Research Articles

Though potentially useful, agricultural byproducts are often discarded because of the lack of specific applications in many industries. However, they have suitable properties for use in the paper industry, according to recent literature. In this study, the suitability of rice husk, peanut husk, and garlic stem as raw materials for the manufacture of a new lignocellulosic bulking agent was investigated, and the best material to replace a commercial wood powder, widely used in Korean duplex board mills, was determined. Many powders were manufactured from agricultural byproducts, and their effects on the physical properties and drying energy requirements of handsheets were evaluated compared to those of a commercial wood powder. All of the powders improved the bulk and dryness after wet pressing, but a reduction in paper strength was unavoidable. In particular, the powder made from rice husk showed a greater bulk and increase in dryness after wet pressing than the commercial wood powder. These findings indicated that these three agricultural byproducts could be used as raw materials for the manufacture of bulking agents, and rice husk was the best agricultural byproduct to replace commercial wood powder in duplex board mills.

Di(2-ethylhexyl) phthalate (DEHP) is a plasticizer that is widely used to soften plastic products. It is an endocrine-disrupting compound, widely considered an environmental contaminant that is difficult to remove or degrade. The radial growth rate (ur), mycelial biomass, intracellular and extracellular activities of laccase and esterase, intracellular and extracellular contents of protein and glycogen, and the contents of soluble and insoluble glucans were evaluated in colonies of Lentinula edodes, grown in various concentrations of DEHP (0, 750, 1200, and 1500 mg/L) on agar. Glucose and yeast extracts were added to all media. The highest ur was shown in medium lacking DEHP, followed by that shown in the medium containing 1500 mg of DEHP/L. The greatest protein extracellular contents were observed in medium with added DEHP. The largest extracellular glycogen contents and mycelial biomass were found in media containing 1200 and 1500 mg of DEHP/L, respectively. These results suggest that DEHP was degraded and used as a substrate by L. edodes during diauxic growth (glucose metabolized first, followed by DEHP), and laccases were more important than esterases in the metabolism of DEHP. L. edodes can be used to remove DEHP from phthalate-polluted environments.

Safe and environmentally friendly oil-resistant packaging paper is strongly desired in the food packaging industry. In the present work, chitosan (CTS) and chitosan/cationic starch (CTS/CS) coated papers were prepared and characterized. The results indicated that both the CTS and CTS/CS coated papers were highly oil resistant, and their oil resistance was increased with an increase in coating weight. The CTS/CS composite showed better thermal stability and water resistance than CTS. Paper coated with the CTS/CS composite containing 1:2 CTS to CS achieved an oil resistance level as required for food packaging. The mechanism of CTS/CS oil resistance, which has not been reported, was investigated by SEM, HPLC and particle size analyzer. The high oil resistance of the CTS/CS-coated paper was attributed to the formation of a film on the surface of the paper and the electrostatic binding between CTS and fatty acid to prevent oil from permeating and transferring.

In past work, QSAR (quantitative structure-activity relationship) models of cinnamaldehyde analogues and derivatives (CADs) have been used to predict the activities of new chemicals based on their mass concentrations, but these approaches are not without shortcomings. Therefore, molar concentrations were used instead of mass concentrations to determine antifungal activity. New QSAR models of CADs against Aspergillus niger and Penicillium citrinum were established, and the molecular design of new CADs was performed. The antifungal properties of the designed CADs were tested, and the experimental Log AR values were in agreement with the predicted Log AR values. The results indicate that the improved QSAR models are more reliable and can be effectively used for CADs molecular design and prediction of the activity of CADs. These findings provide new insight into the development and utilization of cinnamaldehyde compounds.

With high temperature-heat treatment, the dimensional stability and durability of wood is improved and wood color is darkened as well. In this paper, alder birch wood (Betula alnoides) was treated by the Thermo-Vacuum Treatment (TVT). The changes of wood color parameters and the chemical composition were determined by the CIE1976 L*a*b* method and the chemical analysis method, respectively. The results were revealed as follows: (1) A lower value of lightness, L*, and a higher value of total color difference, △E*, were obtained at the higher heat-treatment temperatures and longer treatment time. (2) The higher the heat-treatment temperatures and the longer the heat-treatment times were, the lower the contents of hemicellulose and cellulose were and the higher the content of lignin was. Moreover, Fourier Transform infrared spectroscopy (FTIR) analysis demonstrated that the characteristic absorption peaks of cellulose, hemicellulose, and lignin diminished. The acetylation reaction of hemicellulose and the degradation reaction of groups of lignin side chain occurred during TVT. (3) TVT degraded the chemical composition of cell walls, which resulted in further changes of the wood color. A significant correlation existed between the differences of color indices and the differences of the chemical composition after TVT.

