Volume 11 Issue 1
- Researchpp 95-104Ćilerdžić, J., Stajić, M., and Vukojević, J. (2016). "Activity of Mn-oxidizing peroxidases of Ganoderma lucidum depending on cultivation conditions," BioRes. 11(1), 95-104.AbstractArticlePDF
Trunks and stumps of various deciduous species act as natural habitats for Ganoderma lucidum. The chemical composition of their cell wall affects the development of fungal ligninolytic enzyme system as well as its ability to degrade lignin from the plant cell wall. Additionally, numerous compounds structurally similar to lignin can be degraded by the G. lucidum enzyme system which could take important roles in various biotechnological processes. The laccases, which are the dominant enzymes synthesized by G. lucidum, have been studied more extensively than the Mn-oxidizing peroxidases. Therefore, this study aimed to create the dynamics profile of Mn-oxidizing peroxidases activities in four G. lucidum strains, classifying and determining their properties depending on the cultivation type and plant residue as a carbon source in the medium, as well as to establish whether intraspecific variety exists. The findings suggest that submerged cultivation appeared to be a more appropriate cultivation type for enzyme activities compared with solid-state cultivation, and oak sawdust was a better carbon source than wheat straw. Under the optimum conditions, on day 14, G. lucidum BEOFB 431 was characterized by the highest levels of both Mn-dependent and Mn-independent peroxidase activities (4795.5 and 5170.5 U/L, respectively). Strain, cultivation type, and carbon source were factors that affected the profiles of Mn-oxidizing peroxidases isoenzymes.
- Researchpp 105-125Choi, B., Chung, J. Y., Bae, H. J., Bae, I., Park, S., and Bae, H. (2016). "Functional characterization of cinnamyl alcohol dehydrogenase during developmental stages and under various stress conditions in kenaf (Hibiscus cannabinus L.)," BioRes. 11(1), 105-125.AbstractArticlePDF
In this study, the entire gene encoding cinnamyl alcohol dehydrogenase in kenaf (HcCAD2) was cloned and characterized. CAD is a key enzyme in the last step of lignin biosynthesis. The full-length HcCAD ortholog is composed of a 1,074-bp open reading frame (ORF) encoding 357 amino acids (KM044582). BlastP and a phylogenetic study revealed that the deduced amino acid sequences share the highest similarity with Gossypium hirsutum (ABZ01817) (89%). Upon real-time PCR analysis, HcCAD1 (HM151380) and HcCAD2 were highly up-regulated in 4-week-old stem and mature flower tissues, which was matched with histochemical staining and lignin component analysis. The expression patterns of the two genes differed in response to wound, cold, NaCl, SA, H2O2, ABA, MeJA, and drought. CAD enzyme activity was measured with various aldehydes as substrates to form corresponding alcohols. The results indicated that the preferred substrates were coniferyl and sinapyl aldehydes with high catalytic efficiency.
- Researchpp 126-139Gan, S., Zakaria, S., Ng, P., Chia, C. H., and Chen, R. S. (2016). "Effect of acid hydrolysis and thermal hydrolysis on solubility and properties of oil palm empty fruit bunch fiber cellulose hydrogel," BioRes. 11(1), 126-139.AbstractArticlePDF
Cellulose hydrogel was produced from pretreated oil palm empty fruit bunch fiber (EFB) that went through acid hydrolysis and thermal hydrolysis. The pretreated EFB was dissolved in LiOH/urea aqueous solution using the rapid dissolution method and was subjected to a crosslinking process with the aid of epichlorohydrin to form hydrogel. The effects of both hydrolyses’ time on average molecular weight (Mŋ), solubility, and properties of EFB hydrogels were evaluated. Both hydrolyses led to lower Mŋ, lower crystallinity index (CrI) and hence, resulted in higher cellulose solubility. X-ray diffraction (XRD) characterization revealed the CrI and transition of crystalline structure of EFB from cellulose I to II. The effects of hydrolysis time on the transparency, degree of swelling (DS), and morphology of the regenerated cellulose hydrogel were also investigated using an ultraviolet-visible (UV-Vis) spectrophotometer and a Field emission scanning electron microscope (FESEM), respectively. These findings provide an efficient method to improve the solubility and properties of regenerated cellulose products.
