Research Articles

Spent coffee grounds (SCG) are an abundant lignocellulosic biomass rich in galactomannan and cellulose, rendering them a promising feedstock for biorefinery, especially for the production of manno-oligosaccharides (MOS) as high-value prebiotics. This study investigated the role of α-galactosidase (α-G) in the enzymatic hydrolysis of ammonia-pretreated SCG, with particular emphasis on MOS production and cellulose hydrolysis. Enzymatic hydrolysis was conducted at 50 °C and pH 5.0, and the resulting sugars and MOS were quantified by HPLC. Supplementation with α-G effectively removed α-1,6-linked galactose side groups from galactomannan and increased MOS yield. Notably, the addition of α-G enabled a 50% reduction in mannanase dosage without compromising MOS production, indicating its potential to improve galactomannan conversion efficiency. However, α-G treatment altered the properties of the resulting MOS and was associated with stronger inhibition in MOS-containing cellulase systems. Under the tested conditions, α-G supplementation in MOS-containing systems was associated with additional numerical reductions in glucose yield of 15.8% for CBHI and 8.1% for EGII, whereas little numerical change was observed in the βG system. These results reveal a trade-off associated with α-G supplementation: although it promotes MOS generation, stronger inhibition was observed in MOS-containing cellulase systems, which may impair downstream cellulose hydrolysis.

Plant-derived materials offer sustainable platforms for functional nanomaterial development; however, Leptadenia arborea remains poorly explored for silver nanoparticle (AgNP) synthesis, and quantitative approaches linking phytochemistry, antimicrobial efficacy, and cellular damage are limited. This study investigated L. arborea leaf extract as a reducing and stabilizing system for AgNP synthesis. HPLC identified chlorogenic acid (53.8 µg mL⁻¹) and gallic acid (53.3 µg mL⁻¹) as major phytochemicals. Replicated optimization experiments identified 1:50 extract dilution, 5 mM AgNO₃, 70 °C, and 2 mL extract as optimal conditions, producing a surface plasmon resonance peak at 435 nm. TEM revealed predominantly spherical AgNPs (12 to 24 nm), while XRD showed (111), (200), (220), and (311) reflections characteristic of crystalline face-centered cubic silver. AgNPs produced inhibition zones of 15 ± 0.7 mm against Escherichia coli and 30 ± 1.0 mm against Candida albicans, with an MIC of 0.117 µg mL⁻¹ against E. coli. As a key novelty, AEF enables normalized comparison with reference antimicrobials, while NBIP converts SEM-observed cellular damage into a quantitative index. This framework extends conventional inhibition-based assessment by integrating antimicrobial potency with cellular damage and provides a transferable approach for evaluating plant-derived antimicrobial nanomaterials.

The proximate composition and functional attributes were analyzed for brown seaweeds (Padina vickersiae, Sargassum polycystum, Sargassum vulgare, Turbinaria murrayana, and Turbinaria ornata)relative to the growth of Nile tilapia fish. The collected seaweeds were dried in an oven at 70 °C for 12 h. Seaweed contained a maximum of total protein, dietary fibre, and low concentration of lipids. The nutrient rich seaweeds were mixed with the fish diet at various concentrations (2% to 10%). The formulated feed was fed to tilapia, which improved growth performance, feed conversion ratio, and specific growth rate after 60 days of experiment. At 8% concentration of seaweed in the fish diet fish growth was improved significantly relative to the control diet (p<0.05). To analyse cold stress, Oreochromis niloticus were maintained at 15 °C for seven days. The administered seaweed diet significantly decreased catalase activity (p<0.05) and lipid peroxidation activity (p<0.05) in tilapia fish relative to the  control (without seaweed mixture). The supplemented brown algal diet improved superoxide dismutase enzyme activity (p<0.05) and glutathione S-transferase activity than control fish (p<0.05). The present findings revealed that brown algae have the potential to be used as feed supplements to improve the growth and health benefits of Nile tilapia.

