NC State
  • Editorialpp 5656-5657Hubbe, M. A. (2016)."Paper or plastic? Yes, but not as a mixture," BioRes. 11(3), 5656-5657.AbstractArticlePDF

    As expressed by the chorus lyrics of a song by Dan Einbender, “it really isn’t garbage ‘til you mix it all together. It really isn’t garbage ‘til you throw it away. Separate your paper, plastic, compost, glass and metal. Then you get to use it all another day.” It’s worth paying attention to these lyrics once again in the face of yet another type of product that is starting to show up in stores. Extruded sheets of polyethylene (no. 2 plastic) with as much as 80% ground calcium carbonate content are being sold as “paper”. Calcium carbonate is widely used as a component of real paper. However, it rubs me the wrong way when the word “paper” is being used to refer to something that has no fibers in it and is not formed on a screen and dried. My more serious concern is that such materials, if they become widely used, have the potential to contaminate paper recycling operations.

  • Editorialpp 5658-5659Gangwar, A. K. (2016). "Benefits of polycups stock over other waste paper grades in paper recycling," BioRes. 11(3), 5658-5659.AbstractArticlePDF

    It is never too late or too early to invent alternative processes for the betterment of our routine life. For paper production, trees are being cut in huge quantities each day, and this directly affects our day to day life by making atmospheric conditions less favorable. Waste paper can be recycled on average 4 to 6 times while maintaining acceptable qualities in recycled paper. To save forest resources, we should move ahead towards using more and more waste paper for paper production. A wasted resource can be recycled either to make the same product or by manufacturing new products, e.g. cardboard boxes, newspaper, writing and printing papers, and paper bags, etc. Several waste paper grades are not being fully utilized, and their use might allow increased paper recycling to produce new recovered paper with specified paper qualities. Polycup stock is an example of an under-utilized type of wastepaper that has the potential to substitute effectively for virgin pulp production.

  • Researchpp 5660-5675Jiang, W., Lyu, G., Wu, S., Lucia, L. A., Yang, G., and Liu, Y. (2016). "Supercritical water-induced lignin decomposition reactions: A structural and quantitative study," BioRes. 11(3), 5660-5675.AbstractArticlePDF

    The use of supercritical water for the decomposition of lignin and evaluation of its influence on lignin decomposition and conversion to various products was the thrust of the current study. Poplar alkali lignin (AL), corncob-to-xylitol residue lignin (XRL), and cornstalk-to-ethanol residue lignin (ERL) were the lignin species studied because they constitute the main residual lignins available in the biomass refinery industry. The lignins were characterized by elementary analysis, Fourier transform infrared spectrometry (FT-IR), phosphorus nuclear magnetic resonance (31P-NMR), and X-ray diffraction (XRD), and their hydrothermal depolymerization products were analyzed by gas chromatography-mass spectrometer (GC–MS). The results showed that the residual lignin is a potential source for valuable aromatics. The XRL had the best total phenolics yield, 140 mg/g, while AL had the lowest, 90 mg/g. The maximum yields of phenol (28.94 mg/g) and 4-ethylphenol (36.21 mg/g) were obtained from XRL depolymerization at 375 °C for 30 min, and the optimal yields of guaiacol (14.34 mg/g) and 2,6-dimethoxyphenol (15.67 mg/g) were achieved by AL at 375 °C for 30 min. The information here provides some insights toward developing selective biorefinery methods for lignin-to-organic products conversion processes.

