NC State
  • Editorialpp 295-296Hubbe, M. A. (2008). "Are lignocellulosic resources too valuable to burn?" BioRes. 3(2), 295-296.AbstractPDF
    Lignocellulosic matter often can be counted as a renewable resource, since it is produced by photosynthesis. But there are limits to how much biomass our society can use in a sustainable manner. People can debate whether or not it makes sense to use a substantial portion of lignocellulosic materials as a source of liquid fuel. This essay gives a qualified affirmative answer to the question in its title. However, combustion of lignocellulosic resources can be considered as wasteful and uneconomical, in the long run, if it is inefficient, if it fails to displace the combustion of fossil fuels, or if it displaces a higher-end use, for which there are available customers. In particular, it seems unlikely that combustion of fuels derived from lignocellulosic biomass can, by itself, solve problems that stem from society’s excessive thirst for motor fuels.
  • Researchpp 297-315Sun, Y., Lin, L., Deng, H., Li, J., He, B., Sun, R., and Ouyang, P. (2008). "Structural changes of bamboo cellulose in formic acid," BioRes. 3(2), 297-315.AbstractPDF
    The structure of cellulose from bamboo fiber before and after treatment in formic acid was investigated in comparison with microcrystalline-cellulose by solid state NMR, FTIR, and X-ray diffraction diagrams. Differences of molecular structures among two kinds of celluloses were validated and expatiated. Results from the experiments indicated notable differences in the crystalline or amorphous region of microcrystalline-cellulose and bamboo fiber. CP-MAS 13C-NMR, and FTIR spectroscopy revealed the presence of Iα and Iβ forms in all of the samples. The effect of acid solution was achieved simultaneously both in the crystalline region and the amorphous region, but there was a more intensive effect on the crystalline region for bamboo fiber. All of the cellulose samples revealed the same chain conformation but a different hydrogen bonding pattern. The absorbency of hydrogen bonds shifted to a high wave number and gradually decreased during treatment. The intermolecular hydrogen bond of 6-OH…O-3′ decreased first, and then increased gradually, which indicated that the cellulose bundled together during hydrolysis.
  • Researchpp 316-334Quintero, O. L., Amicarelli, A. A., di Sciascio, F., and Scaglia, G. (2008). "State estimation in alcoholic continuous fermentation of Zymomonas mobilis using recursive Bayesian filtering: A simulation approach," BioRes. 3(2), 316-334.AbstractPDF
    This work presents a state estimator for a continuous bioprocess. To this aim, the Non Linear Filtering theory based on the recursive application of Bayes rule and Monte Carlo techniques is used. Recursive Bayesian Filters Sampling Importance Resampling (SIR) is employed, including different kinds of resampling. Generally, bio-processes have strong non-linear and non-Gaussian characteristics, and this tool becomes attractive. The estimator behavior and performance are illustrated with the continuous process of alcoholic fermentation of Zymomonas mobilis. Not too many applications with this tool have been reported in the biotechnological area.
  • Researchpp 335-345Giese, E. C., Dekker, R. F. H., and Barbosa, A. M. (2008). "Orange bagasse as substrate for the production of pectinase and laccase by Botryosphaeria rhodina MAMB-05 in submerged and solid state fermentation," BioRes. 3(2), 335-345.AbstractPDF
    Orange bagasse comprising pulp tissues, rind, and seeds, constitutes a major industrial food waste arising from processing oranges for juice, and represents a fermentation feedstock for the production of enzymes. Botryosphaeria rhodina MAMB-05 grown on essential oils-extracted orange bagasse in submerged (SmF) and solid-state fermentation (SSF) with and without added nutrients produced pectinase and laccase. Highest enzyme titres (pectinase, 32 U ml-1; laccase, 46 U ml-1) occurred in SSF without added nutrients, indicating nutrient sufficiency of orange bagasse at a solids concentration of 16 % (w v-1) to sustain growth and high enzyme titres. Orange essential oil extract added to nutrient medium containing 1 % glucose in SmF strongly inhibited fungal growth with consequent lower laccase and pectinase activities. The results demonstrate the need to remove the essential oils fraction before citrus waste can be successfully used as a fermentation substrate for enzyme production.
