant opportunities to use the fundamental bottom-up strategy to design a new class of functional materials that are both strong and tough. PMID:26150482

  4. Hairy cellulose nanocrystalloids: a novel class of nanocellulose.

    PubMed

    van de Ven, Theo G M; Sheikhi, Amir

    2016-08-18

    Nanomaterials have secured such a promising role in today's life that imagining the modern world without them is almost impossible. A large fraction of nanomaterials is synthesized from environmentally-dangerous elements such as heavy metals, which have posed serious side-effects to ecosystems. Despite numerous advantages of synthetic nanomaterials, issues such as renewability, sustainability, biocompatibility, and cost efficiency have drawn significant attention towards natural products such as cellulose-based nanomaterials. Within the past decade, nanocelluloses, most remarkably nanocrystalline cellulose (NCC) and nanofibrillated cellulose (NFC), have successfully been used for a wide spectrum of applications spanning from nanocomposites, packaging, and mechanical and rheological property modifications, to chemical catalysis and organic templating. Yet, there has been little effort to introduce fundamentally new polysaccharide-based nanomaterials. We have been able to develop the first kind of cellulose-based nanoparticles bearing both crystalline and amorphous regions. These nanoparticles comprise a crystalline body, similar to conventional NCC, but with polymer chains protruding from both ends; therefore, these particles are called hairy cellulose nanocrystalloids (HCNC). In this article, we touch on the philosophy of HCNC synthesis, the striking superiority over existing nanocelluloses, and applications of this novel class of nanocelluloses. We hope that the emergence of hairy cellulose nanocrystalloids extends the frontiers of sustainable, green nanotechnology. PMID:27453347

  5. Water-repellent cellulose fiber networks with multifunctional properties.

    PubMed

    Bayer, Ilker S; Fragouli, Despina; Attanasio, Agnese; Sorce, Barbara; Bertoni, Giovanni; Brescia, Rosaria; Di Corato, Riccardo; Pellegrino, Teresa; Kalyva, Maria; Sabella, Stefania; Pompa, Pier Paolo; Cingolani, Roberto; Athanassiou, Athanassia

    2011-10-01

    We demonstrate a simple but highly efficient technique to introduce multifunctional properties to cellulose fiber networks by wetting them with ethyl-cyanoacrylate monomer solutions containing various suspended organic submicrometer particles or inorganic nanoparticles. Solutions can be applied on cellulosic surfaces by simple solution casting techniques or by dip coating, both being suitable for large area applications. Immediately after solvent evaporation, ethyl-cyanoacrylate starts cross-linking around cellulose fibers under ambient conditions because of naturally occurring surface hydroxyl groups and adsorbed moisture, encapsulating them with a hydrophobic polymer shell. Furthermore, by dispersing various functional particles in the monomer solutions, hydrophobic ethyl-cyanoacrylate nanocomposites with desired functionalities can be formed around the cellulose fibers. To exhibit the versatility of the method, cellulose sheets were functionalized with different ethyl-cyanoacrylate nanocomposite shells comprising submicrometer wax or polytetrafluoroethylene particles for superhydophobicity, MnFe(2)O(4) nanoparticles for magnetic activity, CdSe/ZnS quantum dots for light emission, and silver nanoparticles for antimicrobial activity. Morphological and functional properties of each system have been studied by scanning and transmission electron microscopy, detailed contact angle measurements, light emission spectra and E. coli bacterial growth measurements. A plethora of potential applications can be envisioned for this technique, such as food and industrial packaging, document protection, catalytic cellulosic membranes, textronic (electrofunctional textiles), electromagnetic devices, authentication of valuable documents, and antimicrobial wound healing products to name a few. PMID:21902239

  6. Cellulose Synthesis in Agrobacterium tumefaciens

    SciTech Connect

    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

  7. Ultrasonic dyeing of cellulose nanofibers.

    PubMed

    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

  8. Process Dependence of Cellulose Nanofiber Fabrication

    NASA Astrophysics Data System (ADS)

    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.

  9. Cellulose nanocrystals/cellulose core-in-shell nanocomposite assemblies.

    PubMed

    Magalhães, Washington Luiz Esteves; Cao, Xiaodong; Lucia, Lucian A

    2009-11-17

    We report herein for the first time how a co-electrospinning technique can be used to overcome the issue of orienting cellulose nanocrystals within a neat cellulose matrix. A home-built co-electrospinning apparatus was fabricated that was comprised of a high-voltage power supply, two concentric capillary needles, and one screw-type pump syringe. Eucalyptus-derived cellulose was dissolved in N-methylmorpholine oxide (NMMO) at 120 degrees C and diluted with dimethyl sulfoxide (DMSO) which was used in the external concentric capillary needle as the shell solution. A cellulose nanocrystal suspension obtained by the sulfuric acid hydrolysis of bleached sisal and cotton fibers was used as the core liquid in the internal concentric capillary needle. Three flow rate ratios between the shell and core, four flow rates for the shell dope solution, and four high voltages were tested. The resultant co-electrospun composite fibers were collected onto a grounded metal screen immersed in cold water. Micrometer and submicrometer cellulose fiber assemblies were obtained which were reinforced with cellulose nanocrystals and characterized by FESEM, FTIR, TGA, and XRD. Surprisingly, it was determined that the physical properties for the cellulose controls are superior to the composites; in addition, the crystallinity of the controls was slightly greater. PMID:19731951

  10. [Microcrystalline cellulose and their flow -- morphological properties modifications as an effective excpients in tablet formulation technology containing lattice established API and also dry plant extract].

    PubMed

    Zgoda, Marian Mikołaj; Nachajski, Michał Jakub; Kołodziejczyk, Michał Krzysztof

    2009-01-01

    The production technology of powder cellulose (Arbocel) and microcrystaline cellulose (Vivapur) and their application in the composition of direct compression tablet mass was provided. The function of silicified microcrystaline cellulose type Prosolv in the direct compression process of dry plant extract was discussed. An analysis of the chemical structure of cellulose fiber (Vitacel) enabled determining its properties and applications in the manufacture of diet supplement, pharmaceutical and food products. PMID:19580170

  11. IMPACTS OF BIOFILM FORMATION ON CELLULOSE FERMENTATION

    SciTech Connect

    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. Low pour crude oil compositions

    SciTech Connect

    Motz, K.L.; Latham, R.A.; Statz, R.J.

    1990-05-22

    This patent describes and improvement in the process of transporting waxy crude oils through a pipeline. It comprises: incorporating into the crude oil an effective pour point depressant amount of an additive comprising a polymer selected from the group consisting of copolymers of ethylene and acrylonitrile, and terpolymers of ethylene, acrylonitrile and a third monomer selected from the group consisting of vinyl acetate, carbon monoxide, alkyl acrylates, alkyl methacrylates, alkyl vinyl ethers, vinyl chloride, vinyl fluoride, acrylic acid, and methacrylic acid, wherein the amount of third monomer in the terpolymer ranges from about 0.1 to about 10.0 percent by weight.

  13. Analysis of the DWPF glass pouring system using neural networks

    SciTech Connect

    Calloway, T.B. Jr.; Jantzen, C.M.; Medich, L.; Spennato, N.

    1997-08-05

    Neural networks were used to determine the sensitivity of 39 selected Melter/Melter Off Gas and Melter Feed System process parameters as related to the Defense Waste Processing Facility (DWPF) Melter Pour Spout Pressure during the overall analysis and resolution of the DWPF glass production and pouring issues. Two different commercial neural network software packages were used for this analysis. Models were developed and used to determine the critical parameters which accurately describe the DWPF Pour Spout Pressure. The model created using a low-end software package has a root mean square error of {+-} 0.35 inwc (< 2% of the instrument`s measured range, R{sup 2} = 0.77) with respect to the plant data used to validate and test the model. The model created using a high-end software package has a R{sub 2} = 0.97 with respect to the plant data used to validate and test the model. The models developed for this application identified the key process parameters which contribute to the control of the DWPF Melter Pour Spout pressure during glass pouring operations. The relative contribution and ranking of the selected parameters was determined using the modeling software. Neural network computing software was determined to be a cost-effective software tool for process engineers performing troubleshooting and system performance monitoring activities. In remote high-level waste processing environments, neural network software is especially useful as a replacement for sensors which have failed and are costly to replace. The software can be used to accurately model critical remotely installed plant instrumentation. When the instrumentation fails, the software can be used to provide a soft sensor to replace the actual sensor, thereby decreasing the overall operating cost. Additionally, neural network software tools require very little training and are especially useful in mining or selecting critical variables from the vast amounts of data collected from process computers.

  14. Antibacterial activity of nanocomposites of copper and cellulose.

    PubMed

    Pinto, Ricardo J B; Daina, Sara; Sadocco, Patrizia; Pascoal Neto, Carlos; Trindade, Tito

    2013-01-01

    The design of cheap and safe antibacterial materials for widespread use has been a challenge in materials science. The use of copper nanostructures combined with abundant biopolymers such as cellulose offers a potential approach to achieve such materials though this has been less investigated as compared to other composites. Here, nanocomposites comprising copper nanofillers in cellulose matrices have been prepared by in situ and ex situ methods. Two cellulose matrices (vegetable and bacterial) were investigated together with morphological distinct copper particulates (nanoparticles and nanowires). A study on the antibacterial activity of these nanocomposites was carried out for Staphylococcus aureus and Klebsiella pneumoniae, as pathogen microorganisms. The results showed that the chemical nature and morphology of the nanofillers have great effect on the antibacterial activity, with an increase in the antibacterial activity with increasing copper content in the composites. The cellulosic matrices also show an effect on the antibacterial efficiency of the nanocomposites, with vegetal cellulose fibers acting as the most effective substrate. Regarding the results obtained, we anticipate the development of new approaches to prepare cellulose/copper based nanocomposites thereby producing a wide range of interesting antibacterial materials with potential use in diverse applications such as packaging or paper coatings. PMID:24455681

  15. Cellulose fermentation by nitrogen-fixing anaerobic bacteria

    SciTech Connect

    Canale-Parola, E.

    1992-12-13

    In anaerobic natural environments cellulose is degraded to methane, carbon dioxide and other products by the combined activities of many diverse microorganisms. We are simulating processes occurring in natural environments by constructing biologically-defined, stable, heterogeneous bacterial communities (consortia) that we use as in vitro systems for quantitative studies of cellulose degradation under conditions of combined nitrogen deprivation. These studies include the investigation of (i) metabolic interactions among members of cellulose-degrading microbial populations, and (ii) processes that regulate the activity or biosynthesis of cellulolytic enzymes. In addition, we are studying the sensory mechanisms that, in natural environments, may enable motile cellulolytic bacteria to migrate toward cellulose. This part of our work includes biochemical characterization of the cellobiose chemoreceptor of cellulolytic bacteria. Finally, an important aspect of our research is the investigation of the mechanisms by which multienzyme complexes of anaerobic bacteria catalyze the depolymerization of crystalline cellulose and of other plant cell wall polysacchaddes. The research will provide fundamental information on the physiology and ecology of cellulose-fermenting, N{sub 2}-fixing bacteria, and on the intricate processes involved in C and N cycling in anaerobic environments. Furthermore, the information will be valuable for the development of practical applications, such as the conversion of plant biomass (e.g., agricultural, forestry and municipal wastes) to automotive fuels such as ethanol.

  16. Antibacterial Activity of Nanocomposites of Copper and Cellulose

    PubMed Central

    Pinto, Ricardo J. B.; Daina, Sara; Neto, Carlos Pascoal; Trindade, Tito

    2013-01-01

    The design of cheap and safe antibacterial materials for widespread use has been a challenge in materials science. The use of copper nanostructures combined with abundant biopolymers such as cellulose offers a potential approach to achieve such materials though this has been less investigated as compared to other composites. Here, nanocomposites comprising copper nanofillers in cellulose matrices have been prepared by in situ and ex situ methods. Two cellulose matrices (vegetable and bacterial) were investigated together with morphological distinct copper particulates (nanoparticles and nanowires). A study on the antibacterial activity of these nanocomposites was carried out for Staphylococcus aureus and Klebsiella pneumoniae, as pathogen microorganisms. The results showed that the chemical nature and morphology of the nanofillers have great effect on the antibacterial activity, with an increase in the antibacterial activity with increasing copper content in the composites. The cellulosic matrices also show an effect on the antibacterial efficiency of the nanocomposites, with vegetal cellulose fibers acting as the most effective substrate. Regarding the results obtained, we anticipate the development of new approaches to prepare cellulose/copper based nanocomposites thereby producing a wide range of interesting antibacterial materials with potential use in diverse applications such as packaging or paper coatings. PMID:24455681

  17. Cellulose Derivatives for Water Repellent Properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  18. Cellulose Derivatives for Water Repellent Properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Synthesis and structural characterizations of nitro-benzyl cellulose, amino-benzyl cellulose and pentafluoro –benzyl cellulose were carried out. Cellulose derivatives were synthesized by etherification process in lithium chloride/N,N-dimethylacetamide homogeneous solution. Nitrobenzylation was effec...

  19. Assemblies of Cellulose Nanocrystals

    NASA Astrophysics Data System (ADS)

    Kumacheva, Eugenia

    The entropically driven coassembly of nanorods (cellulose nanocrystals, CNCs) and different types of nanoparticles (NPs), including dye-labeled latex NPs, carbon dots and plasmonic NPs was experimentally studied in aqueous suspensions and in solid films. In mixed CNC-NP suspensions, phase separation into an isotropic NP-rich and a chiral nematic CNC-rich phase took place; the latter contained a significant amount of NPs. Drying the mixed suspension resulted in CNC-NP films with planar disordered layers of NPs, which alternated with chiral nematic CNC-rich regions. In addition, NPs were embedded in the chiral nematic domains. The stratified morphology of the films, together with a random distribution of NPs in the anisotropic phase, led to the films having close-to-uniform fluorescence, birefringence, and circular dichroism properties.

  20. Perichromism: a powerful tool for probing the properties of cellulose and its derivatives.

    PubMed

    Fidale, Ludmila C; Heinze, Thomas; El Seoud, Omar A

    2013-03-01

    This overview is concerned with the use of certain dyes (perichromic indicators, hereafter designated as "probes") in order to determine the properties of cellulose, its solutions and solid derivatives. It is arranged as follows: (i) the properties of cellulose and its derivatives that are relevant to their applications are listed; (ii) a general discussion is presented on how perichromism can be employed in order to gain information on the medium where the probe is present; (iii) the results of perichromism, as applied to cellulose, cellulose solutions, and derivative films are discussed. PMID:23465911

  1. Visualization of Nanofibrillar Cellulose in Biological Tissues Using a Biotinylated Carbohydrate Binding Module of β-1,4-Glycanase.

    PubMed

    Knudsen, Kristina Bram; Kofoed, Christian; Espersen, Roall; Højgaard, Casper; Winther, Jakob Rahr; Willemoës, Martin; Wedin, Irene; Nuopponen, Markus; Vilske, Sara; Aimonen, Kukka; Weydahl, Ingrid Elise Konow; Alenius, Harri; Norppa, Hannu; Wolff, Henrik; Wallin, Håkan; Vogel, Ulla

    2015-08-17

    Nanofibrillar cellulose is a very promising innovation with diverse potential applications including high quality paper, coatings, and drug delivery carriers. The production of nanofibrillar cellulose on an industrial scale may lead to increased exposure to nanofibrillar cellulose both in the working environment and the general environment. Assessment of the potential health effects following exposure to nanofibrillar cellulose is therefore required. However, as nanofibrillar cellulose primarily consists of glucose moieties, detection of nanofibrillar cellulose in biological tissues is difficult. We have developed a simple and robust method for specific and sensitive detection of cellulose fibers, including nanofibrillar cellulose, in biological tissue, using a biotinylated carbohydrate binding module (CBM) of β-1,4-glycanase (EXG:CBM) from the bacterium Cellulomonas fimi. EXG:CBM was expressed in Eschericia coli, purified, and biotinylated. EXG:CBM was shown to bind quantitatively to five different cellulose fibers including four different nanofibrillar celluloses. Biotinylated EXG:CBM was used to visualize cellulose fibers by either fluorescence- or horse radish peroxidase (HRP)-tagged avidin labeling. The HRP-EXG:CBM complex was used to visualize cellulose fibers in both cryopreserved and paraffin embedded lung tissue from mice dosed by pharyngeal aspiration with 10-200 μg/mouse. Detection was shown to be highly specific, and the assay appeared very robust. The present method represents a novel concept for the design of simple, robust, and highly specific detection methods for the detection of nanomaterials, which are otherwise difficult to visualize. PMID:26208679

  2. Magnetic cellulose-derivative structures

    DOEpatents

    Walsh, Myles A.; Morris, Robert S.

    1986-09-16

    Structures to serve as selective magnetic sorbents are formed by dissolving a cellulose derivative such as cellulose triacetate in a solvent containing magnetic particles. The resulting solution is sprayed as a fine mist into a chamber containing a liquid coagulant such as n-hexane in which the cellulose derivative is insoluble but in which the coagulant is soluble or miscible. On contact with the coagulant, the mist forms free-flowing porous magnetic microspheric structures. These structures act as containers for the ion-selective or organic-selective sorption agent of choice. Some sorbtion agents can be incorporated during the manufacture of the structure.

  3. Thermophilic degradation of cellulosic biomass

    NASA Astrophysics Data System (ADS)

    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.

  4. Magnetic cellulose-derivative structures

    DOEpatents

    Walsh, M.A.; Morris, R.S.

    1986-09-16

    Structures to serve as selective magnetic sorbents are formed by dissolving a cellulose derivative such as cellulose triacetate in a solvent containing magnetic particles. The resulting solution is sprayed as a fine mist into a chamber containing a liquid coagulant such as n-hexane in which the cellulose derivative is insoluble but in which the coagulant is soluble or miscible. On contact with the coagulant, the mist forms free-flowing porous magnetic microspheric structures. These structures act as containers for the ion-selective or organic-selective sorption agent of choice. Some sorption agents can be incorporated during the manufacture of the structure. 3 figs.

  5. Application de l'A.D.L, pour la mesure du champ de vitesses instationnaires de llecoulement a Ilechappement d'un moteur a combustion interne

    NASA Astrophysics Data System (ADS)

    Boutrif, M. S.; Thelliez, M.

    1993-01-01

    We present experimental results of instantaneous velocity measurement, which were obtained by application of the laser Doppler anemometry (L.D.A.) at the exhaust pipe of a reciprocating engine under real working conditions. First of all, we show that the instantaneous velocity is monodimensional along a straight exhaust pipe, and that the boundary layer develops within a 2mm thickness. We also show that the cylinder discharges in two phases : the blow down period and the final part of exhaust stroke. We also make obvious, that the flow escapes very quickly : its velocity varies between - 100m/s and 200m/s within a period shorter than 1ms ; thereby, we do record the acoustic resonance phenomenon, when the engine speed is greater than 3 000rpm. Finally, we show that in the exhaust pipe the apparent fluctuation - i.e. the cyclic dispersion and the actual turbulence - may reach 15%. Nous présentons des résultats expérimentaux du champ de vitesses instationnaires, obtenus par adaptation et application de la vélocimétrie laser interférentielle communément appelée à effet Doppler (L.D.A.), à l'échappement d'un moteur altematif à combustion inteme en fonctionnement nominal. Tout d'abord, nous montrons que dans un tube d'échappement long et droit, la vitesse instantanée est bien monodimensionnelle et que l'écoulement occupe la quasitotalité de la section droite géométrique du tube (une couche limite d'épaisseur inférieure à 2mm se développe très près de la paroi du tube). Nous pouvons également décrire la vidange du cylindre du moteur étudié en deux phases principales : bouffée d'échappement et refoulement des gaz brûlés par le piston. Nous mettons de même en évidence l'état très pulsé de l'écoulement, puisqu'en un intervalle de temps inférieur à 1ms, la vitesse de l'écoulement varie de - 100m/s à 200m/s ; nous enregistrons ainsi l'apparition du phénomène de résonance acoustique à des vitesses de rotation supérieures à 3 500

  6. Novel In Vivo-Degradable Cellulose-Chitin Copolymer from Metabolically Engineered Gluconacetobacter xylinus▿ †

    PubMed Central

    Yadav, Vikas; Paniliatis, Bruce J.; Shi, Hai; Lee, Kyongbum; Cebe, Peggy; Kaplan, David L.

    2010-01-01

    Despite excellent biocompatibility and mechanical properties, the poor in vitro and in vivo degradability of cellulose has limited its biomedical and biomass conversion applications. To address this issue, we report a metabolic engineering-based approach to the rational redesign of cellular metabolites to introduce N-acetylglucosamine (GlcNAc) residues into cellulosic biopolymers during de novo synthesis from Gluconacetobacter xylinus. The cellulose produced from these engineered cells (modified bacterial cellulose [MBC]) was evaluated and compared with cellulose produced from normal cells (bacterial cellulose [BC]). High GlcNAc content and lower crystallinity in MBC compared to BC make this a multifunctional bioengineered polymer susceptible to lysozyme, an enzyme widespread in the human body, and to rapid hydrolysis by cellulase, an enzyme commonly used in biomass conversion. Degradability in vivo was demonstrated in subcutaneous implants in mice, where modified cellulose was completely degraded within 20 days. We provide a new route toward the production of a family of tailorable modified cellulosic biopolymers that overcome the longstanding limitation associated with the poor degradability of cellulose for a wide range of potential applications. PMID:20656868

  7. Cellulose membrane as a biomaterial: from hydrolysis to depolymerization with electron beam.

    PubMed

    Eo, Mi Young; Fan, Huan; Cho, Yun Ju; Kim, Soung Min; Lee, Suk Keun

    2016-01-01

    The cellulose membrane (CM) is a major component of plant cell walls and is both a chemically and mechanically stable synthetic polymer with many applications for use in tissue engineering. However, due to its dissolution difficulty, there are no known physiologically relevant or pharmaceutically clinical applications for this polymer. Thus, research is underway on controlled and adjusted forms of cellulose depolymerization. To advance the study of applying CM for tissue engineering, we have suggested new possibilities for electron beam (E-beam) treatment of CM. Treatment of CM with an E-beam can modify physical, chemical, molecular and biological properties, so it can be studied continuously to improve its usefulness and to enhance value. We review clinical applications of CM, cellulose binding domains, cellulose crosslinking proteins, conventional hydrolysis of cellulose, and depolymerization with radiation and focus our experiences with depolymerization of E-beam irradiated CM in this article. PMID:27418974

  8. Silicon cantilever functionalization for cellulose-specific chemical force imaging of switchgrass

    DOE PAGESBeta

    Lee, Ida; Evans, Barbara R.; Foston, Marcus B.; Ragauskas, Arthur J.

    2015-05-08

    A method for direct functionalization of silicon and silicon nitride cantilevers with bifunctional silanes was tested with model surfaces to determine adhesive forces for different hydrogen-bonding chemistries. Application for biomass surface characterization was tested by mapping switchgrass and isolated switchgrass cellulose in topographic and force-volume mode using a cellulose-specific cantilever.

  9. PRETREATMENT AND SUBSTRATE EVALUATION FOR THE ENZYMATIC HYDROLYSIS OF CELLULOSIC WASTES

    EPA Science Inventory

    Presented are initial studies aimed at determining the applicability of various pretreatment methods and existing cellulosic wastes to a process for the conversion of cellulose to glucose and other reducing sugars. In this process, a cellulase from a mutant of Trichoderma viride ...

  10. Physical and mechanical testing of essential oil-embedded cellulose ester films

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Polymer films made from cellulose esters are useful for embedding plant essential oils, either for food packaging or air freshener applications. Studies and testing were done on the physical and mechanical properties of cellulose ester-based films incorporating essential oils (EO) from lemongrass (C...

  11. Kits and methods of detection using cellulose binding domain fusion proteins

    DOEpatents

    Shoseyov, O.; Yosef, K.

    1998-04-14

    A cellulose binding domain (CBD) having a high affinity for crystalline cellulose and chitin is disclosed, along with methods for the molecular cloning and recombinant production. Fusion products comprising the CBD and a second protein are likewise described. A wide range of applications are contemplated for both the CBD and the fusion products, including drug delivery, affinity separations, and diagnostic techniques. 16 figs.

  12. Kits and methods of detection using cellulose binding domain fusion proteins

    DOEpatents

    Shoseyov, Oded

    1998-01-01

    A cellulose binding domain (CBD) having a high affinity for crystalline cellulose and chitin is disclosed, along with methods for the molecular cloning and recombinant production thereof. Fusion products comprising the CBD and a second protein are likewise described. A wide range of applications are contemplated for both the CBD and the fusion products, including drug delivery, affinity separations, and diagnostic techniques.

  13. 40 CFR 80.1456 - What are the provisions for cellulosic biofuel waiver credits?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... biofuel waiver credits? 80.1456 Section 80.1456 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... What are the provisions for cellulosic biofuel waiver credits? (a) If EPA reduces the applicable volume of cellulosic biofuel pursuant to section 211(o)(7)(D)(i) of the Clean Air Act (42 U.S.C....

  14. 40 CFR 80.1456 - What are the provisions for cellulosic biofuel waiver credits?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... biofuel waiver credits? 80.1456 Section 80.1456 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... What are the provisions for cellulosic biofuel waiver credits? (a) If EPA reduces the applicable volume of cellulosic biofuel pursuant to section 211(o)(7)(D)(i) of the Clean Air Act (42 U.S.C....

  15. 40 CFR 80.1456 - What are the provisions for cellulosic biofuel waiver credits?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... biofuel waiver credits? 80.1456 Section 80.1456 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... What are the provisions for cellulosic biofuel waiver credits? (a) If EPA reduces the applicable volume of cellulosic biofuel pursuant to section 211(o)(7)(D)(i) of the Clean Air Act (42 U.S.C....

  16. 40 CFR 80.1456 - What are the provisions for cellulosic biofuel waiver credits?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... biofuel waiver credits? 80.1456 Section 80.1456 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... What are the provisions for cellulosic biofuel waiver credits? (a) If EPA reduces the applicable volume of cellulosic biofuel pursuant to section 211(o)(7)(D)(i) of the Clean Air Act (42 U.S.C....

  17. Silicon cantilever functionalization for cellulose-specific chemical force imaging of switchgrass

    SciTech Connect

    Lee, Ida; Evans, Barbara R; Foston, Marcus B; Ragauskas, Arthur J

    2015-01-01

    A method for direct functionalization of silicon and silicon nitride cantilevers with bifunctional silanes was tested with model surfaces to determine adhesive forces for different hydrogen-bonding chemistries. Application for biomass surface characterization was tested by mapping switchgrass and isolated switchgrass cellulose in topographic and force-volume mode using a cellulose-specific cantilever.

  18. Hydrogen peroxide production from fibrous pectic cellulose analogs and effect on dermal fibroblasts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Naturally derived products with folklore remedies have in recent years been reconsidered for their benefit to wound healing i.e., honey’s application to chronic wound dressing products. Similarly, we have undertaken an evaluation of Fibrous pectin-cellulose (FPC) (cellulose blended with primary cel...

  19. A functional cellulose synthase from ascidian epidermis

    PubMed Central

    Matthysse, Ann G.; Deschet, Karine; Williams, Melanie; Marry, Mazz; White, Alan R.; Smith, William C.

    2004-01-01

    Among animals, urochordates (e.g., ascidians) are unique in their ability to biosynthesize cellulose. In ascidians cellulose is synthesized in the epidermis and incorporated into a protective coat know as the tunic. A putative cellulose synthase-like gene was first identified in the genome sequences of the ascidian Ciona intestinalis. We describe here a cellulose synthase gene from the ascidian Ciona savignyi that is expressed in the epidermis. The predicted C. savignyi cellulose synthase amino acid sequence showed conserved features found in all cellulose synthases, including plants, but was most similar to cellulose synthases from bacteria, fungi, and Dictyostelium discoidium. However, unlike other known cellulose synthases, the predicted C. savignyi polypeptide has a degenerate cellulase-like region near the carboxyl-terminal end. An expression construct carrying the C. savignyi cDNA was found to restore cellulose biosynthesis to a cellulose synthase (CelA) minus mutant of Agrobacterium tumefaciens, showing that the predicted protein has cellulose synthase activity. The lack of cellulose biosynthesis in all other groups of metazoans and the similarity of the C. savignyi cellulose synthase to enzymes from cellulose-producing organisms support the hypothesis that the urochordates acquired the cellulose biosynthetic pathway by horizontal transfer. PMID:14722352

  20. Towards electronic paper displays made from microbial cellulose.

    PubMed

    Shah, Jay; Brown, R Malcolm

    2005-01-01

    Cellulose (in the form of printed paper) has always been the prime medium for displaying information in our society and is far better than the various existing display technologies. This is because of its high reflectivity, contrast, low cost and flexibility. There is a major initiative to push for a dynamic display technology that emulates paper (popularly known as "electronic paper"). We have successfully demonstrated the proof of the concept of developing a dynamic display on cellulose. To the best of our knowledge, this is the first significant effort to achieve an electronic display using bacterial cellulose. First, bacterial cellulose is synthesized in a culture of Acetobacter xylinum in standard glucose-rich medium. The bacterial cellulose membrane thus formed (not pulp) is dimensionally stable, has a paper-like appearance and has a unique microfibrillar nanostructure. The technique then involves first making the cellulose an electrically conducting (or semi-conducting) sheet by depositing ions around the microfibrils to provide conducting pathways and then immobilizing electrochromic dyes within the microstructure. The whole system is then cased between transparent electrodes, and upon application of switching potentials (2-5 V) a reversible color change can be demonstrated down to a standard pixel-sized area (ca. 100 microm2). Using a standard back-plane or in-plane drive circuit, a high-resolution dynamic display device using cellulose as substrate can be constructed. The major advantages of such a device are its high paper-like reflectivity, flexibility, contrast and biodegradability. The device has the potential to be extended to various applications, such as e-book tablets, e-newspapers, dynamic wall papers, rewritable maps and learning tools. PMID:15538556

  1. Preparation and characterization of transparent PMMA-cellulose-based nanocomposites.

    PubMed

    Kiziltas, Esra Erbas; Kiziltas, Alper; Bollin, Shannon C; Gardner, Douglas J

    2015-01-01

    Nanocomposites of polymethylmethacrylate (PMMA) and cellulose were made by a solution casting method using acetone as the solvent. The nanofiber networks were prepared using three different types of cellulose nanofibers: (i) nanofibrillated cellulose (NFC), (ii) cellulose nanocrystals (CNC) and (iii) bacterial cellulose from nata de coca (NDC). The loading of cellulose nanofibrils in the PMMA varied between 0.25 and 0.5 wt%. The mechanical properties of the composites were evaluated using a dynamic mechanical thermal analyzer (DMTA). The flexural modulus of the nanocomposites reinforced with NDC at the 0.5 wt% loading level increased 23% compared to that of pure PMMA. The NFC composite also exhibited a slightly increased flexural strength around 60 MPa while PMMA had a flexural strength of 57 MPa. The addition of NDC increased the storage modulus (11%) compared to neat PMMA at room temperature while the storage modulus of PPMA/CNC nanocomposite containing 0.25 and 0.5 wt% cellulose increased about 46% and 260% to that of the pure PMMA at the glass transition temperature, respectively. Thermogravimetric analysis (TGA) indicated that there was no significant change in thermal stability of the composites. The UV-vis transmittance of the CNF nanocomposites decreased by 9% and 27% with the addition of 0.25 wt% CNC and NDC, respectively. This work is intended to spur research and development activity for application of CNF reinforced PMMA nanocomposites in applications such as: packaging, flexible screens, optically transparent films and light-weight transparent materials for ballistic protection. PMID:25965497

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  3. Immobilization of β-glucosidase from Aspergillus niger on κ-carrageenan hybrid matrix and its application on the production of reducing sugar from macroalgae cellulosic residue.

    PubMed

    Tan, Inn Shi; Lee, Keat Teong

    2015-05-01

    A novel concept for the synthesis of a stable polymer hybrid matrix bead was developed in this study. The beads were further applied for enzyme immobilization to produce stable and active biocatalysts with low enzyme leakage, and high immobilization efficiency, enzyme activity, and recyclability. The immobilization conditions, including PEI concentration, activation time and pH of the PEI solution were investigated and optimized. All formulated beads were characterized for its functionalized groups, composition, surface morphology and thermal stability. Compared with the free β-glucosidase, the immobilized β-glucosidase on the hybrid matrix bead was able to tolerate broader range of pH values and higher reaction temperature up to 60 °C. The immobilized β-glucosidase was then used to hydrolyse pretreated macroalgae cellulosic residue (MCR) for the production of reducing sugar and a hydrolysis yield of 73.4% was obtained. After repeated twelve runs, immobilized β-glucosidase retained about 75% of its initial activity. PMID:25465785

  4. A novel adsorbent TEMPO-mediated oxidized cellulose nanofibrils modified with PEI: Preparation, characterization, and application for Cu(II) removal.

