Displaying all 15 publications

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  1. Sajab MS, Chia CH, Zakaria S, Khiew PS
    Bioresour Technol, 2013 Jan;128:571-7.
    PMID: 23211482 DOI: 10.1016/j.biortech.2012.11.010
    Oil palm empty fruit bunch (EFB) fibers were employed to remove dyes from aqueous solutions via adsorption approaches. The EFB fibers were modified using citric acid (CA) and polyethylenimine (PEI) to produce anionic and cationic adsorbents, respectively. The CA modified EFB fibers (CA-EFB) and PEI-modified EFB fibers (PEI-EFB) were used to study the efficiency in removing cationic methylene blue (MB) and anionic phenol red (PR) from aqueous solutions, respectively, at different pHs, temperatures and initial dye concentrations. The adsorption data for MB on the CA-EFB fitted the Langmuir isotherm, while the adsorption of PR on the PEI-EFB fitted the Freundlich isotherm, suggesting a monolayer and heterogeneous adsorption behavior of the adsorption processes, respectively. Both modified fibers can be regenerated up to seven adsorption/desorption cycles while still providing as least 70% of the initial adsorption capacity.
  2. Arris FA, Thai VTS, Manan WN, Sajab MS
    Foods, 2020 Nov 29;9(12).
    PMID: 33260330 DOI: 10.3390/foods9121769
    Process-based contaminants in food-particularly in vegetable oils-have been a topic of interest due to their potential health risk on humans. Oral consumption above the tolerable daily intake might result in health risks. Therefore, it is critical to correctly address the food contaminant issues with a proper mitigation plan, in order to reduce and subsequently remove the occurrence of the contaminant. 3-monochloropropane-1,3-diol (3-MCPD), an organic chemical compound, is one of the heat- and process-induced food contaminants, belonging to a group called chloropropanols. This review paper discusses the occurrence of the 3-MCPD food contaminant in different types of vegetable oils, possible 3-MCPD formation routes, and also methods of reduction or removal of 3-MCPD in its free and bound esterified forms in vegetable oils, mostly in palm oil due to its highest 3-MCPD content.
  3. Ibrahim F, Mohan D, Sajab MS, Bakarudin SB, Kaco H
    Polymers (Basel), 2019 Sep 23;11(10).
    PMID: 31547544 DOI: 10.3390/polym11101544
    In this study, lignin has been extracted from oil palm empty fruit bunch (EFB) fibers via an organosolv process. The organosolv lignin obtained was defined by the presence of hydroxyl-containing molecules, such as guaiacyl and syringyl, and by the presence of phenolic molecules in lignin. Subsequently, the extracted organosolv lignin and graphene nanoplatelets (GNP) were utilized as filler and reinforcement in photo-curable polyurethane (PU), which is used in stereolithography 3D printing. The compatibility as well as the characteristic and structural changes of the composite were identified through the mechanical properties of the 3D-printed composites. Furthermore, the tensile strength of the composited lignin and graphene shows significant improvement as high as 27%. The hardness of the photo-curable PU composites measured by nanoindentation exhibited an enormous improvement for 0.6% of lignin-graphene at 92.49 MPa with 238% increment when compared with unmodified PU.
  4. Salleh KM, Zakaria S, Sajab MS, Gan S, Kaco H
    Int J Biol Macromol, 2019 Jun 15;131:50-59.
    PMID: 30844455 DOI: 10.1016/j.ijbiomac.2019.03.028
    A green regenerated superabsorbent hydrogel was fabricated with mixtures of dissolved oil palm empty fruit bunch (EFB) cellulose and sodium carboxymethylcellulose (NaCMC) in NaOH/urea system. The formation of hydrogel was aided with epichlorohydrin (ECH) as a crosslinker. The resultant regenerated hydrogel was able to swell >80,000% depending on the NaCMC concentrations. The hydrogel absorbed water rapidly upon exposure to water up to 48 h and gradually declined after 72 h. The crosslinked of covalent bond of COC between dissolved EFB cellulose (EFBC) with NaCMC was confirmed with Attenuated total reflectance Fourier transform infrared (ATR-FT-IR) spectroscopy. Crystallinity and thermal stability of the hydrogel samples were depended on the concentrations of NaCMC, crosslinking, and swelling process. The strength and stability of crosslinked network was studied by examining the gel fraction of hydrogel. This study explored the swelling ability and probable influenced factors towards physical and chemical properties of hydrogel.
  5. Feng H, Wang Z, Sajab MS, Abdul PM, Ding G
    Int J Biol Macromol, 2023 Jan 10;230:123210.