  • Researchpp 346-362Deka, M., and Petrič, M. (2008). "Photo-degradation of water borne acrylic coated modified and non-modified wood during artificial light exposure," BioRes. 3(2), 346-362.AbstractPDF
    A series of experiments were carried out to investigate photo-degradation of thermally modified (at 210oC and minus 0.9 bars for two hours) and non-modified spruce wood [Picea abies L (Karst)], coated with transparent and semitransparent (with 3% pigment content) acrylic coatings during artificial UV light irradiation for 200 hours. Photo-degradation was evaluated in terms of colour changes throughout the irradiation period at an interval of 50 hours, along with IR and EPR spectroscopic study. One set of modified and non-modified woods was painted with coatings, while the other set was covered with free films made of coatings, just to simulate coated wood. The colour changes for both modified and non-modified wood samples without paint-coat or free film cover were comparable to that of wood samples with paint-coat and free film cover for transparent coat type, which indicated its ineffective-ness to prevent photo-degradation of wood underneath. However, the colour changes for both modified and non-modified wood samples with paint-coat and free film cover were much lower than those of samples without paint-coat or free film cover for semitransparent coat type, which might be due to hindrance of transmission of light energy through pigment to reach the underlying wood surface. On the other hand, whole substrate-coating system showed better photo-stability, when thermally modified wood was used as substrate. However, the colour changes of paint-coated and free-film covered samples for both modified and non modified woods might be due to colour changes of wood specimen underneath, because free films of both the coat types showed negligible colour change during UV irradiation.
  • Researchpp 363-382Xu, C., Su, H., and Cang, D. (2008). "Liquefaction of corn distillers dried grains with solubles (DDGS) in hot-compressed phenol," BioRes. 3(2), 363-382.AbstractPDF
    The present work aims to liquefy corn Distillers Dried Grains with Solubles (DDGS), a by-product in corn ethanol production, to produce liquid products as a potential substitute for petroleum-derived phenol or an additive in the manufacturing of phenolic resins. Efficient liquefaction of DDGS has been realized with hot-compressed phenol at 200-450°C. Effects of liquefaction temperature, initial phenol/DDGS ratio (wt/wt), residence time, and catalysts on yields of liquefaction products, as well as characterizations of typical liquid and solid products, have been investigated. The yield of liquid products increased with temperature, while it peaked at around 300°C, due to condensation/cracking reactions of the liquid intermediates/products to form solid products (i.e., coke/char) at temperatures higher than 300°C. The liquid yield increased monotonically with the initial phenol/DDGS ratio for a specified treatment time and temperature. An increased residence time generally produced a lower yield of liquid products, and a higher yield of solid residue, which was likely due to the increased coke/char formation from liquid products for a prolonged residence time. The yield of liquid products reached a maximum of 97 wt% at 300°C for 5 min-operation with Phenol/DDGS of 2/1. K2CO3, Rb2CO3, and NaOH were found very effective catalysts for enhancing the liquid yields. The use of these catalysts resulted in a 25% relative increase in the liquid yields for 5 minute operation with Phenol/DDGS of 1/1 at 300°C.
  • Researchpp 383-402Ekhtera, M. H., Rezayati Charani, P., Ramezani, O., and Azadfallah, M. (2008). "Effects of poly-aluminum chloride, starch, alum, and rosin on the rosin sizing, strength, and microscopic appearance of paper prepared from old corrugated container (OCC) pulp," BioRes. 3(2), 383-402.AbstractPDF
    The influence of rosin (0.1-0.3%), alum (0.4-0.6%), polyaluminum chloride (0.3-0.7%), and starch (0.5-1.5%) in the making of paper from old corrugated container (OCC) pulp on the freeness, breaking length, tear index, and burst index of pulp and paper sheets was studied. Using a full factorial design to identify the optimum operating conditions, equations relating the dependent variables to the operational variables of the chemical additives were derived that reproduced the former with errors lower than 5%. Using a high starch (1.5%), high PAC (0.7%), low alum (0.4%), and low rosin (0.1%) combination led to pulp that was sufficient to obtain paper with good strength properties (breaking length 5720m; burst index: 3.1 kPam2g-1; tear index: 6.2mNm2/g; Cobb test: 94; fold endurance: 1.52). SEM analysis showed increasing bonding between fibers together at this level of additives. The influence of starch on Cobb test values was not significant.
