NC State
  • 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.