Asiah Nusaibah Masri

Oil Palm Empty Fruit Bunch (OPEFB), an abundant lignocellulosic biomass in Malaysia, is a promising feedstock for producing Total Reducing Sugar (TRS), although its recalcitrant structure limits enzymatic conversion. This study proposes a novel double-stage ozonolysis pretreatment integrated with intermediate alkaline swelling to enhance cellulose accessibility and saccharification efficiency. Structural modifications were confirmed through compositional analysis, TGA, XRD, FTIR, and SEM. Enzymatic saccharification (ES) was optimized using Response Surface Methodology (RSM) based on a Face-Centered Central Composite Design (FCCCD), evaluating reaction time, biomass loading, and temperature. Analysis of Variance (ANOVA) indicated a significant model (R2 = 0.88), with optimal conditions of 44 h reaction time, 1.8 % w/v biomass loading, and 50 °C temperature, achieving a maximum TRS yield of 42.75%. The double-stage ozonolysis outperformed single-stage and alkaline pretreatments, yielding the highest cellulose enrichment (up to 79 wt%) and improved digestibility. Kinetic analysis revealed a substantial reduction in the Michaelis-Menten constant ( ) from 175.713 to 9.010 mg/mL, indicating enhanced enzyme–substrate affinity. These findings demonstrate a robust and efficient strategy for improving biomass-to-sugar conversion. Copyright © 2026 by Authors, Published by BCREC Publishing Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Natural Deep Eutectic Solvents (NADES) were synthesized from food-grade components and evaluated as green extractants for the simultaneous recovery and liquid chromatography coupled to quadrupole-Orbitrap mass spectrometry (LC–Q-Orbitrap-MS) analysis of biopesticide residues in a complex matrix like honey. Conventional solid–liquid extraction (SLE) was applied, initially using choline chloride-2,3-butanediol (1:4, molar ratio) as the NADES extractant solvent, before systematically evaluating other NADES formulations. Extraction parameters, such as time (10 min, 20 min, and 30 min), technique (rotary mixing vs. sonication), and NADES composition, namely lactic acid–glucose–water (LGH, 5:1:9, molar ratio), lactic acid–glycerol–water (LGLH, 1:1:3, molar ratio), urea–glycerol–water (UGLH, 1:1:2, molar ratio), and choline chloride–2,3-butanediol (ChClBt, 1:4, molar ratio), were systematically optimized. Rotating agitation for 10 min yielded the highest overall recoveries and was therefore selected as the optimal extraction time. Rotary shaking was chosen over sonication due to its superior performance across both simple and complex matrices. Among the NADES tested, UGLH proved to be the most effective composition for the honey matrix. The analytical method was validated for the honey matrix. Linearity showed excellent performance across the tested concentration range, with R² values above 0.95 for all analytes. Matrix effects were within ±20% for nearly half of the compounds, while a few exhibited moderate matrix enhancement. Recoveries ranged from 50.1% to 120.5% at 500 µg/kg and 1000 µg/kg, demonstrating acceptable extraction performance. Intra-day and inter-day precision showed relative standard deviations (RSDs) below 20% for most analytes. Limits of quantification (LOQs) were established at 500 µg/kg for eight compounds based on recovery and precision criteria. These results confirm the suitability of the proposed NADES-based method for sensitive and reliable analysis of biopesticide residues in honey. When compared to conventional extraction methods, the proposed NADES-based protocol proved to be a greener alternative, achieving the highest AGREEprep score due to its use of non-toxic solvents, lower waste generation, and overall sustainability.

Carbon dioxide electrochemical reduction (CO2ER) presents numerous advantages in mitigating greenhouse gas emissions by converting CO2 into value-added chemicals and can be integrated with renewable energy sources such as solar and wind. Nevertheless, establishing an electrochemically stable catalytic system that can effectively decrease the overpotential while maintaining high current density and faradaic efficiency is challenging. The precise mechanisms causing the reactions and the specific functions of the electrode with electrolytes are still not fully understood. Hence, a significant increase in attention has been paid to using ionic liquids (ILs) as electrolytes for CO2ER. This phenomenon is attributed to the unique capabilities of ILs to reduce overpotential, increase current density, and improve electrochemical stability. Therefore, this study evaluated the effect of incorporating ILs into electrolytes to comprehend the cation and anion influences on CO2ER reactions. Linear sweep voltammetry (LSV) and chronoamperometry (CA) were employed to examine the reduction peaks and current density values for different electrolytes, respectively. Consequently, a 0.1 M NBu4PF6 acetonitrile solution containing 1-ethyl-3-methylimidazolium tetrafluoroborate [EMIM][BF4] demonstrated a significantly lower onset potential of the reduction by 320 mV. A reduced CO2ER efficiency involving ILs with long alkyl chains was also observed. Meanwhile, a novel hypothesis concerning molecular orbitals for the CO2ER reaction mechanism was discussed. Overall, various performance variables (reduction stability, applied potential, and current density) of CO2ER were improved using cations with short alkyl chains, anions with high highest occupied molecular orbital (HOMO) levels, and appropriate solvation media. These findings can serve as selection criteria to aid in choosing appropriate ionic liquids for CO2 electrochemical reduction (CO2ER).

One of the hardest processes encountered by petroleum refining is sulfur elimination from fuel oil. There are many traditional methods executed but they caused drawbacks such as poor selectivity of sulfur compounds and toxic raw materials. Extractive oxidative desulfurization (EODS) caught the interest of researchers due to high selectivity of sulfur compounds and great desulfurization. Currently, researchers are investigating the use of ionic liquids (ILs) as green extractant, unfortunately they are expensive. This research is proposing and comparing the use of cheap biodegradable solvents called deep eutectic solvents (DESs), as extractants in removing sulfur from fuel oil. The DESs are synthesized through a combination of choline chloride - orcinol and choline chloride - ethylene glycol, and their structure is confirmed through FTIR. Their thermal properties are characterized by DSC and TGA. Their desulfurization performance is evaluated by type of DESs, different ratios of DES and model oil, different ratios of oxidant and sulfone and various temperatures which these factors are found to influence the result. The optimum conditions are found to be at 1:1 for DES and model oil ratio, 4 for O/S ratio and temperature at 85 °C with the extraction efficiency of 99.98%. In conclusion, this DES has high potential to be the cheap green alternative to the conventional extractant for extractive oxidative desulfurization process.

This study describes the potential conversion of dried microalgae. Chlorella vulgaris (C. vulgaris) into fatty acid methyl ester (FAME) using the direct transesterification (DT) method and using ionic liquids (ILs) as a catalyst. In this work, the performance of monocationic IL, namely 1-butyl-1-methylpyrrolidinium bromide (IL 1), and dicationic IL, namely 1,4-bis(1-methylpyrrolidinium-1-yl) butane dibromide (IL 2), as catalysts was compared for DT of C. vulgaris under microwave irradiation. The results revealed that IL 2 showed a better performance in catalyzing the DT reaction by producing 87.9 mg/g% of FAME, while the use of IL 1 led to 74.3 mg/g% of FAME under optimum conditions. The kinetic study for direct transesterification of C. vulgaris showed that the reaction followed a first order kinetic reaction where the activation energies were calculated to be 22.2499 kJ mol⁻¹ and 22.0413 kJ mol⁻¹ for IL 1 and IL 2, respectively.