- Researchpp 140-158Tanninen, P., Leminen, V., Kainusalmi, M., and Varis, J. (2016). "Effect of process parameter variation on the dimensions of press-formed paperboard trays," BioRes. 11(1), 140-158.AbstractArticlePDF
The dimensional accuracy of packages has a great effect on operation of the production and supply chain. In this research, the dimensional accuracy of trays made of polymer-coated paperboard and the effect of all essential press forming process parameters on outer dimensions of the trays were studied to obtain data for the press forming and lid sealing process optimization and for the forming tool design. Paperboard trays were analysed and measured with a quality monitoring system that includes a smart camera and a backlit table. Trays with varying dimensions were sealed to investigate the effect of the package size and the product weight to the residual oxygen in the package’s headspace gas. Results showed that all heat related parameters, i.e.,mould temperatures, dwell time, and pressing speed can be used to adjust the outer dimensions of the paperboard tray. Lid sealing process was found to reduce size of the trays and even out size differences substantially. All produced trays were measured to be bigger both in length and in width compared to the design values of the mould set. Therefore the mould set has to be designed undersized to obtain trays with certain outer dimensions.
- Researchpp 159-173Chen, Q., Endo, T., and Wang, Q. (2016). "Characterization of microcrystalline cellulose after pretreatment with low concentrations of ionic liquid-H2O for a pyrolysis process," BioRes. 11(1), 159-173.AbstractArticlePDF
Microcrystalline cellulose (MCC) samples pretreated by ionic liquid (ILs)-H2O mixtures were studied for application in a pyrolysis process. A 1-ethyl-3-methylimidazolium methanesulfonate [Emim][MeSO3]-H2O mixture with solid acid catalyst Nafion®NR50 was used in the pretreatment process. A lower amount of hydrogen bonding between neighboring pretreated MCC chains resulted from a less ordered cellulose structure, leading to lower crystallinity, decreased molecular weight and reduced thermal stability. The pyrolysis result showed that the yields of char were lower, the average reaction rate increased, and the DTG peak temperature decreased relative to the untreated MCC. The amount and concentration of the hydrogen gas obtained from the pyrolysis of sample 90(20) (4.00 mmol/g-sample) was higher than that obtained from the pyrolysis of the MCC (3.26 mmol/g-sample). This study explores MCC (pretreated by ionic liquid-H2O mixtures) with a recyclable solid acid catalyst under varying pretreatment conditions, as a potential raw feed material, to be applied in the pyrolysis process.
- Researchpp 174-181Wang, J., Gao, Z., Tu, D., He, Z., Lin, X., and Sun, J. (2016). "Dimensional stability of board manufactured with wood-based panel laths," BioRes. 11(1), 174-181.AbstractArticlePDF
The overall objective was to use waste plywood and medium density fiberboard (MDF) to manufacture a new type of board. The dimensional stability of board was improved by mechanical inhibition between laths along the thickness direction. Its modulus of rupture (MOR) and dimensional stability were tested to determine whether it satisfied the Chinese national standard. The innovational points lie in the treatment to improve dimensional stability and raw materials. The MOR of board manufactured with MDF was superior to that manufactured with plywood, although the MOR of MDF was lower than the MOR of plywood. The IT and DT of new manufactured boards decreased more than 33.48% compared to the raw materials. Besides, the warpage and thickness variation tended to be stabilized with cyclical tests continuing. This result indicated that the treatment of mechanical inhibition between laths along thickness direction could improve the dimensional stability of boards. In addition, MDF was a suitable raw material for the new board.