  • Researchpp 403-424El-Sharkawy, K., Haavisto, S., Koskenhely, K., and Paulapuro, H. (2008). "Effect of fiber flocculation and filling design on refiner loadability and refining characteristics," BioRes. 3(2), 403-424.AbstractPDF
    The loadability of a pulp refiner was studied using refiner data such as gap movement, total power, no-load power, and net refining power. Two different types of pulp and three different types of refiner filling were used in the study. The floc formation and floc size of each pulp was studied in a flow channel simulating filling grooves. The loadability of the pulp refiner was linked to refining effects such as fiber shortening, and internal and external fibrillation. The trapping point of the refiner, and therefore refiner loadability, was found to be more related to fiber characteristics such as fiber length and coarseness, while being less dependent on refining consistency in the range of 2.0-5.5%. The data on the formation of flocs and floc size was used to explain the trapping of fibers between refiner bars and the refiner gap width. Filling design characteristics such as groove width and cutting speed affect the gap width and trapping of flocs inside the refiner. Fillings with high cutting speed tend to break flocs composed of long and short fibers at the same rate and therefore both types of floc maintain the same gap width. On the other hand, wide-groove fillings with lower cutting speed have a gentler effect and the differences in fiber characteristics are easily reflected in the gap width and trapping point. Fillings with low cutting speed have a greater straightening effect than fiber cutting, whereas narrow-bar fillings have a more noticeable effect on fiber cutting, external fibrillation, and fiber swelling.
  • Researchpp 425-436Porankiewicz, B., and Wieloch, G. (2008). "Drill wear during the boring of particle board: A multi-factor analysis including effects of mineral contaminants," BioRes. 3(2), 425-436.AbstractPDF
    This paper evaluates and discusses multifactor non-linear, statistical dependencies of drill side-edges recession VBK and drill diameter recession delta DW on the cutting path length LC, the content of hard mineral contaminants CMC, the size of contaminant particles SMC, and the Mohs hardness MH. Significant influence of the cutting path LC, the content CMC of hard mineral contaminants (HMC), and the size of contaminant particles SMC was found, whereas the Mohs hardness MH of the contamination particles was less important.
  • Researchpp 437-451Brännström, M., Manninen, J., and Oja, J. (2008). "Predicting the strength of sawn wood by tracheid laser scattering," BioRes. 3(2), 437-451.AbstractPDF
    An industrial laser light scattering scanner, designed to detect the spiral grain angle of logs by the light scattering along the grain, was used on two large samples of Norway spruce (Picea abies (var. Karst)) in various sawn dimensions (approximately 750 pieces). Additional measurements were made by other techniques, such as X-ray scanning, resonance frequency measurement, and various manual measurements. The strength properties of the boards were measured by destructive testing in four-point bending according to European standard. Multivariate methods (PLS) were used to model the relationship between the bending strength of the board (MOR) and the measurements. Based only on the output from the simple tracheid scattering equipment, a model for MOR achieved an R² exceeding 0.3. Combinations with average density or outer shape parameters from log scanning resulted in R² 0.4 and 0.3 respectively, although these parameters alone only accounted for R² 0.2. The results can be used to increase the understanding of strength in wood and in an improved industrial strength-grading process.