    PMID: 36639077 DOI: 10.1016/j.ijbiomac.2023.123210
    This is the first report of the use of steam flash explosion (SFE) to prepare chitinous nanoparticles from black soldier fly (BSF). SFE treatment was performed at a steam pressure of 0.45 to 1.60 MPa with a holding time of 60 s. As the pressure increased, the particle size of the chitinous particles decreased. Under SFE at 1.60 MPa, chitinous nanoparticles with sizes ranging from 59 to 162 nm were produced. SEM, AFM, Raman spectroscopy, FT-IR spectroscopy, 1H NMR, TGA, and DSC were used to characterize the BSF chitin materials. It was demonstrated that SFE treatment deacetylated chitin to obtain chitosan with 91.24 % deacetylation. In addition, the polymer backbone was maintained, and the degree of polymerization of chitosan nanoparticles was reduced. The activity of the cationic groups of chitosan nanoparticles was improved, thereby enhancing the temperature sensitivity of the polymeric material. It can be concluded that the SFE one-step processing method is a simple and efficient way to prepare homogeneous biomaterial nanoparticles. This study has implications for the development of chitosan nanomaterials for biomedical applications.
  6. Sajab MS, Mohan D, Santanaraj J, Chia CH, Kaco H, Harun S, et al.
    Sci Rep, 2019 08 12;9(1):11703.
    PMID: 31406228 DOI: 10.1038/s41598-019-48274-2
    The recognition of cellulose nanofibrils (CNF) in the past years as a high prospect material has been prominent, but the impractical cellulose extraction method from biomass remained as a technological barrier for industrial practice. In this study, the telescopic approach on the fractionation of lignin and cellulose was performed by organosolv extraction and catalytic oxidation from oil palm empty fruit bunch fibers. The integration of these techniques managed to synthesize CNF in a short time. Aside from the size, the zeta potential of CNF was measured at -41.9 mV, which allow higher stability of the cellulose in water suspension. The stability of CNF facilitated a better dispersion of Fe(0) nanoparticles with the average diameter size of 52.3-73.24 nm through the formulation of CNF/Fe(0). The total uptake capacity of CNF towards 5-fluorouracil was calculated at 0.123 mg/g. While the synergistic reactions of adsorption-oxidation were significantly improved the removal efficacy three to four times greater even at a high concentration of 5-fluorouracil. Alternatively, the sludge generation after the oxidation reaction was completely managed by the encapsulation of Fe(0) nanoparticles in regenerated cellulose.
  7. Mohan D, Teong ZK, Sajab MS, Kamarudin NHN, Kaco H
    Polymers (Basel), 2021 Jun 08;13(12).
    PMID: 34201366 DOI: 10.3390/polym13121912
    The tendency to use cellulose fibrils for direct ink writing (DIW) of three-dimensional (3D) printing has been growing extensively due to their advantageous mechanical properties. However, retaining cellulose in its fibrillated forms after the printing process has always been a challenge. In this study, cellulose macrofibrils (CMFs) from oil palm empty fruit bunch (OPEFB) fibers were partially dissolved for consistent viscosity needed for DIW 3D printing. The printed CMF structure obtained from optimized printing profiles (volumetric flow rate, Qv = 9.58 mm/s; print speed, v = 20 mm/s), exhibited excellent mechanical properties (tensile strength of 66 MPa, Young's modulus of 2.16 GPa, and elongation of 8.76%). The remarkable structural and morphological effects of the intact cellulose fibrils show a homogeneous distribution with synthesized precipitated calcium carbonate (CaCO3) nanoparticles. The shear-aligned CMF/CaCO3 printed composite exhibited a sustained therapeutic drug release profile that can reduce rapid release that has adverse effects on healthy cells. In comparison with the initial burst release of 5-fluorouracil (5-FU) by CaCO3, the controlled release of 5-fluorouracil can be varied (48 to 75%) with the composition of CMF/CaCO3 allowing efficient release over time.
  8. Salleh KM, Zakaria S, Sajab MS, Gan S, Chia CH, Jaafar SNS, et al.
    Int J Biol Macromol, 2018 Oct 15;118(Pt B):1422-1430.