    PubMed

    Zhang, Nan; Zang, Guo-Long; Shi, Chen; Yu, Han-Qing; Sheng, Guo-Ping

    2016-10-01

    This study describes the preparation of a novel adsorbent based on cellulose nanofibrils by first TEMPO mediated oxidation and then PEI grafting (TOCN-PEI) for heavy metal removal. FTIR results demonstrated the successful introduction of the adsorption functional groups (carboxyl and amino groups), and the elemental analysis and acid base titration were used to quantify the contents of these introduced groups. The kinetics curve suited the pseudo-second-order model better and the equilibrium data well fitted the Langmuir model, with the maximum Cu(II) uptake of 52.32mgg(-1). Kinetic study showed that the PEI grafting increased the initial adsorption rate of the TOCN-PEI compared with the adsorbents without PEI. Thermodynamic study was carried out through isothermal titration calorimetry (ITC) measurement and the binding reaction was found to be exothermic and driven by enthalpy change. The adsorption process by TOCN-PEI was pH dependent, and decreasing pH would lead to desorption of Cu(II) ions, thus make the reuse of the absorbent more convenient through adsorption-desorption cycles. PMID:27208612

  5. Preparation and application of cellulose acetate/Fe films in the degradation of Reactive Black 5 dye through photo-Fenton reaction.

    PubMed

    Ribeiro, Karine; de Andrade, Tamara Maria; Fujiwara, Sérgio Toshio

    2016-07-01

    In this study, the Reactive Black 5 dye degradation and textile effluent were investigated using the photo-Fenton process employing immobilized Fe(3+) in acetate cellulose films. The films prepared were characterized through Fourier transform infrared spectroscopy, atomic absorption spectroscopy, scanning electron microscopy - energy-dispersive spectroscopy and ultraviolet visible spectroscopy. The factorial design revealed that the best conditions for the Reactive Black 5 dye degradation were obtained using the film containing 5% Fe (w/w), 100 mg L(-1) H2O2 and pH 4.0. In studies using artificial light, the dye degradation was 99.29% and the chemical oxygen demand (COD) reduction was 90% after 45 min of treatment. In the process assisted by sunlight, the degradation was 86% and the COD reduction was 70% considering the same time of treatment. At pH 6.0 and artificial light, the dye degradation was 98.90% and the COD reduction was 78%, indicating that the material prepared can be used at pH values greater than 3 without the occurrence of hydrated ferric oxides precipitation. It was also observed that the material can be reused seven consecutive times without substantial loss of efficacy in dye degradation. Furthermore, the proposed material reduces the COD of a textile effluent by 72% after 300 min of treatment. PMID:26675986

  6. Cellulose biosynthesis in Acetobacter xylinum

    SciTech Connect

    Lin, F.C.

    1988-01-01

    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-{beta}-D-glucan polymer. Electron microscopy revealed that clusters of fibrils were assembled within minutes. Individual fibrils are 17 {plus minus} 2 angstroms in diameter. Evidence for the cellulosic composition of newly synthesized fibrils was based on incorporation of tritium from UDP-({sup 3}H) glucose binding of gold-labeled cellobiohydrolase, and an electron diffraction pattern identified as cellulose II polymorph instead of cellulose I.

  7. Cellulose nanowhiskers extracted from TEMPO-oxidized jute fibers.

    PubMed

    Cao, Xinwang; Ding, Bin; Yu, Jianyong; Al-Deyab, Salem S

    2012-10-01

    Cellulose nanowhiskers is a kind of renewable and biocompatible nanomaterials evoke much interest because of its versatility in various applications. Here, for the first time, a novel controllable fabrication of cellulose nanowhiskers from jute fibers with a high yield (over 80%) via a 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)/NaBr/NaClO system selective oxidization combined with mechanical homogenization is reported. The versatile jute cellulose nanowhiskers with ultrathin diameters (3-10 nm) and high crystallinity (69.72%), contains C6 carboxylate groups converted from C6 primary hydroxyls, which would be particularly useful for applications in the nanocomposites as reinforcing phase, as well as in tissue engineering, pharmaceutical and optical industries as additives. PMID:22840042

  8. High-yield production of extracellular type-I cellulose by the cyanobacterium Synechococcus sp. PCC 7002

    PubMed Central

    Zhao, Chi; Li, Zhongkui; Li, Tao; Zhang, Yingjiao; Bryant, Donald A; Zhao, Jindong

    2015-01-01

    Cellulose synthase, encoded by the cesA gene, is responsible for the synthesis of cellulose in nature. We show that the cell wall of the cyanobacterium Synechococcus sp. PCC 7002 naturally contains cellulose. Cellulose occurs as a possibly laminated layer between the inner and outer membrane, as well as being an important component of the extracellular glycocalyx in this cyanobacterium. Overexpression of six genes, cmc–ccp–cesAB–cesC–cesD–bgl, from Gluconacetobacter xylinus in Synechococcus sp. PCC 7002 resulted in very high-yield production of extracellular type-I cellulose. High-level cellulose production only occurred when the native cesA gene was inactivated and when cells were grown at low salinity. This system provides a method for the production of lignin-free cellulose from sunlight and CO2 for biofuel production and other biotechnological applications. PMID:27462405

  9. High-yield production of extracellular type-I cellulose by the cyanobacterium Synechococcus sp. PCC 7002.

    PubMed

    Zhao, Chi; Li, Zhongkui; Li, Tao; Zhang, Yingjiao; Bryant, Donald A; Zhao, Jindong

    2015-01-01

    Cellulose synthase, encoded by the cesA gene, is responsible for the synthesis of cellulose in nature. We show that the cell wall of the cyanobacterium Synechococcus sp. PCC 7002 naturally contains cellulose. Cellulose occurs as a possibly laminated layer between the inner and outer membrane, as well as being an important component of the extracellular glycocalyx in this cyanobacterium. Overexpression of six genes, cmc-ccp-cesAB-cesC-cesD-bgl, from Gluconacetobacter xylinus in Synechococcus sp. PCC 7002 resulted in very high-yield production of extracellular type-I cellulose. High-level cellulose production only occurred when the native cesA gene was inactivated and when cells were grown at low salinity. This system provides a method for the production of lignin-free cellulose from sunlight and CO2 for biofuel production and other biotechnological applications. PMID:27462405

  10. Occurrence of Cellulose-Producing Gluconacetobacter spp. in Fruit Samples and Kombucha Tea, and Production of the Biopolymer.

    PubMed

    Neera; Ramana, Karna Venkata; Batra, Harsh Vardhan

    2015-06-01

    Cellulose producing bacteria were isolated from fruit samples and kombucha tea (a fermented beverage) using CuSO4 solution in modified Watanabe and Yamanaka medium to inhibit yeasts and molds. Six bacterial strains showing cellulose production were isolated and identified by 16S rRNA gene sequencing as Gluconacetobacter xylinus strain DFBT, Ga. xylinus strain dfr-1, Gluconobacter oxydans strain dfr-2, G. oxydans strain dfr-3, Acetobacter orientalis strain dfr-4, and Gluconacetobacter intermedius strain dfr-5. All the cellulose-producing bacteria were checked for the cellulose yield. A potent cellulose-producing bacterium, i.e., Ga. xylinus strain DFBT based on yield (cellulose yield 5.6 g/L) was selected for further studies. Cellulose was also produced in non- conventional media such as pineapple juice medium and hydrolysed corn starch medium. A very high yield of 9.1 g/L cellulose was obtained in pineapple juice medium. Fourier transform infrared spectrometer (FT-IR) analysis of the bacterial cellulose showed the characteristic peaks. Soft cellulose with a very high water holding capacity was produced using limited aeration. Scanning electron microscopy (SEM) was used to analyze the surface characteristics of normal bacterial cellulose and soft cellulose. The structural analysis of the polymer was performed using (13)C solid-state nuclear magnetic resonance (NMR). More interfibrillar space was observed in the case of soft cellulose as compared to normal cellulose. This soft cellulose can find potential applications in the food industry as it can be swallowed easily without chewing. PMID:25926011

  11. Oxidoreductive cellulose depolymerization by the enzymes cellobiose dehydrogenase and glycoside hydrolase 61.

    PubMed

    Langston, James A; Shaghasi, Tarana; Abbate, Eric; Xu, Feng; Vlasenko, Elena; Sweeney, Matt D

    2011-10-01

    Several members of the glycoside hydrolase 61 (GH61) family of proteins have recently been shown to dramatically increase the breakdown of lignocellulosic biomass by microbial hydrolytic cellulases. However, purified GH61 proteins have neither demonstrable direct hydrolase activity on various polysaccharide or lignacious components of biomass nor an apparent hydrolase active site. Cellobiose dehydrogenase (CDH) is a secreted flavocytochrome produced by many cellulose-degrading fungi with no well-understood biological function. Here we demonstrate that the binary combination of Thermoascus aurantiacus GH61A (TaGH61A) and Humicola insolens CDH (HiCDH) cleaves cellulose into soluble, oxidized oligosaccharides. TaGH61A-HiCDH activity on cellulose is shown to be nonredundant with the activities of canonical endocellulase and exocellulase enzymes in microcrystalline cellulose cleavage, and while the combination of TaGH61A and HiCDH cleaves highly crystalline bacterial cellulose, it does not cleave soluble cellodextrins. GH61 and CDH proteins are coexpressed and secreted by the thermophilic ascomycete Thielavia terrestris in response to environmental cellulose, and the combined activities of T. terrestris GH61 and T. terrestris CDH are shown to synergize with T. terrestris cellulose hydrolases in the breakdown of cellulose. The action of GH61 and CDH on cellulose may constitute an important, but overlooked, biological oxidoreductive system that functions in microbial lignocellulose degradation and has applications in industrial biomass utilization. PMID:21821740

  12. The bioactive composite film prepared from bacterial cellulose and modified by hydrolyzed gelatin peptide.

    PubMed

    Lin, Shih-Bin; Chen, Chia-Che; Chen, Li-Chen; Chen, Hui-Huang

    2015-05-01

    The hydrolyzed gelatin peptides, obtained from the hydrolysis of Tilapia nilotica skin gelatin with alcalase and pronase E, were fractionated using an ultrafiltration system into hydrolyzed gelatin peptides-a (10 kDa membrane), hydrolyzed gelatin peptides-b1, and hydrolyzed gelatin peptides-b2 (5 kDa membrane) fractions. The highest oxygen radical absorbance capacity was observed in hydrolyzed gelatin peptides-b2, which contained more nonpolar amino acids than the other hydrolyzed gelatin peptides. Hydrolyzed gelatin peptides-b2 at a concentration of 12.5 mg/ml exhibited the highest proliferation ability and increased the expression of Type I procollagen mRNA, which indicated an enhanced collagen synthesis. Hydrolyzed gelatin peptides protected Detroit 551 cells from 2,2'-azobis(2-amidinopropane) dihydrochloride-induced oxidative damage and increased cell viability. Hydroxylpropylmethyl cellulose-modified bacterial cellulose and dried fabricated biofilm were less eligible for Detroit 551 cell proliferation than bacterial cellulose. The release of hydrolyzed gelatin peptides in bacterial cellulose film was slower than that in hydroxylpropylmethyl cellulose-modified bacterial cellulose and dried fabricated biofilm; thus, bacterial cellulose film and hydroxylpropylmethyl cellulose-modified bacterial cellulose and dried fabricated biofilm are suitable candidates for applications in delayed release type and rapid release type biofilms, respectively. PMID:25614493

  13. Variation in oxygen isotope fractionation during cellulose synthesis: intramolecular and biosynthetic effects.

    PubMed

    Sternberg, Leonel; Pinzon, Maria Camila; Anderson, William T; Jahren, A Hope

    2006-10-01

    The oxygen isotopic composition of plant cellulose is commonly used for the interpretations of climate, ecophysiology and dendrochronology in both modern and palaeoenvironments. Further applications of this analytical tool depends on our in-depth knowledge of the isotopic fractionations associated with the biochemical pathways leading to cellulose. Here, we test two important assumptions regarding isotopic effects resulting from the location of oxygen in the carbohydrate moiety and the biosynthetic pathway towards cellulose synthesis. We show that the oxygen isotopic fractionation of the oxygen attached to carbon 2 of the glucose moieties differs from the average fractionation of the oxygens attached to carbons 3-6 from cellulose by at least 9%, for cellulose synthesized within seedlings of two different species (Triticum aestivum L. and Ricinus communis L.). The fractionation for a given oxygen in cellulose synthesized by the Triticum seedlings, which have starch as their primary carbon source, is different than the corresponding fractionation in Ricinus seedlings, within which lipids are the primary carbon source. This observation shows that the biosynthetic pathway towards cellulose affects oxygen isotope partitioning, a fact heretofore undemonstrated. Our findings may explain the species-dependent variability in the overall oxygen isotope fractionation during cellulose synthesis, and may provide much-needed insight for palaeoclimate reconstruction using fossil cellulose. PMID:16930314

  14. Electrospun cellulose nitrate and polycaprolactone blended nanofibers

    NASA Astrophysics Data System (ADS)

    Nartker, Steven; Hassan, Mohamed; Stogsdill, Michael

    2015-03-01

    Pure cellulose nitrate (CN) and blends of CN and polycaprolactone were electrospun to form nonwoven mats. Polymers were dissolved in a mixed solvent system of tetrahydrofuran and N,N-dimethylformamide. The concentrations were varied to obtain sub-micron and nanoscale fiber mats. Fiber mats were analyzed using scanning electron microscopy, contact angle analysis, Fourier transform infrared spectroscopy and thermal gravimetric analysis. The fiber morphology, surface chemistry and contact angle data show that these electrospun materials are suitable for applications including biosensing, biomedical and tissue engineering.

  15. Cellulose nanofibrils improve the properties of all-cellulose composites by the nano-reinforcement mechanism and nanofibril-induced crystallization

    NASA Astrophysics Data System (ADS)

    Yang, Quanling; Saito, Tsuguyuki; Berglund, Lars A.; Isogai, Akira

    2015-10-01

    All-cellulose nanocomposite films containing crystalline TEMPO-oxidized cellulose nanofibrils (TOCNs) of 0-1 wt% were fabricated by mixing aqueous TOCN dispersions with alkali/urea/cellulose (AUC) solutions at room temperature. The mixtures were cast on glass plates, soaked in an acid solution, and the regenerated gel-like films were washed with water and then dried. The TOCN did not form agglomerates in the composites, and had the structure of TOCN-COOH, forming hydrogen bonds with the hydroxyl groups of the regenerated cellulose molecules. X-ray diffraction analysis revealed that the matrix cellulose molecules increased the cellulose II crystal size upon incorporation of TOCN. As a result, the TOCN/AUC composite films had high Young's modulus, tensile strength, thermal stability and oxygen-barrier properties. The TOCN/AUC composite films are promising all-cellulose nanocomposites for versatile applications as new bio-based materials.All-cellulose nanocomposite films containing crystalline TEMPO-oxidized cellulose nanofibrils (TOCNs) of 0-1 wt% were fabricated by mixing aqueous TOCN dispersions with alkali/urea/cellulose (AUC) solutions at room temperature. The mixtures were cast on glass plates, soaked in an acid solution, and the regenerated gel-like films were washed with water and then dried. The TOCN did not form agglomerates in the composites, and had the structure of TOCN-COOH, forming hydrogen bonds with the hydroxyl groups of the regenerated cellulose molecules. X-ray diffraction analysis revealed that the matrix cellulose molecules increased the cellulose II crystal size upon incorporation of TOCN. As a result, the TOCN/AUC composite films had high Young's modulus, tensile strength, thermal stability and oxygen-barrier properties. The TOCN/AUC composite films are promising all-cellulose nanocomposites for versatile applications as new bio-based materials. Electronic supplementary information (ESI) available: Fig. S1-S3 show an AFM image of TOCN, SEM

  16. Thermal Behaviour of Nanocomposites based on Glycerol Plasticized Thermoplastic Starch and Cellulose Nanocrystallites

    NASA Astrophysics Data System (ADS)

    Kaushik, Anupama; Kaur, Ramanpreet

    2011-12-01

    The objective of this study was to study the thermal behaviour of cellulose nanocrystals/TPS based nanocomposites. Nanocrystalline cellulose was isolated from cotton linters using sonochemical method and characterized through WAXRD & TEM. These nanocrystals were then dispersed in glycerol plasticized starch in varying proportions and films were cast. The thermal degradation of thermoplastic starch/cellulose nanocrystallite nanocomposites was studied using TGA under nitrogen atmosphere. Thermal degradation was carried out for nanocomposites at a rate of 10 °C/min and at different rates under nitrogen atmosphere namely 2, 5, 10, 20 and 40 °C/min for nanocomposites containing 10% cellulose nanocrystals. Ozawa and Flynn and Kissinger methods were used to determine the apparent activation energy of these nanocomposites. The addition of cellulose nanocrystallites produced a significant effect on the activation energy for thermal degradation of the composites materials in comparison with the matrix alone. These nanocomposites are potential applicant for food packaging applications.

  17. Gravity effects on cellulose assembly

    NASA Technical Reports Server (NTRS)

    Brown, R. M. Jr; Kudlicka, K.; Cousins, S. K.; Nagy, R.; Brown RM, J. r. (Principal Investigator)

    1992-01-01

    The effect of microgravity on cellulose synthesis using the model system of Acetobacter xylinum was the subject of recent investigations using The National Aeronautics and Space Administration's Reduced Gravity Laboratory, a modified KC-135 aircraft designed to produce 20 sec of microgravity during the top of a parabolic dive. Approximately 40 parabolas were executed per mission, and a period of 2 x g was integral to the pullout phase of each parabola. Cellulose biosynthesis was initiated on agar surfaces, liquid growth medium, and buffered glucose during parabolic flight and terminated with 2.0% sodium azide or 50.0% ethanol. While careful ground and in-flight controls indicated normal, compact ribbons of microbial cellulose, data from five different flights consistently showed that during progression into the parabola regime, the cellulose ribbons became splayed. This observation suggests that some element of the parabola (the 20 sec microgravity phase, the 20 sec 2 x g phase, or a combination of both) was responsible for this effect. Presumably the cellulose I alpha crystalline polymorph normally is produced under strain, and the microgravity/hypergravity combination may relieve this stress to produce splayed ribbons. An in-flight video microscopy analysis of bacterial motions during a parabolic series demonstrated that the bacteria continue to synthesize cellulose during all phases of the parabolic series. Thus, the splaying may be a reflection of a more subtle alteration such as reduction of intermicrofibrillar hydrogen bonding. Long-term microgravity exposures during spaceflight will be necessary to fully understand the cellulose alterations from the short-term microgravity experiments.

  18. Comparison of Cellulose Ib Simulations with Three Carbohydrate Force Fields

    SciTech Connect

    Matthews, J. F.; Beckham, G. T.; Bergenstrahle, M.; Brady, J. W.; Himmel, M. E.; Crowley, M. F.

    2012-02-14

    Molecular dynamics simulations of cellulose have recently become more prevalent due to increased interest in renewable energy applications, and many atomistic and coarse-grained force fields exist that can be applied to cellulose. However, to date no systematic comparison between carbohydrate force fields has been conducted for this important system. To that end, we present a molecular dynamics simulation study of hydrated, 36-chain cellulose I{beta} microfibrils at room temperature with three carbohydrate force fields (CHARMM35, GLYCAM06, and Gromos 45a4) up to the near-microsecond time scale. Our results indicate that each of these simulated microfibrils diverge from the cellulose I{beta} crystal structure to varying degrees under the conditions tested. The CHARMM35 and GLYCAM06 force fields eventually result in structures similar to those observed at 500 K with the same force fields, which are consistent with the experimentally observed high-temperature behavior of cellulose I. The third force field, Gromos 45a4, produces behavior significantly different from experiment, from the other two force fields, and from previously reported simulations with this force field using shorter simulation times and constrained periodic boundary conditions. For the GLYCAM06 force field, initial hydrogen-bond conformations and choice of electrostatic scaling factors significantly affect the rate of structural divergence. Our results suggest dramatically different time scales for convergence of properties of interest, which is important in the design of computational studies and comparisons to experimental data. This study highlights that further experimental and theoretical work is required to understand the structure of small diameter cellulose microfibrils typical of plant cellulose.

  19. Microfibrillated cellulose: morphology and accessibility

    SciTech Connect

    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.

  20. Cellulose Nanocrystals as Water in Water Emulsion Stabilizers

    NASA Astrophysics Data System (ADS)

    Peddireddy, Karthik Reddy; Capron, Isabelle; Nicolai, Taco; Benyahia, Lazhar

    Cellulose is the most abundant polymer on the earth. Thus, it is very much desirable to find as many practical applications as possible for it. Cellulose, in its original form, contains both amorphous and crystalline parts. It is possible to separate both parts by dissolving the amorphous part in concentrated sulfuric acid. The remaining crystalline cellulose part exist in the form of rod-like particles. The dimensions of the particles depend on the source. We produce the particles from the acid hydrolysis of cotton cellulose fibers. It results in cellulose nanocrystals (CNCs) with dimensions of ~150 nm x 6 nm x 6 nm. It is well known that CNCs could very efficiently stabilize oil in water (O/W) emulsions by forming very dense monolayers of CNCs at O-W interfaces. However, it is not yet known whether they could also stabilize water in water (W/W) emulsions. The W/W emulsions can be produced by any two incompatible polymers. It is challenging to find effective stabilizers for W/W emulsions due to ultralow interfacial tension and large interfacial thickness. In this talk, I will show the efficiency and effectiveness of these one-dimensional rods as W/W emulsion stabilizers.

  1. Hydrolysis of cellulose catalyzed by novel acidic ionic liquids.

    PubMed

    Zhuo, Kelei; Du, Quanzhou; Bai, Guangyue; Wang, Congyue; Chen, Yujuan; Wang, Jianji

    2015-01-22

    The conversion of cellulosic biomass directly into valuable chemicals becomes a hot subject. Six novel acidic ionic liquids (ILs) based on 2-phenyl-2-imidazoline were synthesized and characterized by UV-VIS, TGA, and NMR. The novel acidic ionic liquids were investigated as catalysts for the hydrolysis of cellulose in 1-butyl-3-methylimidazolium chloride ([Bmim]Cl). The acidic ionic liquids with anions HSO4(-) and Cl(-) showed better catalytic performance for the hydrolysis of cellulose than those with H2PO4(-). The temperature and dosage of water affect significantly the yield of total reducing sugar (TRS). When the hydrolysis of cellulose was catalyzed by 1-propyl sulfonic acid-2-phenyl imidazoline hydrogensulfate (IL-1) and the dosage of water was 0.2g, the TRS yield was up to 85.1% within 60 min at 100°C. These new acidic ionic liquids catalysts are expected to have a wide application in the conversion of cellulose into valuable chemicals. PMID:25439867

  2. Multifilament cellulose/chitin blend yarn spun from ionic liquids.

    PubMed

    Mundsinger, Kai; Müller, Alexander; Beyer, Ronald; Hermanutz, Frank; Buchmeiser, Michael R

    2015-10-20

    Cellulose and chitin, both biopolymers, decompose before reaching their melting points. Therefore, processing these unmodified biopolymers into multifilament yarns is limited to solution chemistry. Especially the processing of chitin into fibers is rather limited to distinctive, often toxic or badly removable solvents often accompanied by chemical de-functionalization to chitosan (degree of acetylation, DA, <50%). This work proposes a novel method for the preparation of cellulose/chitin blend fibers using ionic liquids (ILs) as gentle, removable, recyclable and non-deacetylating solvents. Chitin and cellulose are dissolved in ethylmethylimidazolium propionate ([C2mim](+)[OPr](-)) and the obtained one-pot spinning dope is used to produce multifilament fibers by a continuous wet-spinning process. Both the rheology of the corresponding spinning dopes and the structural and physical properties of the obtained fibers have been determined for different biopolymer ratios. With respect to medical or hygienic application, the cellulose/chitin blend fiber show enhanced water retention capacity compared to pure cellulose fibers. PMID:26256157

  3. Enhanced electromechanical behaviors of cellulose ZnO hybrid nanocomposites

    NASA Astrophysics Data System (ADS)

    Mun, Seongchoel; Min, Seung-Ki; Kim, Hyun Chan; Im, Jongbeom; Geddis, Demetris L.; Kim, Jaehwan

    2015-04-01

    Inorganic-organic hybrid composite has attracted as its combined synergistic properties. Cellulose based inorganicorganic hybrid composite was fabricated with semiconductive nanomaterials which has functionality of nanomaterial and biocompatibility piezoelectricity, high transparency and flexibility of cellulose electro active paper namely EAPap. ZnO is providing semiconductive functionality to EAPap for hybrid nanocomposite by simple chemical reaction. Cellulose- ZnO hybrid nanocomposite (CEZOHN) demonstrates novel electrical, photoelectrical and electromechanical behaviors. This paper deals with methods to improve electromechanical property of CEZOHN. The fabrication process is introduced briefly, charging mechanism and evaluation is studied with measured piezoelectric constant. And its candidate application will be discussed such as artificial muscle, energy harvester, strain sensor, flexible electrical device.

  4. Radiation grafting studies of acrylic acid onto cellulose triacetate membranes

    NASA Astrophysics Data System (ADS)

    Mazzei, R. O.; Smolko, E.; Torres, A.; Tadey, D.; Rocco, C.; Gizzi, L.; Strangis, S.

    2002-05-01

    Polymer surface modifications were obtained by the application of radiation treatments, etching and grafting of acrylic acid monomers on different membranes of cellulose triacetate materials. Cellulose triacetate foils from pellet dissolution and commercial cellulose triacetate solid state nuclear track detector membranes were assayed. Irradiation with fission fragments from Cf-252 source to obtain a porous structure, 25 MeV proton beam and Co-60 γ-source to produce peroxides were employed in the experiments. The present work gives the grafting yield of AAc monomer onto CTA membranes as a function of diverse variables including irradiation parameters ( γ-dose, Cf-252 ff irradiation time, proton fluency and electronic energy loss (d E/d x) e), structural parameters (pore diameter and pore density, etching time and etching temperature) and grafting parameters (monomer and Mohr salt concentration, grafting time and grafting temperature).

  5. The effects of cypermethrin pour-on and piperonyl butoxide on Triatoma infestans under laboratory conditions.

    PubMed

    Amelotti, Ivana; Catalá, Silvia S; Gorla, David E

    2010-11-01

    The effect of exposing Triatoma infestans to chickens treated with cypermethrin pour-on combined with piperonyl butoxide (PBO) was studied. Four groups of treated chickens and one control group were used. Each treatment received 1 or 2 ml of the cypermethrin formulation with and without PBO. Independent groups of nymphs were fed 1, 7, 15, 30, and 45 d after the treatment application. Blood intake was estimated after each feeding occasion. Up to 15 d after the pour-on application, high mortality was observed in all nymphs fed on treated chickens (> 93% +/- 12), and lower than the nymphs of the control group (< 33% +/- 15). After 30 d of the pour-on application, there was significantly different mortality between the treatment with 1 ml (80% +/- 9) and 2 ml (> 96% +/- 5); no difference was observed between groups with or without PBO addition. After 45 d of the pour-on application, the treatments did not show significant differences (77% +/- 7), although all treatments showed higher mortality than the control group (10% +/- 9). Up to 45 d after the pour-on application, blood intake by nymphs exposed to treated chickens (0.85 +/- 0.96 mg/nymph) was lower than blood intake by nymphs exposed to control chickens (6.7 +/- 5 mg/nymph). This study shows that cypermethrin pour-on produces high mortality and reduces the blood intake of third-instar nymphs of T. infestans up to 45 d after the insecticide application to chickens. PBO did not produce a detectable effect. PMID:21175064

  6. Microbial Cellulose Assembly in Microgravity

    NASA Technical Reports Server (NTRS)

    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.

  7. Cellulose degradation by polysaccharide monooxygenases.

    PubMed

    Beeson, William T; Vu, Van V; Span, Elise A; Phillips, Christopher M; Marletta, Michael A

    2015-01-01

    Polysaccharide monooxygenases (PMOs), also known as lytic PMOs (LPMOs), enhance the depolymerization of recalcitrant polysaccharides by hydrolytic enzymes and are found in the majority of cellulolytic fungi and actinomycete bacteria. For more than a decade, PMOs were incorrectly annotated as family 61 glycoside hydrolases (GH61s) or family 33 carbohydrate-binding modules (CBM33s). PMOs have an unusual surface-exposed active site with a tightly bound Cu(II) ion that catalyzes the regioselective hydroxylation of crystalline cellulose, leading to glycosidic bond cleavage. The genomes of some cellulolytic fungi contain more than 20 genes encoding cellulose-active PMOs, suggesting a diversity of biological activities. PMOs show great promise in reducing the cost of conversion of lignocellulosic biomass to fermentable sugars; however, many questions remain about their reaction mechanism and biological function. This review addresses, in depth, the structural and mechanistic aspects of oxidative depolymerization of cellulose by PMOs and considers their biological function and phylogenetic diversity. PMID:25784051

  8. A Molecular Description of Cellulose Biosynthesis

    PubMed Central

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

    2016-01-01

    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 which it is synthesized is now only beginning to emerge. On the basis of recent advances in structural and molecular biology on bacterial cellulose synthases, we review emerging concepts of how the enzymes polymerize glucose molecules, how the nascent polymer is transported across the plasma membrane, and how bacterial cellulose biosynthesis is regulated during biofilm formation. Additionally, we review evolutionary commonalities and differences between cellulose synthases that modulate the nature of the cellulose product formed. PMID:26034894

  9. Characterization of Cellulose Synthesis in Plant Cells

    PubMed Central

    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

  10. A molecular description of cellulose biosynthesis.

    PubMed

    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 which it is synthesized is now only beginning to emerge. On the basis of recent advances in structural and molecular biology on bacterial cellulose synthases, we review emerging concepts of how the enzymes polymerize glucose molecules, how the nascent polymer is transported across the plasma membrane, and how bacterial cellulose biosynthesis is regulated during biofilm formation. Additionally, we review evolutionary commonalities and differences between cellulose synthases that modulate the nature of the cellulose product formed. PMID:26034894

  11. Characterization of Cellulose Synthesis in Plant Cells.

    PubMed

    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

  12. 21 CFR 573.420 - Ethyl cellulose.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ..., FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.420 Ethyl cellulose. The food additive ethyl cellulose may be safely used in animal feed in accordance with the following prescribed conditions: (a) The food additive is a cellulose ether...

  13. 21 CFR 573.420 - Ethyl cellulose.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ..., FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.420 Ethyl cellulose. The food additive ethyl cellulose may be safely used in animal feed in accordance with the following prescribed conditions: (a) The food additive is a cellulose ether...

  14. 21 CFR 573.420 - Ethyl cellulose.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ..., FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.420 Ethyl cellulose. The food additive ethyl cellulose may be safely used in animal feed in accordance with the following prescribed conditions: (a) The food additive is a cellulose ether...

  15. Iodine catalyzed acetylation of starch and cellulose

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  16. Method of producing thin cellulose nitrate film

    DOEpatents

    Lupica, S.B.

    1975-12-23

    An improved method for forming a thin nitrocellulose film of reproducible thickness is described. The film is a cellulose nitrate film, 10 to 20 microns in thickness, cast from a solution of cellulose nitrate in tetrahydrofuran, said solution containing from 7 to 15 percent, by weight, of dioctyl phthalate, said cellulose nitrate having a nitrogen content of from 10 to 13 percent.

  17. Microbial Cellulose Utilization: Fundamentals and Biotechnology

    PubMed Central

    Lynd, Lee R.; Weimer, Paul J.; van Zyl, Willem H.; Pretorius, Isak S.

