Different Forms Of Cellulose Research Articles

Biochemical characterization of xylanase GH11 isolated from Aspergillus niger BCC14405 (XylB) and its application in xylooligosaccharide production.

To develop an endo-β-1,4-xylanase with high specificity for production of prebiotic xylooligosaccharides that optimally works at moderate temperature desirable to reduce the energy cost in the production process. The xylB gene, encoding for a glycosyl hydrolase family 11 xylanase from a thermoresistant fungus, Aspergillus niger BCC14405 was expressed in a methylotrophic yeast P. pastoris KM71 in a secreted form. The recombinant XylB showed a high specific activity of 3852 and 169 Umg-1 protein on beechwood xylan and arabinoxylan, respectively with no detectable side activities against different forms of cellulose (Avicel Ò PH101 microcrystalline cellulose, phosphoric acid swollen cellulose and carboxymethylcellulose). The enzyme worked optimally at 45°C, pH 6.0. It showed a specific cleavage pattern by releasing xylobiose (X2) as the major product from xylooligosaccharides (X3 to X6) substrates. The highest XOS yield of 708mgg-1 substrate comprising X2, X3 and X6 was obtained from beechwood xylan hydrolysis. The enzyme is potent for XOS production and for saccharification of lignocellulosic biomass.

Cellulose‐based Supercapacitors: Material and Performance Considerations

One of the biggest challenges we will face over the next few decades is finding a way to power the future while maintaining strong socioeconomic growth and a clean environment. A transition from the use of fossil fuels to renewable energy sources is expected. Cellulose, the most abundant natural biopolymer on earth, is a unique, sustainable, functional material with exciting properties: it is low‐cost and has hierarchical fibrous structures, a high surface area, thermal stability, hydrophilicity, biocompatibility, and mechanical flexibility, which makes it ideal for use in sustainable, flexible energy storage devices. This review focuses on energy storage applications involving different forms of cellulose (i.e., cellulose microfibers, nanocellulose fibers, and cellulose nanocrystals) in supercapacitors, with particular emphasis on new trends and performance considerations relevant to these fields. Recent advances and approaches to obtaining high capacity devices are evaluated and the limitations of cellulose‐based systems are discussed. For the first time, a combination of device‐specific factors such as electrode structures, mass loadings, areal capacities, and volumetric properties are taken into account, so as to evaluate and compare the energy storage performance and to better assess the merits of cellulose‐based materials with respect to real applications.

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

The thermochemistry of samples of amorphous cellulose, cellulose I, cellulose II, and cellulose III was studied by using oxygen bomb calorimetry, solution calorimetry in which the solvent was cadoxen (a cadmium ethylenediamine solvent), and with a Physical Property Measurement System (PPMS) in zero magnetic field to measure standard massic heat capacities Cp,w∘ over the temperature range T=(2 to 302)K. The samples used in this study were prepared so as to have different values of crystallinity indexes CI and were characterized by X-ray diffraction, by Karl Fischer moisture determination, and by using gel permeation chromatography to determine the weight average degree of polymerization DPw. NMR measurements on solutions containing the samples dissolved in cadoxen were also performed in an attempt to resolve the issue of the equivalency or non-equivalency of the nuclei in the different forms of cellulose that were dissolved in cadoxen. While large differences in the NMR spectra for the various cellulose samples in cadoxen were not observed, one cannot be absolutely certain that these cellulose samples are chemically equivalent in cadoxen. Equations were derived which allow one to adjust measured property values of cellulose samples having a mass fraction of water wH2O to a reference value of the mass fraction of water wref. The measured thermodynamic properties (standard massic enthalpy of combustion ΔcHw∘, standard massic enthalpy of solution ΔsolHw∘, and Cp,w∘) were used in conjunction with the measured CI values to calculate values of the changes in the standard massic enthalpies of reactionΔrHw∘∗, the standard massic entropies of reaction ΔrSw∘∗, the standard massic Gibbs free energies of reaction ΔrGw∘∗, and the standard massic heat capacity ΔrCp,w∘, for the interconversion reactions of the pure (CI=100) cellulose allomorphs, i.e., cellulose(am), cellulose I(cr), cellulose II(cr), and cellulose II(cr), at the temperature T=298.15K, the pressure p∘=0.1MPa, and wH2O=0.073. The “∗” denotes that the thermodynamic property pertains to pure cellulose allomorphs. Values of standard massic enthalpy differences Δ0THw∘, standard massic entropy differences Δ0TSw∘, and the standard massic thermal function Φw∘=Δ0TSw∘-Δ0THw∘/T were calculated from the measured heat capacities for the cellulose samples and for the pure cellulose allomorphs. The extensive literature pertinent to the thermodynamic properties of cellulose has been summarized and, in many cases, property values have been calculated or recalculated from previously reported data. The thermodynamic property data show that cellulose(am) is the least stable of the cellulose allomorphs considered in this study. However, due to the uncertainties in the measured property values, it is not possible to use these values to order the relative stabilities of the cellulose (I, II, and III) crystalline allomorphs with a reasonable degree of certainty. Nevertheless, based on chemical reactivity information, the qualitative order of stability for these three allomorphs is cellulose III(cr)>cellulose II(cr)>cellulose Iβ(cr) at T=298.15K. However, as evidenced by the fact that cellulose I(cr) can be reformed by the application of heat and water to a sample of cellulose III(cr), the differences in the stabilities of these three allomorphs appear to be small and may be temperature dependent.Standard thermodynamic formation properties as well as property values for the conversion reactions of the cellulose allomorphs to α-d-glucose(cr) have been calculated on the assumption that Sw∘→0 as T→0.The values for the standard massic Gibbs free energy of reactionΔrGw∘ for the conversion of the cellulose allomorphs to α-d-glucose(cr), with the exception of anhydrous cellulose(am), all have positive values and thus are thermodynamically not favored for mass fractions of water wH2O<0.073.