    PMID: 29964115 DOI: 10.1016/j.ijbiomac.2018.06.159
    Dissolved oil palm empty fruit bunch (EFB) cellulose in NaOH/urea solvent was mixed with sodium carboxymethylcellulose (NaCMC) to form a green regenerated superabsorbent hydrogel. The effect of concentration of epichlorohydrin (ECH) as the crosslinker on the formation, physical, and chemical properties of hydrogel was studied. Rapid formation and higher gel content of hydrogel were observed at 10% concentration of ECH. The superabsorbent hydrogel was successfully fabricated in this study with the swelling ability >100,000%. Hydrogel with higher concentration of ECH showed opposite trend by having higher superabsorbent property than that of lower concentration. The covalent bond of COC was observed with Attenuated total reflectance fourier transform infrared (ATR-FT-IR) spectroscopy to confirm the occurrence of crosslinking. The physical and chemical properties of hydrogel were affected by swelling phenomenon. Hydrogel with higher degree of swelling exhibited lower moisture retention and higher transparency. Moreover, the weight of the superabsorbent hydrogel increased with the decrement of pH value of external media (distilled water). This study provided substantial information on the effect of different percentage of ECH as crosslinker on hydrogel basic properties. Furthermore, this study affords correlation of many essential driving forces that affected hydrogel superabsorbent property.
  9. Mohan D, Sajab MS, Kaco H, Bakarudin SB, Noor AM
    Nanomaterials (Basel), 2019 Dec 03;9(12).
    PMID: 31817002 DOI: 10.3390/nano9121726
    The recognition of nanocellulose has been prominent in recent years as prospect materials, yet the ineffectiveness of nanocellulose to disperse in an organic solvent has restricted its utilization, especially as a reinforcement in polymer nanocomposite. In this study, cellulose has been isolated and defibrillated as cellulose nanofibrils (CNF) from oil palm empty fruit bunch (EFB) fibers. Subsequently, to enhance its compatibility with UV-curable polyurethane (PU)-based resin, the surface hydrophilicity of CNF has been tailored with polyethylene glycol (PEG), as well as reduced graphene oxide (rGO). The dispersibility of reinforced modified CNF in UV-curable PU was examined through the transmittance interruption of resin, chemical, and mechanical properties of the composite printed using the stereolithographic technique. Evidently, the enhanced compatibility of modified CNF and UV-curable PU was shown to improve the tensile strength and hardness of the composites by 37% and 129%, respectively.
  10. Mohan D, Khairullah NF, How YP, Sajab MS, Kaco H
    Polymers (Basel), 2020 Apr 23;12(4).
    PMID: 32340327 DOI: 10.3390/polym12040986
    Drug delivery constitutes the formulations, technologies, and systems for the transport of pharmaceutical compounds to specific areas in the body to exert safe therapeutic effects. The main criteria for selecting the correct medium for drug delivery are the quantity of the drug being carried and the amount of time required to release the drug. Hence, this research aimed to improve the aforementioned criteria by synthesizing a medium based on calcium carbonate-nanocellulose composite and evaluating its efficiency as a medium for drug delivery. Specifically, the efficiency was assessed in terms of the rates of uptake and release of 5-fluorouracil. Through the evaluation of the morphological and chemical properties of the synthesized composite, the established 3D printing profiles of nanocellulose and CaCO3 took place following the layer-by-layer films. The 3D printed double laminated CaCO3-nanocellulose managed to release the 5-fluorouracil as an effective single composition and in a time-controlled manner.
  11. Zaidi SAS, Kwan CE, Mohan D, Harun S, Luthfi AAI, Sajab MS
    Materials (Basel), 2023 Feb 22;16(5).
    PMID: 36902909 DOI: 10.3390/ma16051793
    As additive manufacturing continues to evolve, there is ongoing discussion about ways to improve the layer-by-layer printing process and increase the mechanical strength of printed objects compared to those produced by traditional techniques such as injection molding. To achieve this, researchers are exploring ways of enhancing the interaction between the matrix and filler by introducing lignin in the 3D printing filament processing. In this work, research has been conducted on using biodegradable fillers of organosolv lignin, as a reinforcement for the filament layers in order to enhance interlayer adhesion by using a bench-top filament extruder. Briefly, it was found that organosolv lignin fillers have the potential to improve the properties of polylactic acid (PLA) filament for fused deposition modeling (FDM) 3D printing. By incorporating different formulations of lignin with PLA, it was found that using 3 to 5% lignin in the filament leads to an improvement in the Young's modulus and interlayer adhesion in 3D printing. However, an increment of up to 10% also results in a decrease in the composite tensile strength due to the lack of bonding between the lignin and PLA and the limited mixing capability of the small extruder.
  12. Mohan D, Teong ZK, Bakir AN, Sajab MS, Kaco H
    Polymers (Basel), 2020 Aug 20;12(9).