    2002-01-01

    Fundamental features of microbial cellulose utilization are examined at successively higher levels of aggregation encompassing the structure and composition of cellulosic biomass, taxonomic diversity, cellulase enzyme systems, molecular biology of cellulase enzymes, physiology of cellulolytic microorganisms, ecological aspects of cellulase-degrading communities, and rate-limiting factors in nature. The methodological basis for studying microbial cellulose utilization is considered relative to quantification of cells and enzymes in the presence of solid substrates as well as apparatus and analysis for cellulose-grown continuous cultures. Quantitative description of cellulose hydrolysis is addressed with respect to adsorption of cellulase enzymes, rates of enzymatic hydrolysis, bioenergetics of microbial cellulose utilization, kinetics of microbial cellulose utilization, and contrasting features compared to soluble substrate kinetics. A biological perspective on processing cellulosic biomass is presented, including features of pretreated substrates and alternative process configurations. Organism development is considered for “consolidated bioprocessing” (CBP), in which the production of cellulolytic enzymes, hydrolysis of biomass, and fermentation of resulting sugars to desired products occur in one step. Two organism development strategies for CBP are examined: (i) improve product yield and tolerance in microorganisms able to utilize cellulose, or (ii) express a heterologous system for cellulose hydrolysis and utilization in microorganisms that exhibit high product yield and tolerance. A concluding discussion identifies unresolved issues pertaining to microbial cellulose utilization, suggests approaches by which such issues might be resolved, and contrasts a microbially oriented cellulose hydrolysis paradigm to the more conventional enzymatically oriented paradigm in both fundamental and applied contexts. PMID:12209002

  18. Atomic-scale modeling of cellulose nanocrystals

    NASA Astrophysics Data System (ADS)

    Wu, Xiawa

    Cellulose nanocrystals (CNCs), the most abundant nanomaterials in nature, are recognized as one of the most promising candidates to meet the growing demand of green, bio-degradable and sustainable nanomaterials for future applications. CNCs draw significant interest due to their high axial elasticity and low density-elasticity ratio, both of which are extensively researched over the years. In spite of the great potential of CNCs as functional nanoparticles for nanocomposite materials, a fundamental understanding of CNC properties and their role in composite property enhancement is not available. In this work, CNCs are studied using molecular dynamics simulation method to predict their material' behaviors in the nanoscale. (a) Mechanical properties include tensile deformation in the elastic and plastic regions using molecular mechanics, molecular dynamics and nanoindentation methods. This allows comparisons between the methods and closer connectivity to experimental measurement techniques. The elastic moduli in the axial and transverse directions are obtained and the results are found to be in good agreement with previous research. The ultimate properties in plastic deformation are reported for the first time and failure mechanism are analyzed in details. (b) The thermal expansion of CNC crystals and films are studied. It is proposed that CNC film thermal expansion is due primarily to single crystal expansion and CNC-CNC interfacial motion. The relative contributions of inter- and intra-crystal responses to heating are explored. (c) Friction at cellulose-CNCs and diamond-CNCs interfaces is studied. The effects of sliding velocity, normal load, and relative angle between sliding surfaces are predicted. The Cellulose-CNC model is analyzed in terms of hydrogen bonding effect, and the diamond-CNC model compliments some of the discussion of the previous model. In summary, CNC's material properties and molecular models are both studied in this research, contributing to

  19. Printed optically transparent graphene cellulose electrodes

    NASA Astrophysics Data System (ADS)

    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 < 100 Ω/sq. Experimental studies show that the optical transmittance and sheet resistance of the G-CMC conductive electrode is a dependent on the film thickness (ie. superimposed printed layers). The printed electrodes have also been doped with AuCl3 to increase electrical conductivity without significantly increasing film thickness and, thereby, maintain high optical transparency.

  20. Possibility of cellulose-based electro-active paper energy scavenging transducer.

    PubMed

    Abas, Zafar; Kim, Heung Soo; Zhai, Lindong; Kim, Jaehwan; Kim, Joo Hyung

    2014-10-01

    In this paper, a cellulose-based Electro-Active Paper (EAPap) energy scavenging transducer is presented. Cellulose is proven as a smart material, and exhibits piezoelectric effect. Specimens were prepared by coating gold electrodes on both sides of cellulose film. The fabricated specimens were tested by a base excited aluminum cantilever beam at resonant frequency. Different tests were performed with single and multiple parallel connected electrodes coated on the cellulose film. A maximum of 131 mV output voltage was measured, when three electrodes were connected in parallel. It was observed that voltage output increases significantly with the area of electrodes. From these results, it can be concluded that the piezoelectricity of cellulose-based EAPap can be used in energy transduction application. PMID:25942809

  1. Synthesis of Multifunctional Cellulose Nanocrystals for Lectin Recognition and Bacterial Imaging

    PubMed Central

    Zhou, Juan; Butchosa, Núria; Jayawardena, H. Surangi N.; Park, JaeHyeung; Zhou, Qi; Yan, Mingdi; Ramström, Olof

    2015-01-01

    Multifunctional cellulose nanocrystals have been synthesized and applied as a new type of glyconanomaterial in lectin binding and bacterial imaging. The cellulose nanocrystals were prepared by TEMPO-mediated oxidation and acidic hydrolysis, followed by functionalization with a quinolone fluorophore and carbohydrate ligands. The cellulose nanocrystals were subsequently applied in interaction studies with carbohydrate-binding proteins and in bacterial imaging. The results show that the functional cellulose nanocrystals could selectively recognize the corresponding cognate lectins. In addition, mannosylated nanocrystals were shown to selectively interact with FimH-presenting E. coli, as detected by TEM and confocal fluorescence microscopy. These glyconanomaterials provide a new application of cellulose nanocrystals in biorecognition and imaging. PMID:25738860

  2. Thermal behavior of nano cellulose doped polymer dispersed liquid crystal (PDLC)

    NASA Astrophysics Data System (ADS)

    Kashyap, Swati; Saxena, S. K.; Gupta, S. J.; Mahajan, Jyoti

    2016-05-01

    Nano cellulose or cellulose nanofibers (CNF) material is composed of Nano sized cellulose fibrils with a high aspect ratio and typical lateral dimensions are 20-50 nm. Its pseudo-plastic characteristics exhibit the property of certain gels or fluids (viscous) and over a period of time, becomes, Thixotropic. The ability of CNFs to go into a PDLC ultrasonically with a helical arrangement results in dried CNF films. The films thus acquire attractive thermal properties, creating possibilities for their use in various applications. In this presentation, we discuss the thermal behavior of Nano cellulose doped in PDLC that governs the formation of the desired helical structure. By comparison with the corresponding self-assembly processes of other rod-like nanoparticles, for example, carbon nanotubes particles, we outline in the present paper the variation in the number of mesogen phases in varying compositions of Nano Cellulose doped PDLCs.

  3. Microcrystalline-cellulose and polypropylene based composite: A simple, selective and effective material for microwavable packaging.

    PubMed

    Ummartyotin, S; Pechyen, C

    2016-05-20

    Cellulose based composite was successfully designed as active packaging with additional feature of microwavable properties. Small amount of cellulose with 10 μm in diameter was integrated into polypropylene matrix. The use of maleic anhydride was employed as coupling agent. Thermal and mechanical properties of cellulose based composite were superior depending on polypropylene matrix. Crystallization temperature and compressive strength were estimated to be 130 °C and 5.5 MPa. The crystal formation and its percentage were therefore estimated to be 50% and it can be predicted on the feasibility of microwavable packaging. Morphological properties of cellulose based composite presented the good distribution and excellent uniformity. It was remarkable to note that cellulose derived from cotton can be prepared as composite with polypropylene matrix. It can be used as packaging for microwave application. PMID:26917383

  4. MICROBIAL FERMENTATION OF ABUNDANT BIOPOLYMERS: CELLULOSE AND CHITIN

    SciTech Connect

    Leschine, Susan

    2009-10-31

    Our research has dealt with seven major areas of investigation: i) characterization of cellulolytic members of microbial consortia, with special attention recently given to Clostridium phytofermentans, a bacterium that decomposes cellulose and produces uncommonly large amounts of ethanol, ii) investigations of the chitinase system of Cellulomonas uda; including the purification and characterization of ChiA, the major component of this enzyme system, iii) molecular cloning, sequence and structural analysis of the gene that encodes ChiA in C. uda, iv) biofilm formation by C. uda on nutritive surfaces, v) investigations of the effects of humic substances on cellulose degradation by anaerobic cellulolytic microbes, vi) studies of nitrogen metabolism in cellulolytic anaerobes, and vii) understanding the molecular architecture of the multicomplex cellulase-xylanase system of Clostridium papyrosolvens. Also, progress toward completing the research of more recent projects is briefly summarized. Major accomplishments include: 1. Characterization of Clostridium phytofermentans, a cellulose-fermenting, ethanol-producing bacterium from forest soil. The characterization of a new cellulolytic species isolated from a cellulose-decomposing microbial consortium from forest soil was completed. This bacterium is remarkable for the high concentrations of ethanol produced during cellulose fermentation, typically more than twice the concentration produced by other species of cellulolytic clostridia. 2. Examination of the use of chitin as a source of carbon and nitrogen by cellulolytic microbes. We discovered that many cellulolytic anaerobes and facultative aerobes are able to use chitin as a source of both carbon and nitrogen. This major discovery expands our understanding of the biology of cellulose-fermenting bacteria and may lead to new applications for these microbes. 3. Comparative studies of the cellulase and chitinase systems of Cellulomonas uda. Results of these studies indicate

  5. Cellulose/CaCO3 nanocomposites: microwave ionic liquid synthesis, characterization, and biological activity.

    PubMed

    Ma, Ming-Guo; Dong, Yan-Yan; Fu, Lian-Hua; Li, Shu-Ming; Sun, Run-Cang

    2013-02-15

    The purposes of this article are to synthesize the biomass-based hybrid nanocomposites using green method in green solvent and evaluate its biological activity. In this paper, microwave-assisted ionic liquid method is applied to the preparation of cellulose/CaCO(3) hybrid nanocomposites in the alkali extraction cellulose using CaCl(2) and Na(2)CO(3) as starting reactants. The ionic liquid acts as the excellent solvent for absorbing microwave and the dissolution of cellulose, and the synthesis of cellulose/CaCO(3) nanocomposites. The influences of reaction parameters such as the cellulose concentration and the types of solvent on the products were investigated. The increasing cellulose concentration favored the growth of CaCO(3). The morphologies of CaCO(3) changed from polyhedral to cube to particle with increasing cellulose concentration. Moreover, the solvents had an effect on the shape and dispersion of CaCO(3). Cytotoxicity experiments demonstrated that the cellulose/CaCO(3) nanocomposites had good biocompatibility and could be a candidate for the biomedical applications. PMID:23399205

  6. Rheological behaviors in the regimes from dilute to concentrated in cellulose solutions dissolved at low temperature.

    PubMed

    Lue, Ang; Zhang, Lina

    2009-05-13

    Cellulose was dissolved rapidly in 9.5 wt.-% NaOH/4.5 wt.-% thiourea aqueous solution pre-cooled to -5 degrees C to prepare cellulose solution with different concentrations. The rheological properties of the cellulose solutions in wide concentration regimes from dilute (0.008 wt.-%) to concentrated (4.0 wt.-%) at 25 degrees C were investigated. On the basis of data from the steady-shear flow test, the critical overlap (c*), the entanglement (c(e)) and the gel (c(g)) concentrations of the cellulose solution at 25 degrees C were determined, respectively, to be 0.10 wt.-%, 0.53 wt.-% and 2.50 wt.-%, in accordance with the results of storage modulus (G') versus c by dynamic test. Moreover, the Cox-Merz deviation at relatively low concentrations was in good agreement with the micro-gel particles in dilute regime. As the cellulose concentration increased, a homogeneous 3-dimensional network formed in the cellulose solution in the concentrated regime, and further increasing of the concentration led to micro-phase separation as determined by the time-temperature superposition (tTS). So far, this complex cellulose solution has been successfully described by the concentration regime theory for the first time, and the relatively molecular morphologies in each regime have been determined, providing useful information for the applications of the cellulose solution systems. PMID:19039777

  7. An Atomic Force Microscopy Study of the Mechanism of Cellulose Biodegradation

    NASA Astrophysics Data System (ADS)

    Quirk, Amanda; Chen, Maohui; Cockburn, Darrell; Regli, Sarah; Clarke, Anthony; Dutcher, John; Lipkowski, Jacek; Roscoe, Sharon

    2009-03-01

    Cellulose, a biopolymer consisting of long chain β-(1->4) linked glucose sugars, is used as structural material by plants and bacteria. Degradation of cellulose to glucose, a sugar easily fermented to ethanol, occurs by the enzymatic hydrolysis of cellulose by cellulase enzymes. The enzymes have a complex structure including carbohydrate binding modules and catalytic domains responsible for the binding and degradation of cellulose, respectively. Atomic force microscopy (AFM) was used to study native cellulose films prepared from Acetobacter xylinum using a novel application of the Langmuir-Blodgett technique. These films allowed AFM images of single fibers and their microfibril structure to be obtained. Further in situ AFM studies of single fibers were performed in solution using cellulolytic enzymes. The in situ degradation of cellulose fibers was monitored over 20-hours using AFM. These studies provided insight into the degradation timeline of a single fiber. Complementary studies of proteins adsorbed on cellulose fibers revealed information about the binding of the enzymes to the substrate. Studying the modular enzyme action separately will provide insight into the mechanism of cellulose binding and contribute to our understanding of the degradation process.

  8. Cellulose nanocrystal from pomelo (C. Grandis osbeck) albedo: Chemical, morphology and crystallinity evaluation

    NASA Astrophysics Data System (ADS)

    Zain, Nor Fazelin Mat; Yusop, Salma Mohamad; Ahmad, Ishak

    2013-11-01

    Citrus peel is one of the under-utilized waste materials that have potential in producing a valuable fibre, which are cellulose and cellulose nanocrystal. Cellulose was first isolated from pomelo (C. Grandis Osbeck) albedo by combination of alkali treatment and bleaching process, followed by acid hydrolysis (65% H2SO4, 45 °C, 45min) to produce cellulose nanocrystal. The crystalline, structural, morphological and chemical properties of both materials were studied. Result reveals the crystallinity index obtained from X-ray diffraction for cellulose nanocrystal was found higher than extracted cellulose with the value of 60.27% and 57.47%, respectively. Fourier transform infrared showed that the chemical treatments removed most of the hemicellulose and lignin from the pomelo albedo fibre. This has been confirmed further by SEM and TEM for their morphological studies. These results showed that cellulose and cellulose nanocrystal were successfully obtained from pomelo albedo and might be potentially used in producing functional fibres for food application.

  9. Cellulose nanocrystal from pomelo (C. Grandis osbeck) albedo: Chemical, morphology and crystallinity evaluation

    SciTech Connect

    Zain, Nor Fazelin Mat; Yusop, Salma Mohamad; Ahmad, Ishak

    2013-11-27

    Citrus peel is one of the under-utilized waste materials that have potential in producing a valuable fibre, which are cellulose and cellulose nanocrystal. Cellulose was first isolated from pomelo (C. Grandis Osbeck) albedo by combination of alkali treatment and bleaching process, followed by acid hydrolysis (65% H{sub 2}SO{sub 4}, 45 °C, 45min) to produce cellulose nanocrystal. The crystalline, structural, morphological and chemical properties of both materials were studied. Result reveals the crystallinity index obtained from X-ray diffraction for cellulose nanocrystal was found higher than extracted cellulose with the value of 60.27% and 57.47%, respectively. Fourier transform infrared showed that the chemical treatments removed most of the hemicellulose and lignin from the pomelo albedo fibre. This has been confirmed further by SEM and TEM for their morphological studies. These results showed that cellulose and cellulose nanocrystal were successfully obtained from pomelo albedo and might be potentially used in producing functional fibres for food application.

  10. In Vivo Curdlan/Cellulose Bionanocomposite Synthesis by Genetically Modified Gluconacetobacter xylinus.

    PubMed

    Fang, Ju; Kawano, Shin; Tajima, Kenji; Kondo, Tetsuo

    2015-10-12

    Bacterial cellulose pellicle produced by Gluconacetobacter xylinus (G. xylinus) is one of the best biobased materials having a unique supernetwork structure with remarkable physiochemical properties for a wide range of medical and tissue-engineering applications. It is still necessary to modify them to obtain materials suitable for biomedical use with satisfactory mechanical strength, biodegradability, and bioactivity. The aim of this research was to develop a gene-transformation route for the production of bacterial cellulose/Curdlan (β-1,3-glucan) nanocomposites by separate but simultaneous in vivo synthesis of cellulose and Curdlan. Modification of the cellulose-nanofiber-producing system of G. xylinus enabled Curdlan to be synthesized simultaneously with cellulose nanofibers in vivo, resulting in biopreparation of nanocomposites. The obtained Curdlan/cellulose composites were characterized, and their properties were compared with those of normal bacterial cellulose pellicles, indicating that Curdlan mixed with the cellulose nanofibers at the nanoscale without disruption of the nanofiber network structure in the pellicle. PMID:26360299

  11. Three-dimensional cellulose sponge: Fabrication, characterization, biomimetic mineralization, and in vitro cell infiltration.

    PubMed

    Joshi, Mahesh Kumar; Pant, Hem Raj; Tiwari, Arjun Prasad; Maharjan, Bikendra; Liao, Nina; Kim, Han Joo; Park, Chan Hee; Kim, Cheol Sang

    2016-01-20

    In this study, cellulose based scaffolds were produced by electrospinning of cellulose acetate (CA) solution followed by its saponification with NaOH/ethanol system for 24h. The resulting nonwoven cellulose mat was treated with sodium borohydride (SB) solution. In situ hydrolysis of SB solution into the pores of the membrane produced hydrogen gas resulting a three-dimensional (3D) cellulose sponge. SEM images demonstrated an open porous and loosely packed fibrous mesh compared to the tightly packed single-layered structure of the conventional electrospun membrane. 3D cellulose sponge showed admirable ability to nucleate bioactive calcium phosphate (Ca-P) crystals in simulated body fluid (SBF) solution. SEM-EDX and X-ray diffraction studies revealed that the minerals deposited on the nanofibers have the nonstoichiometric composition similar to that of hydroxyapatite, the mineralized component of the bone. 3D cellulose sponge exhibited the better cell infiltration, spreading and proliferation compared to 2D cellulose mat. Therefore, a facile fabrication of 3D cellulose sponge with improved mineralization represents an innovative strategy for the bone tissue engineering applications. PMID:26572341

  12. Preliminary modulus calculations for cellulose

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Young's modulus is a measure of the inherent stiffness of an elastic material. In the case of cellulose, it quantifies the ability of the material to undergo changes in length as tension or compression forces are applied. The modulus can be calculated by performing tensile tests on cotton fiber...

  13. Production of Bacterial Cellulose from Alternate Feedstocks

    SciTech Connect

    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.

  14. Production of bacterial cellulose from alternate feedstocks

    SciTech Connect

    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.

  15. Lung biodurability and free radical production of cellulose nanomaterials.

    PubMed

    Stefaniak, Aleksandr B; Seehra, Mohindar S; Fix, Natalie R; Leonard, Stephen S

    2014-10-01

    Abstract The potential applications of cellulose nanomaterials in advanced composites and biomedicine makes it imperative to understand their pulmonary exposure to human health. Here, we report the results on the biodurability of three cellulose nanocrystal (CNC), two cellulose nanofibril (CNF) and a benchmark cellulose microcrystal (CMC) when exposed to artificial lung airway lining fluid (SUF, pH 7.3) for up to 7 days and alveolar macrophage phagolysosomal fluid (PSF, pH 4.5) for up to 9 months. X-ray diffraction analysis was used to monitor biodurability and thermogravimetry, surface area, hydrodynamic diameter, zeta potential and free radical generation capacity of the samples were determined (in vitro cell-free and RAW 264.7 cell line models). The CMC showed no measurable changes in crystallinity (x(CR)) or crystallite size D in either SUF or PSF. For one CNC, a slight decrease in x(CR) and D in SUF was observed. In acidic PSF, a slight increase in x(CR) with exposure time was observed, possibly due to dissolution of the amorphous component. In a cell-free reaction with H₂O₂, radicals were observed; the CNCs and a CNF generated significantly more ·OH radicals than the CMC (p < 0.05). The ·OH radical production correlates with particle decomposition temperature and is explained by the higher surface area to volume ratio of the CNCs. Based on their biodurability, mechanical clearance would be the primary mechanism for lung clearance of cellulose materials. The production of ·OH radicals indicates the need for additional studies to characterize the potential inhalation hazards of cellulose. PMID:25265049

  16. Lung biodurability and free radical production of cellulose nanomaterials

    PubMed Central

    Stefaniak, Aleksandr B.; Seehra, Mohindar S.; Fix, Natalie R.; Leonard, Stephen S.

    2015-01-01

    The potential applications of cellulose nanomaterials in advanced composites and biomedicine makes it imperative to understand their pulmonary exposure to human health. Here, we report the results on the biodurability of three cellulose nanocrystal (CNC), two cellulose nanofibril (CNF) and a benchmark cellulose microcrystal (CMC) when exposed to artificial lung airway lining fluid (SUF, pH 7.3) for up to 7 days and alveolar macrophage phagolysosomal fluid (PSF, pH 4.5) for up to 9 months. X-ray diffraction analysis was used to monitor biodurability and thermogravimetry, surface area, hydrodynamic diameter, zeta potential and free radical generation capacity of the samples were determined (in vitro cell-free and RAW 264.7 cell line models). The CMC showed no measurable changes in crystallinity (xCR) or crystallite size D in either SUF or PSF. For one CNC, a slight decrease in xCR and D in SUF was observed. In acidic PSF, a slight increase in xCR with exposure time was observed, possibly due to dissolution of the amorphous component. In a cell-free reaction with H2O2, radicals were observed; the CNCs and a CNF generated significantly more ●OH radicals than the CMC (p<0.05). The ●OH radical production correlates with particle decomposition temperature and is explained by the higher surface area to volume ratio of the CNCs. Based on their biodurability, mechanical clearance would be the primary mechanism for lung clearance of cellulose materials. The production of ●OH radicals indicates the need for additional studies to characterize the potential inhalation hazards of cellulose. PMID:25265049

  17. Biochemical Disincentives to Fertilizing Cellulosic Ethanol Crops

    NASA Astrophysics Data System (ADS)

    Gallagher, M. E.; Hockaday, W. C.; Snapp, S.; McSwiney, C.; Baldock, J.

    2010-12-01

    Corn grain biofuel crops produce the highest yields when the cropping ecosystem is not nitrogen (N)-limited, achieved by application of fertilizer. There are environmental consequences for excessive fertilizer application to crops, including greenhouse gas emissions, hypoxic “dead zones,” and health problems from N runoff into groundwater. The increase in corn acreage in response to demand for alternative fuels (i.e. ethanol) could exacerbate these problems, and divert food supplies to fuel production. A potential substitute for grain ethanol that could reduce some of these impacts is cellulosic ethanol. Cellulosic ethanol feedstocks include grasses (switchgrass), hardwoods, and crop residues (e.g. corn stover, wheat straw). It has been assumed that these feedstocks will require similar N fertilization rates to grain biofuel crops to maximize yields, but carbohydrate yield versus N application has not previously been monitored. We report the biochemical stocks (carbohydrate, protein, and lignin in Mg ha-1) of a corn ecosystem grown under varying N levels. We measured biochemical yield in Mg ha-1 within the grain, leaf and stem, and reproductive parts of corn plants grown at seven N fertilization rates (0-202 kg N ha-1), to evaluate the quantity and quality of these feedstocks across a N fertilization gradient. The N fertilization rate study was performed at the Kellogg Biological Station-Long Term Ecological Research Site (KBS-LTER) in Michigan. Biochemical stocks were measured using 13C nuclear magnetic resonance spectroscopy (NMR), combined with a molecular mixing model (Baldock et al. 2004). Carbohydrate and lignin are the main biochemicals of interest in ethanol production since carbohydrate is the ethanol feedstock, and lignin hinders the carbohydrate to ethanol conversion process. We show that corn residue carbohydrate yields respond only weakly to N fertilization compared to grain. Grain carbohydrate yields plateau in response to fertilization at

  18. Films prepared from electrosterically stabilized nanocrystalline cellulose.

    PubMed

    Yang, Han; Tejado, Alvaro; Alam, Nur; Antal, Miro; van de Ven, Theo G M

    2012-05-22

    Electrosterically stabilized nanocrystalline cellulose (ENCC) was modified in three ways: (1) the hydroxyl groups on C2 and C3 of glucose repeat units of ENCC were converted to aldehyde groups by periodate oxidation to various extents; (2) the carboxyl groups in the sodium form on ENCC were converted to the acid form by treating them with an acid-type ion-exchange resin; and (3) ENCC was cross-linked in two different ways by employing adipic dihydrazide as a cross-linker and water-soluble 1-ethyl-3-[3-(dimethylaminopropyl)] carbodiimide as a carboxyl-activating agent. Films were prepared from these modified ENCC suspensions by vacuum filtration. The effects of these three modifications on the properties of films were investigated by a variety of techniques, including UV-visible spectroscopy, a tensile test, thermogravimetric analysis (TGA), the water vapor transmission rate (WVTR), and contact angle (CA) studies. On the basis of the results from UV spectra, the transmittance of these films was as high as 87%, which shows them to be highly transparent. The tensile strength of these films was increased with increasing aldehyde content. From TGA and WVTR experiments, cross-linked films showed much higher thermal stability and lower water permeability. Furthermore, although the original cellulose is hydrophilic, these films also exhibited a certain hydrophobic behavior. Films treated by trichloromethylsilane become superhydrophobic. The unique characteristics of these transparent films are very promising for potential applications in flexible packaging and other high-technology products. PMID:22482733

  19. A morpholinium ionic liquid for cellulose dissolution.

    PubMed

    Raut, Dilip G; Sundman, Ola; Su, Weiqing; Virtanen, Pasi; Sugano, Yasuhito; Kordas, Krisztian; Mikkola, Jyri-Pekka

    2015-10-01

    A series of substituted morpholinium ionic salts and allyl ammonium acetates were prepared. Amongst those, N-allyl-N-methylmorpholinium acetate ([AMMorp][OAc]) was found to dissolve cellulose readily without any pre-processing of native cellulose. At 120°C, [AMMorp][OAc] could dissolve 30 wt%, 28 wt% and 25 wt% of cellulose with degree of polymerization (DPn) - 789, 1644 and 2082 respectively, in 20 min. Importantly, SEC analysis indicated that no discernible changes occurred in terms of the degree of polymerization of the different celluloses after regeneration. Furthermore, when comparing the cellulose dissolution capability of these newly synthesized ionic liquids, it is evident that the combination of all three constituents - the morpholinium cation, the existence of an allyl group and choosing the acetate anion are essential for efficient cellulose dissolution. The structure and morphology of the regenerated cellulosic materials were characterized by SEM, XRD, TGA, CP/MAS (13)C NMR and FTIR, respectively. PMID:26076596

  20. Cellulose nanomaterials in water treatment technologies.

    PubMed

    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

  1. Cellulose Nanomaterials in Water Treatment Technologies

    PubMed Central

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

    2015-01-01

    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

  2. Noncovalent Dispersion and Functionalization of Cellulose Nanocrystals with Proteins and Polysaccharides.

    PubMed

    Fang, Wenwen; Arola, Suvi; Malho, Jani-Markus; Kontturi, Eero; Linder, Markus B; Laaksonen, Päivi

    2016-04-11

    Native cellulose nanocrystals (CNCs) are valuable high quality materials with potential for many applications including the manufacture of high performance materials. In this work, a relatively effortless procedure was introduced for the production of CNCs, which gives a nearly 100% yield of crystalline cellulose. However, the processing of the native CNCs is hindered by the difficulty in dispersing them in water due to the absence of surface charges. To overcome these difficulties, we have developed a one-step procedure for dispersion and functionalization of CNCs with tailored cellulose binding proteins. The process is also applicable for polysaccharides. The tailored cellulose binding proteins are very efficient for the dispersion of CNCs due to the selective interaction with cellulose, and only small fraction of proteins (5-10 wt %, corresponds to about 3 μmol g(-1)) could stabilize the CNC suspension. Xyloglucan (XG) enhanced the CNC dispersion above a fraction of 10 wt %. For CNC suspension dispersed with carboxylmethyl cellulose (CMC) we observed the most long-lasting stability, up to 1 month. The cellulose binding proteins could not only enhance the dispersion of the CNCs, but also functionalize the surface. This we demonstrated by attaching gold nanoparticles (GNPs) to the proteins, thus, forming a monolayer of GNPs on the CNC surface. Cryo transmission electron microscopy (Cryo-TEM) imaging confirmed the attachment of the GNPs to CNC solution conditions. PMID:26907991

  3. Investigation and characterization of oxidized cellulose and cellulose nanofiber films

    NASA Astrophysics Data System (ADS)

    Yang, Han

    Over the last two decades, a large amount of research has focused on natural cellulose fibers, since they are "green" and renewable raw materials. Recently, nanomaterials science has attracted wide attention due to the large surface area and unique properties of nanoparticles. Cellulose certainly is becoming an important material in nanomaterials science, with the increasing demand of environmentally friendly materials. In this work, a novel method of preparing cellulose nanofibers (CNF) is being presented. This method contains up to three oxidation steps: periodate, chlorite and TEMPO (2,2,6,6-tetramethylpiperidinyl-1-oxyl) oxidation. The first two oxidation steps are investigated in the first part of this work. Cellulose pulp was oxidized to various extents by a two step-oxidation with sodium periodate, followed by sodium chlorite. The oxidized products can be separated into three different fractions. The mass ratio and charge content of each fraction were determined. The morphology, size distribution and crystallinity index of each fraction were measured by AFM, DLS and XRD, respectively. In the second part of this work, CNF were prepared and modified under various conditions, including (1) the introduction of various amounts of aldehyde groups onto CNF by periodate oxidation; (2) the carboxyl groups in sodium form on CNF were converted to acid form by treated with an acid type ion-exchange resin; (3) CNF were cross-linked in two different ways by employing adipic dihydrazide (ADH) as cross-linker and water-soluble 1-ethyl-3-[3-(dimethylaminopropyl)] carbodiimide (EDC) as carboxyl-activating agent. Films were fabricated with these modified CNF suspensions by vacuum filtration. The optical, mechanical and thermo-stability properties of these films were investigated by UV-visible spectrometry, tensile test and thermogravimetric analysis (TGA). Water vapor transmission rates (WVTR) and water contact angle (WCA) of these films were also studied.

  4. Comparative plasma disposition, bioavailability and efficacy of ivermectin following oral and pour-on administrations in horses.

