Volume 6 Issue 3

Response surface methodology (RSM) was performed to evaluate the effects of dissolved oxygen tension (DOT) and initial pH on the production of carboxymethyl cellulase (CMCase), filter-paper hydrolase (FPase), and β-glucosidase by Aspergillus terreus in a 2 L stirred tank bioreactor. Delignifiedoil palm empty fruit bunch (OPEFB) fibre was used as the main substrate under submerged fermentation. Growth of A. terreus and the production of three main components of cellulase were optimized by central composite design (CCD) design. Statistical analysis of results showed that the individual terms of these two variables (DOT and pH) had significant effects on growth and the production of all components of cellulase. Maximum growth (13.07 g/L) and cellulase activity (CMCase = 50.33 U/mL, FPase = 2.29 U/mL and β-glucosidase = 15.98 U/ml) were obtained when the DOT and initial culture pH were set at 55% and 5.5, respectively. A high proportion of β-glucosidase to FPase (8:1) in cellulase of A. terreus could be beneficial for efficient hydrolysis of cellulosic materials. The use of OPEFB as a main substrate would reduce the cost of fermentation for the production of cellulase.

The penetration of ink into paper affects the final appearance of printing and the amount of ink usage. In this work, UV-curing fluorescent rose ink was used to investigate the penetration and distribution of the ink pigments as well as their correlation with the surface topography of paper. The ink penetration and distribution were characterized with Confocal Laser Scanning Microscopy (CLSM), whereas the microstructure of the paper surface was observed using Atomic Force Microscopy (AFM). The AFM results showed that the surface of the paper coated with kaolin layer was the smoothest among the samples. Also the pore size of the calcium carbonate coating layer was smaller than that of the kaolin coating layer. Meanwhile, the pore size distribution of the calcium carbonate coating layer appeared to be relatively narrow, compared with other samples. The results of CLSM images indicated that the depth, size, and arrangement of pores affected the penetration depth and distribution of ink pigment on coated paper. The large pores led to deeper penetration of ink pigments, and uniform ink absorption occurred when the pore distribution was uniform. The UV-curing ink pigments not only set on the surface of the uncoated paper, but also they penetrated into the paper interior and adhered to the fiber surface.

Pyrolysis of pine wood sawdust was carried out using stepwise isothermal fast pyrolysis (SIFP), focusing on the search of reaction conditions to obtain chemicals in good yields from biomass. SIFP consists of successive isothermal fast pyrolysis reactions, where solid products obtained in the previous isothermal fast pyrolysis become the substrate of the subsequent reaction at a higher temperature. This article reports results obtained by SIFP of pine sawdust between 200 and 600°C using 100°C intervals under vacuum (0.2 mm), using nitrogen as carrier gas. Both sets of reactions made it possible to obtain most of the compounds that have been previously described in conventional fast pyrolysis experiments; however this system produces a smaller number of chemical compounds in each isothermal FP, making it easier to obtain determined chemicals with industrial or research value. Maximum yield of liquid products occurred at 300°C, giving around 30% of bio-oil, which contained mainly phenols and furan derivatives. Liquid-Liquid extraction led to a rich mixture of phenol derivatives. Results showed that SIFP is an interesting technique to obtain enriched fractions of products derived from biomass pyrolysis.

This paper details the effects of two non-ionic surfactants, ELA-7 and PEG 1500, on the soda pulping of wheat straw. The results showed that application of either surfactant improved the pulp yield and decreased the screen rejects. The increase in pulp yield at similar kappa number may be due to higher selectivity of delignification affected by surfactant, which can act as a co-solvent. Addition of ELA-7 to cooking liquor didn’t have significant effect on paper properties. But a significant effect was observed with PEG 1500. In fact, it caused a decrease in burst and tensile index but increased the tear index, probably because of a debonding effect of the surfactant. In addition, application of both surfactants improved brightness for both unbleached and bleached pulp samples.

Wood-decaying fungi present a serious threat to items made from rubberwood (Hevea brasiliensis). Though conventional chemical control has been a successful method for preserving wood against stain and decay fungi growth, the effects of these chemicals are of concern because they create problems for the environment and public health. Pycnoporus sanguineus (P. sanguineus), is a white-rot fungus that invades wood during its growth, storage, or use, causing decay or other property changes. It was considered in this work as a potential source of bioactive compounds and investigated for its natural antifungal activity using a minimum inhibitory concentration assay against wood-degrading fungi. It was found that media consisting of 10.0 g/L malt extract, yeast extract, dextrose, and maltose, respectively at pH 4.7±0.2 provided the highest biomass production by P. sanguineus. Results showed that the antifungal properties of methanol and water extract of P. sanguineus mycelia and supernatant ranged from MIC values of 0.1 to 5.0 µg/µL. 4H-Pyran-4-one,2,3-dihydro-3,5-dihydroxy-6-methyl- (DDMP) was found to be the major component in the extract of this fungus, based on analysis using gas chromatography – mass spectrometry.

