Volume 20 Issue 3

Trichoderma sp. SG2, isolated from the Black Belt soils of Alabama, USA, is a potent natural producer of β-glucosidase and a broad spectrum of cellulolytic and xylanolytic enzymes. This study explored the saccharification of lignocellulosic biomass using crude enzymes from Trichoderma sp. SG2, various pretreatment strategies, mixed feedstock approaches to enhance sugar yield, and enzyme supplementation to reduce costs. Among the pretreatment methods tested for switchgrass, the most effective was sequential H₃PO₄–ethanol, followed by NaOH–H₂SO₄, H₃PO₄–acetone, H₂SO₄–NaOH, and single-agent treatments (H₂SO₄ alone or NaOH alone). Sugar yields were significantly improved by combining pretreated switchgrass with paper powder as a mixed feedstock. The highest glucose (15.8 g/L) and xylose (3.8 g/L) yields were achieved at 10% pretreated switchgrass after 72 h. A key finding was the significant cost reduction and enhanced saccharification efficiency achieved by supplementing SG2 crude enzyme with 50% of the recommended commercial enzyme dosage. Acid-pretreated switchgrass hydrolysis with SG2 enzyme and commercial enzyme supplementation emerged as the most effective strategy. These results highlight Trichoderma sp. SG2 as a promising candidate for developing cost-effective enzyme cocktails for lignocellulosic biomass hydrolysis where 30 to 40% cost of ethanol production process is accounted for enzyme cost.

Timber has natural fire resistance because of its predictable charring behavior. When subjected to high temperatures, timber undergoes pyrolysis, forming an insulating char layer that protects the inner structural core. Eurocode EN 1995-1-2 (2004), commonly known as Eurocode 5 where EC5 specifies 0.5 mm/min charring rate for temperate hardwoods, pertains to timber with density exceeding 450 kg/m³. This paper presents the development of a finite element model (FEM) to predict the charring rate of timber exposed to fire through innovative experimental and numerical approaches. Timber samples were exposed to controlled heat fluxes for 60 min, simulating real-world fire scenarios. The resulting char layer thickness was measured over time. The Malaysian tropical hardwood timber used was Resak (Cotylelobium and Vatica spp.) with density range from 932 kg/m³ to 1125 kg/m³. The proposed FEM was developed using ABAQUS software, which included thermal conductivity and specific heat to simulate the transient heat transfer and degradation processes in timber. It was found that the charring rate of Resak was 0.47 mm/min lower than the rates established in EC5 (2004). The model is validated through experimental data, demonstrating its accuracy in predicting char depth and temperature profiles under standard fire condition. The data are useful when designing the fire safety of timber structures from the Malaysian tropical timber species.

The development of high-performance polystyrene composites modified with recycling waste tire rubbers composed of natural and synthetic rubber mixture is highly desirable for a sustainable society. To tackle the intrinsic fire issue of waste tire rubber and polystyrene (WTRPS) composites for its advanced applications, the synergistic effect of fire additives MXene and poly(p-phenylene oxide) PPO on the performance of WTRPS composites was investigated in this work. The limited oxygen index values of WTRPS composites with MXene and PPO loading at 15 and 40 wt% were  increased to 23.0%, compared to that of WTRPS at 17.0%. Additionally, the heat release rate, total heat release, and peak of heat release rate of resulting composites showed obvious decreases, confirming their synergistic fire retardancy effects on WTRPS composites. The synergistic mechanism was based on the char effect of PPO, heat sink effect of MXene, and catalyst effect of titanium dioxide generated from MXene. The synergistic strategy in this work paves a new avenue to develop fire retarding bio-composites of wood flour reinforced polyhydroxyalkanoates along with environmentally friendly fire additives (e.g., MXene and lignin or phytic acid) for advanced applications.

This study focuses on the development of a xylose-inducible system to produce recombinant α-amylase from the bacterium Thermoactinomyces vulgaris 94-2A (amyTV) in the Bacillus expression system. To achieve this, a gene cassette was constructed using pWH1520 shuttle vector, containing a PxylA promoter comprising glucose box and amyTV gene. The cassette was initially cloned in Escherichia coli for replication and subsequently, introduced into the Bacillus subtilis (GSB26) for expression. To optimize the secretion of α-amylase, different concentrations of xylose were used as inducers. It was found that the maximum amylase activity was achieved when 2% xylose was used as the inducer. Furthermore, using glucose alone and in combination with xylose as inducers indicated that glucose acted as a catabolic repressor for amyTV expression. Moreover, protein was efficiently secreted and did not accumulate in the cellular fractions, even at high expression levels.

The article deals with composite materials based on caustic magnesite binder and wood fillers used in the fabrication of various types of objects in mechanical engineering, construction engineering, and oil and gas industries. Under operational conditions, caustic magnesite composites can be exposed to aggressive actions of microorganisms. This study looked into resistance of wood-filled composites upon exposure to byproducts of filamentous fungi (micromycetes). This research substantiated the choice of model medium for testing – byproducts of metabolism of micromycetes. Designed experiments were carried out. The samples were held in model solutions with different concentrations of aggressive medium agents. Lines of equal values of materials’ resistance were plotted. It was found from experiments that composites without fillers had a lower biocorrosive resistance compared to those filled with pine sawdust.