  • Researchpp 452-460Dawson, L., and Boopathy, R. (2008). "Cellulosic ethanol production from sugarcane bagasse without enzymatic saccharification," BioRes. 3(2), 452-460.AbstractPDF
    Sugarcane processing generates a large volume of bagasse. Disposal of bagasse is critical for both agricultural profitability and environmental protection. Sugarcane bagasse is a renewable resource that can be used to produce ethanol and many other value-added products. In this study, we demonstrate that cane processed bagasse could be used to produce fuel grade ethanol without saccharification. A chemical pre-treatment process using alkaline peroxide and acid hydrolysis was applied to remove lignin, which acts as physical barrier to cellulolytic enzymes. Yeast Saccharomyces cerevisiae ATCC, strain 765, was used in the experiment. The pre-treatment process effectively removed lignin. Ethanol production in the culture sample was monitored using high performance liquid chromatography. The results indicate that ethanol can be made from the sugarcane bagasse.
  • Researchpp 461-476Ni, W., Chen, J., and Xu, Q. (2008). "Synthesis and characterization of hierarchically porous silica with poplar tissue as template with assistance of supercritical CO2," BioRes. 3(2), 461-476.AbstractPDF
    Hierarchically porous silica samples, ranging from mesopores to macropores, were prepared by “nanoscale casting using supercritical (SC) fluids” (NC-SCF) technology and bionics, achieving a biomineralization process in an environmentally friendly and efficient way. These wood-templated SiO2 samples, having special hierarchical pore sizes from 3.3 nm up to 50 μm, were obtained with SC-CO2 precursor solution by a wood-silication method. For this method, the precursor, tetraethyl orthosilicate (TEOS), was dissolved in SC-CO2 and impregnated into poplar tissue cells using SC-CO2 as a mass carrier. After removal of the wood template by calcination in air at suitable temperatures, the porous silica was obtained. The effects of CO2 pressure and precursor concentration on the impregnating ratio were studied, and the products were characterized. SEM experimental results showed that the obtained silica had the same external and internal structures of the original wood. XRD and N2 absorption-desorption results indicated that the silica was amorphous but crystallized with the calcination temperature up to 1000 oC, and had a preferable BET surface area being up to 469 m2/g (600 oC). So this work provides a simple and timesaving route to obtain and control the special microstructure of silica with the aid of a wood template in supercritical CO2.
  • Researchpp 477-490Ander, P., Hildén, L., and Daniel, G. (2008). "Cleavage of softwood kraft pulp fibers by HCl and cellulases," BioRes. 3(2), 477-490.AbstractPDF
    A new pulp fibre testing procedure called the HCl method was used to compare different spruce and pine fibres and mixtures of these fibres to calculate number of fibre cleavages in dislocations and other weak points. This method was compared with treatment of softwood kraft pulp fibres using different cellulase mixtures. The HCl method can distinguish between mill- and laboratory-made softwood kraft pulp fibres from the same wood batch. The sugar release is characterized by xylose and other hemicellulose sugars and little glucose. This is in contrast to cellulases, which despite strong fibre cleavage, did not distinguish between mill- and laboratory-made pulp fibres and released large amounts of glucose from the fibres. Hemicellulose degradation by HCl and deep penetration of the acid into the primary and secondary fibre cell walls at 80°C seems to be of major importance for the differentiation between mill and laboratory pulp fibres. Cellulases, in contrast, act mostly on the fibre surfaces, and deep penetration only takes place in amorphous regions of dislocations.
  • Researchpp 491-502Peters, J., Fischer, K., and Fischer, S. (2008). "Characterization of emissions from thermally modified wood and their reduction by chemical treatment," BioRes. 3(2), 491-502.AbstractPDF
    Thermal treatment is a suitable method for improving the quality of wood types like spruce, beech, or poplar, and thus to open up new fields of application that used to be limited to tropical woods or woods treated with timber preservatives. These thermally treated woods are character-ized by a typical odor caused by degradation products of miscellaneous wood components. The characterization and removal of those odorous substances were investigated using chromatographic and spectroscopic methods. Headspace gas chromatography (GC) in combination with solid-phase microextraction (SPME) was used for a qualitative analysis of volatile wood emissions, and the detectable volatiles were compared before and after solvent extraction. Wood solvent extractives were investigated by means of gas chromatography/mass spectrometry and then evaluated in terms of changes in composition caused by the thermal treatment process.