    PubMed

    Gokbulut, Cengiz; Cirak, Veli Y; Senlik, Bayram; Aksit, Dilek; Durmaz, Murat; McKellar, Quintin A

    2010-05-28

    Pour-on formulations of endectocides decrease the risk of injury for both user and animal, and are particularly convenient for animal owners who can apply the product. This study was designed to investigate the plasma disposition and efficacy of ivermectin (IVM) following pour-on, per os and intravenous administrations. Eighteen female horses weighing 510-610 kg were used in this study. The animals were allocated into three groups (per os, pour-on and intravenous groups). The equine paste, bovine pour-on and bovine injectable formulations of IVM were administered orally, topically and intravenously at the dose rates of 0.2, 0.5 and 0.2mg/kg bodyweight, respectively. Heparinized blood samples and hair samples were collected at various times between 1h and 40 days. The samples were analysed by high performance liquid chromatography with fluorescence detector. Faecal strongyle egg counts (EPG) were performed by a modified McMaster's technique before and at weekly intervals during 10 weeks after treatment. The results indicated that the plasma concentration and systemic availability of IVM was lower but the plasma persistence was prolonged after pour-on administration compared with per os route. IVM (paste) reduced the EPG by >95% for 10 weeks, whereas the reduction in pour-on group varied from 82 to 97%. EPG reduction in pour-on group was lower than that of per os group. Degradation on the application site, cutaneous biotransformation, binding of IVM to the haircoat and/or sebum are probably responsible for the relatively lower bioavailability of IVM in horses after pour-on administration. In conclusion, the poor plasma availability observed after pour-on administration could result in subtherapeutic plasma concentrations, which may promote the development of drug resistance in parasites. PMID:20181429

  5. Cellulose Aggregation under Hydrothermal Pretreatment Conditions.

    PubMed

    Silveira, Rodrigo L; Stoyanov, Stanislav R; Kovalenko, Andriy; Skaf, Munir S

    2016-08-01

    Cellulose, the most abundant biopolymer on Earth, represents a resource for sustainable production of biofuels. Thermochemical treatments make lignocellulosic biomaterials more amenable to depolymerization by exposing cellulose microfibrils to enzymatic or chemical attacks. In such treatments, the solvent plays fundamental roles in biomass modification, but the molecular events underlying these changes are still poorly understood. Here, the 3D-RISM-KH molecular theory of solvation has been employed to analyze the role of water in cellulose aggregation under different thermodynamic conditions. The results show that, under ambient conditions, highly structured hydration shells around cellulose create repulsive forces that protect cellulose microfibrils from aggregating. Under hydrothermal pretreatment conditions, however, the hydration shells lose structure, and cellulose aggregation is favored. These effects are largely due to a decrease in cellulose-water interactions relative to those at ambient conditions, so that cellulose-cellulose attractive interactions become prevalent. Our results provide an explanation to the observed increase in the lateral size of cellulose crystallites when biomass is subject to pretreatments and deepen the current understanding of the mechanisms of biomass modification. PMID:27301535

  6. Cellulose degradation by oxidative enzymes.

    PubMed

    Dimarogona, Maria; Topakas, Evangelos; Christakopoulos, Paul

    2012-01-01

    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. PMID:24688656

  7. Cellulose degradation by oxidative enzymes

    PubMed Central

    Dimarogona, Maria; Topakas, Evangelos; Christakopoulos, Paul

    2012-01-01

    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. PMID:24688656

  8. Hydration of microcrystalline cellulose and milled cellulose studied by sorption calorimetry.

    PubMed

    Kocherbitov, Vitaly; Ulvenlund, Stefan; Kober, Maria; Jarring, Kjell; Arnebrant, Thomas

    2008-03-27

    The hydration of two different polymorphs of microcrystalline cellulose (cellulose I and II), as well as the hydration of amorphous cellulose was studied using water sorption calorimetry, gravimetric water vapor sorption, nitrogen sorption, and X-ray powder diffraction. Amorphous cellulose was prepared by means of ball-milling of microcrystalline cellulose (MCC). Whereas X-ray data showed the untreated MCC to consist of cellulose I, the amorphous cellulose was found to recrystallize into cellulose II after contact with water or water vapor at relative humidities (RHs) above 90%. Sorption isotherms show an increase of water sorption in the sequence cellulose I<cellulose IIcellulose. The enthalpy of water sorption becomes more exothermic in the same sequence. The specific area of cellulose is dramatically higher when calculated from the water adsorption than when calculated from nitrogen adsorption. A proposed mechanism of water sorption by MCC implies the adsorption of water molecules at solid-solid interfaces, i.e., between neighboring microfibrils, which explains the observed difference between water and nitrogen. The Brunauer-Emmett-Teller (BET) model is therefore not appropriate for the description of the hydration of cellulose. Rather, the Langmuir model represents a more accurate description of water sorption by MCC at low RH. At higher RH, the water adsorption competes with capillary condensation. The thickness of microfibrils, as calculated using the fitting of the sorption isotherm of MCC with the Langmuir equation, is about 4 nm. This value compares favorably with literature data. PMID:18307340

  9. Bacterial Cellulose (BC) as a Functional Nanocomposite Biomaterial

    NASA Astrophysics Data System (ADS)

    Nandgaonkar, Avinav Ghanashyam

    Cellulosic is the most abundant biopolymer in the landscape and can be found in many different organisms. It has been already seen use in the medical field, for example cotton for wound dressings and sutures. Although cellulose is naturally occurring and has found a number of applications inside and outside of the medical field, it is not typically produced in its pure state. A lengthy process is required to separate the lignin, hemicelluloses and other molecules from the cellulose in most renewables (wood, agricultural fibers such as cotton, monocots, grasses, etc.). Although bacterial cellulose has a similar chemical structure to plant cellulose, it is easier to process because of the absence of lignin and hemicelluloses which require a lot of energy and chemicals for removal. Bacterial cellulose (BC) is produced from various species of bacteria such as Gluconacetobacter xylinus. Due to its high water uptake, it has the tendency to form gels. It displays high tensile strength, biocompatibility, and purity compared to wood cellulose. It has found applications in fields such as paper, paper products, audio components (e.g., speaker diaphragms), flexible electronics, supercapacitors, electronics, and soft tissue engineering. In my dissertation, we have functionalized and studied BC-based materials for three specific applications: cartilage tissue engineering, bioelectronics, and dye degradation. In our first study, we prepared a highly organized porous material based on BC by unidirectional freezing followed by a freeze-drying process. Chitosan was added to impart additional properties to the resulting BC-based scaffolds that were evaluated in terms of their morphological, chemical, and physical properties for cartilage tissue engineering. The properties of the resulting scaffold were tailored by adjusting the concentration of chitosan over 1, 1.5, and 2 % (by wt-%). The scaffolds containing chitosan showed excellent shape recovery and structural stability after

  10. INTERIOR VIEW, LOOKING WEST, WITH CRANE OPERATOR, TED SEALS, POURING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    INTERIOR VIEW, LOOKING WEST, WITH CRANE OPERATOR, TED SEALS, POURING MOLTEN METAL INTO A 1,300 TON ELECTRIC HOLDING FURNACE OR MIXER. AN ELECTRONIC SCALE RECORDED THAT 50.5 TONS OF METAL WERE POURED INTO THE FURNACE DURING THIS POUR. - American Cast Iron Pipe Company, Mixer Building, 1501 Thirty-first Avenue North, Birmingham, Jefferson County, AL

  11. Preparation and properties of biodegradable films from Sterculia urens short fiber/cellulose green composites.

    PubMed

    Jayaramudu, J; Reddy, G Siva Mohan; Varaprasad, K; Sadiku, E R; Sinha Ray, S; Varada Rajulu, A

    2013-04-01

    The development of commercially viable "green products", based on natural resources for the matrices and reinforcements, in a wide range of applications, is on the rise. The present paper focuses on Sterculia urens short fiber reinforced pure cellulose matrix composite films. The morphologies of the untreated and 5% NaOH (alkali) treated S. urens fibers were observed by SEM. The effect of 5% NaOH treated S. urens fiber (5, 10, 15 and 20% loading) on the mechanical properties and thermal stability of the composites films is discussed. This paper presents the developments made in the area of biodegradable S. urens short fiber/cellulose (SUSF/cellulose) composite films, buried in the soil and later investigated by the (POM), before and after biodegradation has taken place. SUSF/cellulose composite films have great potential in food packaging and for medical applications. PMID:23499104

  12. Preparation of reactive fibre interfaces using multifunctional cellulose derivatives.

    PubMed

    Vega, Beatriz; Wondraczek, Holger; Bretschneider, Leonore; Näreoja, Tuomas; Fardim, Pedro; Heinze, Thomas

    2015-11-01

    Cellulose fibres have poor reactivity and limited potential for surface engineering with advanced chemical functionalization in water. In this work, cellulose fibres were decorated with azide functions by charge-directed self-assembly of a novel water-soluble multifunctional cellulose derivative yielding reactive fibres. Propargylamine and 1-ethynylpyrene were utilized as a proof of concept that alkyne molecules may react with the azide functions of the reactive fibres via copper(I)-catalyzed azide-alkyne Huisgen cycloaddition (CuAAc) reaction in mild conditions. Chemical characterization of the fibres was carried out using classical techniques such as Raman-, fluorescence-, and UV-vis spectroscopy. Among other techniques, time-of-flight secondary ion mass spectrometry (ToF-SIMS), X-ray spectroscopy (XPS), two-photon microscopy (TPM), and inductively coupled plasma mass spectrometry (ICP-MS) were useful tools for additional characterization of the fibres decorated with amino- or photoactive groups. The information gathered in this work might contribute to the basis for the preparation of reactive cellulose-based interfaces with potential application in CuAAc reactions. PMID:26256349

  13. Nano zinc oxide-sodium alginate antibacterial cellulose fibres.

    PubMed

    Varaprasad, Kokkarachedu; Raghavendra, Gownolla Malegowd; Jayaramudu, Tippabattini; Seo, Jongchul

    2016-01-01

    In the present study, antibacterial cellulose fibres were successfully fabricated by a simple and cost-effective procedure by utilizing nano zinc oxide. The possible nano zinc oxide was successfully synthesized by precipitation technique and then impregnated effectively over cellulose fibres through sodium alginate matrix. XRD analysis revealed the 'rod-like' shape alignment of zinc oxide with an interplanar d-spacing of 0.246nm corresponding to the (101) planes of the hexagonal wurtzite structure. TEM analysis confirmed the nano dimension of the synthesized zinc oxide nanoparticles. The presence of nano zinc oxide over cellulose fibres was evident from the SEM-EDS experiments. FTIR and TGA studies exhibited their effective bonding interaction. The tensile stress-strain curves data indicated the feasibility of the fabricated fibres for longer duration utility without any significant damage or breakage. The antibacterial studies against Escherichia coli revealed the excellent bacterial devastation property. Further, it was observed that when all the parameters remained constant, the variation of sodium alginate concentration showed impact in devastating the E. coli. In overall, the fabricated nano zinc oxide-sodium alginate cellulose fibres can be effectively utilized as antibacterial fibres for biomedical applications. PMID:26453887

  14. Cellulose nanocrystals reinforced foamed nitrile rubber nanocomposites.

    PubMed

    Chen, Yukun; Zhang, Yuanbing; Xu, Chuanhui; Cao, Xiaodong

    2015-10-01

    Research on foamed nitrile rubber (NBR)/cellulose nanocrystals (CNs) nanocomposites is rarely found in the literatures. In this paper, CNs suspension and NBR latex was mixed to prepared the foamed NBR/CNs nanocomposites. We found that the CNs mainly located in the cell walls, effectively reinforcing the foamed NBR. The strong interaction between the CNs and NBR matrix restricted the mobility of NBR chains surrounding the CNs, hence increasing the crosslink density of the NBR matrix. CNs exhibited excellent reinforcement on the foamed NBR: a remarkable increase nearly 76% in the tensile strength of the foamed nanocomposites was achieved with a load of only 15 phr CNs. Enhanced mechanical properties make the foamed NBR/CNs nanocomposites a promising damping material for industrial applications with a potential to reduce the petroleum consumption. PMID:26076611

  15. Enzymatic Hydrolysis of Cellulosic Biomass

    SciTech Connect

    Yang, Bin; Dai, Ziyu; Ding, Shi-You; Wyman, Charles E.

    2011-08-22

    Biological conversion of cellulosic biomass to fuels and chemicals offers the high yields to products vital to economic success and the potential for very low costs. Enzymatic hydrolysis that converts lignocellulosic biomass to fermentable sugars may be the most complex step in this process due to substrate-related and enzyme-related effects and their interactions. Although enzymatic hydrolysis offers the potential for higher yields, higher selectivity, lower energy costs, and milder operating conditions than chemical processes, the mechanism of enzymatic hydrolysis and the relationship between the substrate structure and function of various glycosyl hydrolase components are not well understood. Consequently, limited success has been realized in maximizing sugar yields at very low cost. This review highlights literature on the impact of key substrate and enzyme features that influence performance to better understand fundamental strategies to advance enzymatic hydrolysis of cellulosic biomass for biological conversion to fuels and chemicals. Topics are summarized from a practical point of view including characteristics of cellulose (e.g., crystallinity, degree of polymerization, and accessible surface area) and soluble and insoluble biomass components (e.g., oligomeric xylan, lignin, etc.) released in pretreatment, and their effects on the effectiveness of enzymatic hydrolysis. We further discuss the diversity, stability, and activity of individual enzymes and their synergistic effects in deconstructing complex lignocellulosic biomass. Advanced technologies to discover and characterize novel enzymes and to improve enzyme characteristics by mutagenesis, post-translational modification, and over-expression of selected enzymes and modifications in lignocellulosic biomass are also discussed.

  16. Functional biocompatible magnetite-cellulose nanocomposite fibrous networks: Characterization by fourier transformed infrared spectroscopy, X-ray powder diffraction and field emission scanning electron microscopy analysis

    NASA Astrophysics Data System (ADS)

    Habibi, Neda

    2015-02-01

    The preparation and characterization of functional biocompatible magnetite-cellulose nano-composite fibrous material is described. Magnetite-cellulose nano-composite was prepared by a combination of the solution-based formation of magnetic nano-particles and subsequent coating with amino celluloses. Characterization was accomplished using X-ray powder diffraction (XRD), fourier transformed infrared (FTIR) and field emission scanning electron microscopy (FESEM) analysis. The peaks of Fe3O4 in the XRD pattern of nanocomposite confirm existence of the nanoparticles in the amino cellulose matrix. Magnetite-cellulose particles exhibit an average diameter of roughly 33 nm as demonstrated by field emission scanning electron microscopy. Magnetite nanoparticles were irregular spheres dispersed in the cellulose matrix. The vibration corresponding to the Nsbnd CH3 functional group about 2850 cm-1 is assigned in the FTIR spectra. Functionalized magnetite-cellulose nano-composite polymers have a potential range of application as targeted drug delivery system in biomedical field.

  17. A Statistical Treatment of Bioassay Pour Fractions

    NASA Technical Reports Server (NTRS)

    Barengoltz, Jack; Hughes, David W.

    2014-01-01

    The binomial probability distribution is used to treat the statistics of a microbiological sample that is split into two parts, with only one part evaluated for spore count. One wishes to estimate the total number of spores in the sample based on the counts obtained from the part that is evaluated (pour fraction). Formally, the binomial distribution is recharacterized as a function of the observed counts (successes), with the total number (trials) an unknown. The pour fraction is the probability of success per spore (trial). This distribution must be renormalized in terms of the total number. Finally, the new renormalized distribution is integrated and mathematically inverted to yield the maximum estimate of the total number as a function of a desired level of confidence ( P(pour fraction. The extension to recovery efficiency corrections is also presented. Now the product of recovery efficiency and pour fraction may be small enough that the likely value may be much larger than the usual calculation: the number of spores divided by that product. The use of this analysis would not be limited to microbiological data.

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

    PubMed

    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

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

    PubMed

    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

  20. Micromechanics and poroelasticity of hydrated cellulose networks.

    PubMed

    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

  1. Improved Mechanical Properties and Sustained Release Behavior of Cationic Cellulose Nanocrystals Reinforeced Cationic Cellulose Injectable Hydrogels.

    PubMed

    You, Jun; Cao, Jinfeng; Zhao, Yanteng; Zhang, Lina; Zhou, Jinping; Chen, Yun

    2016-09-12

    Polysaccharide-based injectable hydrogels have several advantages in the context of biomedical use. However, the main obstruction associated with the utilization of these hydrogels in clinical application is their poor mechanical properties. Herein, we describe in situ gelling of nanocomposite hydrogels based on quaternized cellulose (QC) and rigid rod-like cationic cellulose nanocrystals (CCNCs), which can overcome this challenge. In all cases, gelation immediately occurred with an increase of temperature, and the CCNCs were evenly distributed throughout the hydrogels. The nanocomposite hydrogels exhibited increasing orders-of-magnitude in the mechanical strength, high extension in degradation and the sustained release time, because of the strong interaction between CCNCs and QC chains mediated by the cross-linking agent (β-glycerophosphate, β-GP). The results of the in vitro toxicity and in vivo biocompatibility tests revealed that the hydrogels did not show obvious cytotoxicity and inflammatory reaction to cells and tissue. Moreover, DOX-encapsulated hydrogels were injected beside the tumors of mice bearing liver cancer xenografts to assess the potential utility as localized and sustained drug delivery depot systems for anticancer therapy. The results suggested that the QC/CCNC/β-GP nanocomposite hydrogels had great potential for application in subcutaneous and sustained delivery of anticancer drug to increase therapeutic efficacy and improve patient compliance. PMID:27519472

  2. Water-soluble cellulose acetate from waste cotton fabrics and the aqueous processing of all-cellulose composites.

    PubMed

    Cao, Jie; Sun, Xunwen; Lu, Canhui; Zhou, Zehang; Zhang, Xinxing; Yuan, Guiping

    2016-09-20

    The objective of this study is to explore the possibility of using waste cotton fabrics (WCFs) as low cost feedstock for the production of value-added products. Our previous study (Tian et al., 2014) demonstrated that acidic ionic liquids (ILs) can be highly efficient catalysts for controllable synthesis of cellulose acetate (CA) due to their dual function of swelling and catalyzing. In this study, an optimized "quasi-homogeneous" process which required a small amount of acidic ILs as catalyst was developed to synthesize water-soluble CA from WCFs. The process was optimized by varying the amounts of ILs and the reaction time. The highest conversion of water-soluble CA from WCFs reached 90.8%. The structure of the obtained water-soluble CA was characterized and compared with the original WCFs. Moreover, we demonstrate for the first time that fully bio-based and transparent all-cellulose composites can be fabricated by simple aqueous blending of the obtained water-soluble CA and two kinds of nanocelluloses (cellulose nanocrystals and cellulose nanofibrils), which is attractive for the applications in disposable packaging materials, sheet coating and binders, etc. PMID:27261730

  3. The case for cellulose production on Mars

    NASA Technical Reports Server (NTRS)

    Volk, Tyler; Rummel, John D.

    1989-01-01

    From examining the consequences of not requiring that all wastes from life support be recycled back to the food plants, it is concluded that cellulose production on Mars could be an important input for many nonmetabolic material requirements on Mars. The fluxes of carbon in cellulose production would probably exceed those in food production, and therefore settlements on Mars could utilize cellulose farms in building a Mars infrastructure.

  4. Tubular cellulose/starch gel composite as food enzyme storehouse.

    PubMed

    Barouni, Eleftheria; Petsi, Theano; Kanellaki, Maria; Bekatorou, Argyro; Koutinas, Athanasios

    2015-12-01

    The objective of this study was to produce a composite biocatalyst, based on porous cellulosic material, produced after wood sawdust delignification (tubular cellulose; TC) and starch gel (SG), for the development of bioprocesses related to enzyme applications. The composite biocatalyst was studied by Scanning Electron Microscopy to observe the SG deposition in the TC pores, and porosimetry analysis to determine the average pore diameter and surface area. The deposition of SG into the TC tubes provided a TC/SG composite with reduced pore sizes. X-ray powder diffractometry showed a decrease of crystallinity with increased SG ratio in the composite. The composite was used as an insoluble carrier for entrapment of the dairy enzyme rennin, leading to the production of an active biocatalyst for milk coagulation (initiation of milk clotting at about 20 min and full coagulation at about 200 min), creating perspectives for several applications in food enzyme research and technology. PMID:26041171

  5. Acidic Ultrafine Tungsten Oxide Molecular Wires for Cellulosic Biomass Conversion.

    PubMed

    Zhang, Zhenxin; Sadakane, Masahiro; Hiyoshi, Norihito; Yoshida, Akihiro; Hara, Michikazu; Ueda, Wataru

    2016-08-22

    The application of nanocatalysis based on metal oxides for biomass conversion is of considerable interest in fundamental research and practical applications. New acidic transition-metal oxide molecular wires were synthesized for the conversion of cellulosic biomass. The ultrafine molecular wires were constructed by repeating (NH4 )2 [XW6 O21 ] (X=Te or Se) along the length, exhibiting diameters of only 1.2 nm. The nanowires dispersed in water and were observed using high-angle annular dark-field scanning transmission electron microscopy. Acid sites were created by calcination without collapse of the molecular wire structure. The acidic molecular wire exhibited high activity and stability and promoted the hydrolysis of the glycosidic bond. Various biomasses including cellulose were able to be converted to hexoses as main products. PMID:27482857

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

    SciTech Connect

    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.

  7. Structure of the Cellulose Synthase Complex of Gluconacetobacter hansenii at 23.4 Å Resolution

    PubMed Central

    Du, Juan; Vepachedu, Venkata; Cho, Sung Hyun; Kumar, Manish; Nixon, B. Tracy

    2016-01-01

    Bacterial crystalline cellulose is used in biomedical and industrial applications, but the molecular mechanisms of synthesis are unclear. Unlike most bacteria, which make non-crystalline cellulose, Gluconacetobacter hansenii extrudes profuse amounts of crystalline cellulose. Its cellulose synthase (AcsA) exists as a complex with accessory protein AcsB, forming a 'terminal complex' (TC) that has been visualized by freeze-fracture TEM at the base of ribbons of crystalline cellulose. The catalytic AcsAB complex is embedded in the cytoplasmic membrane. The C-terminal portion of AcsC is predicted to form a translocation channel in the outer membrane, with the rest of AcsC possibly interacting with AcsD in the periplasm. It is thus believed that synthesis from an organized array of TCs coordinated with extrusion by AcsC and AcsD enable this bacterium to make crystalline cellulose. The only structural data that exist for this system are the above mentioned freeze-fracture TEM images, fluorescence microscopy images revealing that TCs align in a row, a crystal structure of AcsD bound to cellopentaose, and a crystal structure of PilZ domain of AcsA. Here we advance our understanding of the structural basis for crystalline cellulose production by bacterial cellulose synthase by determining a negative stain structure resolved to 23.4 Å for highly purified AcsAB complex that catalyzed incorporation of UDP-glucose into β-1,4-glucan chains, and responded to the presence of allosteric activator cyclic diguanylate. Although the AcsAB complex was functional in vitro, the synthesized cellulose was not visible in TEM. The negative stain structure revealed that AcsAB is very similar to that of the BcsAB synthase of Rhodobacter sphaeroides, a non-crystalline cellulose producing bacterium. The results indicate that the crystalline cellulose producing and non-crystalline cellulose producing bacteria share conserved catalytic and membrane translocation components, and support the

  8. Structure of the cellulose synthase complex of Gluconacetobacter hansenii at 23.4 Å resolution

    DOE PAGESBeta

    Du, Juan; Vepachedu, Venkata; Cho, Sung Hyun; Kumar, Manish; Nixon, B. Tracy; Lai, Hsin -Chih

    2016-05-23

    Bacterial crystalline cellulose is used in biomedical and industrial applications, but the molecular mechanisms of synthesis are unclear. Unlike most bacteria, which make non-crystalline cellulose, Gluconacetobacter hansenii extrudes profuse amounts of crystalline cellulose. Its cellulose synthase (AcsA) exists as a complex with accessory protein AcsB, forming a 'terminal complex' (TC) that has been visualized by freeze-fracture TEM at the base of ribbons of crystalline cellulose. The catalytic AcsAB complex is embedded in the cytoplasmic membrane. The C-terminal portion of AcsC is predicted to form a translocation channel in the outer membrane, with the rest of AcsC possibly interacting with AcsDmore » in the periplasm. It is thus believed that synthesis from an organized array of TCs coordinated with extrusion by AcsC and AcsD enable this bacterium to make crystalline cellulose. The only structural data that exist for this system are the above mentioned freeze-fracture TEM images, fluorescence microscopy images revealing that TCs align in a row, a crystal structure of AcsD bound to cellopentaose, and a crystal structure of PilZ domain of AcsA. Here we advance our understanding of the structural basis for crystalline cellulose production by bacterial cellulose synthase by determining a negative stain structure resolved to 23.4 angstrom for highly purified AcsAB complex that catalyzed incorporation of UDP-glucose into β-1,4-glucan chains, and responded to the presence of allosteric activator cyclic diguanylate. Although the AcsAB complex was functional in vitro, the synthesized cellulose was not visible in TEM. The negative stain structure revealed that AcsAB is very similar to that of the BcsAB synthase of Rhodobacter sphaeroides, a non-crystalline cellulose producing bacterium. Furthermore, the results indicate that the crystalline cellulose producing and non-crystalline cellulose producing bacteria share conserved catalytic and membrane translocation

  9. Structure of the Cellulose Synthase Complex of Gluconacetobacter hansenii at 23.4 Å Resolution.

    PubMed

    Du, Juan; Vepachedu, Venkata; Cho, Sung Hyun; Kumar, Manish; Nixon, B Tracy

    2016-01-01

    Bacterial crystalline cellulose is used in biomedical and industrial applications, but the molecular mechanisms of synthesis are unclear. Unlike most bacteria, which make non-crystalline cellulose, Gluconacetobacter hansenii extrudes profuse amounts of crystalline cellulose. Its cellulose synthase (AcsA) exists as a complex with accessory protein AcsB, forming a 'terminal complex' (TC) that has been visualized by freeze-fracture TEM at the base of ribbons of crystalline cellulose. The catalytic AcsAB complex is embedded in the cytoplasmic membrane. The C-terminal portion of AcsC is predicted to form a translocation channel in the outer membrane, with the rest of AcsC possibly interacting with AcsD in the periplasm. It is thus believed that synthesis from an organized array of TCs coordinated with extrusion by AcsC and AcsD enable this bacterium to make crystalline cellulose. The only structural data that exist for this system are the above mentioned freeze-fracture TEM images, fluorescence microscopy images revealing that TCs align in a row, a crystal structure of AcsD bound to cellopentaose, and a crystal structure of PilZ domain of AcsA. Here we advance our understanding of the structural basis for crystalline cellulose production by bacterial cellulose synthase by determining a negative stain structure resolved to 23.4 Å for highly purified AcsAB complex that catalyzed incorporation of UDP-glucose into β-1,4-glucan chains, and responded to the presence of allosteric activator cyclic diguanylate. Although the AcsAB complex was functional in vitro, the synthesized cellulose was not visible in TEM. The negative stain structure revealed that AcsAB is very similar to that of the BcsAB synthase of Rhodobacter sphaeroides, a non-crystalline cellulose producing bacterium. The results indicate that the crystalline cellulose producing and non-crystalline cellulose producing bacteria share conserved catalytic and membrane translocation components, and support the

  10. Controlling the structure and rheology of TEMPO-oxidized cellulose in zinc chloride aqueous suspensions for fabricating advanced nanopaper

    NASA Astrophysics Data System (ADS)

    Wang, Sha; Zhang, Xin; Hu, Liangbing; Briber, Robert; Wang, Howard; Zhong, Linxin

    Due to its abundance, low-cost, biocompatibility and renewability, cellulose has become an attractive candidate as a functional material for various advanced applications. A key to novel applications is the control of the structure and rheology of suspensions of fibrous cellulose. Among many different approaches of preparing cellulose suspensions, zinc chloride addition to aqueous suspensions is regarded an effective practice. In this study, effects of ZnCl2 concentration on TEMPO-oxidized cellulose (TOC) nanofiber suspensions have been investigated. Highly-transparent cellulose nanofiber suspension can be rapidly obtained by dissolving TOC in 65 wt.% zinc chloride aqueous solutions at room temperature, whereas a transparent zinc ion cross-linked TOC gel could be obtained with zinc chloride concentration as low as 10 wt. %. The structural and rheological characteristics of TOC/ZnCl2 suspensions have been measured to correlate to the performance of thetransparent and flexible nanocellulose paper subsequently produced via vacuum filtration or wet-casting processes.

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

    PubMed

    Lee, Koon-Yang; Tammelin, Tekla; Schulfter, Kerstin; Kiiskinen, Harri; Samela, Juha; Bismarck, Alexander

    2012-08-01

    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, measured to be 71% for BC as compared to NFC of 41%. Nanocellulose papers were prepared from BC and NFC. Both papers possessed similar tensile moduli and strengths of 12 GPa and 110 MPa, respectively. Nanocomposites were manufactured by impregnating the nanocellulose paper with an epoxy resin using vacuum assisted resin infusion. The cellulose reinforced epoxy nanocomposites had a stiffness and strength of approximately ∼8 GPa and ∼100 MPa at an equivalent fiber volume fraction of 60 vol.-%. In terms of the reinforcing ability of NFC and BC in a polymer matrix, no significant difference between NFC and BC was observed. PMID:22839594

  12. Cytocompatible cellulose hydrogels containing trace lignin.

    PubMed

    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

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

    PubMed

    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

  14. Synthesis, micellization behavior and alcohol induced amphipathic cellulose film of cellulose-based amphiphilic surfactant

    NASA Astrophysics Data System (ADS)

    Yang, Fang; Liu, Ya-nan; Yu, Jian-ling; Li, Hai-peng; Li, Gang

    2015-08-01

    This paper presented a novel preparation method of the cellulose-based amphiphilic surfactant, and the surfactant was used to prepare amphipathic cellulose membrane. The native cotton cellulose was tailored to cellulose segments in ionic liquid 1-butyl-3-methylimidazolium chloride. Then, the hydrophobic and hydrophilic modification of cellulose segments were carried out by esterification and graft polymerization of the ɛ-caprolactone (ɛ-CL) monomer onto the hydroxyl group of cellulose as well as sulphonation with sulfamic acid. The amphipathic cellulose membrane was made by cellulose-based amphiphilic surfactant cross-linking with glutaraldehyde. The molecular structure of amphipathic cellulose surfactant was confirmed by FT-IR, and its surface active properties were investigated by Wilhelmy plate method and Steady-state fluorescence probe method, respectively. Experimental results showed that cellulose-based amphiphilic surfactant caused low interfacial tension of 48.62 mN/m and its critical micelle concentration (cmc) value was 0.65 wt% when the grafting ratio of cellulose-g-PCL (poly-caprolactone) was 25.40%. The contact angle between a droplet of water and the surface of membrane was 90.84o, and the surface free energy of the alcohol induced cellulose membrane was 15.7 mJ/m2. This study may help increase using natural and biodegradable surface-activity materials with improved properties as surfactants.