    PMID: 32825377 DOI: 10.3390/polym12091876
    The materials for additive manufacturing (AM) technology have grown substantially over the last few years to fulfill industrial needs. Despite that, the use of bio-based composites for improved mechanical properties and biodegradation is still not fully explored. This limits the universal expansion of AM-fabricated products due to the incompatibility of the products made from petroleum-derived resources. The development of naturally-derived polymers for AM materials is promising with the increasing number of studies in recent years owing to their biodegradation and biocompatibility. Cellulose is the most abundant biopolymer that possesses many favorable properties to be incorporated into AM materials, which have been continuously focused on in recent years. This critical review discusses the development of AM technologies and materials, cellulose-based polymers, cellulose-based three-dimensional (3D) printing filaments, liquid deposition modeling of cellulose, and four-dimensional (4D) printing of cellulose-based materials. Cellulose-based AM material applications and the limitations with future developments are also reviewed.
  13. Sajab MS, Chia CH, Zakaria S, Jani SM, Ayob MK, Chee KL, et al.
    Bioresour Technol, 2011 Aug;102(15):7237-43.
    PMID: 21620692 DOI: 10.1016/j.biortech.2011.05.011
    Chemically modified kenaf core fibres were prepared via esterification in the presence of citric acid (CA). The adsorption kinetics and isotherm studies were carried out under different conditions to examine the adsorption efficiency of CA-treated kenaf core fibres towards methylene blue (MB). The adsorption capacity of the kenaf core fibres increased significantly after the citric acid treatment. The values of the correlation coefficients indicated that the Langmuir isotherm fitted the experimental data better than the Freundlich isotherm. The maximum adsorption capacity of the CA-treated kenaf core fibres was found to be 131.6mg/g at 60°C. Kinetic models, pseudo-first-order, pseudo-second-order and intraparticle diffusion, were employed to describe the adsorption mechanism. The kinetic data were found to fit pseudo-second-order model equation as compared to pseudo-first-order model. The adsorption of MB onto the CA-treated kenaf core fibres was spontaneous and endothermic.
  14. Amran UA, Salleh KM, Zakaria S, Roslan R, Chia CH, Jaafar SNS, et al.
    Polymers (Basel), 2021 Sep 11;13(18).
    PMID: 34577973 DOI: 10.3390/polym13183072
    Development of polyurethane foam (PUF) containing bio-based components is a complex process that requires extensive studies. This work reports on the production of rigid PUFs from polyol obtained via liquefaction of oil palm empty fruit bunch (EFB) biomass with different isocyanate (NCO) indexes. The effect of the NCO index on the physical, chemical and compressive properties of the liquefied EFB-based PUF (EFBPUF) was evaluated. The EFBPUFs showed a unique set of properties at each NCO index. Foaming properties had affected the apparent density and cellular morphology of the EFBPUFs. Increasing NCO index had increased the crosslink density and dimensional stability of the EFBPUFs via formation of isocyanurates, which had also increased their thermal stability. Combination of both foaming properties and crosslink density of the EFBPUFs had influenced their respective compressive properties. The EFBPUF produced at the NCO index of 120 showed the optimum compressive strength and released the least toxic hydrogen cyanide (HCN) gas under thermal degradation. The normalized compressive strength of the EFBPUF at the NCO index of 120 is also comparable with the strength of the PUF produced using petrochemical polyol.
  15. Liu G, Tiang MF, Ma S, Wei Z, Liang X, Sajab MS, et al.
    PeerJ, 2024;12:e16995.
    PMID: 38426145 DOI: 10.7717/peerj.16995
    BACKGROUND: Hermetia illucens (HI), commonly known as the black soldier fly, has been recognized for its prowess in resource utilization and environmental protection because of its ability to transform organic waste into animal feed for livestock, poultry, and aquaculture. However, the potential of the black soldier fly's high protein content for more than cheap feedstock is still largely unexplored.

    METHODS: This study innovatively explores the potential of H. illucens larvae (HIL) protein as a peptone substitute for microbial culture media. Four commercial proteases (alkaline protease, trypsin, trypsase, and papain) were explored to hydrolyze the defatted HIL, and the experimental conditions were optimized via response surface methodology experimental design. The hydrolysate of the defatted HIL was subsequently vacuum freeze-dried and deployed as a growth medium for three bacterial strains (Staphylococcus aureus, Bacillus subtilis, and Escherichia coli) to determine the growth kinetics between the HIL peptone and commercial peptone.

    RESULTS: The optimal conditions were 1.70% w/w complex enzyme (alkaline protease: trypsin at 1:1 ratio) at pH 7.0 and 54 °C for a duration of 4 h. Under these conditions, the hydrolysis of defatted HIL yielded 19.25% ±0.49%. A growth kinetic analysis showed no significant difference in growth parameters (μmax, Xmax, and λ) between the HIL peptone and commercial peptone, demonstrating that the HIL hydrolysate could serve as an effective, low-cost alternative to commercial peptone. This study introduces an innovative approach to HIL protein resource utilization, broadening its application beyond its current use in animal feed.

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