  • Researchpp 503-516Singh, S. P. (2008). "A comparison of different methods of paper surface smoothness evaluation," BioRes. 3(2), 503-516.AbstractPDF
    Smoothness of paper surface is an important property from its printability. A number of techniques are available for characterizing the topographical features of the paper surface. These techniques have led to the development of smoothness testers of various types such as air-leak testers, optical contact testers, surface profilers, and a number of ink and liquid application apparatus to assess the smoothness. While all these methods are intended to serve the same purpose, they differ so greatly in their basic approach that the agreement between them cannot be taken for granted. In the present work, these methods have been applied to characterize the surface of handsheets of mechanical pulps. A comparison of these methods reveals that different methods grade these pulps differently, confirming the multidimensional nature of the surface structure and the fact that no single method is sufficient to describe it completely.
  • Researchpp 517-537Kocaefe, D., Poncsak, S., and Boluk, Y. (2008). "Effect of thermal treatment on the chemical composition and mechanical properties of birch and aspen," BioRes. 3(2), 517-537.AbstractPDF
    The high temperature treatment of wood is one of the alternatives to chemical treatment. During this process, the wood is heated to higher temperatures than those of conventional drying. The wood structure changes due to decomposition of hemicelluloses, ramification of lignin, and crystallization of cellulose. The wood becomes less hygroscopic. These changes improve the dimensional stability of wood, increase its resistance to micro-organisms, darken its color, and modify its hardness. However, wood also might loose some of its elasticity. Consequently, the heat treatment conditions have to be optimized. Therefore, it is important to understand the transformation of the chemical structure of wood caused by the treatment. In this study, the modification of the surface composition of the wood was followed with Fourier transform infrared spectroscopy (FTIR) and inverse gas chromatography (IGC) under different experimental conditions. The effect of maximum treatment temperatures on the chemical composition of Canadian birch and aspen as well as the correlations between their chemical transformation and different mechanical properties are presented. FTIR analysis results showed that the heat treatment affected the chemical composition of birch more compared to that of aspen. The results of IGC tests illustrated that the surfaces of the aspen and birch became more basic with heat treatment. The mechanical properties were affected by degradation of hemicellulose, ramification of lignin and cellulose crystallization.
  • Researchpp 538-548Nada, A. M. A., Kassem, N. F., and Mohamed, S. H. (2008). "Characterization and properties of ion exchangers produced from lignin precipitated after peroxyacid pulping," BioRes. 3(2), 538-548.AbstractPDF
    Pulping of bagasse by one-stage and three-stage peroxyacetic acid was carried out. Characterization of the precipitated lignin from the waste liquor of the pulping process was studied using infrared spec-troscopy. Comparison between the molecular structure of peroxyacid lignin and kraft lignin was investigated. Different lignins were applied to phosphorylation reaction. The sodium binding capacity and metal ions absorption by these lignins were taken into consideration. Infrared spectroscopy of the produced phosphorylated lignin was investigated. The peroxyacid lignin was found to have lower OH, higher COOH, a higher level of phosphate groups, and a higher binding capacity for sodium compared to kraft lignin.
  • Researchpp 549-565Mattinen, M.-L., Suortti, T., Gosselink, R., Argyropoulos, D. S., Evtuguin, D., Suurnäkki, A., de Jong, E., and Tamminen, T. (2008). "Polymerization of different lignins by laccase," BioRes. 3(2), 549-565.AbstractPDF
    In this study the oxidative polymerization of different lignins, i.e. Flax Soda lignin, Spruce EMAL, and Eucalyptus Dioxane lignin by Trametes hirsuta laccase was compared. Initially the structures of the different lignins were compared by Fourier transform infrared spectroscopy. The reactivity of laccase with the different types of lignins in the absence of mediators was examined and verified by oxygen consumption measurements. The molecular weight distributions of treated and untreated lignins were determined by two different size exclusion chromatography methods. Furthermore, the potential of matrix-assisted laser desorption/ionisation-time of flight-mass spectroscopy for determination of the absolute molecular weights of the different lignins was evaluated. The data showed that all the technical lignins could be activated and polymerized by laccase to different degrees. The efficiency as indicated by measurements of the degree of polymerization was found to increase in the order of Spruce EMAL < Eucalyptus Dioxane lignin < Flax Soda lignin. Overall, this data supplies foundations for using enzymes more efficiently in the enzymatic upgrading of lignin.