  15. First come, first served. Does pouring sequence matter for consumption?

    PubMed

    Stroebele-Benschop, Nanette; Dieze, Anastasia; Hilzendegen, Carolin

    2016-10-01

    Various environmental factors associated with eating and drinking affect people's food choice and food intake. Lately, the role of tableware has been studied in more detail. The aim of this study was to determine whether pouring sequence of food components affects portion size. Study 1 invited participants to pour a beverage containing both apple juice and sparkling water. Pouring apple juice first increased juice by almost 25% compared to pouring water first. Pouring water first increased water by almost 19% compared to pouring juice first confirming our hypothesis that pouring sequence affects the ratio poured. Study 2 asked participants to prepare themselves a snack containing cereals with milk. Within-subject comparisons revealed that pouring milk before cereals significantly increased both milk and cereal amounts resulting in larger overall portion size compared to pouring cereals before adding milk. Habitual tendencies for preparing foods causing a perception bias or a perception bias itself could be possible explanations for the divergent study findings. These findings show for the first time the influence of pouring and preparation sequence on portion size. PMID:27417334

  16. Dispersion of cellulose nanofibers in biopolymer based nanocomposites

    NASA Astrophysics Data System (ADS)

    Wang, Bei

    The focus of this work was to understand the fundamental dispersion mechanism of cellulose based nanofibers in bionanocomposites. The cellulose nanofibers were extracted from soybean pod and hemp fibers by chemo-mechanical treatments. These are bundles of cellulose nanofibers with a diameter ranging between 50 to 100 nm and lengths of thousands of nanometers which results in very high aspect ratio. In combination with a suitable matrix polymer, cellulose nanofiber networks show considerable potential as an effective reinforcement for high quality specialty applications of bio-based nanocomposites. Cellulose fibrils have a high density of --OH groups on the surface, which have a tendency to form hydrogen bonds with adjacent fibrils, reducing interaction with the surrounding matrix. The use of nanofibers has been mostly restricted to water soluble polymers. This thesis is focused on synthesizing the nanocomposite using a solid phase matrix polypropylene (PP) or polyethylene (PE) by hot compression and poly (vinyl alcohol) (PVA) in an aqueous phase by film casting. The mechanical properties of nanofiber reinforced PVA film demonstrated a 4-5 fold increase in tensile strength, as compared to the untreated fiber-blend-PVA film. It is necessary to reduce the entanglement of the fibrils and improve their dispersion in the matrix by surface modification of fibers without deteriorating their reinforcing capability. Inverse gas chromatography (IGC) was used to explore how various surface treatments would change the dispersion component of surface energy and acid-base character of cellulose nanofibers and the effect of the incorporation of these modified nanofibers into a biopolymer matrix on the properties of their nano-composites. Poly (lactic acid) (PLA) and polyhydroxybutyrate (PHB) based nanocomposites using cellulose nanofibers were prepared by extrusion, injection molding and hot compression. The IGC results indicated that styrene maleic anhydride coated and ethylene

  17. Plasma-enhanced synthesis of green flame retardant cellulosic materials

    NASA Astrophysics Data System (ADS)

    Totolin, Vladimir

    The natural fiber-containing fabrics and composites are more environmentally friendly, and are used in transportation (automobiles, aerospace), military applications, construction industries (ceiling paneling, partition boards), consumer products, etc. Therefore, the flammability characteristics of the composites based on polymers and natural fibers play an important role. This dissertation presents the development of plasma assisted - green flame retardant coatings for cellulosic substrates. The overall objective of this work was to generate durable flame retardant treatment on cellulosic materials. In the first approach sodium silicate layers were pre-deposited onto clean cotton substrates and cross linked using low pressure, non-equilibrium oxygen plasma. A statistical design of experiments was used to optimize the plasma parameters. The modified cotton samples were tested for flammability using an automatic 45° angle flammability test chamber. Aging tests were conducted to evaluate the coating resistance during the accelerated laundry technique. The samples revealed a high flame retardant behavior and good thermal stability proved by thermo-gravimetric analysis. In the second approach flame retardant cellulosic materials have been produced using a silicon dioxide (SiO2) network coating. SiO 2 network armor was prepared through hydrolysis and condensation of the precursor tetraethyl orthosilicate (TEOS), prior coating the substrates, and was cross linked on the surface of the substrates using atmospheric pressure plasma (APP) technique. Due to protection effects of the SiO2 network armor, the cellulosic based fibers exhibit enhanced thermal properties and improved flame retardancy. In the third approach, the TEOS/APP treatments were extended to linen fabrics. The thermal analysis showed a higher char content and a strong endothermic process of the treated samples compared with control ones, indicating a good thermal stability. Also, the surface analysis proved

  18. Highly Effective Electromagnetic Interference Shielding Materials based on Silver Nanowire/Cellulose Papers.

    PubMed

    Lee, Tae-Won; Lee, Sang-Eui; Jeong, Young Gyu

    2016-05-25

    We fabricated silver nanowire (AgNW)-coated cellulose papers with a hierarchical structure by an efficient and facile dip-coating process, and investigated their microstructures, electrical conductivity and electromagnetic interference (EMI) shielding effectiveness. SEM images confirm that AgNWs are coated dominantly on the paper surfaces, although they exist partially in the inner parts of the cellulose papers, which demonstrates that the AgNW density gradually decreases in thickness direction of the AgNW/cellulose papers. This result is supported by the anisotropic apparent electrical conductivity of the AgNW/cellulose papers depending on in-plane or thickness direction. Even for a AgNW/cellulose paper obtained by a single dip-coating cycle, the apparent electrical conductivity in the in-plane direction of 0.34 S/cm is achieved, which is far higher than the neat cellulose paper with ∼10(-11) S/cm. In addition, the apparent electrical conductivity of the papers in the in-plane direction increases significantly from 0.34 to 67.51 S/cm with increasing the number of dip-coating cycle. Moreover, although the AgNW/cellulose paper with 67.51 S/cm possesses 0.53 vol % AgNW only, it exhibits high EMI shielding performance of ∼48.6 dB at 1 GHz. This indicates that the cellulose paper structure is highly effective to form a conductive AgNW network. Overall, it can be concluded that the AgNW/cellulose papers with high flexibility and low density can be used as electrically conductive components and EMI shielding elements in advanced application areas. PMID:27156577

  19. Conception d'un circuit d'etouffement pour photodiodes a avalanche en mode geiger pour integration heterogene 3d

    NASA Astrophysics Data System (ADS)

    Boisvert, Alexandre

    Le Groupe de Recherche en Appareillage Medical de Sherbrooke (GRAMS) travaille actuellement sur un programme de recherche portant sur des photodiodes a avalanche mono-photoniques (PAMP) operees en mode Geiger en vue d'une application a la tomographie d'emission par positrons (TEP). Pour operer dans ce mode; la PAMP, ou SPAD selon l'acronyme anglais (Single Photon Avalanche Diode), requiert un circuit d'etouffement (CE) pour, d'une part, arreter l'avalanche pouvant causer sa destruction et, d'autre part. la reinitialiser en mode d'attente d'un nouveau photon. Le role de ce CE comprend egalement une electronique de communication vers les etages de traitement avance de signaux. La performance temporelle optimale du CE est realisee lorsqu'il est juxtapose a la PAMP. Cependant, cela entraine une reduction de la surface photosensible ; un element crucial en imagerie. L'integration 3D, a base d'interconnexions verticales, offre une solution elegante et performante a cette problematique par l'empilement de circuits integres possedant differentes fonctions (PAMP, CE et traitement avance de signaux). Dans l'approche proposee, des circuits d'etouffement de 50 pm x 50 pm realises sur une technologie CMOS 130 mn 3D Tezzaron, contenant chacun 112 transistors, sont matrices afin de correspondre a une matrice de PAMP localisee sur une couche electronique superieure. Chaque circuit d'etouffement possede une gigue temporelle de 7,47 ps RMS selon des simulations faites avec le logiciel Cadence. Le CE a la flexibilite d'ajuster les temps d'etouffement et de recharge pour la PAMP tout en presentant une faible consommation de puissance (~ 0,33 mW a 33 Mcps). La conception du PAMP necessite de supporter des tensions superieures aux 3,3 V de la technologie. Pour repondre a ce probleme, des transistors a drain etendu (DEMOS) ont ete realises. En raison de retards de production par Ies fabricants, les circuits n'ont pu etre testes physiquement par des mesures. Les resultats de ce memoire

  20. Fabrication of electric papers of graphene nanosheet shelled cellulose fibres by dispersion and infiltration as flexible electrodes for energy storage

    NASA Astrophysics Data System (ADS)

    Kang, Yan-Ru; Li, Ya-Li; Hou, Feng; Wen, Yang-Yang; Su, Dong

    2012-05-01

    An electrically conductive and electrochemically active composite paper of graphene nanosheet (GNS) coated cellulose fibres was fabricated via a simple paper-making process of dispersing chemically synthesized GNS into a cellulose pulp, followed by infiltration. The GNS nanosheet was deposited onto the cellulose fibers, forming a coating, during infiltration. It forms a continuous network through a bridge of interconnected cellulose fibres at small GNS loadings (3.2 wt%). The GNS/cellulose paper is as flexible and mechanically tough as the pure cellulose paper. The electrical measurements show the composite paper has a sheet resistance of 1063 Ω □-1 and a conductivity of 11.6 S m-1. The application of the composite paper as a flexible double layer supercapacitor in an organic electrolyte (LiPF6) displays a high capacity of 252 F g-1 at a current density of 1 A g-1 with respect to GNS. Moreover, the paper can be used as the anode in a lithium battery, showing distinct charge and discharge performances. The simple process for synthesising the GNS functionalized cellulose papers is attractive for the development of high performance papers for electrical, electrochemical and multifunctional applications.An electrically conductive and electrochemically active composite paper of graphene nanosheet (GNS) coated cellulose fibres was fabricated via a simple paper-making process of dispersing chemically synthesized GNS into a cellulose pulp, followed by infiltration. The GNS nanosheet was deposited onto the cellulose fibers, forming a coating, during infiltration. It forms a continuous network through a bridge of interconnected cellulose fibres at small GNS loadings (3.2 wt%). The GNS/cellulose paper is as flexible and mechanically tough as the pure cellulose paper. The electrical measurements show the composite paper has a sheet resistance of 1063 Ω □-1 and a conductivity of 11.6 S m-1. The application of the composite paper as a flexible double layer supercapacitor

  1. Pyrolytic sugars from cellulosic biomass

    NASA Astrophysics Data System (ADS)

    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

  2. [Audiometry in the cellulose industry].

    PubMed

    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

  3. Production of nanotubes in delignified porous cellulosic materials after hydrolysis with cellulase.

    PubMed

    Koutinas, Αthanasios Α; Papafotopoulou-Patrinou, Evgenia; Gialleli, Angelika-Ioanna; Petsi, Theano; Bekatorou, Argyro; Kanellaki, Maria

    2016-08-01

    In this study, tubular cellulose (TC), a porous cellulosic material produced by delignification of sawdust, was treated with a Trichoderma reesei cellulase in order to increase the proportion of nano-tubes. The effect of enzyme concentration and treatment duration on surface characteristics was studied and the samples were analyzed with BET, SEM and XRD. Also, a composite material of gelatinized starch and TC underwent enzymatic treatment in combination with amylase (320U) and cellulase (320U) enzymes. For TC, the optimum enzyme concentration (640U) led to significant increase of TC specific surface area and pore volume along with the reduction of pore diameter. It was also shown that the enzymatic treatment did not result to a significant change of cellulose crystallinity index. The produced nano-tubular cellulose shows potential for application to drug and chemical preservative delivery systems. PMID:26996258

  4. Modified cellulose synthase gene from 'Arabidopsis thaliana' confers herbicide resistance to plants

    SciTech Connect

    Somerville, Chris R.; Scieble, Wolf

    2000-10-11

    Cellulose synthase ('CS'), a key enzyme in the biosynthesis of cellulose in plants is inhibited by herbicides comprising thiazolidinones such as 5-tert-butyl-carbamoyloxy-3-(3-trifluromethyl) phenyl-4-thiazolidinone (TZ), isoxaben and 2,6-dichlorobenzonitrile (DCB). Two mutant genes encoding isoxaben and TZ-resistant cellulose synthase have been isolated from isoxaben and TZ-resistant Arabidopsis thaliana mutants. When compared with the gene coding for isoxaben or TZ-sensitive cellulose synthase, one of the resistant CS genes contains a point mutation, wherein glycine residue 998 is replaced by an aspartic acid. The other resistant mutation is due to a threonine to isoleucine change at amino acid residue 942. The mutant CS gene can be used to impart herbicide resistance to a plant; thereby permitting the utilization of the herbicide as a single application at a concentration which ensures the complete or substantially complete killing of weeds, while leaving the transgenic crop plant essentially undamaged.

  5. Bionanocomposite films based on plasticized PLA-PHB/cellulose nanocrystal blends.

    PubMed

    Arrieta, M P; Fortunati, E; Dominici, F; López, J; Kenny, J M

    2015-05-01

    Optically transparent plasticized poly(lactic acid) (PLA) based bionanocomposite films intended for food packaging were prepared by melt blending. Materials were plasticized with 15wt% of acetyl(tributyl citrate) (ATBC) to improve the material processability and to obtain flexibile films. Poly(hydroxybutyrate) (PHB) was used to increase PLA crystallinity. The thermal stability of the PLA-PHB blends was improved by the addition of 5 wt% of cellulose nanocrystals (CNC) or modified cellulose nanocrystals (CNCs) synthesized from microcrystalline cellulose. The combination of ATBC and cellulose nanocrystals, mainly the better dispersed CNCs, improved the interaction between PLA and PHB. Thus, an improvement on the oxygen barrier and stretchability was achieved in PLA-PHB-CNCs-ATBC which also displayed somewhat UV light blocking effect. All bionanocomposite films presented appropriate disintegration in compost suggesting their possible applications as biodegradable packaging materials. PMID:25659698

  6. Modified cellulose synthase gene from Arabidopsis thaliana confers herbicide resistance to plants

    DOEpatents

    Somerville, Chris R.; Scheible, Wolf

    2007-07-10

    Cellulose synthase ("CS"), a key enzyme in the biosynthesis of cellulose in plants is inhibited by herbicides comprising thiazolidinones such as 5-tert-butyl-carbamoyloxy-3-(3-trifluromethyl)phenyl-4-thiazolidinone (TZ), isoxaben and 2,6-dichlorobenzonitrile (DCB). Two mutant genes encoding isoxaben and TZ-resistant cellulose synthase have been isolated from isoxaben and TZ-resistant Arabidopsis thaliana mutants. When compared with the gene coding for isoxaben or TZ-sensitive cellulose synthase, one of the resistant CS genes contains a point mutation, wherein glycine residue 998 is replaced by an aspartic acid. The other resistant mutation is due to a threonine to isoleucine change at amino acid residue 942. The mutant CS gene can be used to impart herbicide resistance to a plant; thereby permitting the utilization of the herbicide as a single application at a concentration which ensures the complete or substantially complete killing of weeds, while leaving the transgenic crop plant essentially undamaged.

  7. An Improved X-ray Diffraction Method For Cellulose Crystallinity Measurement

    SciTech Connect

    Ju, Xiaohui; Bowden, Mark E.; Brown, Elvie E.; Zhang, Xiao

    2015-06-01

    We show in this work a modified X-ray diffraction method to determine cellulose crystallinity index (CrI). Nanocrystalline cellulose (NCC) dervided from bleached wood pulp was used as a model substrate. Rietveld refinement was applied with consideration of March-Dollase preferred orientation at the (001) plane. In contrast to most previous methods, three distinct amorphous peaks identified from new model samples which are used to calculate CrI. A 2 theta range from 10° to 75° was found to be more suitable to determine CrI and crystallite structural parameters such as d-spacing and crystallite size. This method enables a more reliable measurement of CrI of cellulose and may be applicable to other types of cellulose polymorphs.

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

    PubMed

    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

  9. Conformational studies of cellulosic fragments by DFT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The study of cellulosic fragments by DFTr is a continuation of our efforts to produce quality structural data that will be valuable to those working in the field of cellulose structure and enzymatic degradation. Using a reduced basis set and density functional DFTr (B3LYP), optimization of cellulosi...

  10. Synthesis of Cellulose Acetate from Cotton Byproducts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cotton burr and cottonseed hull are relatively inexpensive cotton byproducts. In an effort to derive greater value out of these natural renewable materials, we have succeeded in converting part of them into cellulose acetate without prior chemical breakdown or physical separation of cellulose, ligni...

  11. Idealized powder diffraction patterns for cellulose polymorphs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cellulose samples are routinely analyzed by X-ray diffraction to determine their crystal type (polymorph) and crystallinity. However, the connection is seldom made between those efforts and the crystal structures of cellulose that have been determined with synchrotron X-radiation and neutron diffrac...

  12. Diffraction from nonperiodic models of cellulose crystals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Powder and fiber diffraction patterns were calculated for model cellulose crystallites with chains 20 glucose units long. Model sizes ranged from four chains to 169 chains, based on cellulose I' coordinates, and were subjected to various combinations of energy minimization and molecular dynamics (M...

  13. Selective solvent extraction of cellulosic material

    DOEpatents

    Wang, Daniel I. C.; Avgerinos, George C.

    1983-01-01

    Cellulosic products having a high hemicellulose to lignin weight ratio are obtained by extracting a cellulosic composition with basic ethanol-water solution having a pH between about 12 and about 14 at a temperature between about 15.degree. and about 70.degree. C. and for a time period between about 2 and about 80 hours.

  14. 21 CFR 172.870 - Hydroxypropyl cellulose.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Hydroxypropyl cellulose. 172.870 Section 172.870 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Multipurpose Additives § 172.870 Hydroxypropyl cellulose. The food...

  15. Cellulose biosynthesis inhibitors - a multifunctional toolbox.

    PubMed

    Tateno, Mizuki; Brabham, Chad; DeBolt, Seth

    2016-01-01

    In the current review, we examine the growing number of existing Cellulose Biosynthesis Inhibitors (CBIs) and based on those that have been studied with live cell imaging we group their mechanism of action. Attention is paid to the use of CBIs as tools to ask fundamental questions about cellulose biosynthesis. PMID:26590309

  16. Salmonella promotes virulence by repressing cellulose production

    PubMed Central

    Pontes, Mauricio H.; Lee, Eun-Jin; Choi, Jeongjoon; Groisman, Eduardo A.

    2015-01-01

    Cellulose is the most abundant organic polymer on Earth. In bacteria, cellulose confers protection against environmental insults and is a constituent of biofilms typically formed on abiotic surfaces. We report that, surprisingly, Salmonella enterica serovar Typhimurium makes cellulose when inside macrophages. We determine that preventing cellulose synthesis increases virulence, whereas stimulation of cellulose synthesis inside macrophages decreases virulence. An attenuated mutant lacking the mgtC gene exhibited increased cellulose levels due to increased expression of the cellulose synthase gene bcsA and of cyclic diguanylate, the allosteric activator of the BcsA protein. Inactivation of bcsA restored wild-type virulence to the Salmonella mgtC mutant, but not to other attenuated mutants displaying a wild-type phenotype regarding cellulose. Our findings indicate that a virulence determinant can promote pathogenicity by repressing a pathogen's antivirulence trait. Moreover, they suggest that controlling antivirulence traits increases long-term pathogen fitness by mediating a trade-off between acute virulence and transmission. PMID:25848006

  17. Salmonella promotes virulence by repressing cellulose production.

    PubMed

    Pontes, Mauricio H; Lee, Eun-Jin; Choi, Jeongjoon; Groisman, Eduardo A

    2015-04-21

    Cellulose is the most abundant organic polymer on Earth. In bacteria, cellulose confers protection against environmental insults and is a constituent of biofilms typically formed on abiotic surfaces. We report that, surprisingly, Salmonella enterica serovar Typhimurium makes cellulose when inside macrophages. We determine that preventing cellulose synthesis increases virulence, whereas stimulation of cellulose synthesis inside macrophages decreases virulence. An attenuated mutant lacking the mgtC gene exhibited increased cellulose levels due to increased expression of the cellulose synthase gene bcsA and of cyclic diguanylate, the allosteric activator of the BcsA protein. Inactivation of bcsA restored wild-type virulence to the Salmonella mgtC mutant, but not to other attenuated mutants displaying a wild-type phenotype regarding cellulose. Our findings indicate that a virulence determinant can promote pathogenicity by repressing a pathogen's antivirulence trait. Moreover, they suggest that controlling antivirulence traits increases long-term pathogen fitness by mediating a trade-off between acute virulence and transmission. PMID:25848006

  18. Enzymatic degradation of (ligno)cellulose.

    PubMed

    Bornscheuer, Uwe; Buchholz, Klaus; Seibel, Jürgen

    2014-10-01

    Glycoside-degrading enzymes play a dominant role in the biochemical conversion of cellulosic biomass into low-price biofuels and high-value-added chemicals. New insight into protein functions and substrate structures, the kinetics of recognition, and degradation events has resulted in a substantial improvement of our understanding of cellulose degradation. PMID:25136976

  19. Book review: "cellulose science and technology"

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cellulose Science and Technology” by Jean-Luc Wertz, Olivier Bédué and Jean P. Mercier is a fairly comprehensive, up-to-date introduction to many areas of cellulose science. Their summary of a vast and often controversial literature is reasonably comprehensive. It requires little background to re...

  20. Selective solvent extraction of cellulosic material

    DOEpatents

    Wang, D.I.C.; Avgerinos, G.C.

    1983-07-26

    Cellulosic products having a high hemicellulose to lignin weight ratio are obtained by extracting a cellulosic composition with basic ethanol-water solution having a pH between about 12 and about 14 at a temperature between about 15 and about 70 C and for a time period between about 2 and about 80 hours. 6 figs.

  1. Update on Models of Cellulose Crystals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper describes progress in the computational modeling of cellulose crystals since our 2007 report. These crystal models are needed to better understand the interactions of cotton cellulose with water, enzymes and chemical finishing agents. Previous models resulted from molecular dynamics si...

  2. Plutonium Immobilization Program cold pour tests

    SciTech Connect

    Hovis, G.L.; Stokes, M.W.; Smith, M.E.; Wong, J.W.

    1999-07-01

    The Plutonium Immobilization Program (PIP) is a joint venture between the Savannah River Site, Lawrence Livermore National Laboratory, Argonne National Laboratory, and Pacific Northwest National Laboratory to carry out the disposition of excess weapons-grade plutonium. This program uses the can-in-canister (CIC) approach. CIC involves encapsulating plutonium in ceramic forms (or pucks), placing the pucks in sealed stainless steel cans, placing the cans in long cylindrical magazines, latching the magazines to racks inside Defense Waste Processing Facility (DWPF) canisters, and filling the DWPF canisters with high-level waste glass. This process puts the plutonium in a stable form and makes it attractive for reuse. At present, the DWPF pours glass into empty canisters. In the CIC approach, the addition of a stainless steel rack, magazines, cans, and ceramic pucks to the canisters introduces a new set of design and operational challenges: All of the hardware installed in the canisters must maintain structural integrity at elevated (molten-glass) temperatures. This suggests that a robust design is needed. However, the amount of material added to the DWPF canister must be minimized to prevent premature glass cooling and excessive voiding caused by a large internal thermal mass. High metal temperatures, minimizing thermal mass, and glass flow paths are examples of the types of technical considerations of the equipment design process. To determine the effectiveness of the design in terms of structural integrity and glass-flow characteristics, full-scale testing will be conducted. A cold (nonradioactive) pour test program is planned to assist in the development and verification of a baseline design for the immobilization canister to be used in the PIP process. The baseline design resulting from the cold pour test program and CIC equipment development program will provide input to Title 1 design for second-stage immobilization. The cold pour tests will be conducted in two

  3. Anaerobic digestion of cellulosic wastes

    SciTech Connect

    Donaldson, T.L.; Lee, D.D.

    1984-01-01

    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.

  4. Photophysics of alloxazines on cellulose.

    PubMed

    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

  5. Anaerobic digestion of cellulosic wastes

    SciTech Connect

    Lee, D.D.; Donaldson, T.L.

    1985-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  7. Hybrid HPMC nanocomposites containing bacterial cellulose nanocrystals and silver nanoparticles.

    PubMed

    George, Johnsy; Kumar, Ranganathan; Sajeevkumar, Vallayil Appukuttan; Ramana, Karna Venkata; Rajamanickam, Ramalingam; Abhishek, Virat; Nadanasabapathy, Shanmugam; Siddaramaiah

    2014-05-25

    Hydroxypropyl methyl cellulose (HPMC) based hybrid nanocomposites reinforced with bacterial cellulose nanocrystals (BCNC) and silver nanoparticles (AgNPs) had been prepared and characterised. BCNC was capable of improving the tensile strength and modulus of HPMC, but they made the film more brittle. The addition of AgNPs along with BCNC, helped to regain some of the lost elongation properties without affecting other properties. Moisture sorption analysis proved that the hydrophilicity of the nanocomposite decreased considerably by the addition of these nanomaterials. Several mathematical models were also used to fit the experimental sorption results. A unique combination of two nanomaterials was highly effective in overcoming certain limitations of nanocomposites which uses only one type of nanomaterial. This type of hybrid nanocomposites with superior properties is expected to be useful in eco-friendly food packaging applications. PMID:24708982

  8. Oxidised regenerated cellulose: an effective emergency haemostatic in burns surgery.

    PubMed

    Hazarika, E Z

    1985-07-01

    A 26-year-old man with 40% full-thickness burns was treated by excision and split-skin grafting on the 7th post-burn day. He developed bleeding 1 hour post-operatively which persisted despite the use of pressure dressings, elevation of the limbs, the administration of fresh frozen plasma, platelet-rich plasma, calcium, whole blood and cryoprecipitate respectively over a period of 11 hours. The bleeding was finally controlled under general anaesthesia by clot removal, bipolar electro-coagulation of miniscule oozing points, replacement of the meshed skin graft and the application of a layer of oxidised regenerated cellulose over the grafted area. The properties and uses of oxidised regenerated cellulose are outlined. PMID:3893594

  9. All natural cellulose acetate-Lemongrass essential oil antimicrobial nanocapsules.

    PubMed

    Liakos, Ioannis L; D'autilia, Francesca; Garzoni, Alice; Bonferoni, Cristina; Scarpellini, Alice; Brunetti, Virgilio; Carzino, Riccardo; Bianchini, Paolo; Pompa, Pier Paolo; Athanassiou, Athanassia

    2016-08-30

    Nanocapsules and nanoparticles play an essential role in the delivery of pharmaceutical agents in modern era, since they can be delivered in specific tissues and cells. Natural polymers, such as cellulose acetate, are becoming very important due to their availability, biocompatibility, absence of toxicity and biodegradability. In parallel, essential oils are having continuous growth in biomedical applications due to the inherent active compounds that they contain. A characteristic example is lemongrass oil that has exceptional antimicrobial properties. In this work, nanocapsules of cellulose acetate with lemongrass oil were developed with the solvent/anti-solvent method with resulting diameter tailored between 95 and 185nm. Various physico-chemical and surface analysis techniques were employed to investigate the formation of the nanocapsules. These all-natural nanocapsules found to well bioadhere to mucous membranes and to have very good antimicrobial properties at little concentrations against Escherichia coli and Staphylococcus aureus. PMID:26827919

  10. Optimization of synergism of a recombinant auxiliary activity 9 from Chaetomium globosum with cellulase in cellulose hydrolysis.

    PubMed

    Kim, In Jung; Nam, Ki Hyun; Yun, Eun Ju; Kim, Sooah; Youn, Hak Jin; Lee, Hee Jin; Choi, In-Geol; Kim, Kyoung Heon

    2015-10-01

    Auxiliary activity family 9 (AA9, formerly known as glycoside hydrolase family 61 or polysaccharide monooxygenase) is a group of fungal proteins that were recently found to have a significant synergism with cellulase in cellulose hydrolysis via the oxidative cleavage of glycosidic bonds of cellulose chains. In this study, we report the active expression of a recombinant fungal AA9 from Chaetomium globosum (CgAA9) in a bacterial host, Escherichia coli, and the optimization of its synergistic activity in cellulose hydrolysis by using cellulase. The recombinant CgAA9 (0.9 mg/g cellulose) exhibited 1.7-fold synergism in the hydrolysis of Avicel when incubated with 0.9 filter paper units of Celluclast 1.5 L/g cellulose. The first study of the active expression of AA9 using a bacterial host and its synergistic optimization could be useful for the industrial application of AA9 for the saccharification of lignocellulose. PMID:25936375

  11. Increases thermal stability and cellulose-binding capacity of Cryptococcus sp. S-2 lipase by fusion of cellulose binding domain derived from Trichoderma reesei

    SciTech Connect

    Thongekkaew, Jantaporn; Ikeda, Hiroko; Iefuji, Haruyuki

    2012-03-30

    Highlights: Black-Right-Pointing-Pointer The CSLP and fusion enzyme were successfully expressed in the Pichia pastoris. Black-Right-Pointing-Pointer The fusion enzyme was stable at 80 Degree-Sign C for 120-min. Black-Right-Pointing-Pointer The fusion enzyme was responsible for cellulose-binding capacity. Black-Right-Pointing-Pointer The fusion enzyme has an attractive applicant for enzyme immobilization. -- Abstract: To improve the thermal stability and cellulose-binding capacity of Cryptococcus sp. S-2 lipase (CSLP), the cellulose-binding domain originates from Trichoderma reesei cellobiohydrolase I was engineered into C-terminal region of the CSLP (CSLP-CBD). The CSLP and CSLP-CBD were successfully expressed in the Pichia pastoris using the strong methanol inducible alcohol oxidase 1 (AOX1) promoter and the secretion signal sequence from Saccharomyces cerevisiae ({alpha} factor). The recombinant CSLP and CSLP-CBD were secreted into culture medium and estimated by SDS-PAGE to be 22 and 27 kDa, respectively. The fusion enzyme was stable at 80 Degree-Sign C and retained more than 80% of its activity after 120-min incubation at this temperature. Our results also found that the fusion of fungal exoglucanase cellulose-binding domain to CSLP is responsible for cellulose-binding capacity. This attribute should make it an attractive applicant for enzyme immobilization.

  12. Ultrathin cellulose nanosheet membranes for superfast separation of oil-in-water nanoemulsions

    NASA Astrophysics Data System (ADS)

    Zhou, Ke; Zhang, Qiu Gen; Li, Hong Mei; Guo, Nan Nan; Zhu, Ai Mei; Liu, Qing Lin

    2014-08-01

    Oily wastewater is generated in diverse industrial processes, and its treatment has become crucial due to increasing environmental concerns. Herein, novel ultrathin nanoporous membranes of cellulose nanosheets have been fabricated for separation of oil-in-water nanoemulsions. The fabrication approach is facile and environmentally friendly, in which cellulose nanosheets are prepared by freeze-extraction of a very dilute cellulose solution. The as-prepared membranes have a cellulose nanosheet layer with a cut-off of 10-12 nm and a controllable thickness of 80-220 nm. They allow ultrafast water permeation and exhibit excellent size-selective separation properties. A 112 nm-thick membrane has a water flux of 1620 l m-2 h-1 bar-1 and a ferritin rejection of 92.5%. These membranes have been applied to remove oil from its aqueous nanoemulsions successfully, and they show an ultrafast and effective separation of oil-in-water nanoemulsions. The newly developed ultrathin cellulose membranes have a wide application in oily wastewater treatment, separation and purification of nanomaterials.Oily wastewater is generated in diverse industrial processes, and its treatment has become crucial due to increasing environmental concerns. Herein, novel ultrathin nanoporous membranes of cellulose nanosheets have been fabricated for separation of oil-in-water nanoemulsions. The fabrication approach is facile and environmentally friendly, in which cellulose nanosheets are prepared by freeze-extraction of a very dilute cellulose solution. The as-prepared membranes have a cellulose nanosheet layer with a cut-off of 10-12 nm and a controllable thickness of 80-220 nm. They allow ultrafast water permeation and exhibit excellent size-selective separation properties. A 112 nm-thick membrane has a water flux of 1620 l m-2 h-1 bar-1 and a ferritin rejection of 92.5%. These membranes have been applied to remove oil from its aqueous nanoemulsions successfully, and they show an ultrafast and effective

  13. Synthesis of hybrid cellulose nanocomposite bonded with dopamine SiO2/TiO2 and its antimicrobial activity

    NASA Astrophysics Data System (ADS)

    Ramesh, Sivalingam; Kim, Gwang-Hoon; Kim, Jaehwan; Kim, Joo-Hyung

    2015-04-01

    Organic-inorganic hybrid material based cellulose was synthesized by the sol-gel approach. The explosion of activity in this area in the past decade has made tremendous progress in industry or academic both fundamental understanding of sol-gel process and applications of new functionalized hybrid materials. In this present research work, we focused on cellulose-dopamine functionalized SiO2/TiO2 hybrid nanocomposite by sol-gel process. The cellulose-dopamine hybrid nanocomposite was synthesized via γ-aminopropyltriethoxysilane (γ-APTES) coupling agent by in-situ sol-gel process. The chemical structure of cellulose-amine functionalized dopamine bonding to cellulose structure with covalent cross linking hybrids was confirmed by FTIR spectral analysis. The morphological analysis of cellulose-dopamine nanoSiO2/TiO2 hybrid nanocomposite materials was characterized by XRD, SEM and TEM. From this different analysis results indicate that the optical transparency, thermal stability, control morphology of cellulose-dopamine-SiO2/TiO2 hybrid nanocomposite. Furthermore cellulose-dopamine-SiO2/TiO2 hybrid nanocomposite was tested against pathogenic bacteria for antimicrobial activity.

  14. Simulations of cellulose translocation in the bacterial cellulose synthase suggest a regulatory mechanism for the dimeric structure of cellulose

    DOE PAGESBeta

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

    2016-01-29

    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 tomore » 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 processive

  15. Simulations of cellulose translocation in the bacterial cellulose synthase suggest a regulatory mechanism for the dimeric structure of cellulose

    PubMed Central

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

    2016-01-01

    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. 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 processive cycle and

  16. Effects of Dilute Acid Pretreatment on Cellulose DP and the Relationship Between DP Reduction and Cellulose Digestibility

    SciTech Connect

    Wang, W.; Chen, X.; Tucker, M.; Himmel, M. E.; Johnson, D. K.

    2012-01-01

    The degree of polymerization(DP) of cellulose is considered to be one of the most important properties affecting the enzymatic hydrolysis of cellulose. Various pure cellulosic and biomass materials have been used in a study of the effect of dilute acid treatment on cellulose DP. A substantial reduction in DP was found for all pure cellulosic materials studied even at conditions that would be considered relatively mild for pretreatment. The effect of dilute acid pretreatment on cellulose DP in biomass samples was also investigated. Corn stover pretreated with dilute acid under the most optimal conditions contained cellulose with a DPw in the range of 1600{approx}3500, which is much higher than the level-off DP(DPw 150{approx}300) obtained with pure celluloses. The effect of DP reduction on the saccharification of celluloses was also studied. From this study it does not appear that cellulose DP is a main factor affecting cellulose saccharification.