A new method for measuring scouring efficiency of natural fibers based on the cellulose-binding domain-β-glucuronidase fused protein

Cellulose-binding domains (CBDs) are characterized by their ability to strongly bind to different forms of cellulose. This study examined the use of a recombinant CBD fused to the reporter enzyme β-glucuronidase (CBD-GUS) to determine the extent of removal of the water-repellent waxy component of cotton fiber cuticles following hydrolytic treatment, i.e., scouring. The CBD-GUS test displayed higher sensitivity and repeatability than conventional water absorb techniques applied in the textile industry. Increases in the levels of CBD-GUS bound to the exposed cellulose correlated to increases in the fabric’s hydrophilicity as a function of the severity of the scouring treatment applied, clearly indicating that the amount of bound enzyme increases proportionally with the amount of available binding sites. The binding of CBD-GUS also gave measurable and repeatable results when used on untreated or raw fabrics in comparison with conventional water drop techniques. The quantitative response of the reaction as bound enzyme activity was optimized for fully wettable fabrics. A minimal free enzyme concentration-to-swatch weight ratio of 75:1 was found to be necessary to ensure enzyme saturation (i.e., a linear response), corresponding to a free enzyme-to-bound enzyme ratio of at least 3:5.

The role played by microorganisms in the biogenesis of soil cracks: importance of substrate quantity and quality

The development of cracks in soils has a significant effect on important soil processes such as gaseous diffusion, water flow and root development. It is the heterogeneity and tortuosity of the resulting cracks which are important as they influence and control such processes. The microbial contribution to crack formation was therefore assessed by quantifying the heterogeneity and connectivity of cracks which developed following the addition of substrates differing in quantity and quality to a sandy loam soil. The heterogeneity and connectivity of the cracks was assessed using probability and Monte Carlo techniques respectively, which provided an estimate of how the occurrence of cracks varied with sample area and the nature of the route taken by a random walker in such a space. Increasing the amount of glucose added resulted in significantly ( P<0.05) less heterogeneous and less tortuous cracks on subsequent drying of the soil, after the soil had been incubated for 2 weeks at 15°C in a slurried state. The addition of glucose or different forms of cellulose, such as a native pulverised cellulose and a highly crystalline cellulose, generally resulted in significantly ( P<0.05) less heterogeneous and less tortuous cracks than those formed in the absence of a substrate addition. However, the addition of carboxymethylcellulose to soil initially prevented crack formation and after a 5 or 15 day incubation period resulted in the formation of cracks which were significantly ( P<0.05) more heterogeneous than those generated by unamended soil after equivalent incubation periods. Soil amended with glucose, a water soluble source of carbon, resulted in the formation of cracks which were significantly ( P<0.05) less heterogeneous and less tortuous than those generated in soil amended with either pulverised native cellulose or highly crystalline cellulose, both of which are water insoluble sources of carbon. The extent of the heterogeneity or connectivity of the cracks was shown to depend on the recalcitrance of the substrate and the incubation period before the soil slurries were allowed to dry and crack. Microorganisms were thus shown to contribute to the formation of cracks, as well as hindering crack formation, highlighting a dual role as potential degraders, as well as producers, of soil binding agents.