In Malaysia, the depletion of raw materials is beginning to affect particleboard mills, as production could decrease or cease. This will impact the Malaysian wood-based economy, both locally and globally. The use of non-wood lignocellulosic feedstocks is essential to diversify feedstock sources for mills. This study investigated the mechanical properties of particleboard (density = 700 kg/m³) made of kenaf core, rubberwood, and mixed tropical wood with different kenaf core ratios. The kenaf core ratios for the particleboards were 20%, 30%, and 40%, respectively. Boards with the dimensions 500 mm × 700 mm × 16 mm were produced. The experimental activities to determine the mechanical properties of particleboard, especially the modulus of rupture (MOR), modulus of elasticity (MOE), and internal bond (IB) were conducted based on European standards of EN 310:1993 and EN 319:1993 using a Universal Testing Machine. The results showed that 20%, 30%, and 40% of the kenaf core ratios passed the minimum requirements for board Type P2 based on European standards of EN 312:2010. The board performance was compared with commercial boards by local manufacturers. The kenaf core performance could be further optimized for commercialization.

Wood flour sheets were prepared by wet extrusion molding using hydroxypropyl methylcellulose (HPMC) and citric acid (CA) as a molding aid and crosslinking agent, respectively. The effects of heat treatment (160 to 180 °C, 0.5 to 1.5 h) on moisture absorption, tensile properties, water stability, and dissolution behavior of CA and HPMC were investigated. Moisture absorption decreased from approximately 9% to 8% at 20 °C and 65% relative humidity (RH), and from approximately 15% to 12% at 70 °C and 90% RH. The tensile strength measured at 20 °C and 65% RH remained nearly constant regardless of the heat-treatment severity, whereas the tensile strength at 70 °C and 90% RH was significantly improved by the heat treatment. Water immersion tests showed that the heat-treated sheets exhibited improved structural stability and reduced water absorption compared to the oven-dried control. HPLC analysis revealed that the dissolution ratios of both CA and HPMC decreased markedly with increasing heat treatment severity. The simultaneous reduction in CA and HPMC dissolution suggests that heat treatment promoted CA-mediated crosslinking and insolubilization of HPMC within the sheet structure. These changes contributed to improved water stability and retention of mechanical properties under high-temperature/high-humidity conditions, thereby enhancing the overall environmental stability of the wood flour sheets.

This study characterized Thymus maroccanus essential oil (TMEO) and compared its antimicrobial activity with carvacrol and their combination. The TMEO was obtained by microwave-assisted hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC–MS), revealing a carvacrol-dominant profile (71.04%) with 11 compounds representing 98.52% of the volatile fraction. Antimicrobial activity was assessed against Gram-positive and Gram-negative bacteria and clinical Candida isolates using disc diffusion minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and minimum fungicidal concentration (MFC) assays. TMEO showed low MIC values and bactericidal activity against Staphylococcus aureus and Micrococcus luteus (MBC/MIC ≤ 2), while Escherichia coli was less susceptible. Notably, TMEO consistently outperformed carvacrol alone, indicating that the activity of the whole oil cannot be explained by its major component only. A 1:1 (v/v) TMEO–carvacrol combination further improved antimicrobial activity against several strains, particularly Gram-positive bacteria and Candida albicans. However, in the absence of interaction assays, this effect is interpreted as enhanced combined activity rather than confirmed synergy. The observed differences in susceptibility are consistent with known structural and physiological variation among microorganisms. In conclusion, T. maroccanus was found to be a carvacrol-rich chemotype with promising antimicrobial activity, warranting further mechanistic, safety, and formulation studies for practical  applications.

Valonia tannin, a typical hydrolysable tannin, was used as the raw material and sucrose as the cross-linking agent to investigate the influence of sucrose proportion on the structure and performance of the adhesive. The aim was to evaluate the feasibility of utilizing hydrolysable tannins for wood adhesives. Fourier transform infrared spectroscopy confirmed that valonia tannin belongs to a typical hydrolysable gallotannin, with ester bond linkages and ortho-trisubstituted benzene ring structures present in the molecule. The bonding performance results showed that as the sucrose proportion increased from 66.7% to 100%, the dry strength increased from 1.04 to 1.43 MPa, and the warm-water strength increased from 0.46 to 0.84 MPa, meeting the requirements for Class II plywood specified in the GB/T 17657 (2022) standard. Increasing the sucrose proportion promoted the dehydration of sucrose toward 5-hydroxymethylfurfural, which is proposed to subsequently form a dense three-dimensional cross-linked network with valonia tannin based on our group’s prior condensed-tannin studies, effectively compensating for the deficiencies of hydrolysable tannins in terms of low reactivity and unstable ester bonds. This study provides a theoretical basis and experimental support for the high-value utilization of hydrolysable tannins in the field of wood adhesives.