  17. Antibacterial paperboard packaging using microfibrillated cellulose.

    PubMed

    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

  18. Cellulose production and cellulose synthase gene detection in acetic acid bacteria.

    PubMed

    Valera, Maria José; Torija, Maria Jesús; Mas, Albert; Mateo, Estibaliz

    2015-02-01

    The ability of acetic acid bacteria (AAB) to produce cellulose has gained much industrial interest due to the physical and chemical characteristics of bacterial cellulose. The production of cellulose occurs in the presence of oxygen and in a glucose-containing medium, but it can also occur during vinegar elaboration by the traditional method. The vinegar biofilm produced by AAB on the air-liquid interface is primarily composed of cellulose and maintains the cells in close contact with oxygen. In this study, we screened for the ability of AAB to produce cellulose using different carbon sources in the presence or absence of ethanol. The presence of cellulose in biofilms was confirmed using the fluorochrome Calcofluor by microscopy. Moreover, the process of biofilm formation was monitored under epifluorescence microscopy using the Live/Dead BacLight Kit. A total of 77 AAB strains belonging to 35 species of Acetobacter, Komagataeibacter, Gluconacetobacter, and Gluconobacter were analysed, and 30 strains were able to produce a cellulose biofilm in at least one condition. This cellulose production was correlated with the PCR amplification of the bcsA gene that encodes cellulose synthase. A total of eight degenerated primers were designed, resulting in one primer pair that was able to detect the presence of this gene in 27 AAB strains, 26 of which formed cellulose. PMID:25381910

  19. Evaluation of cellulose and carboxymethyl cellulose/poly(vinyl alcohol) membranes.

    PubMed

    Ibrahim, Maha M; Koschella, Andreas; Kadry, Ghada; Heinze, Thomas

    2013-06-01

    Cellulose was isolated from rice straw and converted to carboxymethyl cellulose (CMC). Both polymers were crosslinked with poly(vinyl alcholo) (PVA). The physical properties of the resulting membranes were characterized by FT-IR, TGA, DSC and SEM. The cellulose and CMC were first prepared from bleached rice straw pulp. The infrared spectroscopy of the resulting polymer membranes indicated a decrease in the absorbance of the OH group at 3300-3400 cm(-1), which is due to bond formation with either the cellulose or CMC with the PVA. The thermal stability of PVA/cellulose and PVA/CMC membranes was lower than PVA membrane. The surface of the resulting polymer membranes showed smooth surface in case of the PVA/CMC membrane and rough surface in case of the PVA/cellulose membrane. Desalination test, using 0.2% NaCl, showed that pure PVA membranes had no effect while membranes containing either cellulose or CMC as filler were able to decrease the content of the NaCl from the solution by 25% and 15%, respectively. Transport properties, including water and chloroform vapor were studied. The moisture transport was reduced by the presence of both cellulose and CMC. Moreover, the membranes containing cellulose and CMC showed significantly reduced flux compared to the pure PVA. The water sorption, solubility and soaking period at different pH solutions were also studied and showed that the presence of both cellulose and CMC influences the properties. PMID:23618287

  20. A synergetic approach for estimating the local direct aerosol forcing: Application to an urban zone during the Expérience sur Site pour Contraindre les Modèles de Pollution et de Transport d'Emission (ESCOMPTE) experiment

    NASA Astrophysics Data System (ADS)

    Roger, J. C.; Mallet, M.; Dubuisson, P.; Cachier, H.; Vermote, E.; Dubovik, O.; Despiau, S.

    2006-07-01

    A method dedicated to the investigation of direct radiative forcing of the main anthropogenic aerosol species (ammonium sulfate, black carbon, particulate organic matter) is presented. We computed the direct radiative aerosol forcing at the top of atmosphere (TOA), at the bottom of atmosphere (BOA), and into the atmospheric layer (ATM). The methodology is based on chemical, photometric, and satellite measurements. We first determined the optical properties of the main aerosol species and then computed their direct radiative impact at local scale. The method was applied to a periurban zone during the Expérience sur Site pour Contraindre les Modèles de Pollution et de Transport d'Emission experiment. Optical computations indicate that the single scattering albedo, for the total aerosol population in the external mixture, is equal to 0.83 ± 0.04 at 550 nm, indicative of a strong absorption of the solar radiation. At the same time the mean asymmetry parameter is equal to 0.59 ± 0.04, and the mean aerosol optical thickness is equal to 0.30 ± 0.02, at 550 nm. The anthropogenic urban aerosol layer reduces significantly the daily surface illumination (-24 W m-2 > ΔFBOA > -47.5 W m-2) by reflection to space (-6 W m-2 > ΔFTOA > -9 W m-2) and by absorption of the solar radiation into the atmosphere (17 W m-2 < ΔFATM < 39 W m-2). The available resulting energy in the atmospheric column heats the lowermost part of the atmosphere from 1.1°K d-1 to 2.8°K d-1. Our study shows that the black carbon particles have a large contribution to the BOA forcing (almost 50% of the total daily forcing), whereas the ammonium sulfate particles contribute only to about 10%. Conversely, the TOA daily forcing is mostly driven by the ammonium sulfate aerosol (around 50%).

  1. Cellulose-reinforced composites and SRIM and RTM modeling

    NASA Astrophysics Data System (ADS)

    Fahrurrozi, Mohammad

    Structural reaction injection molding (SRIM) cellulosic/polyurethane composites were prepared from various forms of cellulosic mats, and elastomeric polyurea-urethane (PUU) and rigid polyurethane (PU) formulations. Mats (woven and non-woven) prepared from different sources of fibers with lignin content ranging from zero (cotton) to at least 10% (sugar cane and kenaf fibers) performed comparably in PUU/cellulosic composites. Young's modulus and tensile strength of PUU/cellulosic composites were doubled with 5% and 7% fiber loading respectively. Young's modulus and tensile strength of PU/cellulosic composites were improved by 300% and 30%, respectively, with 7% fiber loading, whereas their bending moduli and strengths were improved up to 100% and 50%, respectively, with 18% fiber loading. However, the mechanical properties of PU composites were more sensitive to the fiber properties and fiber macroscopic arrangements. The study with chemical ratio variations indicates that as the fiber loading increases, the cellulose hydroxyl presence starts shifting the chemical balance and thus should be accounted for. Mats prepared from sugar cane fibers extracted from rind with low alkali concentration (0.2 N) followed by steam explosion require lower injection pressures compared to the ones prepared from fiber obtained from higher alkali treatment (above 0.5 N) without steam explosion. Hence, the steam exploded mats are more suitable for SRIM purposes. The PU kinetics was studied using an adiabatic temperature rise method. An Arrhenius type empirical equation was used to fit the data. The fitted equation was second order to the partial conversion, and the gelling time at adiabatic condition is less than 5 seconds (much quicker than the 10 to 12 seconds in mold gel time quoted by the manufacturer). FORTRAN programs were written to solve the SRIM model based on Darcy's equation. The model incorporated heat transfer and chemical reaction. The modeling was intended to aid in

  2. FRONT VIEW OF POURING FROM #61 HOLDING FURNACE AT #02 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    FRONT VIEW OF POURING FROM #61 HOLDING FURNACE AT #02 STATION INTO THREE VERTICAL MOLDS SUBMERGED IN A WATER-FILLED TANK BELOW THE CASTING FLOOR. THE CASTING CREW'S JOBS DURING THIS PHASE OF THE OPERATION INCLUDE REGULATING THE POURING RATE AND MONITORING THE VALVE RODS THAT CONTROL THE WATER SPRAYS ON THE MOLDS. DIFFERENT ALLOYS REQUIRE SPECIFIC POURING SPEEDS AND WATER PRESSURES. - American Brass Foundry, 70 Sayre Street, Buffalo, Erie County, NY

  3. Degradation of cellulose by basidiomycetous fungi.

    PubMed

    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

  4. Recycling of cellulosic fibers by enzymatic process.

    PubMed

    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

  5. Structure and Dynamics of Cellulose Molecular Solutions

    NASA Astrophysics Data System (ADS)

    Wang, Howard; Zhang, Xin; Tyagi, Madhusudan; Mao, Yimin; Briber, Robert

    Molecular dissolution of microcrystalline cellulose has been achieved through mixing with ionic liquid 1-Ethyl-3-methylimidazolium acetate (EMIMAc), and organic solvent dimethylformamide (DMF). The mechanism of cellulose dissolution in tertiary mixtures has been investigated by combining quasielastic and small angle neutron scattering (QENS and SANS). As SANS data show that cellulose chains take Gaussian-like conformations in homogenous solutions, which exhibit characteristics of having an upper critical solution temperature, the dynamic signals predominantly from EMIMAc molecules indicate strong association with cellulose in the dissolution state. The mean square displacement quantities support the observation of the stoichiometric 3:1 EMIMAc to cellulose unit molar ratio, which is a necessary criterion for the molecular dissolution of cellulose. Analyses of dynamics structure factors reveal the temperature dependence of a slow and a fast process for EMIMAc's bound to cellulose and in DMF, respectively, as well as a very fast process due possibly to the rotational motion of methyl groups, which persisted to near the absolute zero.

  6. Production and modification of nanofibrillated cellulose using various mechanical processes: a review.

    PubMed

    Abdul Khalil, H P S; Davoudpour, Y; Islam, Md Nazrul; Mustapha, Asniza; Sudesh, K; Dungani, Rudi; Jawaid, M

    2014-01-01

    Nanofibrillated cellulose from biomass has recently gained attention owing to their biodegradable nature, low density, high mechanical properties, economic value and renewability. Although they still suffer from two major drawbacks. The first challenge is the exploration of raw materials and its application in nanocomposites production. Second one is high energy consumption regarding the mechanical fibrillation. However, pretreatments before mechanical isolation can overcome this problem. Hydrophilic nature of nano-size cellulose fibers restricts good dispersion of these materials in hydrophobic polymers and therefore, leads to lower mechanical properties. Surface modification before or after mechanical defibrillation could be a solution for this problem. Additionally, drying affects the size of nanofibers and its properties which needs to study further. This review focuses on recent developments in pretreatments, nanofibrillated cellulose production and its application in nanopaper applications, coating additives, security papers, food packaging, and surface modifications and also for first time its drying. PMID:24274556

  7. Environmentally friendly ultrosound synthesis and antibacterial activity of cellulose/Ag/AgCl hybrids.

    PubMed

    Dong, Yan-Yan; Deng, Fu; Zhao, Jin-Jin; He, Jing; Ma, Ming-Guo; Xu, Feng; Sun, Run-Cang

    2014-01-01

    This study aims to investigate the fabrication and property of cellulose/Ag/AgCl hybrids. In this article, preparation of cellulose/Ag/AgCl hybrids was reported using the cellulose solution, AgNO₃, AlCl₃·6H₂O with ultrasound agitation method. The cellulose solution was synthesized by the dissolution of the microcrystalline cellulose in NaOH/urea aqueous solution. Influences of the experimental parameters of ultrasound treatment time and ultrasonic intermittent on the hybrids were investigated. The phase, microstructure, thermal stability, and morphology of the hybrids were characterized by X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectrometry, thermogravimetric analysis (TGA), differential thermal analysis (DTA), and scanning electron microscopy (SEM). Results showed the successful synthesis of cellulose/Ag/AgCl hybrids with good thermal stability. Moreover, the hybrids displayed desirable antimicrobial activities. Compared with other conventional methods, the rapid, green, and environmentally friendly ultrasound agitation method opens a new window to the high value-added applications of biomass. PMID:24274493

  8. Green route to modification of wood waste, cellulose and hemicellulose using reactive extrusion.

    PubMed

    Vaidya, Alankar A; Gaugler, Marc; Smith, Dawn A

    2016-01-20

    A large volume of wood waste is produced in timber processing industry which traditionally used in low value applications. Here, value addition to the wood waste (Sander dust) and cellulose, hemicellulose isolated thereof by functionalisation using cyclic anhydrides in a solvent-free and green reactive extrusion process is reported. The effect of extrusion temperature, catalyst and different weight ratios of Sander dust (SD):succinic anhydride (SA) on the esterification reaction is evaluated. The esterified products were characterised by the acid value, degree of substitution (DS), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), solid state (13)C NMR and thermo-gravimetric analysis (TGA). Under optimum extrusion conditions, mixed esters are formed, with highest acid value obtained for succinylation of cellulose (0.122 g/g at DS of 0.350) which is two times higher compared to succinylated SD (0.059 g/g at a weight gain of 0.452) and hemicellulose (0.043 g/g at DS of 0.290). The reactivity trend for individual anhydride was: (1) SA-Cellulose>SD>hemicellulose; (2) maleic anhydride (MA)-SD>hemicellulose>cellulose and (3) dodecenyl succinic anhydride (DDSA)-SD ≈ cellulose ≫ hemicellulose. The pendant free carboxyl groups generated through functionalisation of wood waste, cellulose and hemicellulose without the presence of polymeric carriers will allow more tailored or targeted modification of wood-plastic composites. PMID:26572467

  9. Preparation and characterization of directly compactible layer-by-layer nanocoated cellulose.

    PubMed

    Strydom, Schalk J; Otto, Daniel P; Liebenberg, Wilna; Lvov, Yuri M; de Villiers, Melgardt M

    2011-02-14

    Microcrystalline cellulose is a commonly used direct compression tablet diluent and binder. It is derived from purified α-cellulose in an environmentally unfriendly process that involves mineral acid catalysed hydrolysis. In this study Kraft softwood fibers was nanocoated using a layer-by-layer self-assembling process. Powder flow and compactibility results showed that the application of nano-thin polymer layers on the fibers turned non-flowing, non-compacting cellulose into powders that can be used in the direct compression of tablets. The powder flow properties and tableting indices of compacts compressed from these nanocoated microfibers were similar or better than that of directly compactible microcrystalline cellulose powders. Cellulose microfibers coated with four PSS/PVP bilayers had the best compaction properties while still producing tablets that were able to absorb water and disintegrate and did not retard the dissolution of a model drug acetaminophen. The advantages of nanocoating rather than traditional pharmaceutical coating are that it add less than 1% to the weight of the fibers and allows control of the molecular properties of the surface and the thickness of the coat to within a few nanometers. This process is potentially friendlier to the environment because of the type and quantity of materials used. Also, it does not involve acid-catalyzed hydrolysis and neutralization of depolymerized cellulose. PMID:21056645

  10. Amphiphilic Cellulose Ethers Designed for Amorphous Solid Dispersion via Olefin Cross-Metathesis.

    PubMed

    Dong, Yifan; Mosquera-Giraldo, Laura I; Taylor, Lynne S; Edgar, Kevin J

    2016-02-01

    The design of cellulose ether-based amphiphiles has been difficult and limited because of the harsh conditions typically required for appending ether moieties to cellulose. Olefin cross-metathesis recently has been shown to be a valuable approach for appending a variety of functional groups to cellulose ethers and esters, provided that an olefin handle for metathesis can be attached. This synthetic pathway gives access to these functional derivatives under very mild conditions and at high efficiency. Modification of ethyl cellulose by metathesis to prepare useful derivatives, for example, for solubility and bioavailability enhancement of drugs by amorphous solid dispersion (ASD), has been limited by the low DS(OH) of commercial ethyl cellulose derivatives. This is problematic because ethyl cellulose is otherwise a very attractive substrate for synthesis of amphiphilic derivatives by olefin metathesis. Herein we explore two methods for opening up this design space for ether-based amphiphiles, for example, permitting synthesis of more hydrophilic derivatives. One approach is to start with the more hydrophilic commercial methyl cellulose, which contains much higher DS(OH) and therefore is better suited for introduction of high DS of olefin metathesis "handles". In another approach, we explored a homogeneous one-pot synthesis methodology from cellulose, where controlled DS of ethyl groups was introduced at the same time as the ω-unsaturated alkyl groups, thereby permitting complete control of DS(OH), DS(Et), and ultimately DS of the functional group added by metathesis. We describe the functionalized derivatives available by these successful approaches. In addition, we explore new methods for reduction of the unsaturation in initial metathesis products to provide robust methods for enhancing product stability against further radical-catalyzed reactions. We demonstrate initial evidence that the products show strong promise as amphiphilic matrix polymers for amorphous

  11. Synthesis and Characterization of Cellulose Derivatives for Water Repellent Properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this 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 homogene...

  12. Novel antimicrobial and biofilm-controlling cellulosic polymers

    NASA Astrophysics Data System (ADS)

    Padmanabhuni, Revathi V.

    Cotton and cellulose acetate (CA) are cellulosic polymers with versatile applications. Like any other polymeric materials, cellulosic materials are also susceptible to microbial contamination and cause serious nosocomial infections. Hence, there is a definite need to develop antimicrobial cellulosic materials to prevent microbial colonization. Henceforth, we prepared a suitable polycation to treat cotton fabrics and CA films by LbL self-assembly process to achieve potent antimicrobial functions. The treated fabrics demonstrated total kill against E. coli and S. aureus in 2 h contact time whereas treated CA films, even after 6 h, could inactivate only 98 % of bacteria. Since CA films are more hydrophobic, have less surface charge, and surface area than cotton fabrics, LbL procedure was not much effective for CA films to achieve potent antimicrobial functions. Yet, CA is another very important cellulosic polymer with various applications in which antimicrobial activity is often desired. So, to improve the antimicrobial activity of CA films, we designed a novel strategy to coat the surface of CaCO3 fillers with quaternary ammonium salts (QAS)based fatty acids to make the filler surface organophilic and accomplish antibacterial activity concurrently, rendering the resulting polymer-filler composites antimicrobial. Thus, a series of QAS-based fatty acids (C8-C16) were synthesized, coated onto CaCO 3, and used as antimicrobial additives (5 %) in CA films. Although C8-quat-CaCO 3 could only provide 94 % of reduction of bacteria, both C12- and C16- quats and their corresponding quat-coated CaCO3 provided a total kill of S. aureus and E. coli in 2 h. These findings suggested that it is feasible to use QAS-based fatty acids to coat CaCO3 and use them as antimicrobial additives of CA films to achieve potent antimicrobial effects. Building on these results, to further evaluate the applicability of the antimicrobial filler strategy, we synthesized an N-halamine based fatty acid

  13. A two step method for the preparation of carbamate cross-linked cellulose films using an ionic liquid and their water retention properties.

    PubMed

    Amarasekara, Ananda S; Hasan, Muhammad A; Ha, Uyen

    2016-12-10

    Carbamate cross-linked cellulose films can be prepared in a two step method using cellulose dissolved in 1-n-butyl-3-methylimidazolium chloride ionic liquid. The new technique involves casting the film from cellulose ionic liquid solution onto a glass surface and application of alkyl/aryl diisocyanate in dry dimethylsulfoxide solution onto the cellulose - ionic liquid coating on glass and allowing the cross-linking reaction to occur on the pre-formed cellulose coating. The carbamate cross-linked cellulose films formed were characterized by FT-IR, and TG-DTA. The water retention values of the films are shown to decrease with the increase in hydrophobicity of the alky/aryl group linker in the carbamate bridges. PMID:27577890

  14. Production of permeable cellulose triacetate membranes

    DOEpatents

    Johnson, B.M.

    1986-12-23

    A phase inversion process for the preparation of cellulose triacetate (CTA) and regenerated cellulose membranes is disclosed. Such membranes are useful as supports for liquid membranes in facilitated transport processes, as microfiltration membranes, as dialysis or ultrafiltration membranes, and for the preparation of ion-selective electrodes. The process comprises the steps of preparing a casting solution of CTA in a solvent comprising a mixture of cyclohexanone and methylene chloride, casting a film from the casting solution, and immersing the cast film in a methanol bath. The resulting CTA membrane may then be hydrolyzed to regenerated cellulose using conventional techniques.

  15. Production of permeable cellulose triacetate membranes

    DOEpatents

    Johnson, Bruce M.

    1986-01-01

    A phase inversion process for the preparation of cellulose triacetate (CTA) and regenerated cellulose membranes is disclosed. Such membranes are useful as supports for liquid membranes in facilitated transport processes, as microfiltration membranes, as dialysis or ultrafiltration membranes, and for the preparation of ion-selective electrodes. The process comprises the steps of preparing a casting solution of CTA in a solvent comprising a mixture of cyclohexanone and methylene chloride, casting a film from the casting solution, and immersing the cast film in a methanol bath. The resulting CTA membrane may then be hydrolyzed to regenerated cellulose using conventional techniques.

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

    PubMed

    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

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

    PubMed

    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

  18. Cellulose nanofiber extraction from grass by a modified kitchen blender

    NASA Astrophysics Data System (ADS)

    Nakagaito, Antonio Norio; Ikenaga, Koh; Takagi, Hitoshi

    2015-03-01

    Cellulose nanofibers have been used to reinforce polymers, delivering composites with strength that in some cases can be superior to that of engineering plastics. The extraction of nanofibers from plant fibers can be achieved through specialized equipment that demands high energy input, despite delivering extremely low yields. The high extraction cost confines the use of cellulose nanofibers to the laboratory and not for industrial applications. This study aims to extract nanofibers from grass by using a kitchen blender. Earlier studies have demonstrated that paper sheets made of blender-extracted nanofibers (after 5 min to 10 min of blending) have strengths on par with paper sheets made from commercially available cellulose nanofibers. By optimizing the design of the blender bottle, nanofibrillation can be achieved in shorter treatment times, reducing the energy consumption (in the present case, to half) and the overall extraction cost. The raw materials used can be extended to the residue straw of agricultural crops, as an alternative to the usual pulp fibers obtained from wood.

  19. Physical and mechanical properties of modified bacterial cellulose composite films

    NASA Astrophysics Data System (ADS)

    Indrarti, Lucia; Indriyati, Syampurwadi, Anung; Pujiastuti, Sri

    2016-02-01

    To open wide range application opportunities of Bacterial Cellulose (BC) such as for agricultural purposes and edible film, BC slurries were blended with Glycerol (Gly), Sorbitol (Sor) and Carboxymethyl Cellulose (CMC). The physical and mechanical properties of BC composites were investigated to gain a better understanding of the relationship between BC and the additive types. Addition of glycerol, sorbitol and CMC influenced the water solubility of BC composite films. FTIR analysis showed the characteristic bands of cellulose. Addition of CMC, glycerol, and sorbitol slightly changed the FTIR spectrum of the composites. Tensile test showed that CMC not only acted as cross-linking agent where the tensile strength doubled up to 180 MPa, but also acted as plasticizer with the elongation at break increased more than 100% compared to that of BC film. On the other hand, glycerol and sorbitol acted as plasticizers that decreased the tensile strength and increased the elongation. Addition of CMC can improve film transparency, which is quite important in consumer acceptance of edible films in food industry.

  20. Multi-scale Characterization of Cellulose TEMPO-Nanofiber Suspension

    NASA Astrophysics Data System (ADS)

    Mao, Yimin; Liu, Kai; Hsiao, Benjamin

    Cellulose nanofiber (CNF) suspensions were characterized at multiple length scales. CNF suspension was prepared by applying 2,2,6,6-tetramethyl-1- piperidinyloxy (TEMPO) oxidation method to dry wood pulp. TEMPO method was able to produce fine fibers with a cross section dimension being in the order of magnitude of several nanometers, and length being several hundred nanometers. The surface was negatively charged. Charge density was characterized by Zeta-potential measurement. Both small-angle X-ray (SAXS) and small-angle neutron (SANS) methods were employed to examine fiber dimensions in solution. Data fitting indicated that newly-developed ribbon model was able to capture the essence of CNF's geometry, which is also computationally economic. The rectangular-shaped cross section was consistent to cellulose's crystal structure; and was able to provide insights into how cellulose crystals were biologically synthesized and packed in nature. Multi-angle dynamic light scattering (DLS) was used to study CNF's diffusion properties. A strong scattering-angle dependence of auto-correlation function was observed. The characterization is useful to understanding suspension quality of CNF, and can provide guideline for follow-up research aimed for a variety of applications.

  1. Modification of nanofibrillated cellulose using amphiphilic block-structured galactoglucomannans.

    PubMed

    Lozhechnikova, Alina; Dax, Daniel; Vartiainen, Jari; Willför, Stefan; Xu, Chunlin; Österberg, Monika

    2014-09-22

    Nanofibrillated cellulose (NFC) and hemicelluloses have shown to be highly promising renewable components both as barrier materials and in novel biocomposites. However, the hydrophilic nature of these materials restricts their use in some applications. In this work, the usability of modified O-acetyl galactoglucomannan (GGM) for modification of NFC surface properties was studied. Four GGM-block-structured, amphiphilic derivatives were synthesized using either fatty acids or polydimethylsiloxane as hydrophobic tails. The adsorption of these GGM derivatives was consecutively examined in aqueous solution using a quartz crystal microbalance with dissipation monitoring (QCM-D). It was found that the hydrophobic tails did not hinder adsorption of the GGM derivatives to cellulose, which was concluded to be due to the presence of the native GGM-block with high affinity to cellulose. The layer properties of the adsorbed block-co-polymers were discussed and evaluated. Self-standing NFC films were further prepared and coated with the GGM derivatives and the effect of the surface modification on wetting properties and oxygen permeability (OP) of the modified films was assessed. PMID:24906743

  2. Brittle Culm1, a COBRA-Like Protein, Functions in Cellulose Assembly through Binding Cellulose Microfibrils

    PubMed Central

    Zhang, Baocai; Liu, Xiangling; Yan, Meixian; Zhang, Lanjun; Shi, Yanyun; Zhang, Mu; Qian, Qian; Li, Jiayang; Zhou, Yihua

    2013-01-01

    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. PMID:23990797

  3. Bacterial Cellulose Supported Gold Nanoparticles with Excellent Catalytic Properties.

    PubMed

    Chen, Meiyan; Kang, Hongliang; Gong, Yumei; Guo, Jing; Zhang, Hong; Liu, Ruigang

    2015-10-01

    Amidoxime surface functionalized bacterial cellulose (AOBC) has been successfully prepared by a simple two-step method without obviously changing the morphology of bacterial cellulose. AOBC has been used as the reducing agent and carrier for the synthesis of gold nanoparticles (AuNPs) that distributed homogeneously on bacterial cellulose surface. Higher content in amidoxime groups in AOBC is beneficial for the synthesis of AuNPs with smaller and more uniform size. The AuNPs/AOBC nanohybrids have excellent catalytic activity for reduction of 4-nitrophenol (4-NP) by using NaBH4. It was found that catalytic activity of AuNPs/AOBC first increases with increasing NaBH4 concentration and temperature, and then leveled off at NaBH4 concentration above 238 mM and temperature above 50 °C. Moreover, AuNPs with smaller size have higher catalytic activity. The highest apparent turnover frequency of AuNPs/AOBC is 1190 h(-1). The high catalytic activity is due to the high affinity of 4-NP with AuNPs/AOBC and the reduced product 4-aminophenol has good solubility in water in the presence of AuNPs/AOBC. The catalytic stability of the AuNPs/AOBC was estimated by filling a fluid column contained AuNPs/AOBC and used for continuously catalysis of the reduction of 4-NP by using NaBH4. The column works well without detection of 4-NP in the eluent after running for more than two months, and it is still running. This work provides an excellent catalyst based on bacterial cellulose stabilized AuNPs and has promising applications in industry. PMID:26357993

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

    PubMed

    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

  5. Fabrication of electric papers of graphene nanosheet shelled cellulose fibres by dispersion and infiltration as flexible electrodes for energy storage.

    PubMed

    Kang, Yan-Ru; Li, Ya-Li; Hou, Feng; Wen, Yang-Yang; Su, Dong

    2012-05-21

    An electrically conductive and electrochemically active composite paper of graphene nanosheet (GNS) coated cellulose fibres was fabricated via a simple paper-making process of dispersing chemically synthesized GNS into a cellulose pulp, followed by infiltration. The GNS nanosheet was deposited onto the cellulose fibers, forming a coating, during infiltration. It forms a continuous network through a bridge of interconnected cellulose fibres at small GNS loadings (3.2 wt%). The GNS/cellulose paper is as flexible and mechanically tough as the pure cellulose paper. The electrical measurements show the composite paper has a sheet resistance of 1063 Ω□(-1) and a conductivity of 11.6 S m(-1). The application of the composite paper as a flexible double layer supercapacitor in an organic electrolyte (LiPF(6)) displays a high capacity of 252 F g(-1) at a current density of 1 A g(-1) with respect to GNS. Moreover, the paper can be used as the anode in a lithium battery, showing distinct charge and discharge performances. The simple process for synthesising the GNS functionalized cellulose papers is attractive for the development of high performance papers for electrical, electrochemical and multifunctional applications. PMID:22535335

  6. Optical and mechanical properties of nanofibrillated cellulose: Toward a robust platform for next-generation green technologies.

    PubMed

    Simão, Claudia D; Reparaz, Juan S; Wagner, Markus R; Graczykowski, Bartlomiej; Kreuzer, Martin; Ruiz-Blanco, Yasser B; García, Yamila; Malho, Jani-Markus; Goñi, Alejandro R; Ahopelto, Jouni; Sotomayor Torres, Clivia M

    2015-08-01

    Nanofibrillated cellulose, a polymer that can be obtained from one of the most abundant biopolymers in nature, is being increasingly explored due to its outstanding properties for packaging and device applications. Still, open challenges in engineering its intrinsic properties remain to address. To elucidate the optical and mechanical stability of nanofibrillated cellulose as a standalone platform, herein we report on three main findings: (i) for the first time an experimental determination of the optical bandgap of nanofibrillated cellulose, important for future modeling purposes, based on the onset of the optical bandgap of the nanofibrillated cellulose film at Eg≈275 nm (4.5 eV), obtained using absorption and cathodoluminescence measurements. In addition, comparing this result with ab-initio calculations of the electronic structure the exciton binding energy is estimated to be Eex≈800 meV; (ii) hydrostatic pressure experiments revealed that nanofibrillated cellulose is structurally stable at least up to 1.2 GPa; and (iii) surface elastic properties with repeatability better than 5% were observed under moisture cycles with changes of the Young modulus as large as 65%. The results obtained show the precise determination of significant properties as elastic properties and interactions that are compared with similar works and, moreover, demonstrate that nanofibrillated cellulose properties can be reversibly controlled, supporting the extended potential of nanofibrillated cellulose as a robust platform for green-technology applications. PMID:25933520

  7. Improved assay for quantitating adherence of ruminal bacteria to cellulose.

    PubMed Central

    Rasmussen, M A; White, B A; Hespell, R B

    1989-01-01

    A quantitative technique suitable for the determination of adherence of ruminal bacteria to cellulose was developed. This technique employs adherence of cells to cellulose disks and alleviates the problem of nonspecific cell entrapment within cellulose particles. By using this technique, it was demonstrated that the adherence of Ruminococcus flavefaciens FD1 to cellulose was inhibited by formaldehyde, methylcellulose, and carboxymethyl cellulose. Adherence was unaffected by acid hydrolysates of methylcellulose, glucose, and cellobiose. PMID:2782879

  8. Reactive Liftoff of Crystalline Cellulose Particles

    PubMed Central

    Teixeira, Andrew R.; Krumm, Christoph; Vinter, Katherine P.; Paulsen, Alex D.; Zhu, Cheng; Maduskar, Saurabh; Joseph, Kristeen E.; Greco, Katharine; Stelatto, Michael; Davis, Eric; Vincent, Brendon; Hermann, Richard; Suszynski, Wieslaw; Schmidt, Lanny D.; Fan, Wei; Rothstein, Jonathan P.; Dauenhauer, Paul J.

    2015-01-01

    The condition of heat transfer to lignocellulosic biomass particles during thermal processing at high temperature (>400 °C) dramatically alters the yield and quality of renewable energy and fuels. In this work, crystalline cellulose particles were discovered to lift off heated surfaces by high speed photography similar to the Leidenfrost effect in hot, volatile liquids. Order of magnitude variation in heat transfer rates and cellulose particle lifetimes was observed as intermediate liquid cellulose droplets transitioned from low temperature wetting (500–600 °C) to fully de-wetted, skittering droplets on polished surfaces (>700 °C). Introduction of macroporosity to the heated surface was shown to completely inhibit the cellulose Leidenfrost effect, providing a tunable design parameter to control particle heat transfer rates in industrial biomass reactors. PMID:26057818

  9. 21 CFR 172.870 - Hydroxypropyl cellulose.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... additive is used in accordance with good manufacturing practice. ... CONSUMPTION Multipurpose Additives § 172.870 Hydroxypropyl cellulose. The food additive hydroxypropyl... accordance with the following prescribed conditions: (a) The additive consists of one of the following: (1)...

  10. Rheological properties of sulfoacetate derivatives of cellulose.

    PubMed

    Chauvelon, Gaëlle; Doublier, Jean-Louis; Buléon, Alain; Thibault, Jean-François; Saulnier, Luc

    2003-04-01

    Water-soluble cellulose acetate sulfate derivatives (CAS) have been prepared through chemical reaction involving sulfuric acid as a catalyst. These CAS have been obtained from cellulosic materials of different origins (pure cellulose, wheat bran, maize bran) and their rheological behavior in salt-free aqueous solution has been estimated in dilute and semi-dilute regime using dynamic viscoelastic and viscosity measurements. Influence of concentration, temperature of solubilization and temperature of measurement has been investigated. Weak gel-like properties were exhibited at elevated concentration (typically above 7-8 g/L). These systems also exhibited thixotropic properties: the structure was partly broken down upon shearing and recovered at rest. They also displayed thermoreversibility with large hysteresis, the melting temperature being approximately 15 degrees C higher than the temperature at which gelation took place. These overall observations clearly indicate that these distinctive properties arise from intermolecular association of the macromolecular chains of the cellulose derivative. PMID:12668095

  11. Conversion of cellulosic materials to sugar

    DOEpatents

    Wilke, Charles R.; Mitra, Gautam

    1976-08-03

    A process for the production of sugar, mainly glucose, by the enzymatic degradation of cellulosic materials, particularly cellulosic wastes, which comprises hydrolyzing the cellulosic material in the presence of cellulase enzyme to produce a sugar solution and recovering from the hydrolysis products a major proportion of the cellulase enzyme used in the hydrolysis reaction for re-use. At least a portion of the required makeup cellulase enzyme is produced in a two-stage operation wherein, in the first stage, a portion of the output sugar solution is utilized to grow a cellulase-secreting microorganism, and, in the second stage, cellulase enzyme formation is induced in the microorganism-containing culture medium by the addition of an appropriate inducer, such as a cellulosic material. Cellulase enzyme is precipitated from the culture liquid by the addition of an organic solvent material, such as a low molecular weight alkyl ketone or alcohol, and the cellulase precipitate is then fed to the hydrolysis reaction.