Combustion demonstration using updated flame tornado

The combustion reaction is a significant topic of discussion in general chemistry, organic chemistry, and laboratory safety components of most high school and undergraduate chemistry curricula. This demonstration uses the combustion of different forms of cellulose and an updated version of the "flame tornado" as an ignition source to illustrate the factors affecting the combustion process. The objectives of the experiment are (i) to illustrate the factors affecting the rate of a combustion reaction and (ii) to demonstrate the factors affecting the production of a flame by using the flame tornado. The demonstration is utilized in an inquiry-based approach for asking students how nitrocellulose can be ignited if placed approximately one meter over a flame. The demonstration is safe, inexpensive, and gives reproducible results.

A simultaneous TG-DTA study of the degradation in nitrogen of cellulose to carbon, alone and in the presence of other pharmaceutical excipients

The heat treatment of an α-cellulose and a microcrystalline cellulose (Avicel ®) in nitrogen gives a one-stage degradation to carbon. This degradation suffers a temperature transposition in the presence of pharmaceutical excipients, namely dibasic calcium phosphate, stearic acid, magnesium stearate, and silicon dioxide. It is possible to produce a kinetic evaluation of these thermal analysis studies in terms of a comparative method by constructing the theoretical TG trace of the binary mixture based on a presumed no-interaction between the two components. There is a variation in behavior to be noted in the different forms of cellulose, and also different values are shown for the Arrhenius parameters. Such variations are also noted in the Avicel ® degradation in the presence of other materials. These observations should be of use in the characterization of pharmaceutical excipients. The Arrhenius parameters for α-cellulose degradation using D3 (three-dimensional diffusion) mechanism at the temperature range from 580 to 630 K are 289.32 kJ mol −1 and 1.85×10 23 for E act and A, respectively. The Arrhenius parameters for Avicel ® degradation using F1 (first-order) mechanism at the temperature range from 562 to 604 K are 291.35 kJ mol −1 and 1.26×10 25 for E act and A, respectively.

Cellulose microfibrils, cell motility, and plasma membrane protein organization change in parallel during culmination in Dictyostelium discoideum.

Prestalk cells of Dictyostelium discoideum contribute cellulose to two distinct structures, the stalk tube and the stalk cell wall, during culmination. This paper demonstrates by freeze fracture electron microscopy that two distinct types of intramembrane particle aggregates, which can be characterized as cellulose microfibril terminal complexes, occur in the plasma membranes of cells synthesizing these different forms of cellulose. The same terminal complexes were observed in situ in developing culminants and in vitro in monolayer cells induced to synthesize the two types of cellulose. We propose that cessation of cell motility is associated with a change in packing and intramembrane mobility of the particle aggregates, which cause a change in the nature of the cellulose synthesized. The terminal complexes are compared to those described in other organisms and related to the previous hypothesis of two modes of cellulose synthesis in Dictyostelium.

Microcrystalline forms of cellulose as substrates for strains of clostridium thermocellum and cellulase formation

Clostridium thermocellum strains ATCC 27405, NCIB 10682 and LQR1 have been examined for saccharification of different forms of cellulose and their ability to produce cellulase. Strain ATCC 27405 was the most effective in metabolising Avicel, filter paper and cellulose CF11 (the most resistant substrate). Strain LQR1 was the least effective, strain NCIB 10682 had an intermediate activity. All strains metabolised cellobiose rapidly but produced a deficient cell-free cellulase, with up to half the potency of that from cellulose-grown cultures. Strains NCIB 10682 and LQR1 secreted three-fold more β-glucosidase than strain ATCC 27405, which however secreted the best cellulase, itself not necessarily related to maximum CM-cellulase activity. Strain ATCC 27405 grown in media MJ, GS-2 or DSM indicated medium MJ produced the most active and stable cellulase over 120 h growth; medium GS-2 produced cellulase more rapidly, of the same activity but of less stability; medium DSM gave cellulase most rapidly, but of lower activity and even greater instability, but accompanied by a 30% conversion of the initial cellulose to sugar.

