Research Articles

The residual peels of andiroba seeds were submitted to alkaline pretreatment that aimed to maximize the recovery of fermented sugar. Evaluation of the best operation performance via the reaction time variables (20, 60, and 100 min), NaOH concentration (2, 3, and 4% (m/v)), and temperature (60, 90, and 120 °C) at a fixed solids concentration of 5% (m/v) was performed. A Box-Behnken experimental design was used. Lignocellulosic material was characterized by cellulose (30.57 ± 1.00%), hemicellulose (15.08 ± 0.65%), lignin (36.02 ± 1.05%), extractives (7.49 ± 0.03%), and ash (1.53 ± 0.28%). The optimization was performed using the response surface methodology approach. The model provided a coefficient of determination (R2) of 0.95. The predicted optimal conditions for the process were a reaction time of 100 min, NaOH concentration of 4% (m/v), and temperature of 120 °C, which allowed the authors to obtain a saccharification of approximately 47.9%.

The selective removal of lignin can be a profitable value-added utilization for the pre-hydrolysis liquor (PHL) produced during kraft-based dissolving pulp production. In this work, the soluble lignin was removed from PHL using CaCl2, Al2(SO4)3, cationic polyacrylamide (CPAM), and a CPAM/Al2(SO4)3 dual-system treatment. The results of zeta potential recording revealed that 8.86% of soluble lignin was removed by CaCl2 treatment through charge neutralization and adsorption, and 13.1% soluble lignin was removed by CPAM through charge neutralization and flocculation bridging. The optimal dosages of CaCl2, CPAM, Al2(SO4)3, and CPAM/Al2(SO4)3 dual-system treatments were 2.0 wt%, 30 ppm, 300 ppm, and 60/300 ppm respectively, at which the soluble lignin removals were 8.09%, 9.24%, 18.3%, and 25.0%, respectively. Additionally, the total sugar loss by the CPAM/Al2(SO4)3 dual-system treatment was higher than that by other individual systems; however, the soluble lignin selective removal by the CaCl2 treatment was the highest, at over 80%.

To study the influence of process parameter changes on the properties of raw material obtained from corn rind, a central composite design (CCD) methodology with four factors and five levels was applied to statistically optimize the parameters. The stalk size, soaking time, working temperature, and processing speed were selected as influencing factors. The available fiber ratio, initial beating degree, and fiber aspect ratio were chosen as indicators. Response surface analysis methodology was employed for optimization. The results showed that the optimal range of parameters were as follows: 8 to 13 cm for the stalk size, 18 h for the soaking time, 60 °C for the working temperature, and 98 to 112 r·min-1 for the processing speed. In this optimal condition, the available fiber ratio was higher than 95%, initial beating degree was greater than 11 °SR, and fiber aspect ratio was greater than 50. The results could be applied to design and optimize the D200 type stalk fiber preparation machine and the process of making raw material.

Reducing particleboard thickness is one of the major approaches to decrease consumption volume of particleboard for furniture manufacture. This study employed an adhesive mixture of polymeric methane diphenyl diisocyanate (PMDI) and urea formaldehyde (UF) to produce single-layer medium density thin rice straw particleboard. The effects of various PMDI/UF formulations as well as board density on mechanical properties and water resistance of rice straw particleboard were studied. The results indicated that the mechanical properties and water resistance of the thin rice straw particleboard were appreciably affected by resin formulation. The panels bonded with PMDI/UF adhesive mixtures had mechanical properties and water resistance far superior to those bonded with UF. Higher PMDI content levels in resin mixtures led to improved mechanical properties and water resistance. Density influenced mechanical properties and water resistance of the thin rice straw particleboard. Increasing the density of the panel could upgrade the mechanical properties of the thin rice straw particleboard. The experimental outcomes showed that PMDI/UF resin systems had potential to substitute for pure PMDI resin in producing thin rice straw particleboard, which could effectively lower manufacturing cost and bring economic efficiencies due to reduced amount of pricey PMDI.

This experiment evaluated the taxonomic diversity of the fungal community in conventional (AP) and organic (OAP) apple pomace using high-throughput sequencing, applying fungal genetic barcodes to functional guilds. The most abundant taxonomic groups identified in both AP and OAP were the genera Aureobasidium, Cladosporium, and Alternaria, classified into the pathotroph-saprotroph-symbiotroph guild. The phenotype microarray provided insight into the role of the apple pomace fungal community in the ecosystem. It is theorized that adding apple pomace to the soil may improve the bioavailability of bioresource-based polyols. Evaluation of the antagonistic ability of the AP fungal community and Trichoderma atroviride G79/11 strain against pathogenic fungi was performed. Trichoderma G79/11 developed well on apple pomace and revealed the antagonistic mode against tested fungal plant pathogens. Therefore, it could be applied to soil as a formulation of AP with spores or AP with metaferm biopreparation.