A bacterial consortium was used to assess the potential of bioremediation for treating textile wastewater and evaluating the phytotoxicity effects of biotreated wastewater using tomato seed germination and seedling growth. The optimum conditions for bioremediation were achieved by varying the concentration of inoculum, temperature, incubation time and concentration of textile wastewater for maximum decolorization were 8 mL inoculum, 37 °C, 4 days incubation time, and 25 to 50 mL of the textile wastewater. The optimized treatment was implemented in a laboratory-scale bioreactor, resulting in substantial improvement in the measured wastewater-quality parameters. The COD removal reached approximately 86%, while TSS removal exceeded 80%. The untreated textile wastewater (TW) resulted in a decline in tomato seed germination and seedling development, whereas biotreated wastewater (Bt-W) improved growth performance. The percentage of germination in the control, TW, and Bt-W was 94%, 81%, and 90%, respectively. The seedling vigor index was highest in Bt-W (676.80), compared with the control (655.18) and TW (567.0). Under laboratory scale conditions, bacterial consortium-based biotreatment caused reduction of wastewater related phytotoxic effects and potential future development of reused wastewater from textile effluents. The approach supports the United Nations Sustainable Development Goals.

Composite boards were produced using Tetra Pak ground material and wood fiber, and the effects of the mixture ratio on the properties of the boards were determined. The main purpose of the study was to obtain a fiber board by bonding Tetra Pak material with wood fiber using phenol formaldehyde adhesive. For this purpose, waste Tetra Pak boxes were collected after domestic use and ground in a high-speed grinding machine. The obtained ground material (Tetra Pak material) was mixed with the wood fiber used in fiberboard production at different ratios of Tetra Pak material (0%, 33%, 66%, and 100%). These mixtures were glued using phenol formaldehyde. Each mixture was first formed into a sheet and then pressed in a hot press using a metal mold. After pressing, the physical (density, water absorption, and thickness swelling) and mechanical properties (modulus of rupture, modulus of elasticity, internal bond, and hardness) were determined. According to the data obtained, increasing the proportion of Tetra Pak material in the produced panels improved their physical properties while decreasing their mechanical properties. The modulus of rupture and modulus of elasticity values for group 1 and group 4 decreased from 32.1 to 10.4 N/mm² and from 2777 to 1019 N/mm², respectively.

An integrated CaO–Fenton waste-to-resource strategy was evaluated for converting anaerobic sewage digestate into a microbiologically safe and nutritionally functional solution for hydroponic lettuce (Lactuca sativa L.) cultivation. Lime stabilization at dosages up to 35% achieved near-complete pathogen inactivation. Beside substantial decreases in total solids (TS), total volatile solids (TVS), chemical oxygen demand (COD), NH₄⁺ ions, and heavy metals.  Subsequent Fenton oxidation using hydrogen peroxide (H₂O₂) and Fe²⁺ ensured complete microbial sterilization and further improved effluent quality, achieving additional reductions in TS (87.7%), TVS (100%), COD (52.5%), and BOD (52.4%). When applied in a deep-water culture (DWC) hydroponic system, CaO–Fenton-TD supported plant growth with moderate biomass reductions but significantly increased the accumulation of bioactive compounds with potential nutritional value, including ascorbic acid, total carotenoids, total phenolics, and total flavonoids, relative to the control. One-way ANOVA followed by Tukey’s HSD confirmed that both CaO stabilization and Fenton oxidation had significant effects (P ≤ 0.05) on the physicochemical and microbial properties of the digestate. Overall, the results demonstrated the feasibility of using CaO–Fenton-treated anaerobic digestate in hydroponic systems. The proposed approach supports circular economy by promoting nutrient recovery and beneficial reuse of digestate, thereby reducing waste-disposal burdens and dependence on conventional mineral fertilizers.