  12. 21 CFR 172.868 - Ethyl cellulose.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... in accordance with the following prescribed conditions: (a) The food additive is a cellulose ether containing ethoxy (OC2H5) groups attached by an ether linkage and containing on an anhydrous basis not...

  13. 21 CFR 172.868 - Ethyl cellulose.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... in accordance with the following prescribed conditions: (a) The food additive is a cellulose ether containing ethoxy (OC2H5) groups attached by an ether linkage and containing on an anhydrous basis not...

  14. Dissolution enthalpies of cellulose in ionic liquids.

    PubMed

    Parviainen, Helena; Parviainen, Arno; Virtanen, Tommi; Kilpeläinen, Ilkka; Ahvenainen, Patrik; Serimaa, Ritva; Grönqvist, Stina; Maloney, Thaddeus; Maunu, Sirkka Liisa

    2014-11-26

    In this work, interactions between cellulose and ionic liquids were studied calorimetrically and by optical microscopy. Two novel ionic liquids (1,5-Diazabicyclo[4.3.0]non-5-enium propionate and N-methyl-1,5-diazabicyclo[4.3.0]non-5-enium dimethyl phosphate) and 1-ethyl-3-methylimidazolium acetate-water mixtures were used as solvents. Optical microscopy served in finding the extent of dissolution and identifying the dissolution pattern of the cellulose sample. Calorimetric studies identified a peak relating to dissolution of cellulose in solvent. The transition did, however, not indicate complete dissolution, but rather dissolution inside fibre or fibrils. This method was used to study differences between four cellulose samples with different pretreatment or origins. PMID:25256460

  15. Reactive Liftoff of Crystalline Cellulose Particles

    NASA Astrophysics Data System (ADS)

    Teixeira, Andrew R.; Krumm, Christoph; Vinter, Katherine P.; Paulsen, Alex D.; Zhu, Cheng; Maduskar, Saurabh; Joseph, Kristeen E.; Greco, Katharine; Stelatto, Michael; Davis, Eric; Vincent, Brendon; Hermann, Richard; Suszynski, Wieslaw; Schmidt, Lanny D.; Fan, Wei; Rothstein, Jonathan P.; Dauenhauer, Paul J.

    2015-06-01

    The condition of heat transfer to lignocellulosic biomass particles during thermal processing at high temperature (>400 °C) dramatically alters the yield and quality of renewable energy and fuels. In this work, crystalline cellulose particles were discovered to lift off heated surfaces by high speed photography similar to the Leidenfrost effect in hot, volatile liquids. Order of magnitude variation in heat transfer rates and cellulose particle lifetimes was observed as intermediate liquid cellulose droplets transitioned from low temperature wetting (500-600 °C) to fully de-wetted, skittering droplets on polished surfaces (>700 °C). Introduction of macroporosity to the heated surface was shown to completely inhibit the cellulose Leidenfrost effect, providing a tunable design parameter to control particle heat transfer rates in industrial biomass reactors.

  16. 21 CFR 172.870 - Hydroxypropyl cellulose.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... additive is used in accordance with good manufacturing practice. ... CONSUMPTION Multipurpose Additives § 172.870 Hydroxypropyl cellulose. The food additive hydroxypropyl... accordance with the following prescribed conditions: (a) The additive consists of one of the following: (1)...

  17. Reactive Liftoff of Crystalline Cellulose Particles.

    PubMed

    Teixeira, Andrew R; Krumm, Christoph; Vinter, Katherine P; Paulsen, Alex D; Zhu, Cheng; Maduskar, Saurabh; Joseph, Kristeen E; Greco, Katharine; Stelatto, Michael; Davis, Eric; Vincent, Brendon; Hermann, Richard; Suszynski, Wieslaw; Schmidt, Lanny D; Fan, Wei; Rothstein, Jonathan P; Dauenhauer, Paul J

    2015-01-01

    The condition of heat transfer to lignocellulosic biomass particles during thermal processing at high temperature (>400 °C) dramatically alters the yield and quality of renewable energy and fuels. In this work, crystalline cellulose particles were discovered to lift off heated surfaces by high speed photography similar to the Leidenfrost effect in hot, volatile liquids. Order of magnitude variation in heat transfer rates and cellulose particle lifetimes was observed as intermediate liquid cellulose droplets transitioned from low temperature wetting (500-600 °C) to fully de-wetted, skittering droplets on polished surfaces (>700 °C). Introduction of macroporosity to the heated surface was shown to completely inhibit the cellulose Leidenfrost effect, providing a tunable design parameter to control particle heat transfer rates in industrial biomass reactors. PMID:26057818

  18. Rapid saccharification for production of cellulosic biofuels.

    PubMed

    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

  19. Evaluation of the genotoxicity of cellulose nanofibers

    PubMed Central

    de Lima, Renata; Feitosa, Leandro Oliveira; Maruyama, Cintia Rodrigues; Barga, Mariana Abreu; Yamawaki, Patrícia Cristina; Vieira, Isolda Jesus; Teixeira, Eliangela M; Corrêa, Ana Carolina; Mattoso, Luiz Henrique Caparelli; Fraceto, Leonardo Fernandes

    2012-01-01

    Background Agricultural products and by products provide the primary materials for a variety of technological applications in diverse industrial sectors. Agro-industrial wastes, such as cotton and curaua fibers, are used to prepare nanofibers for use in thermoplastic films, where they are combined with polymeric matrices, and in biomedical applications such as tissue engineering, amongst other applications. The development of products containing nanofibers offers a promising alternative for the use of agricultural products, adding value to the chains of production. However, the emergence of new nanotechnological products demands that their risks to human health and the environment be evaluated. This has resulted in the creation of the new area of nanotoxicology, which addresses the toxicological aspects of these materials. Purpose and methods Contributing to these developments, the present work involved a genotoxicological study of different nanofibers, employing chromosomal aberration and comet assays, as well as cytogenetic and molecular analyses, to obtain preliminary information concerning nanofiber safety. The methodology consisted of exposure of Allium cepa roots, and animal cell cultures (lymphocytes and fibroblasts), to different types of nanofibers. Negative controls, without nanofibers present in the medium, were used for comparison. Results The nanofibers induced different responses according to the cell type used. In plant cells, the most genotoxic nanofibers were those derived from green, white, and brown cotton, and curaua, while genotoxicity in animal cells was observed using nanofibers from brown cotton and curaua. An important finding was that ruby cotton nanofibers did not cause any significant DNA breaks in the cell types employed. Conclusion This work demonstrates the feasibility of determining the genotoxic potential of nanofibers derived from plant cellulose to obtain information vital both for the future usage of these materials in

  20. Biodegradable cellulose acetate nanofiber fabrication via electrospinning.

    PubMed

    Christoforou, Theopisti; Doumanidis, Charalabos

    2010-09-01

    Nanofiber manufacturing is one of the key advancements in nanotechnology today. Over the past few years, there has been a tremendous growth of research activities to explore electrospinning for nanofiber formation from a rich variety of materials. This quite simple and cost effective process operates on the principle that the solution is extracted under the action of a high electric field. Once the voltage is sufficiently high, a charged jet is ejected following a complicated looping trajectory. During its travel, the solvent evaporates leaving behind randomly oriented nanofibers accumulated on the collector. The combination of their nanoscale dimensionality, high surface area, porosity, flexibility and superior strength makes the electrospun fibers suitable for several value-added applications, such as filters, protecting clothes, high performance structures and biomedical devices. In this study biodegradable cellulose acetate (CA) nanofibrous membranes were produced using electrospinning. The device utilized consisted of a syringe equipped with a metal needle, a microdialysis pump, a high voltage supply and a collector. The morphology of the yielded fibers was determined using SEM. The effect of various parameters, including electric field strength, tip-to-collector distance, solution feed rate and composition on the morphological features of the electrospun fibers was examined. The optimum operating conditions for the production of uniform, non-beaded fibers with submicron diameter were also explored. The biodegradable CA nanofiber membranes are suitable as tissue engineering scaffolds and as reinforcements of biopolymer matrix composites in foils by ultrasonic welding methods. PMID:21133179

  1. Cellulose fractionation with IONCELL-P.

    PubMed

    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

  2. Enthalpic studies of xyloglucan-cellulose interactions.

    PubMed

    Lopez, Marie; Bizot, Hervé; Chambat, Gérard; Marais, Marie-France; Zykwinska, Agata; Ralet, Marie-Christine; Driguez, Hugues; Buléon, Alain

    2010-06-14

    We report a study of xyloglucan (XG)-cellulose interactions made possible by the preparation of various well-defined cellulosic and xyloglucosidic substrates. Bacterial microcrystalline cellulose (BMCC) as well as cellulose whiskers (CellWhisk) were used as cellulosic substrates. Xyloglucosidic substrates were obtained from Rubus cells and Tamarindus indica seeds. Different primary structure characteristics of XGs such as the backbone length and the nature of the side chains, as well as their repartition, were considered in order to examine the influence of the primary structure on their interaction capacity. Two complementary approaches were carried out: first, the determination of adsorption isotherms and its associated models, and second, an enthalpic study using isothermal titration calorimetry (ITC). This study highlighted that an increase of XG interaction capacity occurred with increasing XG molecular weight. Furthermore, we determined that a minimum of 12 glucosyl residues on the backbone is required to observe significant interactions. Moreover, both the presence of trisaccharidic side chains with fucosyl residues and an increase of unsubstituted glucosyl residues enhanced XG-cellulose interactions. The evolution of adsorption isotherms with temperature and ITC measurements showed that two different processes were occurring, one exothermic and one endothermic, respectively. Although the presence of an exothermic interaction mechanism has long been established, the presence of an endothermic interaction mechanism has never been reported. PMID:20433133

  3. Utilization of biocatalysts in cellulose waste minimization

    SciTech Connect

    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.

  4. A statistical treatment of bioassay pour fractions

    NASA Astrophysics Data System (ADS)

    Barengoltz, Jack; Hughes, David

    A bioassay is a method for estimating the number of bacterial spores on a spacecraft surface for the purpose of demonstrating compliance with planetary protection (PP) requirements (Ref. 1). The details of the process may be seen in the appropriate PP document (e.g., for NASA, Ref. 2). In general, the surface is mechanically sampled with a damp sterile swab or wipe. The completion of the process is colony formation in a growth medium in a plate (Petri dish); the colonies are counted. Consider a set of samples from randomly selected, known areas of one spacecraft surface, for simplicity. One may calculate the mean and standard deviation of the bioburden density, which is the ratio of counts to area sampled. The standard deviation represents an estimate of the variation from place to place of the true bioburden density commingled with the precision of the individual sample counts. The accuracy of individual sample results depends on the equipment used, the collection method, and the culturing method. One aspect that greatly influences the result is the pour fraction, which is the quantity of fluid added to the plates divided by the total fluid used in extracting spores from the sampling equipment. In an analysis of a single sample’s counts due to the pour fraction, one seeks to answer the question: What is the probability that if a certain number of spores are counted with a known pour fraction, that there are an additional number of spores in the part of the rinse not poured. This is given for specific values by the binomial distribution density, where detection (of culturable spores) is success and the probability of success is the pour fraction. A special summation over the binomial distribution, equivalent to adding for all possible values of the true total number of spores, is performed. This distribution when normalized will almost yield the desired quantity. It is the probability that the additional number of spores does not exceed a certain value. Of course

  5. A statistical treatment of bioassay pour fractions

    NASA Astrophysics Data System (ADS)

    Barengoltz, Jack; Hughes, David

    A bioassay is a method for estimating the number of bacterial spores on a spacecraft surface for the purpose of demonstrating compliance with planetary protection (PP) requirements (Ref. 1). The details of the process may be seen in the appropriate PP document (e.g., for NASA, Ref. 2). In general, the surface is mechanically sampled with a damp sterile swab or wipe. The completion of the process is colony formation in a growth medium in a plate (Petri dish); the colonies are counted. Consider a set of samples from randomly selected, known areas of one spacecraft surface, for simplicity. One may calculate the mean and standard deviation of the bioburden density, which is the ratio of counts to area sampled. The standard deviation represents an estimate of the variation from place to place of the true bioburden density commingled with the precision of the individual sample counts. The accuracy of individual sample results depends on the equipment used, the collection method, and the culturing method. One aspect that greatly influences the result is the pour fraction, which is the quantity of fluid added to the plates divided by the total fluid used in extracting spores from the sampling equipment. In an analysis of a single sample’s counts due to the pour fraction, one seeks to answer the question: What is the probability that if a certain number of spores are counted with a known pour fraction, that there are an additional number of spores in the part of the rinse not poured. This is given for specific values by the binomial distribution density, where detection (of culturable spores) is success and the probability of success is the pour fraction. A special summation over the binomial distribution, equivalent to adding for all possible values of the true total number of spores, is performed. This distribution when normalized will almost yield the desired quantity. It is the probability that the additional number of spores does not exceed a certain value. Of course

  6. 16 CFR 1209.31 - Purpose and applicability.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Standard for Cellulose Insulation (16 CFR part 1209, subpart A). This subpart B includes requirements for... INTERIM SAFETY STANDARD FOR CELLULOSE INSULATION Certification § 1209.31 Purpose and applicability. (a.... (b) Applicability. (1) Cellulose insulation which is subject to the standard includes all...

  7. 16 CFR 1209.31 - Purpose and applicability.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Standard for Cellulose Insulation (16 CFR part 1209, subpart A). This subpart B includes requirements for... INTERIM SAFETY STANDARD FOR CELLULOSE INSULATION Certification § 1209.31 Purpose and applicability. (a.... (b) Applicability. (1) Cellulose insulation which is subject to the standard includes all...

  8. 16 CFR 1209.31 - Purpose and applicability.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Standard for Cellulose Insulation (16 CFR part 1209, subpart A). This subpart B includes requirements for... INTERIM SAFETY STANDARD FOR CELLULOSE INSULATION Certification § 1209.31 Purpose and applicability. (a.... (b) Applicability. (1) Cellulose insulation which is subject to the standard includes all...

  9. 16 CFR 1209.31 - Purpose and applicability.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Standard for Cellulose Insulation (16 CFR part 1209, subpart A). This subpart B includes requirements for... INTERIM SAFETY STANDARD FOR CELLULOSE INSULATION Certification § 1209.31 Purpose and applicability. (a.... (b) Applicability. (1) Cellulose insulation which is subject to the standard includes all...

  10. 16 CFR 1209.31 - Purpose and applicability.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Standard for Cellulose Insulation (16 CFR part 1209, subpart A). This subpart B includes requirements for... INTERIM SAFETY STANDARD FOR CELLULOSE INSULATION Certification § 1209.31 Purpose and applicability. (a.... (b) Applicability. (1) Cellulose insulation which is subject to the standard includes all...

  11. Position-specific measurement of oxygen isotope ratios in cellulose: Isotopic exchange during heterotrophic cellulose synthesis

    NASA Astrophysics Data System (ADS)

    Waterhouse, John S.; Cheng, Shuying; Juchelka, Dieter; Loader, Neil J.; McCarroll, Danny; Switsur, V. Roy; Gautam, Lata

    2013-07-01

    We describe the first reported method for the measurement of oxygen isotope ratios at each position in the glucose units of the cellulose molecule. The overall process comprises a series of synthetic organic sequences, by which α-cellulose is hydrolysed to glucose, and oxygen atoms at specific positions in the glucose molecule are removed in samples of benzoic acid for measurement of δ18O. Values of δ18O at specific positions in cellulose are calculated from these δ18O values and the overall δ18O value of the cellulose. We apply the method to determine the degree to which oxygen atoms at each position undergo isotopic exchange with water during heterotrophic cellulose synthesis, such as occurs in the cambium of trees. To do this we extract α-cellulose from wheat seedlings germinated in the dark in aqueous media of differing oxygen isotope ratios. Results indicate that oxygen atoms at positions 5 and 6 (O-5 and O-6 respectively) undergo around 80% exchange with medium water, O-3 undergoes around 50% exchange, and O-2 and O-4 do not undergo isotopic exchange. The results have important implications for extracting palaeoclimatic records from oxygen isotope time series obtained from tree ring cellulose. As O-5 and O-6 undergo significant exchange with medium water during heterotrophic cellulose synthesis, oxygen isotopes at these positions in tree ring cellulose should carry a predominantly trunk (source) water signal. On the other hand, O-2 and O-4 should retain the isotopic signature of leaf water in tree ring cellulose. Our method therefore potentially enables the separate reconstruction of past temperature and humidity data from oxygen isotope ratios of tree ring cellulose - something that has hitherto not been possible. The measured degrees of isotopic exchange are to some extent unexpected and cannot be fully explained using current biochemical mechanisms, suggesting that knowledge of these processes is incomplete.

  12. Detailed kinetic and chemometric study of the cellulose thermal breakdown in artificially aged and non aged commercial paper. Different methods for computing activation energy as an assessment model in archaeometric applications

    PubMed Central

    2012-01-01

    Background The thermal oxidative degradation of aged and non aged cellulose samples of commercial paper was studied using thermogravimetry and derivative thermogravimetry under a forced air flow up to 800°C. Results TG and DTG data were processed using two non-isothermal-based model-fitting methods and one based on linear least squares to calculate Ea trend values, measured as a function of artificially induced sample age. The Ea trends thus obtained were compared in order to assess their potential for yielding archaeometric curves. As the trends of first two methods show an inversion of the direction between non aged cellulose samples and artificially aged samples, while the third method does not, an in-depth study was carried out using a multilinearity assumption. Conclusions The results are discussed and the outcomes indicate that the above cited inversion is real and not linked to the method. Additionally, it was evidenced that the number of points used for the estimation of linear least squares model parameters is of capital importance. PMID:22594442

  13. Mapping of a Cellulose-Deficient Mutant Named dwarf1-1 in Sorghum bicolor to the Green Revolution Gene gibberellin20-oxidase Reveals a Positive Regulatory Association between Gibberellin and Cellulose Biosynthesis.

    PubMed

    Petti, Carloalberto; Hirano, Ko; Stork, Jozsef; DeBolt, Seth

    2015-09-01

    Here, we show a mechanism for expansion regulation through mutations in the green revolution gene gibberellin20 (GA20)-oxidase and show that GAs control biosynthesis of the plants main structural polymer cellulose. Within a 12,000 mutagenized Sorghum bicolor plant population, we identified a single cellulose-deficient and male gametophyte-dysfunctional mutant named dwarf1-1 (dwf1-1). Through the Sorghum propinquum male/dwf1-1 female F2 population, we mapped dwf1-1 to a frameshift in GA20-oxidase. Assessment of GAs in dwf1-1 revealed ablation of GA. GA ablation was antagonistic to the expression of three specific cellulose synthase genes resulting in cellulose deficiency and growth dwarfism, which were complemented by exogenous bioactive gibberellic acid application. Using quantitative polymerase chain reaction, we found that GA was positively regulating the expression of a subset of specific cellulose synthase genes. To cross reference data from our mapped Sorghum sp. allele with another monocotyledonous plant, a series of rice (Oryza sativa) mutants involved in GA biosynthesis and signaling were isolated, and these too displayed cellulose deficit. Taken together, data support a model whereby suppressed expansion in green revolution GA genes involves regulation of cellulose biosynthesis. PMID:26198258

  14. Mapping of a Cellulose-Deficient Mutant Named dwarf1-1 in Sorghum bicolor to the Green Revolution Gene gibberellin20-oxidase Reveals a Positive Regulatory Association between Gibberellin and Cellulose Biosynthesis1[OPEN

    PubMed Central

    Petti, Carloalberto; Hirano, Ko; Stork, Jozsef; DeBolt, Seth

    2015-01-01

    Here, we show a mechanism for expansion regulation through mutations in the green revolution gene gibberellin20 (GA20)-oxidase and show that GAs control biosynthesis of the plants main structural polymer cellulose. Within a 12,000 mutagenized Sorghum bicolor plant population, we identified a single cellulose-deficient and male gametophyte-dysfunctional mutant named dwarf1-1 (dwf1-1). Through the Sorghum propinquum male/dwf1-1 female F2 population, we mapped dwf1-1 to a frameshift in GA20-oxidase. Assessment of GAs in dwf1-1 revealed ablation of GA. GA ablation was antagonistic to the expression of three specific cellulose synthase genes resulting in cellulose deficiency and growth dwarfism, which were complemented by exogenous bioactive gibberellic acid application. Using quantitative polymerase chain reaction, we found that GA was positively regulating the expression of a subset of specific cellulose synthase genes. To cross reference data from our mapped Sorghum sp. allele with another monocotyledonous plant, a series of rice (Oryza sativa) mutants involved in GA biosynthesis and signaling were isolated, and these too displayed cellulose deficit. Taken together, data support a model whereby suppressed expansion in green revolution GA genes involves regulation of cellulose biosynthesis. PMID:26198258

  15. Enzymatic hydrolysis and recrystallization behavior of initially amorphous cellulose.

    PubMed

    Bertran, M S; Dale, B E

    1985-02-01

    Cellulose samples from cotton and wood pulps with varying low degrees of crystallinity (mechanically decrystallized) were studied. The influence of initial cellulose crystallinity on sugar yield after enzymatic hydrolysis was determined by two different methods. As expected, samples with low crystallinity were much more accessible to enzymatic attack and glucose yields were higher than were samples of high initial crystallinity. Hydrolysis of cellulose seems more dependent on cellulose crystallinity than on the source of cellulose. It is known that decrystallized or amorphous cellulose can recrystallize under proper conditions, e.g., during acid hydrolysis. The data reported here also reveal some recrystallization during enzymatic hydrolysis which probably occurs simulataneously with a selective enzymatic attack on the amorphous regions of cellulose. In all cases, the amorphous celluloses recrystallized in the original lattice form, that of native cellulose. PMID:18553653

  16. Versatile Molding Process for Tough Cellulose Hydrogel Materials

    PubMed Central

    Kimura, Mutsumi; Shinohara, Yoshie; Takizawa, Junko; Ren, Sixiao; Sagisaka, Kento; Lin, Yudeng; Hattori, Yoshiyuki; Hinestroza, Juan P.

    2015-01-01

    Shape-persistent and tough cellulose hydrogels were fabricated by a stepwise solvent exchange from a homogeneous ionic liquid solution of cellulose exposure to methanol vapor. The cellulose hydrogels maintain their shapes under changing temperature, pH, and solvents. The micrometer-scale patterns on the mold were precisely transferred onto the surface of cellulose hydrogels. We also succeeded in the spinning of cellulose hydrogel fibers through a dry jet-wet spinning process. The mechanical property of regenerated cellulose fibers improved by the drawing of cellulose hydrogel fibers during the spinning process. This approach for the fabrication of tough cellulose hydrogels is a major advance in the fabrication of cellulose-based structures with defined shapes. PMID:26537533

  17. Versatile Molding Process for Tough Cellulose Hydrogel Materials.

    PubMed

    Kimura, Mutsumi; Shinohara, Yoshie; Takizawa, Junko; Ren, Sixiao; Sagisaka, Kento; Lin, Yudeng; Hattori, Yoshiyuki; Hinestroza, Juan P

    2015-01-01

    Shape-persistent and tough cellulose hydrogels were fabricated by a stepwise solvent exchange from a homogeneous ionic liquid solution of cellulose exposure to methanol vapor. The cellulose hydrogels maintain their shapes under changing temperature, pH, and solvents. The micrometer-scale patterns on the mold were precisely transferred onto the surface of cellulose hydrogels. We also succeeded in the spinning of cellulose hydrogel fibers through a dry jet-wet spinning process. The mechanical property of regenerated cellulose fibers improved by the drawing of cellulose hydrogel fibers during the spinning process. This approach for the fabrication of tough cellulose hydrogels is a major advance in the fabrication of cellulose-based structures with defined shapes. PMID:26537533

  18. Versatile Molding Process for Tough Cellulose Hydrogel Materials

    NASA Astrophysics Data System (ADS)

    Kimura, Mutsumi; Shinohara, Yoshie; Takizawa, Junko; Ren, Sixiao; Sagisaka, Kento; Lin, Yudeng; Hattori, Yoshiyuki; Hinestroza, Juan P.

    2015-11-01

    Shape-persistent and tough cellulose hydrogels were fabricated by a stepwise solvent exchange from a homogeneous ionic liquid solution of cellulose exposure to methanol vapor. The cellulose hydrogels maintain their shapes under changing temperature, pH, and solvents. The micrometer-scale patterns on the mold were precisely transferred onto the surface of cellulose hydrogels. We also succeeded in the spinning of cellulose hydrogel fibers through a dry jet-wet spinning process. The mechanical property of regenerated cellulose fibers improved by the drawing of cellulose hydrogel fibers during the spinning process. This approach for the fabrication of tough cellulose hydrogels is a major advance in the fabrication of cellulose-based structures with defined shapes.

  19. New Insights into Hydrogen Bonding and Stacking Interactions in Cellulose

    SciTech Connect

    Langan, Paul

    2011-01-01

    In this quantum chemical study, we explore hydrogen bonding (H-bonding) and stacking interactions in different crystalline cellulose allomorphs, namely cellulose I and cellulose IIII. We consider a model system representing a cellulose crystalline core, made from six cellobiose units arranged in three layers with two chains per layer. We calculate the contributions of intrasheet and intersheet interactions to the structure and stability in both cellulose I and cellulose IIII crystalline cores. Reference structures for this study were generated from molecular dynamics simulations of water-solvated cellulose I and IIII fibrils. A systematic analysis of various conformations describing different mutual orientations of cellobiose units is performed using the hybrid density functional theory (DFT) with the M06-2X with 6-31+G (d, p) basis sets. We dissect the nature of the forces that stabilize the cellulose I and cellulose IIII crystalline cores and quantify the relative strength of H-bonding and stacking interactions. Our calculations demonstrate that individual H-bonding interactions are stronger in cellulose I than in cellulose IIII. We also observe a significant contribution from cooperative stacking interactions to the stabilization of cellulose I . In addition, the theory of atoms-in-molecules (AIM) has been employed to characterize and quantify these intermolecular interactions. AIM analyses highlight the role of nonconventional CH O H-bonding in the cellulose assemblies. Finally, we calculate molecular electrostatic potential maps for the cellulose allomorphs that capture the differences in chemical reactivity of the systems considered in our study.

  20. Kinetics of Cellulose Digestion by Fibrobacter succinogenes S85

    PubMed Central

    Maglione, G.; Russell, J. B.; Wilson, D. B.

    1997-01-01

    Growing cultures of Fibrobacter succinogenes S85 digested cellulose at a rapid rate, but nongrowing cells and cell extracts did not have detectable crystalline cellulase activity. Cells that had been growing exponentially on cellobiose initiated cellulose digestion and succinate production immediately, and cellulose-dependent succinate production could be used as an index of enzyme activity against crystalline cellulose. Cells incubated with cellulose never produced detectable cellobiose, and cells that were preincubated for a short time with thiocellobiose lost their ability to digest cellulose (competitive inhibition [K(infi)] of only 0.2 mg/ml or 0.56 mM). Based on these results, the crystalline cellulases of F. succinogenes were very sensitive to feedback inhibition. Different cellulose sources bound different amounts of Congo red, and the binding capacity was HCl-regenerated cellulose > ball-milled cellulose > Sigmacel > Avicel > filter paper. Congo red binding capacity was highly correlated with the maximum rates of metabolism of cellulose digestion and inversely related to K(infm). Congo red (250 (mu)g/ml) did not inhibit the growth of F. succinogenes S85 on cellobiose, but this concentration of Congo red inhibited the rate of ball-milled cellulose digestion. A Lineweaver-Burk plot of ball-milled cellulose digestion rate versus the amount of cellulose indicated that Congo red was a competitive inhibitor of cellulose digestion (K(infi) was 250 (mu)g/ml). PMID:16535519

  1. Biocompatible Bacterial Cellulose-Poly(2-hydroxyethyl methacrylate) Nanocomposite Films

    PubMed Central

    Figueiredo, Andrea G. P. R.; Figueiredo, Ana R. P.; Alonso-Varona, Ana; Fernandes, Susana C. M.; Palomares, Teodoro; Rubio-Azpeitia, Eva; Barros-Timmons, Ana; Silvestre, Armando J. D.; Pascoal Neto, Carlos; Freire, Carmen S. R.

    2013-01-01

    A series of bacterial cellulose-poly(2-hydroxyethyl methacrylate) nanocomposite films was prepared by in situ radical polymerization of 2-hydroxyethyl methacrylate (HEMA), using variable amounts of poly(ethylene glycol) diacrylate (PEGDA) as cross-linker. Thin films were obtained, and their physical, chemical, thermal, and mechanical properties were evaluated. The films showed improved translucency compared to BC and enhanced thermal stability and mechanical performance when compared to poly(2-hydroxyethyl methacrylate) (PHEMA). Finally, BC/PHEMA nanocomposites proved to be nontoxic to human adipose-derived mesenchymal stem cells (ADSCs) and thus are pointed as potential dry dressings for biomedical applications. PMID:24093101

  2. Properties of cellulose derivatives produced from radiation—Modified cellulose pulps

    NASA Astrophysics Data System (ADS)

    Iller, Edward; Stupińska, Halina; Starostka, Paweł

    2007-07-01

    The aim of project was elaboration of radiation methods for properties modification of cellulose pulps using for derivatives production. The selected cellulose pulps were exposed to an electron beam with energy 10 MeV in a linear accelerator. After irradiation pulps underwent the structural and physico-chemical investigations. The laboratory test for manufacturing carboxymethylocellulose (CMC), cellulose carbamate (CC) and cellulose acetate (CA) with cellulose pulps irradiated dose 10 and 15 kGy have been performed. Irradiation of the pulp influenced its depolimerisation degree and resulted in the drop of viscosity of CMC. However, the expected level of cellulose activation expressed as a rise of the substitution degree or increase of the active substance content in the CMC sodium salt was not observed. In the case of cellulose esters (CC, CA) formation, the action of ionising radiation on cellulose pulps with the dose 10 and 15 kGy enables obtaiment of the average values of polimerisation degree as required for CC soluble in aqueous sodium hydroxide solution. The properties of derivatives prepared by means of radiation and classic methods were compared.

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

    PubMed

    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

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

    PubMed Central

    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

  5. Biohydrogen production from cellulosic hydrolysate produced via temperature-shift-enhanced bacterial cellulose hydrolysis.

    PubMed

    Lo, Yung-Chung; Su, Yi-Chen; Chen, Chun-Yen; Chen, Wen-Ming; Lee, Kuo-Shing; Chang, Jo-Shu

    2009-12-01

    A "temperature-shift" strategy was developed to improve reducing sugar production from bacterial hydrolysis of cellulosic materials. In this strategy, production of cellulolytic enzymes with Cellulomonas uda E3-01 was promoted at a preferable temperature (35 degrees C), while more efficient enzymatic cellulose hydrolysis was achieved under an elevated culture temperature (45 degrees C), at which cell growth was inhibited to avoid consumption of reducing sugar. This temperature-shift strategy was shown to markedly increase the reducing sugar (especially, monosaccharide and disaccharide) concentration in the hydrolysate while hydrolyzing pure (carboxymethyl-cellulose, xylan, avicel and cellobiose) and natural (rice husk, rice straw, bagasse and Napier-grass) cellulosic materials. The cellulosic hydrolysates from CMC and xylan were successfully converted to H(2) via dark fermentation with Clostridium butyricum CGS5, attaining a maximum hydrogen yield of 4.79 mmol H(2)/g reducing sugar. PMID:19604692

  6. Acid hydrolysis of cellulosic fibres: Comparison of bleached kraft pulp, dissolving pulps and cotton textile cellulose.