- Researchpp 182-194Qin, L., Lin, L., and Fu, F. (2016). "Microstructural and micromechanical characterization of modified urea-formaldehyde resin penetration of wood," BioRes. 11(1), 182-194.AbstractArticlePDF
Characterization of the adhesive penetration behavior in wood is highly desired for optimizing the manufacturing processes and product properties. In this study, modified urea-formaldehyde (UF) adhesive was used to prepare glued laminated timber (Cryptomeria fortunei Hooibrenk). The depth of gross penetration was measured by fluorescence microscopy (FM), which showed the UF passed through 1.5 to 3.5 earlywood tracheids (with an average penetration depth of 88.95 ± 27.49 μm) or 0.5 to 4.0 latewood tracheids (with an average penetration depth of 36.39 ± 15.14 μm). In addition, the distribution of cell wall penetration was observed clearly by confocal laser scanning microscopy (CLSM). The adhesive was found to diffuse into the cell walls of surface tissues embedded in the UF. To verify the results from CLSM, the mechanical properties of cell walls with and without adhesive penetration were measured through nanoindentation (NI). The reduced elastic modulus of exposed cell walls (18.10 GPa) was roughly equal to that of fully filled cell walls (17.68 GPa) but significantly greater than that of reference ones (15.71 GPa). The hardness showed a similar variation trend for these three types of cell walls. Combining the three techniques, both the microstructure and micromechanics of the adhesive penetration behavior can be quantitatively identified in a complementary manner.
- Researchpp 195-208Klímek, P., Wimmer, R., Brabec, M., and Sebera, V. (2016). "Novel sandwich panel with interlocking plywood kagome lattice core and grooved particleboard facings," BioRes. 11(1), 195-208.AbstractArticlePDF
A new sandwich composite structure was prepared that utilizes classic wood-based composites as the core and face materials. Particleboards were used as faces, which covered a plywood-made iso-grid core. A new type of core-face fixation was suggested and assessed. The sandwich panels can be regarded as lightweight, as their density was below 400 kg/m3. Digital image correlation (DIC) was used to determine Poisson’s ratios and obtain additional insight into the deformation behavior of the sandwich panel. DIC was also employed to assess the core-face bonding, which was based on imprinted grooves on one side of the particleboard face. The results include strength in edgewise and flatwise compression and flexural properties. The latter were determined through three-point bending tests. Comparable strength properties were found relative to the literature, which means that this new type of sandwich panel demonstrates a competitive property profile. It was concluded that the developed sandwich panel is versatile, and the hollow spaces in the core can be filled with insulation materials such as fibers or foams. Surfaces can also be covered with some overlay, delivering improved bending performance.
- Researchpp 209-222Mračková, E., Krišťák, L., Kučerka, M., Gaff, M., and Gajtanska, M. (2016). "Creation of wood dust during wood processing: Size analysis, dust separation, and occupational health," BioRes. 11(1), 209-222.AbstractArticlePDF
Mechanical separators and fabric filters are being used to remove airborne fine particles generated during the processing and handling of wood. Such particles might have a harmful effect on employee health, not only in small- but also in large-scale wood processing facilities. The amount of wood dust and its dispersion conditions vary according to geometric boundary conditions. Thus, the dispersion conditions could be changed by changing the linear size of the particles. Moreover, the smaller the particles are, the more harmful they can be. It is necessary to become familiar with properties, from a health point of view, of wood dust generated from processing. Wood dust has to be sucked away from the processing area. The fractional separation efficiency of wood dust can be improved using exhaust and filtering devices. Filtration efficiency depends on moisture content, particle size, and device performance. Because of the carcinogenicity of wood dust, the concentration of wood dust in air has to be monitored regularly. Based on the results hereof, a conclusion can be made that both mechanical separators of types SEA and SEB as well as the fabric filters with FINET PES 1 textile are suitable for the separation of wet saw dust from all types of wooden waste produced within the process.
- Researchpp 223-234Fajdiga, G., Zafošnik, B., Gospodarič, B., and Straže, A. (2016). "Compression test of thermally-treated beech wood: Experimental and numerical analysis," BioRes. 11(1), 223-234.AbstractArticlePDF
Experimental and numerical analysis of a compression test carried out on samples of as-received and thermally-treated beech (Fagus sylvatica L.) wood is presented. In a normal climate, samples with the dimensions of 20 x 20 x 20 mm were exposed to static compressive loads parallel and transverse to the grain. Afterwards, the test was modelled using the finite element method. It was confirmed that, after thermal modification, the wood’s density decreased and the stiffness in both tested directions increased. After the thermal treatment, the strength of beech wood increased in the direction parallel to the grain and decreased in the direction transverse to the grain. Based on the comparison of experimental and numerical results, it is possible to use the hyperelastic constitutive law to reasonably model the force and displacement obtained in the compression test samples.