The nature of the cellulose-binding domain effects the activities of a bacterial endoglucanase on different forms of cellulose

The cellulose-binding domain (CBDCenC) of endoglucanase C (CenC) from Cellulomonas fimi binds to amorphous (phosphoric acid-swollen) cellulose (PASC) but not to bacterial microcrystalline cellulose (BMCC), whereas that of endoglucanase A (CBDCenA) binds to both forms of cellulose. Substitution of CBDCenC for CBDCenA in endoglucanase A (CenA) affects the activity of the enzyme on different forms of cellulose. The hybrid enzyme (CenC″A) is less active than CenA on BMCC and Avicel. The two forms of the enzyme have similar activity on PASC. CenC″A is more active than CenA on cellulose azure and carboxymethyl cellulose. CenC″A binds to phosphoric acid-swollen cellulose but not to crystalline cellulose. The hybrid enzyme is less sensitive than CenA to C. fimi protease, probably as a consequence of replacement of the prolyl-threonyl linker of CenA by a triprolyl linker from CenC.

The nature of the cellulose-binding domain effects the activities of a bacterial endoglucanase on different forms of cellulose

The cellulose-binding domain (CBDCenC) of endoglucanase C (CenC) from Cellulomonas fimi binds to amorphous (phosphoric acid-swollen) cellulose (PASC) but not to bacterial microcrystalline cellulose (BMCC), whereas that of endoglucanase A (CBDCenA) binds to both forms of cellulose. Substitution of CBDCenC for CBDCenA in endoglucanase A (CenA) affects the activity of the enzyme on different forms of cellulose. The hybrid enzyme (CenC″A) is less active than CenA on BMCC and Avicel. The two forms of the enzyme have similar activity on PASC. CenC″A is more active than CenA on cellulose azure and carboxymethyl cellulose. CenC″A binds to phosphoric acid-swollen cellulose but not to crystalline cellulose. The hybrid enzyme is less sensitive than CenA to C. fimi protease, probably as a consequence of replacement of the prolyl-threonyl linker of CenA by a triprolyl linker from CenC.

Thermal degradation of cellulose in nitrogen

AbstractThe thermal degradation of four different forms of cellulose in nitrogen has been studied by using a thermobalance. In TG experiments a total weight loss at 900°C was 80% in the cases of film and pulp samples and 83% for two powder forms. The results for the isothermal degradation of the four samples at 270°C are plotted as degree of degradation α against reduced time t/t0.5 and compared with the master plots of Sharp, Brindley, and Achar. The experimental data fit most closely the plot for the Avrami‐Erofeev equation in the form kt = {–ln (1–α)}1/n where n = 2. An activation energy of 144 kJ/mole has been found for the degradation of one of the celluloses from the results of isothermal runs at six different temperatures. It is postulated here that the thermal degradation occurs by random nucleation and nucleus growth in the cellulose fibrils so as to yield a carbon whose microporous structure is a replica of the pore system in the parent cellulose.

Significance of the crystal structure of cellulose in the production and action of cellulase

Trichoderma viride grown on synthetic medium containing the various crystal modifications of cellulose formed enzymes which were preferentially capable of solubilizing the homologous forms. The enzymic dissolution of crystalline cellulose I and II was in accordance with the Schutz law, whereas that of II IV followed second-order kinetics. The dissolution of crystalline cellulose IV followed no recognizable reaction order. The different forms of cellulose varied from each other in their growth-supporting, -inducing, and -reacting capabilities. The enzymes induced on various cellulose forms were also different in their thermostability, and the rates of inactivation were dependent on the type of substrate used in the assay. Activation energy measurements for different enzyme-substrate combinations showed that different, enzyme systems were induced in the presence of different crystal forms and that crystal structure was a significant determinant of the effectiveness of cellulase systems. X-ray diffraction studies showed that the crystal structure as well as the crystallinity of various forms of cellulose remained largely unchanged during their dissolution. An electron-microscopic study indicated that enzymic degradation of cellulose involved fragmentation which appeared to be initiated by the formation of longitudinal fissures.

Cellulolytic preparations from micro-organisms of the rumen and from Myrothecium verrucaria.