Increasing demand for resonance spruce has led to gradual depletion of resources in traditional areas. Consequently, to meet the need for raw material to manufacture musical instruments, sorting has become the key operation of exploitation. This study was completed on the largest Romanian resonance wood resource, to maximize outputs of flitches for violin, cello, and double bass instruments by optimizing traditional requirements regarding quality of raw material with its current level. Ten resonance spruces were felled and gradually turned into semi-manufactured musical instruments. The material was analysed for defects in all stages of conversion. The frequency of zero defective samples was 60%. Evolution of defects along the trees indicated the tree section from 1 m to 12 m above the ground for musical instruments manufacturing. Output in terms of flitches ranged from one tree to another: between 19 and 32% if calculated from logs volume, and between 13 and 30% if calculated from volume of the standing trees. The results advocated for relaxing traditional requirements on resonance logs, at least regarding buttress and knottiness. Thus, recommendations are made, from the perspective of increasing efficiency, on the admissibility of defects and size diversification of musical instruments.

The objective of this study was to measure compressive strength properties perpendicular to the fiber of green Eucalyptus nitens specimens. The data was measured for clear 50 × 50 × 150 mm specimens obtained from 17-year-old trees that were harvested at the Ñuble region in Chile, and the data comprised modulus of elasticity (Ec), compressive strength (ƒc), basic density, initial moisture content, and some anatomical characteristics of the wood. The experimental design emphasized the influence of the radial position of the wood within the logs (defined as inner-wood, middle-wood, and outer-wood) on the measurements, and the results showed that the modulus of elasticity, compressive strength, and the basic density all increased from core to bark. The compressive strength of outer-wood showed a strong and positive relation with the basic density. Cell wall thickness and wall cell area showed a significant positive correlation with compressive strength.

Acid sulfite pretreatment has been shown to be an effective and practical method for improving the enzymatic hydrolysis of corn stover (CS) for bioethanol production. In the present study, the changes in the structures and properties of CS during the acid sulfite pretreatment process were investigated. The results showed that the crystallinity of cellulose in CS was increased by the pretreatment. The recalcitrant structure of untreated CS was destroyed by the acid sulfite pretreatment, which led to an increase in surface area being exposed. Thermogravimetric analysis indicated that the temperature for the maximum mass loss rate of the acid sulfite-pretreated CS shifted by 40 °C compared to that of the untreated CS. Large amounts of gas species, such as CO2, CO, CH4, and H2O, were released during the pyrolysis process. This work provides a theoretical reference to the determination of the optimal pretreatment parameters for the conversion of CS into bioethanol.

Cellulose nanomaterials with high yield and desired properties were sustainably produced using a facile recyclable acid treatment (oxalic acid) with mineral acid catalysis at ambient pressure. The resultant nanocellulose was uniform in dimensions (diameter and length distributions) and highly dispersible in the aqueous phase. The nanocellulose with yield up to 33.9%, a zeta potential of -53.9 mV, and 100% volume stability (24 h) was achieved via oxalic acid treatment in conjunction with sulfuric acid addition. The coating of such nanocellulose on paper created a uniform and dense layer on the surface, which lowered Gurley air permeability (i.e., prolonging the time required for air flow from 3.9 to 681.9 s per 100 mL). Moreover, the coated paper showed a complete grease barrier after 48 h and presented easy-cleaning behavior. The approach developed in this work offers an adoptable guidance to design green and sustainable easy-cleaning surfaces. In turn, this approach will provide potential applications of nanocellulose for green based packaging and environmental protection.

Wood products, especially those used in outdoor conditions, can be damaged by dimensional changes and decay fungi. It is therefore advised to use impregnation treatments to mitigate these hazards. While the potency of the chemicals employed in the treatments is important, characterization of the treatments is also crucial to ensure deep and durable protection. In this study, eastern white pine (Pinus strobus L.) and white spruce (Picea glauca (Moench) Voss) were impregnated with propiconazole and 3-iodo-2-propynyl butylcarbamate (IPBC) through diffusion. Instead of using pressure treatments, the samples were dipped in solutions containing amine oxides, which can diffuse into the wood. The treatments were characterized by the mass of fungicide impregnated, fungicide leaching, and the impregnation depths of both the fungicides and the amine oxides. It was found that the treatment impregnated slightly more than 0.040 kg/m3 of both fungicides, meeting EU standards. It was also shown that the presence of amine oxides slightly prevented the leaching of the fungicides in white pine. The penetration of the amine oxides was several millimeters deep in all directions, but the penetrations of the fungicides were much shorter and only longitudinal.