Milk and cream are often sold in beverage carton packaging. After use, the unconsumed liquid residues and adhering content remain in this packaging. These food residues end up in the recycling cycle, where they pose troubles in the aqueous processing. The aim of this empirical study was to quantify milk and cream residues in beverage carton packaging from recycling streams. 949 recovered cartons that had been filled with milk or cream and consumed in Germany, Austria, and the Czech Republic were analyzed by gravimetric measurement. For 1-liter cartons, the mean value of the residual quantity was 6.6 g residue for every liter filling quantity, with a range of 1.0 to 71.9 g/L. This corresponds to 0.66% residual quantity by mass, with an assumed density of 1.0 g/cm³. Considering a mean value for all the carton weights with residual quantity of 35.8 g for 1-liter cartons, here some cartons without closures, and 29.2 g without residual quantity, this results in a packaging material content of 81% by mass for recycling. The rest is food waste that ends up in the recycling stream. This can be a task for packaging designers to further improve easy-to-empty solutions.

Engineered laminated bamboo plays a crucial role in structural applications, addressing challenges such as bamboo’s natural variability, species differences, adhesives, and loading direction. This study examines the bending performance of three-layered laminated bamboo configurations using two species, Gigantochloa scortechinii and G. levis, bonded with phenol-resorcinol-formaldehyde (PRF) and polyurethane (PUR) adhesives. Laminated bamboo was assembled with lay-up patterns (parallel and perpendicular) and arrangements (vertical, horizontal, and mixed). Four-point bending tests under flatwise and edgewise loading were used to determine flexural performance and failure modes. Results showed that PUR-bonded bamboo had lower thickness swelling (TS) and water absorption (WA). While bamboo species did not significantly affect bending performance, the adhesive type, lay-up pattern, and arrangement were influential. Flatwise loading improved the modulus of elasticity (MOE) by 5% but reduced the modulus of rupture (MOR) by 10% compared to    edgewise loading. PRF-bonded bamboo outperformed PUR in strength, making it preferable for structural use. Vertical arrangements with PRF and PUR adhesives yielded optimal bending performance, emphasizing the importance of adhesive selection and configuration in enhancing laminated bamboo’s structural properties.

Indonesian agriculture faces multifaceted challenges, particularly the need to enhance productivity while maintaining environmental sustainability to ensure high-quality food production. Soil degradation and excessive use of chemical fertilizers have contributed significantly to declining soil fertility and land degradation. This study aims to evaluate the effectiveness of biochar and compost derived from lignocellulosic baglog, spent substrate from Ganoderma lucidum mushroom cultivation, to improve soil quality and fertility, especially under sub-optimal soil conditions. The treatments were tested on tomato plants using different application rates. A factorial Completely Randomized Design (CRD) was employed, comprising two factors with three replications. The first factor was the baglog waste compost dosage at four levels: B0 (0 g/polybag), B1 (200 g/polybag), B2 (300 g/polybag), and B3 (400 g/polybag). The second factor was the biochar dosage, also at four levels: K0 (0 g/polybag), K1 (250 g/polybag), K2 (500 g/polybag), and K3 (750 g/polybag). Key growth parameters, plant height, number of leaves, stem diameter, and leaf area, showed notable improvement compared to control plants grown without biochar or baglog compost. Applying both in balanced amounts is essential to promote optimal tomato plant growth.

Sporisorium reilianum is an emerging fungal resource rich in dietary fiber (DF), but conventional extraction yields suboptimal functionality. Using Sporisorium reilianum as raw material, the extraction process of modified dietary fiber (DF) was optimized through response surface methodology by adjusting the compound enzyme concentration, enzymatic hydrolysis time, material-to-liquid ratio, pH, and temperature. The optimal modification conditions for xylanase were a material-to-liquid ratio of 1:14.8 (g/mL), enzymatic hydrolysis temperature of 63 ℃, and pH of 6.24, with an average yield of modified soluble DF (S-SDF) of 15.1%. The swelling power, water-holding capacity, and oil-holding capacity of S-SDF were significantly higher than those of unmodified SDF. The overall adsorption capacities for cholesterol and sodium cholate of S-SDF and modified insoluble DF (S-IDF) were higher than those of unmodified IDF and SDF. The glucose adsorption capacity followed the order: S-IDF > IDF > S-SDF > SDF, and it exhibited dose-dependence. The modified DF still retained crystallinity having the same crystalline form. The monosaccharides remained predominantly composed of glucose. The modified DF showed superior adsorption capacities, enabling applications in cholesterol-lowering foods and gut health products.

The sound absorption properties of shredded paper wastes (SPW) were evaluated. Two impedance tubes (large and small) were used to measure the sound absorption coefficient of different thicknesses of SPW sound-absorber (20, 40, 60, 80, and 100 mm). As the thickness of the SPW sound-absorber increased, the optimum sound absorption coefficient was shifted to a lower frequency direction. Based on the KS F 3503 (2002) standard, the sound absorption coefficients were 0.3 M for 20 mm, 0.5 M for 40 mm and 60 mm, and 0.7 M for both 80 mm and 100 mm. The sound absorption properties of this SPW showed comparable or better performance than other eco-friendly fibrous sound absorbers. SPW has not been previously considered for recycling applications. The findings imply that SPW has good sound absorption properties and can thus be employed as a cost-effective and environmentally friendly sound-absorbing material.