  • Researchpp 5676-5686Wang, F., Ai, M., Yang, G., Chen, J., Chen, X., and Huang, F. (2016). "Influence of carbon source on the production of extracellular ligninolytic enzymes by Phanerochaete chrysosporium," BioRes. 11(3), 5676-5686.AbstractArticlePDF
    The effect of altering the carbon source in the growing environment was investigated relative to the production of ligninolytic enzymes by Phanerochaete chrysosporium. Glucose, cellobiose, and cellulose (or mixtures thereof) were used as the carbon sources. Glucose oxidase and glyoxal oxidase activities in all carbon sources were produced during cultivation. High peak levels (0.17 to 0.24 IU/mL) of manganese peroxidase activity were observed only in mediums containing oligosaccharides. Lignin peroxidase activity was high in glucose medium (0.21 IU/mL of peak value); however, minimal amounts were formed in the cellulose medium (0.01 IU/mL of peak value). High amounts of cellobiose:quinone oxidoreductase (3.33-3.99 IU/mL of peak value) and cellobiose dehydrogenase (0.04-0.2 IU/mL of peak value) were measured when P. chrysosporium was grown on a medium containing cellulose. This work discovered that the mixture of glucose and cellulose as a carbon source favored high co-production of ligninolytic enzymes by P. chrysosporium.
  • Researchpp 5687-5702Ethaib, S., Omar, R., Siti Mazlina, M. K., Dayang Radiah, A. B., and Syafiie, S. (2016). "Microwave-assisted dilute acid pretreatment and enzymatic hydrolysis of sago palm bark," BioRes. 11(3), 5687-5702.AbstractArticlePDF

    Maximizing the amount of monomeric sugar yield from lignocellulosic materials requires an effective pretreatment process and identification of an optimal enzyme loading for cost-effectiveness. In this work, a microwave-diluted sulfuric acid pretreatment was applied prior to enzymatic hydrolysis of sago palm bark (SPB). Characterization of the solid fraction was completed before and after the pretreatment process. Analysis of SPB ash showed a presence of 6.8% silica. There was a 32% reduction in lignin content, an increased crystallinity from 29% to 47%, and clear damage and fragmentation to the surface structure of SPB after the pretreatment. Inhibitors were not detectable in the liquor after the microwave-acid pretreatment. The enzymatic hydrolysis of SPB was employed by adding 6 to 42 FPU/g of cellulase and 50 U/g of β-glucosidase to identify the optimal cellulase loading at fixed β-glucosidase loading. The maximum total monomeric sugar yield and total reducing sugar (using DNS method) at 77 mg/g and 378 mg/g were achieved using 24 FPU/g of cellulose, respectively. Thus, this enzyme loading can be recommended for further microwave-acid pretreatment and enzymatic hydrolysis of SPB.

  • Researchpp 5703-5721Gao, Z., Zhang, X., Wang, Y., Yang, R., Wang, G., and Wang, Z. (2016). "Measurement of the Poisson's ratio of materials based on the bending mode of the cantilever plate," BioRes. 11(3), 5703-5721.AbstractArticlePDF

    Principles and methods to dynamically test the Poisson’s ratio of isotropic material and timber are proposed in this work. Five species of lumbers were processed into cantilever plates of tangential, radial, and cross sections with different length-width ratios of 6, 5, 4, and 3. The “Shell 63” element in ANSYS software was adopted to calculate strain and stress under the first-order bending mode. The paste position of the strain rosette for the Poisson’s ratio of timber was obtained through strain-stress relationship and regression analysis under states of stress, strain analysis, and plane stress. This method was also applied to steel, aluminum, and glass. For both isotropic and orthotropic materials such as timber, the paste positions of the strain rosette were determined by the position where transverse stress within the plate was zero during the first-order bending vibration. Meanwhile, the lateral and longitudinal strains of the spectrum were measured using the transient excitation method. In the spectrum, the ratio of linear amplitude between the lateral and longitudinal strain of the first-order bending frequency was taken as the measured value of the Poisson’s ratio of the material. The accuracy of the results was verified by axial tension and static four-point bending tests.