The present paper aims to investigate the physical characteristics of sawdust relative to its use as an adsorbent for removal of an acid dye (Orange G) from aqueous solutions. The raw sawdust was sieved to have a uniform size and was activated by sulphuric acid by refluxing the content at 60 oC for 4 h. Surface morphology and surface functional groups of both raw and modified sawdust samples were investigated by Scanning Electron Microscope (SEM), Energy Dispersive X-ray Analysis (EDX), Fourier Transformation Infrared (FTIR), and elemental analysis. All these analyses displayed significant change in the structure of the sawdust. The data obtained from batch adsorption experiments for the removal of the selected dye confirmed that adsorption characteristics of the modified sawdust were better than those of raw sawdust.

Simultaneous saccharification and fermentation (SSF) of alkaline pretreated cogongrass to ethanol was optimized using the commercial cellulase Accellerase 1500 and Ethanol Red dry yeast. Cogongrass was pretreated with 10% (wt) NaOH at room temperature for 24 hours, resulting in an increase in the cellulose percentage from 38.5% to 60.5%. Each SSF of alkali-pretreated cogongrass was carried out with 1 g/L of dry yeast loading at pH 5.0 under 150 rpm shaking. Response surface methodology (RSM) based on a three-level three-factor Box-Behnken design was employed to optimize the key variables within the following ranges: cellulase concentration per unit gram water-insoluble cellulose (WIS) (0.15-0.25 mL/g-WIS), substrate concentration (5-15 % WIS, w/w), and temperature (35-45°C) for the SSF process. The response surface model arrived at the optimum SSF conditions: cellulase concentration of 0.255 ml/g-WIS, temperature at 37.5°C, and substrate concentration of 7.28% WIS for obtaining 80.3 % ethanol yield in 72 h. The optimal conditions were verified experimentally with an average absolute relative deviation of 3.01 %. Also, the SSF was scaled up to a 5-L rotary drum reactor filled with 1 kg of substrate under the optimal conditions, and an ethanol yield of 76.2% was obtained.

In this study the thermal conductivity of different wood materials was determined. For this purpose, Scots pine (Pinus sylvestris L.), Uludag fir (Abies Bornmülleriana Matff), Oriental beech (Fagus orientalis L), Oak (Quercus robur L.), and Chestnut of Anatolia (Castanea sativa Mill.) woods were used. In the test, the thermal conductivity of the woods was measured according to procedure of ASTM C 1113-99 standards. The lowest thermal conductivity was obtained in the perpendicular direction of Scots pine samples as 0.156 Kcal/mh°C. The highest thermal conductivity was obtained from perpendicular direction of samples in Oriental beech as 0.331 Kcal/mh°C.

Continuous process improvement and automation have proven to be powerful tools for the wood processing industries in order to obtain better final product quality and thus increase profits. Abrasive machining represents an important and relevant process in the manufacturing and processing of wood products, which also implies high cost of materials and labor; therefore, special attention to this process is necessary. The objective of this work was to evaluate and demonstrate a process control system for use in the abrasive machining of wood and wood-based products. A control system was created on LabView® to integrate the monitoring process and the actions required, depending on the abrasive machining process conditions. The system acquires information from the optical sensor to detect loading and activate the cleaning system. The system continuously monitors the condition of the abrasive belt (tool wear) by using an acoustic emission sensor and alerts the operator of the status of the belt (green, yellow, and red lights indicating satisfactory, medium, and poor belt condition). The system also incorporates an additional safety device, which helps prevent permanent damage to the belt, equipment, or workpiece by alerting the operator when an excessive temperature has been reached. The process control system proved that automation permits enhancement in the consistency of the belt cleaning technique by the elimination of the human errors. Furthermore, this improvement also affects the cost by extending the life of the belt, which reduces setup time, belt cost, operation cost, as well as others.

The hydrolytic potential of cellulases produced by Trichoderma viride, Trichoderma pseudokoningii, Trichoderma koningii, and Trichoderma reesei with addition of exogenous β-glucosidase was evaluated on cellulose of steam-pretreated Lespedeza. The T. viride enzyme achieved the highest glucose conversion (90.09%), while T. pseudokoningii cellulase achieved the highest ratio of cellobiose to glucose (4.94%) at the end of hydrolysis. Enzymatic adsorption on the substrate was evaluated on filter paper activity and β-glucosidase activity in the corresponding digest with the obtained T. cellulases. T. viride cellulase possessed an efficient adsorption-desorption on the substrate and reached the highest FPA difference (0.72 U/mL) among enzyme activities, indicating to its excellent hydrolysis capability. However, β-glucosidase in T. viride cellulase system showed close bonding on the substrate, suggesting that efficiencies of adsorption-desorption on the cellulose are different between the entire cellulase system and β-glucosidase. T. viride cellulase, with active endogenous β-glucosidase (1.60 U/mL), has compatible synergism with the additional exogenous β-glucosidase.