Straw powders were blended with hydrolyzed soy protein isolate (HSPI) modified urea-formaldehyde (UF) resins to produce biodegradable seedling containers. The tensile strength and the degradability of the seedling containers were characterized. Moreover, the degradation behavior of modified UF resins was investigated using 15N isotopic tracing, dynamic mechanical analysis, 13C CP/MAS NMR spectroscopy, and a scanning electron microscope-energy dispersive spectrometer. The results showed that the best tensile strength of the seedling containers made from HSPI-modified UF resins was improved by 6% compared with the seedling containers made from UF resins. The degradability of the seedling containers made from modified UF resins was improved 8.8 times more than that of unmodified UF resins. HSPI can lower the cross-linking degree of UF resins. The HSPI and urea-formaldehyde molecular chains in the resins were decomposed simultaneously in the soil. After degradation, nodular particles that appeared to be coalesced by small globular particles remained. In the process of degradation, modified UF resins can provide a nitrogen source for crops.

Extracts from the inner stem bark of Berberis vulgaris were analyzed for their antioxidant activity using the 1,1-dipheny-2-picrylhydrazyl (DPPH) method and compared with ascorbic acid (AA) and butylated hydroxytoluene (BHT). The most active extracts were analyzed for their chemical composition using gas chromatography-mass spectrometry. Acetone extract was found to be the most active as an antioxidant agent at 98.61%, which was higher than the value of vitamin C (93.03%) at the concentration of 0.16 mg/mL. The major components identified in the acetone extract were tetracosanoic acid, methyl ester (26.36%), followed by phthalic acid, diisooctyl ester (20.93%), 1,2-bis(trimethylsiloxy) ethane (10.26%), and 1,2-benzendicarboxylic acid, diisononyl ester (8.70%). The dissolved water:methanol (1:1 v/v) partitioned from acetone extract afforded 12 fractions; among them, fraction F11 was found to have good antioxidant activity (95.41%) at the concentration of 0.16 mg/mL. The major compounds identified in F11 were N-methyl-4-(hydroxybenzyl)-1,2,3,4-tetrahydroisoquinoloine (28.82%), 9-α-hydroxy-17β-(trimethylsilyl-oxy)-4-anderostene-3-methyloxime (13.97%), ribitol, pentaacetate (9.76%), 1-methyl-4-[4,5-dihydroxyphenyl]-hexahydropyridine (6.83%), and 2-ethylacridine (4.77%).

Extruded wood-plastic composites (WPCs) are increasingly regarded as promising materials for future manufacturing industries. It is necessary to select and tune the post-processing methods to be able to utilize these materials fully. In this development, temperature-related material properties and the cooling rate are important indicators. This paper presents the results of natural cooling in a factory environment fit into a cooling curve function with temperature zones for forming, cutting, and packaging overlaid using a WPC material. This information is then used in the evaluation of manufacturability and productivity in terms of cost effectiveness and technical quality by comparing the curve to actual production time data derived from a prototype post-process forming line. Based on this information, speed limits for extrusion are presented. This paper also briefly analyzes techniques for controlling material cooling to counter the heat loss before post-processing.

The efficient biosynthesis of methane from renewable biomass resources is discussed in this paper. Herbal-extraction process residues (HPR) are an excellent raw material for anaerobic digestion because of their abundant trace elements and fermentation stability. Anaerobic co-digestion of wheat straw with HPR was evaluated at HPR/wheat straw ratios (based on total solids (TS), of wheat straw) of 3%, 5%, and 10 % with anaerobic sludge at 35±1 °C during 30-d anaerobic digestion. The best performance was achieved with 5% HPR added to the reactor, with cumulative methane production of 13,130 mL and cumulative methane yield of 260.5 mL/g TSadded, respectively. Cumulative methane production increased by 31.4% compared to the 9995 mL achieved in mono-digestion with wheat straw. Furthermore, higher activities of protease and total dehydrogenase and higher ATP levels were displayed during the co-digestion process. The high methane yield in this study demonstrates the great potential of co-digestion of renewable biomass as a feedstock for the economical production of methane.

The structure and properties of ethanol organosolv lignin (EOL) extracted from bamboo under various conditions were characterized. EOL yield increased at high temperatures of 160 to 200 °C and a reaction time of 1 to 3 h. The nitrogen content in lignin was low, with a maximum of 0.62%. The carbon content increased with increasing temperature and prolonged time, whereas oxygen content showed an inverse trend. EOL extracted from bamboo showed high purity levels (more than 95.5% Klason lignin) with low impurity contents (carbohydrate and ash). The severity of the process increased the carboxylic acid and phenolic hydroxyl group contents and also decreased the methoxyl group content. The molecular weight of EOL varied depending on the extraction condition. The FT-IR and NMR spectra revealed that the main structure did not significantly change. From the spectra, it is clear that EOL extracted from bamboo can be classified as an HGS (H–p-hydroxyphenyl, G–guaiacyl, and S–syringyl, respectively) type. Clear β-O-4, β-β, and β-5’ linkages were observed.