  • Researchpp 5722-5730Song, C. J., Lee, Y. S., and Lee, J. W. (2016). "Enhanced production of cellulase from the agricultural by-product rice bran by Escherichia coli JM109/LBH-10 with a shift in vessel pressure of a pilot-scale bioreactor," BioRes. 11(3), 5722-5730.AbstractArticlePDF
    The optimal vessel pressure of the bioreactor for cell growth and the production of cellulase, as well as the effect of a shift in pressure within the reactor on cellulase production were investigated. The optimal vessel pressure for the cell growth of E. coli JM109/LBH-10 was 0.08 MPa, whereas that for the production of cellulase was 0.04 MPa. The maximal production of cellulase by E. coli JM109/LBH-10 with a shift in the vessel pressure from 0.08 to 0.04 MPa after 24 h was 636.8 U/mL, which was 1.2 times higher than that without a shift. The shift in vessel pressure optimized for cell growth to that for the production of cellulase after the mid-term log-phase resulted in higher cell growth and cellulase production. A simple process with a shift in the vessel pressure of bioreactors to enhance the production of cellulase from agricultural by-products has been developed and can be directly applied to the industrial-scale production of cellulases.
  • Researchpp 5731-5742Sun, Y., Ma, Y., Fang, G., Li, S., and Fu, Y. "Synthesis of acid hydrolysis lignin-g-poly-(acrylic acid) hydrogel superabsorbent composites and adsorption of lead ions," BioRes. 11(3), 5731-5742.AbstractArticlePDF

    A series of acid hydrolysis lignin-g-poly-(acrylic acid) (AHL-g-PAA) composites was prepared by grafting acid hydrolysis lignin on the surface of the polyacrylic acid network. The results of structure analysis revealed that AHL-g-PAA had been grafted. The surface morphologies of the hydrogels were improved, as shown by scanning electron microscopy observation. The AHL-g-PAA hydrogel had high water absorption and it possessed sensitivity to external pH stimulus. This study also revealed that the adsorption capacity of AHL-g-PAA was 235 mg/g for Pb(II) ions. The adsorption kinetics data could be described by the pseudo-second-order model, and the adsorption isotherm agrees well with the Langmuir model.

  • Researchpp 5743-5750Wang, Z., Yang, X., Sun, B., Chai, Y., Liu, J., and Cao, J. "Effect of vacuum heat treatment on the chemical composition of larch wood," BioRes. 11(3), 5743-5750.AbstractArticlePDF

    The effects of vacuum heat treatment were studied relative to the chemical composition of larch wood. The samples were heat-treated in vacuum at 160 °C, 200 °C, and 240 °C for 4 h, and the chemical changes were investigated by wet chemical analysis, elemental analysis, calorific value determination, and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS). The relative percentage contents of lignin and extractives increased after heat treatment. Additionally, the relative percentage contents of holocellulose, cellulose, and hemicelluloses decreased as a result of the thermo-vacuum treatment. Elemental analysis showed a slight reduction in the contents of hydrogen and oxygen. Vacuum heat treatment also increased the calorific value compared with untreated samples.

  • Researchpp 5751-5766Khandanlou, R., Ngoh, G. C., and Chong, W. T. "Feasibility study and structural analysis of cellulose isolated from rice husk: Microwave irradiation, optimization, and treatment process scheme," BioRes. 11(3), 5751-5766.AbstractArticlePDF
    The goal of this study was to pretreat rice husk (RH) using a microwave-assisted pretreatment process coupled with chlorite delignification and alkaline treatment to facilitate the isolation of cellulose. The isolated cellulose was characterized and subjected to structural analysis and a thermal stability test to ascertain the efficiency of the isolation from a visual perspective. The optimum condition for the microwave-assisted pretreatment of RH was determined by response surface methodology (RSM). The effects of three independent variables—microwave power, irradiation time, and solvent ratio—were investigated based on the maximum content of the RH being pretreated. At the optimum parameters of microwave power of 400 w, a 10-min duration, and a solvent ratio of 80.0% v/v, the pretreatment efficiency of RH was 10.0%. Compared with the conventional Soxhlet technique, the microwave pretreatment was superior. The X-ray powder diffraction (PXRD) result for the isolated cellulose showed that cellulose was highly crystalline (CrI = 65.0%). Fourier transform infrared spectroscopy (FT-IR) verified that most of the lignin and hemicelluloses were removed from the isolated cellulose after the chemical treatment. Furthermore, the TGA study revealed that the thermal stability of RH cellulose was higher than the original RH.