    PubMed

    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

  7. Adherence of Clostridium thermocellum to cellulose.

    PubMed Central

    Bayer, E A; Kenig, R; Lamed, R

    1983-01-01

    The adherence of Clostridium thermocellum, a cellulolytic, thermophilic anaerobe, to its insoluble substrate (cellulose) was studied. The adherence phenomenon was determined to be selective for cellulose. The observed adherence was not significantly affected by various parameters, including salts, pH, temperature, detergents, or soluble sugars. A spontaneous adherence-defective mutant strain (AD2) was isolated from the wild-type strain YS. Antibodies were prepared against the bacterial cell surface and rendered specific to the cellulose-binding factor (CBF) by adsorption to mutant AD2 cells. By using these CBF-specific antibodies, crossed immunoelectrophoresis of cell extracts revealed a single discrete precipitation peak in the parent strain which was absent in the mutant. This difference was accompanied by an alteration in the polypeptide profile whereby sonicates of strain YS contained a 210,000-molecular-weight band which was missing in strain AD2. The CBF antigen could be removed from cell extracts by adsorption to cellulose. A combined gel-overlay--immunoelectrophoretic technique demonstrated that the cellulose-binding properties of the CBF were accompanied by carboxymethylcellulase activity. During the exponential phase of growth, a large part of the CBF antigen and related carboxymethylcellulase activity was associated with the cells of wild-type strain YS. However, the amounts decreased in stationary-phase cells. Cellobiose-grown mutant AD2 cells lacked the cell-associated CBF, but the latter was detected in the extracellular fluid. Increased levels of CBF were observed when cells were grown on cellulose. In addition, mutant AD2 regained cell-associated CBF together with the property of cellulose adherence. The presence of the CBF antigen and related adherence characteristics appeared to be a phenomenon common to other naturally occurring strains of this species. Images PMID:6630152

  8. Isolation and Characterization of Two Cellulose Morphology Mutants of Gluconacetobacter hansenii ATCC23769 Producing Cellulose with Lower Crystallinity

    PubMed Central

    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

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

    PubMed

    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

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

    DOE PAGESBeta

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

    2015-03-19

    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 addressmore » 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

  11. APPARATUS FOR MELTING AND POURING METAL

    DOEpatents

    Harris, F.A.

    1958-02-25

    This patent relates to a crucible for melting and pouring a metal under controlled atmospheric conditions. The crucible has a frangible plug in the bottom and a retaining device to prevent the entrance of the broken portions of the plug into the mold without interfering with the flow of the melt. After the charge has been melted, a knockout rod is lowered through the charge and forced against the frangible plug sufficiently to break off the closure disk along a previously scored line. The disk drops onto a retaining grid large enough to permit the flow of metal around the disk and into the mold below. Thts arrangement elimnates the entry of broken portions of the plug into the mold, thereby elimnating a common cause of imperfect castings.

  12. Clean conversion of cellulose into fermentable glucose.

    PubMed

    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

  13. CONSTITUTIVE ANALYSIS OF THE NONLINEAR RHEOLOGICAL BEHAVIOR OF CELLULOSIC FIBER GELS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The ability to predict the rheological performance of various biopolymers is an important tool in optimizing processing procedures in the food industry. The applicability of various integral and differential constitutive models to describe the nonlinear viscolelastic behavior of cellulosic fiber ge...

  14. Aqueous Modification of Nano- and Microfibrillar Cellulose with a Click Synthon.

    PubMed

    Hettegger, Hubert; Beaumont, Marco; Potthast, Antje; Rosenau, Thomas

    2016-01-01

    The modification of cellulose as a renewable resource has received wide attention in research and industry. A major problem regarding chemical modification, including heating and drying, is related to hornification that causes pore-system collapse and results in decreased reactivity and changes in the 3D structure of the material. A mild and green approach for the modification of different never-dried and thus wet cellulose substrates (pulp, nanostructured celluloses, and viscose fibers) by an alkoxysilane-azide in water is presented. A kinetic study of the silanization reaction demonstrates that alkoxy-trans-silanization of the cellulose surface is accomplished in water as a suspension medium within a few hours at room temperature. The resulting, azido-equipped celluloses are widely applicable precursor materials for subsequent functionalization by so-called click chemistry, for example, with a fluorescent Rhodamine derivative as a representative reagent. Successful covalent bonding was shown by GPC and a model reaction. The 3D structure of the materials remained intact, as was inter alia visualized by optical and fluorescence microscopy. PMID:26612209

  15. Suite of Activity-Based Probes for Cellulose-Degrading Enzymes

    SciTech Connect

    Chauvigne-Hines, Lacie M.; Anderson, Lindsey N.; Weaver, Holly M.; Brown, Joseph N.; Koech, Phillip K.; Nicora, Carrie D.; Hofstad, Beth A.; Smith, Richard D.; Wilkins, Michael J.; Callister, Stephen J.; Wright, Aaron T.

    2012-12-19

    Microbial glycoside hydrolases play a dominant role in the biochemical conversion of cellulosic biomass to high-value biofuels. Anaerobic cellulolytic bacteria are capable of producing multicomplex catalytic subunits containing cell-adherent cellulases, hemicellulases, xylanases, and other glycoside hydrolases to facilitate the degradation of highly recalcitrant cellulose and other related plant cell wall polysaccharides. Clostridium thermocellum is a cellulosome producing bacterium that couples rapid reproduction rates to highly efficient degradation of crystalline cellulose. Herein, we have developed and applied a suite of difluoromethylphenyl aglycone, N-halogenated glycosylamine, and 2-deoxy-2-fluoroglycoside activity-based protein profiling (ABPP) probes to the direct labeling of the C. thermocellum cellulosomal secretome. These activity-based probes (ABPs) were synthesized with alkynes to harness the utility and multimodal possibilities of click chemistry, and to increase enzyme active site inclusion for LC-MS analysis. We directly analyzed ABP-labeled and unlabeled global MS data, revealing ABP selectivity for glycoside hydrolase (GH) enzymes in addition to a large collection of integral cellulosome-containing proteins. By identifying reactivity and selectivity profiles for each ABP, we demonstrate our ability to widely profile the functional cellulose degrading machinery of the bacterium. Derivatization of the ABPs, including reactive groups, acetylation of the glycoside binding groups, and mono- and disaccharide binding groups, resulted in considerable variability in protein labeling. Our probe suite is applicable to aerobic and anaerobic cellulose degrading systems, and facilitates a greater understanding of the organismal role associated within biofuel development.

  16. The biodegradability and nontoxicity of carboxymethyl cellulose (DS 0.7) and intermediates

    SciTech Connect

    Ginkel, C.G. van; Gayton, S.

    1996-03-01

    Carboxymethyl cellulose with a DS ranging from 0.4 to 1.3 has become the largest industrial cellulose ether because of tis versatile applications in, for example, detergents and oil drilling. Carboxymethyl cellulose (CMC) with a degree of substitution of 0.7 is a water-soluble polymer. In some cases, CMC ends up in wastewater treatment plants and, ultimately, in the environment. Carboxymethyl cellulose degrades completely at low rates in the environment as demonstrated in a prolonged closed bottle test and in a semicontinuous activated sludge test. The continuous-flow activated sludge (CAS) test simulates sewage treatment plants. In the CAS test the CMC added to raw sewage prior to entering the bioreactor was partly biodegraded by microorganisms. The effluent from the reactor containing intermediates was then used in standard aquatic toxicity tests. No toxicity was shown in the effluent, which indicates that the intermediates formed by biodegradation are not toxic. Carboxymethyl cellulose intermediates produced by a pure culture of a CMC-degrading bacterium were also shown not to be toxic, because no effects were observed at the highest concentrations tested: 0.5 g/L for Selenastrum capricornutum (algae), 1.0 g/L for Daphnia magna (water flea), and 1.0 g/L for Brachydanio rerio (zebra fish). In addition, the nontoxicity of CMC to these aquatic organisms was established with no-effect concentrations of > 0.5 g/L.

  17. A Suite of Activity-Based Probes for Cellulose Degrading Enzymes

    PubMed Central

    Chauvigné-Hines, Lacie M.; Anderson, Lindsey N.; Weaver, Holly M.; Brown, Joseph N.; Koech, Phillip K.; Nicora, Carrie D.; Hofstad, Beth A.; Smith, Richard D.; Wilkins, Michael J.; Callister, Stephen J.; Wright, Aaron T.

    2012-01-01

    Microbial glycoside hydrolases play a dominant role in the biochemical conversion of cellulosic biomass to high-value biofuels. Anaerobic cellulolytic bacteria are capable of producing multicomplex catalytic subunits containing cell-adherent cellulases, hemicellulases, xylanases, and other glycoside hydrolases to facilitate the degradation of highly recalcitrant cellulose and other related plant cell wall polysaccharides. Clostridium thermocellum is a cellulosome producing bacterium that couples rapid reproduction rates to highly efficient degradation of crystalline cellulose. Herein, we have developed and applied a suite of difluoromethylphenyl aglycone, N-halogenated glycosylamine, and 2-deoxy-2-fluoroglycoside activity-based protein profiling (ABPP) probes to the direct labeling of the C. thermocellum cellulosomal secretome. These activity-based probes (ABPs) were synthesized with alkynes to harness the utility and multimodal possibilities of click chemistry, and to increase enzyme active site inclusion for LC-MS analysis. We directly analyzed ABP-labeled and unlabeled global MS data, revealing ABP selectivity for glycoside hydrolase (GH) enzymes, in addition to a large collection of integral cellulosome-containing proteins. By identifying reactivity and selectivity profiles for each ABP, we demonstrate our ability to widely profile the functional cellulose degrading machinery of the bacterium. Derivatization of the ABPs, including reactive groups, acetylation of the glycoside binding groups, and mono- and disaccharide binding groups, resulted in considerable variability in protein labeling. Our probe suite is applicable to aerobic and anaerobic microbial cellulose degrading systems, and facilitates a greater understanding of the organismal role associated with biofuel development. PMID:23176123

  18. Ultrathin cellulose nanosheet membranes for superfast separation of oil-in-water nanoemulsions.

    PubMed

    Zhou, Ke; Zhang, Qiu Gen; Li, Hong Mei; Guo, Nan Nan; Zhu, Ai Mei; Liu, Qing Lin

    2014-09-01

    Oily wastewater is generated in diverse industrial processes, and its treatment has become crucial due to increasing environmental concerns. Herein, novel ultrathin nanoporous membranes of cellulose nanosheets have been fabricated for separation of oil-in-water nanoemulsions. The fabrication approach is facile and environmentally friendly, in which cellulose nanosheets are prepared by freeze-extraction of a very dilute cellulose solution. The as-prepared membranes have a cellulose nanosheet layer with a cut-off of 10-12 nm and a controllable thickness of 80-220 nm. They allow ultrafast water permeation and exhibit excellent size-selective separation properties. A 112 nm-thick membrane has a water flux of 1620 l m(-2) h(-1) bar(-1) and a ferritin rejection of 92.5%. These membranes have been applied to remove oil from its aqueous nanoemulsions successfully, and they show an ultrafast and effective separation of oil-in-water nanoemulsions. The newly developed ultrathin cellulose membranes have a wide application in oily wastewater treatment, separation and purification of nanomaterials. PMID:25073443

  19. Thin-film Nanofibrous Composite Membranes Containing Cellulose or Chitin Barrier Layers Fabricated by Ionic Liquids

    SciTech Connect

    H Ma; B Hsiao; B Chu

    2011-12-31

    The barrier layer of high-flux ultrafiltration (UF) thin-film nanofibrous composite (TFNC) membranes for purification of wastewater (e.g., bilge water) have been prepared by using cellulose, chitin, and a cellulose-chitin blend, regenerated from an ionic liquid. The structures and properties of regenerated cellulose, chitin, and a cellulose-chitin blend were analyzed with thermogravimetric analysis (TGA) and wide-angle X-ray diffraction (WAXD). The surface morphology, pore size and pore size distribution of TFNC membranes were determined by SEM images and molecular weight cut-off (MWCO) methods. An oil/water emulsion, a model of bilge water, was used as the feed solution, and the permeation flux and rejection ratio of the membranes were investigated. TFNC membranes based on the cellulose-chitin blend exhibited 10 times higher permeation flux when compared with a commercial UF membrane (PAN10, Sepro) with a similar rejection ratio after filtration over a time period of up to 100 h, implying the practical feasibility of such membranes for UF applications.

  20. Bioelectrodes based on pseudocapacitive cellulose/polypyrrole composite improve performance of biofuel cell.

    PubMed

    Kizling, Michal; Stolarczyk, Krzysztof; Tammela, Petter; Wang, Zhaohui; Nyholm, Leif; Golimowski, Jerzy; Bilewicz, Renata

    2016-12-01

    Enzymatic electrodes with high internal capacitance, based on cellulose/polypyrrole composite were optimized and utilized to design improved enzymatic fuel cell. Fructose dehydrogenase Gluconobacter sp. specifically adsorbed on the cellulose/polypyrrole matrix and electrophoretically immobilized and electrochemically entrapped Laccase Trametes versicolor, were used as the anode and cathode bioelectrocatalysts, respectively. The cellulose/polypyrrole composite film exhibited pseudocapacitive properties under mild pH conditions. Following modification with carboxylic groups the composite material enabled highly efficient adsorption of enzyme and provided good electrical contact between the enzymatic active sites and the electrode surface. The modified cellulose/polypyrrole composite based electrode was used for the anode leading to mediatorless fructose oxidation giving large catalytic current density, 12.8mAcm(-2). Laccase and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) as the mediator entrapped in the cellulose/polypyrrole composite film generated dioxygen reduction current density of 2mAcm(-2). Application of pseudocapacitive matrix and decreasing the distance between electrodes to 1mm lead to improvement of the biofuel cell power output and its regeneration ability. The power of the cell was found to increase by introduction of a preconditioning step during which the cell was kept at open circuit voltage under fuel flow. After 24h of preconditioning the matrix was recharged and the device output reached the power, 2.1mWcm(-2) and OCV, 0.59V. PMID:26936112

  1. Cellulose oligomers production and separation for the synthesis of new fully bio-based amphiphilic compounds.

    PubMed

    Billès, Elise; Onwukamike, Kelechukwu N; Coma, Véronique; Grelier, Stéphane; Peruch, Frédéric

    2016-12-10

    Cellulose oligomers are water-soluble, on the contrary to cellulose, which greatly increase their application range. In this study, cellulose oligomers were obtained from the acidic hydrolysis of cellulose with phosphoric acid. The global yield in water-soluble oligomers was around 23% with polymerization degree (DP) ranging from 1 to 12. The cellulose oligomers DP distribution was successfully reduced by differential solubilisation in methanol as one of the goals of this work was to avoid the use of a time-consuming full chromatographic separation. The methanol-soluble oligomers were mainly low DP (≤3). The oligomers of higher molar mass, composed of 42% of cellotetraose and 36% of cellopentaose, were then functionalized and coupled with stearic acid through azide-alkyne click chemistry to obtain amphiphilic compounds. The self-assembly of these new bio-based compounds was finally investigated by dynamic light scattering (DLS) and transmission electron microscopy (TEM) and their critical micellar concentration (CMC) was found to be in the same range as alkylmaltosides and alkylglucosides. PMID:27577903

  2. Integrated Gas Sensing System of SWCNT and Cellulose Polymer Concentrator for Benzene, Toluene, and Xylenes

    PubMed Central

    Im, Jisun; Sterner, Elizabeth S.; Swager, Timothy M.

    2016-01-01

    An integrated cellulose polymer concentrator/single-walled carbon nanotube (SWCNT) sensing system is demonstrated to detect benzene, toluene, and xylenes (BTX) vapors. The sensing system consists of functionalized cellulose as a selective concentrator disposed directly on top of a conductive SWCNT sensing layer. Functionalized cellulose concentrator (top layer) selectively adsorbs the target analyte and delivers the concentrated analyte as near as possible to the SWCNT sensing layer (bottom layer), which enables the simultaneous concentrating and sensing within a few seconds. The selectivity can be achieved by functionalizing cellulose acetate with a pentafluorophenylacetyl selector that interacts strongly with the target BTX analytes. A new design of the integrated cellulose concentrator/SWCNT sensing system allows high sensitivity with limits of detection for benzene, toluene, and m-xylene vapors of 55 ppm, 19 ppm, and 14 ppm, respectively, selectivity, and fast responses (<10 s to reach equilibrium), exhibiting the potential ability for on-site, real-time sensing applications. The sensing mechanism involves the selective adsorption of analytes in the concentrator film, which in turn mediates changes in the electronic potentials at the polymer-SWCNT interface and potentially changes in the tunneling barriers between nanotubes. PMID:26848660

  3. Multivalent Anchoring and Oriented Display of Single-Domain Antibodies on Cellulose

    PubMed Central

    Hussack, Greg; Luo, Yan; Veldhuis, Linda; Hall, J. Christopher; Tanha, Jamshid; MacKenzie, Roger

    2009-01-01

    Antibody engineering has allowed for the rapid generation of binding agents against virtually any antigen of interest, predominantly for therapeutic applications. Considerably less attention has been given to the development of diagnostic reagents and biosensors using engineered antibodies. Recently, we produced a novel pentavalent bispecific antibody (i.e., decabody) by pentamerizing two single-domain antibodies (sdAbs) through the verotoxin B subunit (VTB) and found both fusion partners to be functional. Using a similar approach, we have engineered a bispecific pentameric fusion protein consisting of five sdAbs and five cellulose-binding modules (CBMs) linked via VTB. To find an optimal design format, we constructed six bispecific pentamers consisting of three different CBMs, fused to the Staphylococcus aureus-specific human sdAb HVHP428, in both orientations. One bispecific pentamer, containing an N-terminal CBM9 and C-terminal HVHP428, was soluble, non-aggregating, and did not degrade upon storage at 4 °C for over six months. This molecule was dually functional as it bound to cellulose-based filters as well as S. aureus cells. When impregnated in cellulose filters, the bispecific pentamer recognized S. aureus cells in a flow-through detection assay. The ability of pentamerized CBMs to bind cellulose may form the basis of an immobilization platform for multivalent display of high-avidity binding reagents on cellulosic filters for sensing of pathogens, biomarkers and environmental pollutants. PMID:22346702

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

    PubMed

    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

  5. The effect of chitosan concentration on the electrical property of chitosan-blended cellulose electroactive paper

    NASA Astrophysics Data System (ADS)

    Jang, Sang-Dong; Kim, Joo-Hyung; Zhijiang, Cai; Kim, Jaehwan

    2009-01-01

    We studied the effect of chitosan blending on the electrical property of chitosan-blended cellulose electroactive paper (EAPap) under different humidity conditions. As the chitosan blending ratio increased, the real part of the dielectric constant of chitosan-blended cellulose EAPap increased while the dielectric loss factor decreased. From the curve fitting of the measured data using an electrode polarization model, it was found that increasing the chitosan ratio in the EAPap might promote a decrease in the relaxation time of the EAPap, resulting in an increase of the ion mobility and dc conductivity. Over 30% of the chitosan blending ratio, a gradual increment of the ion mobility of the EAPap was observed at 40% relative humidity, while a quadratic increment of the mobility was found at 60% relative humidity condition. This kind of ion-mobility-enhanced cellulose EAPap can be used not only for bending actuators but also for medical applications such as blood clotting patches.

  6. Synthesis and Characterization of Cellulose-Based Hydrogels to Be Used as Gel Electrolytes.

    PubMed

    Navarra, Maria Assunta; Dal Bosco, Chiara; Serra Moreno, Judith; Vitucci, Francesco Maria; Paolone, Annalisa; Panero, Stefania

    2015-01-01

    Cellulose-based hydrogels, obtained by tuned, low-cost synthetic routes, are proposed as convenient gel electrolyte membranes. Hydrogels have been prepared from different types of cellulose by optimized solubilization and crosslinking steps. The obtained gel membranes have been characterized by infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, and mechanical tests in order to investigate the crosslinking occurrence and modifications of cellulose resulting from the synthetic process, morphology of the hydrogels, their thermal stability, and viscoelastic-extensional properties, respectively. Hydrogels liquid uptake capability and ionic conductivity, derived from absorption of aqueous electrolytic solutions, have been evaluated, to assess the successful applicability of the proposed membranes as gel electrolytes for electrochemical devices. To this purpose, the redox behavior of electroactive species entrapped into the hydrogels has been investigated by cyclic voltammetry tests, revealing very high reversibility and ion diffusivity. PMID:26633528

  7. Electrospun and oxidized cellulose materials for environmental remediation of heavy metals in groundwater

    SciTech Connect

    Han, Dong; Halada, Gary P.; Spalding, Brian Patrick; Brooks, Scott C

    2009-12-01

    This chapter focuses on the use of modified cellulosic materials in the field of environmental remediation. Two different chemical methods were involved in fabricating oxidized cellulose (OC), which has shown promise as a metal ion chelator in environmental applications. Electrospinning was utilized to introduce a more porous structure into an oxidized cellulose matrix. FTIR and Raman spectroscopy were used to study both the formation of OC and its surface complexation with metal ions. IR and Raman spectroscopic data demonstrate the formation of characteristic carboxylic groups in the structure of the final products and the successful formation of OC-metal complexes. Subsequent field tests at the Field Research Site at Oak Ridge National Laboratory confirmed the value of OC for sorption of both U and Th ions.

  8. Designing flexible energy and memory storage materials using cellulose modified graphene oxide nanocomposites.

    PubMed

    Kafy, Abdullahil; Sadasivuni, Kishor Kumar; Kim, Hyun-Chan; Akther, Asma; Kim, Jaehwan

    2015-02-28

    The demand for flexible energy storage devices is ever increasing, and several polymer nanocomposites are widely used to fabricate them. Here, we present a cellulose based nanocomposite by incorporating graphene oxide (GO) nanoplatelets modified with hexamethylene diisocyanate grafting agent useful for such versatile applications. The simple method of casting/solvent evaporation is applied to prepare the nanocomposites and GO dispersion in the cellulose matrix was analyzed by Fourier transform infrared spectroscopy, X-ray diffraction studies and scanning electron microscopy. The dielectric and ferroelectric properties of the eco-friendly samples were checked with temperature and voltage variations, which can attribute to flexible energy and memory storage properties. Thus, the cellulose modified GO nanocomposite has turned to be environmentally stable and excellent next generation material for energy storage and electronic devices. PMID:25634070

  9. Haptic device development based on electro static force of cellulose electro active paper

    NASA Astrophysics Data System (ADS)

    Yun, Gyu-young; Kim, Sang-Youn; Jang, Sang-Dong; Kim, Dong-Gu; Kim, Jaehwan

    2011-04-01

    Haptic is one of well-considered device which is suitable for demanding virtual reality applications such as medical equipment, mobile devices, the online marketing and so on. Nowadays, many of concepts for haptic devices have been suggested to meet the demand of industries. Cellulose has received much attention as an emerging smart material, named as electro-active paper (EAPap). The EAPap is attractive for mobile haptic devices due to its unique characteristics in terms of low actuation power, suitability for thin devices and transparency. In this paper, we suggest a new concept of haptic actuator with the use of cellulose EAPap. Its performance is evaluated depending on various actuation conditions. As a result, cellulose electrostatic force actuator shows a large output displacement and fast response, which is suitable for mobile haptic devices.

  10. Response of Cellulose detectors to different doses of 62 MeV protons

    NASA Astrophysics Data System (ADS)

    Tripathy, S. P.; Mishra, R.; Dwivedi, K. K.; Ghosh, S.; Fink, D.; Khathing, D. T.

    2003-08-01

    Optical and thermal responses of two cellulose detectors, Cellulose triacetate (Triafol-TN) and Cellulose acetate butyrate (Triafol-BN), to four different doses of 62 MeV protons were studied using spectroscopic, thermal and track-etching techniques. The spectroscopic analysis revealed that though the optical band-gap in the polymers was affected by proton irradiation, the polymers showed high resistance against any major structural modification by radiation. The thermal stability of the polymers was found to be affected by proton irradiation. The activation energy of etching was found to be almost constant for both the polymers even after irradiation. It is hoped that the findings in this work would be of significant relevance to material science and applications of polymers.

  11. Native Cellulose Microfiber-Based Hybrid Piezoelectric Generator for Mechanical Energy Harvesting Utility.

    PubMed

    Alam, Md Mehebub; Mandal, Dipankar

    2016-01-27

    A flexible hybrid piezoelectric generator (HPG) based on native cellulose microfiber (NCMF) and polydimethylsiloxane (PDMS) with multi wall carbon nanotubes (MWCNTs) as conducting filler is presented where the further chemical treatment of the cellulose and traditional electrical poling steps for piezoelectric voltage generation is avoided. It delivers a high electrical throughput that is an open circuit voltage of ∼30 V and power density ∼9.0 μW/cm(3) under repeated hand punching. We demonstrate to power up various portable electronic units by HPG. Because cellulose is a biocompatible material, suggesting that HPG may have greater potential in biomedical applications such as implantable power source in human body. PMID:26760435

  12. Isolation and characterization of microcrystalline cellulose from oil palm biomass residue.

    PubMed

    Mohamad Haafiz, M K; Eichhorn, S J; Hassan, Azman; Jawaid, M

    2013-04-01

    In this work, we successfully isolated microcrystalline cellulose (MCC) from oil palm empty fruit bunch (OPEFB) fiber-total chlorine free (TCF) pulp using acid hydrolysis method. TCF pulp bleaching carried out using an oxygen-ozone-hydrogen peroxide bleaching sequence. Fourier transform infrared (FT-IR) spectroscopy indicates that acid hydrolysis does not affect the chemical structure of the cellulosic fragments. The morphology of the hydrolyzed MCC was investigated using scanning electron microscopy (SEM), showing a compact structure and a rough surface. Furthermore, atomic force microscopy (AFM) image of the surface indicates the presence of spherical features. X-ray diffraction (XRD) shows that the MCC produced is a cellulose-I polymorph, with 87% crystallinity. The MCC obtained from OPEFB-pulp is shown to have a good thermal stability. The potential for a range of applications such as green nano biocomposites reinforced with this form of MCC and pharmaceutical tableting material is discussed. PMID:23499105

  13. Synthesis and Characterization of Cellulose-Based Hydrogels to Be Used as Gel Electrolytes

    PubMed Central

    Navarra, Maria Assunta; Dal Bosco, Chiara; Serra Moreno, Judith; Vitucci, Francesco Maria; Paolone, Annalisa; Panero, Stefania

    2015-01-01

    Cellulose-based hydrogels, obtained by tuned, low-cost synthetic routes, are proposed as convenient gel electrolyte membranes. Hydrogels have been prepared from different types of cellulose by optimized solubilization and crosslinking steps. The obtained gel membranes have been characterized by infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, and mechanical tests in order to investigate the crosslinking occurrence and modifications of cellulose resulting from the synthetic process, morphology of the hydrogels, their thermal stability, and viscoelastic-extensional properties, respectively. Hydrogels liquid uptake capability and ionic conductivity, derived from absorption of aqueous electrolytic solutions, have been evaluated, to assess the successful applicability of the proposed membranes as gel electrolytes for electrochemical devices. To this purpose, the redox behavior of electroactive species entrapped into the hydrogels has been investigated by cyclic voltammetry tests, revealing very high reversibility and ion diffusivity. PMID:26633528

  14. Processing and characterization of polyols plasticized-starch reinforced with microcrystalline cellulose.

    PubMed

    Rico, M; Rodríguez-Llamazares, S; Barral, L; Bouza, R; Montero, B

    2016-09-20

    Biocomposites suitable for short-life applications such as food packaging were prepared by melt processing and investigated. Biocomposites studied are wheat starch plasticized with two different molecular weight polyols (glycerol and sorbitol) and reinforced with various amounts of microcrystalline cellulose. The effect of the plasticizer type and the filler amount on the processing properties, the crystallization behavior and morphology developed for the materials, and the influence on thermal stability, dynamic mechanical properties and water absorption behavior were investigated. Addition of microcrystalline cellulose led to composites with good filler-matrix adhesion where the stiffness and resistance to humidity absorption were improved. The use of sorbitol as a plasticizer of starch also improved the stiffness and water uptake behavior of the material as well as its thermal stability. Biodegradable starch-based materials with a wide variety of properties can be tailored by varying the polyol plasticizer type and/or by adding microcrystalline cellulose filler. PMID:27261733

  15. Revalorization of sunflower stalks as novel sources of cellulose nanofibrils and nanocrystals and their effect on wheat gluten bionanocomposite properties.

    PubMed

    Fortunati, E; Luzi, F; Jiménez, A; Gopakumar, D A; Puglia, D; Thomas, S; Kenny, J M; Chiralt, A; Torre, L

    2016-09-20

    Novel gluten based bionanocomposites reinforced with cellulose nanofibrils (CNF) and cellulose nanocrystals (CNC) extracted from sunflower stalks by respectively a steam explosion treatment and a hydrolysis procedure, were prepared by casting/evaporation. The extracted cellulose nanomaterials, both CNC and CNF, were embedded in gluten matrix and their effect was investigated. Morphological investigations highlighted that gluten based bionanocomposites showed a homogenous morphology, the absence of visible cellulose nanoreinforcements, and the presence of holes for Gluten_CNF nanocomposites. Gluten_CNF showed a reduction of water vapour permeability coefficients but the values are higher respect to gluten reinforced with CNC. This behaviour could be related to the ability of CNC to increase the tortuous path of gas molecules. Moreover, the results from thermal, mechanical and barrier properties confirmed the strong interactions obtained between CNC and gluten matrix during the process. The study suggested the possibility to re-valorise agricultural wastes with potential applications as reinforcement in polymer matrix bionanocomposites. PMID:27261760

  16. Prospects for Irradiation in Cellulosic Ethanol Production

    PubMed Central

    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

  17. Magnetic alignment and patterning of cellulose fibers

    NASA Astrophysics Data System (ADS)

    Kimura, Fumiko; Kimura, Tsunehisa

    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.

  18. Bacterial cellulose membrane as separation medium

    SciTech Connect

    Shibazaki, Hideki; Kuga, Shigenori; Onabe, Fumihiko; Usuda, Makoto . Faculty of Agriculture)

    1993-11-10

    A thin membrane of bacterial cellulose (BC) obtained from Acetobacter culture was tested for its performance as a dialysis membrane in aqueous systems. The BC membrane showed superior mechanical strength to that of a dialysis-grade regenerated cellulose membrane, allowing the use of a thinner membrane than the latter. As a result, the BC membrane gave higher permeation rates for poly(ethylene glycols) as probe solutes. The cutoff molecular weight of the original BC membrane, significantly greater than that of regenerated cellulose, could be modified by concentrated alkali treatments of the membrane. The nature of the change at the ultrastructural level caused by the alkali treatments was studied by X-ray diffraction and scanning electron microscopy.

  19. Chemical genetics to examine cellulose biosynthesis

    PubMed Central

    Brabham, Chad; DeBolt, Seth

    2013-01-01

    Long-term efforts to decode plant cellulose biosynthesis via molecular genetics and biochemical strategies are being enhanced by the ever-expanding scale of omics technologies. An alternative approach to consider are the prospects for inducing change in plant metabolism using exogenously supplied chemical ligands. Cellulose biosynthesis inhibitors (CBIs) have been identified among known herbicides, during diverse combinatorial chemical libraries screens, and natural chemical screens from microbial agents. In this review, we summarize the current knowledge of the inhibitory effects of CBIs and further group them by how they influence fluorescently tagged cellulose synthase A proteins. Additional attention is paid to the continuing development of the CBI toolbox to explore the cell biology and genetic mechanisms underpinning effector molecule activity. PMID:23372572

  20. Orientation of cellulose nanowhiskers in polyvinyl alcohol

    NASA Astrophysics Data System (ADS)

    Kvien, I.; Oksman, K.

    2007-06-01

    The goal of this study was to align cellulose nanowhiskers in a polymer using a strong magnetic field and thereby obtain a unidirectional reinforced nanocomposite. Cellulose whiskers (2 wt. %) were incorporated in a polyvinyl alcohol matrix using solution casting with water as the solvent. The suspension was cast and the water was evaporated while a homogeneous magnetic field of 7 T was applied. Different microscopy investigations of prepared nanocomposites indicated that the cellulose whiskers were oriented perpendicular to the direction of the magnetic field. Dynamic mechanical thermal analysis further strengthened the idea of alignment because the results showed that the dynamic modulus of the nanocomposite was around 2 GPa higher at room temperature in the aligned direction compared to the transverse direction.