  • Researchpp 566-575Khambalkar, V. P., Karale, D. S., Gadge, S. R., and Dahatonde, S. B. (2008). "Assessment of bioresources potential of a rural village for self energy generation," BioRes. 3(2), 566-575.AbstractPDF
    The present research work assesses the bioenergy available in a rural village for self-sustainable development. The biomass consumption of the village for domestic as well as for all the activities has been collected. The study also entailed the collection of all bioenergy sources available in the village. The bioenergy sources, such as biomass available through forestry, agriculture waste and residues etc., and animal waste (animal dung), have been collected for the exact quantification of the bioenergy generation capacity of the village. From the study it has been found that the village has considerable bioenergy potential. The magnitude of the bioenergy density will help in achieving a self power-generating village. The bioenergy density will also help for the development of a bioenergy atlas for the particular location. A suitable renewable energy generation system in the studied village is being recommended.
  • Reviewpp 576-601Liebert, T., and Heinze, T. (2008). "Interaction of ionic liquids with polysaccharides. 5. Solvents and reaction media for the modification of cellulose," BioRes. 3(2), 576-601.AbstractPDF
    The use of ionic liquids (ILs) in the field of cellulose chemistry opens up a broad variety of new opportunities. Besides the regeneration of the biopolymer to fibers, films, and beads, this new class of cellulose solvents is particularly useful for the homogeneous chemical modification of the polysaccharide. In this review, the potential of ILs as a reaction medium for the homogeneous cellulose functionalization is discussed. It is shown that numerous conversions proceed very efficiently and the ILs may be recycled. But it is also demonstrated that some side reactions have to be considered.
  • Reviewpp 602-626Frybort, S., Mauritz, R., Teischinger, A., and Müller, U. (2008). "Cement bonded composites - A mechanical review," BioRes. 3(2), 602-626.AbstractPDF
    Over the last years promising cement bonded wood composites for structural purposes have evolved. Durability, toughness, high dimen-sional stability, resistance against environmental influences such as biodegradation or weathering but also availability of the raw material as well as economic factors are features which can make cement-bonded composites superior to conventionally bonded composites. This paper reviews the relationship of diverse parameters, including density and particle size on mechanical and physical properties of cement bonded composites, based on published sources from the last 60 years. For general and recent information about bonding mechanisms, compatibility and setting problems, determination and improvement of compatibility, the used raw materials as well as accelerators are discussed. The main part deals with failure mechanisms in connection with several production parameters. Furthermore, the influence of particle size and geometry, orientation of the particles, cement-wood ratio and the effect of accelerators and treatment of the particles on modulus of elasticity, modulus of rupture as well as thickness swelling are discussed.
  • Reviewpp 627-665Hubbe, M. A., Pawlak, J. J., and Koukoulas, A. A. (2008). "Paper's appearance: A review," BioRes. 3(2), 627-665.AbstractPDF
    This review article highlights progress in understanding the optical properties of paper. Paper’s appearance can be defined in terms of its opacity, brightness, color, fluorescent properties, gloss, and various quantities related to its uniformity. The phenomena that give rise to paper’s optical properties, especially its ability to scatter and absorb visible light, are highly dependent on paper’s structure and its chemical composition. In an effort to engineer low-cost products having relative high opacity and brightness, it is necessary to optimize the material selection and processing conditions. The dimensions of solid materials and void structures within the paper are key factors for optimizing the optical properties. In addition, additives including bleaching agents, mineral particles, dyes, and fluorescent whitening agents can impact paper’s optical properties Paper’s appearance depends, in subtle ways, on the processes of its manufacture.