SUMMARY: A study has been made of the degradation of different forms of cellulose (‘eellulolysis’), comprising soluble substituted derivatives (carboxymethyl-cellulose), insoluble cellulose powder, swollen cellulose, hydrocellulose and native cotton fibres, by concentrated suspensions of mixed rumen micro-organisms and by the aerobic fungus Myrothecium verrucaria. Mixed rumen micro-organisms are shown to be one of the most powerful sources of cellulolytic enzyme, in that they produce almost complete solubilization of all the above forms of cellulose in a relatively short period (3 days). Enrichment cultures of rumen micro-organisms were prepared by growing concentrates of mixed micro-organisms on cellulose powder. Cellulolysis was followed by determining the cellulose disappearance, formation of cellulolytic activity and gas evolution. Freeze-dried powders and their derived acetone powders obtained from washed concentrated supensions (non-enrichment cultures) of mixed rumen micro-organisms solubilized up to 80% of insoluble cellulose powder. Cell-free extracts were isolated: (a) from concentrated suspensions and from freeze-dried powders of rumen micro-organisms by extraction with butanol; (b) from concentrated suspensions of enrichment cultures by grinding with alumina at low temperature. The butanol extracts solubilized cellulose powder to a small extent (10% solubilization) and were more effective against the soluble carboxymethyl-cellulose. In contrast, the alumina extracts were more active against insoluble cellulose (30% solubilization) but were only weakly active against carboxymethyl-cellulose. Cell-free filtrates from Myrothecium verrucaria, an aerobic fungus much used in work on cellulose metabolism, were shown to possess cellulolytic properties very similar to those of alumina extracts from enrichment cultures of rumen micro-organisms. The significance of the results is discussed in relation to the mode of breakdown of cellulose.

A NEW TYPE OF CELLULOSE ETHER: THE PREPARATION AND PROPERTIES OF THE ω-(p-AMINOACETOPHENONE) ETHER OF CELLULOSE

With the object of preparing a cellulose ether containing diazotizable amino groups, seven different forms of cellulose, or cellulose derivatives, were treated with 10 different reagents under a variety of conditions. Reasons why only one reagent under one set of conditions gave a product with a substantial degree of substitution (0.35) and with satisfactory physical properties are presented. This resulting ether, the ω-(P-aminoacetophenone) ether of cellulose, was prepared by the reaction between ω-chloro-P-aminoacetophenone and ethanol-washed soda-cellulose (from wood pulp, cotton, paper, or rayon). It can be (a) diazotized and coupled with any of the usual reagents to yield cellulose-azo colors, (b) xanthated, before or after coupling, and spun as rayon filament; if uncoupled at this point it can be diazotized and coupled, (c) dyed directly with acid dyes, (d) rendered organo-soluble by nitration, and (e) carboxymethylated after coupling to yield colored, water-soluble derivatives. It is insoluble in the usual cellulose reagents, and is as stable to acid and alkaline hydrolysis as cellulose.

Hydratation de diverses formes polymorphes de la cellulose

AbstractX‐ray diffraction experiments confirm the data obtained by the blotting or centrifuging method, concerning the action of water which penetrates at different degrees in the regions of cellulose. Different forms of cellulose are more or less easily accessible. X‐rays only show variations of intensity for native cellulose, but the unit cells are changed for lattices II and IIIα; the transformations are still deeper for cellulose IIIβ. X‐ray diffraction does not permit determination of the stoichiometric ratios.

The Parasitism of Botrytis cinerea

Briefly stated, the main point of this article is as follows: In the best known works upon the parasitism of Botrytis and similar fungi too much importance has been ascribed to a cellulose-dissolving enzyme. Two stages in the process should be clearly distinguished: first, a poisoning and killing of the cells; and second, their disintegration and utilization as food by the fungus. The first effect appears to be produced by a substance which there are strong reasons for supposing to be oxalic acid, formed by the fungus as a by-product of its metabolism. Following this, a number of different enzymes are secreted which digest the various constituents of the tissue. The identity of these enzymes probably varies somewhat in different cases, and apparently more than one occurs which affects different forms of cellulose. The substance causing a marked swelling of the cell wall in the lily Botrytis, studied by Ward, and the turnip bacterium by Potter, appears to be an enzyme not ordinarily produced by Botrytis cinerea. In conclusion, it may be remarked that these results have a very suggestive bearing upon the parasitism of many other fungi which bring about a rapid destruction of the host tissue.