Research Output
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PublicationFabrication of active food packaging based on PLA/Chitosan/CNC-containing Coleus aromaticus essential oil: application to Harumanis mango( 2023-12-01)This study aimed to determine the effect of Coleus aromaticus essential oil (CAEO) on the properties of an active film based on polylactic acid (PLA), chitosan (Cs), and cellulose nanocrystal (CNC) in fruit packaging. The films were fabricated via solvent casting technique. The obtained films’ antimicrobial, antioxidant, microstructural, and mechanical properties were studied. Mechanical properties state how adding essentials oil into film improves the elongation breaks significantly (p < 0.05) by 5.3 and 6.1%, respectively, with the addition of 0.4 wt% and 0.8 wt% CAEO which reflets its flexibility. The antioxidant activity of biopolymer film increased significantly (p < 0.05), with antioxidant values ranging from 6.50 to 57.50% with the elevation of CAEO. The inhibitory impact of the film against pathogenic fungus was evaluated in vitro and in vivo by comparing the film with different concentrations of essential oil (EO), as well as the control and chemical fungicide. Disc diffusion was utilised to test mycelial growth suppression, and the film containing 1.2 wt% EO produced the best results. The biofilm containing 1.2 wt% EO successfully reduced illness incidence in vivo with damaged mango. Scanning Electron Microscopy and Transmission Electron Microscopy imaging were used to observe the incorporation of CAEO in the matrix of the film. All Fourier-Transform Infrared spectra of PLA/Cs/CNC and EO blends exhibited the characteristic bands of PLA-based materials. The results indicate that the PLA/Cs/CNC/CAEO films provide a new way to improve microbial safety and extend the shelf life of mango fruit and have the potential for replacement of petroleum-based plastic for fruit packaging applications at the industrial level.
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PublicationMixed Matrix Membrane (MMMs) as Membrane Based Separation Technology: A Review( 2023-01-01)Mixed matrix membrane (MMMs) is an innovative membrane based-separation technology that plays an essential role in liquid and gas separation and purification recently. This review emphasizes mainly on the current MMMs technology. The discussion begins with a background of the MMMs technologies, followed by a comparison between the MMMs technology porous and non-porous membranes. Following that, state-of-the-art MMMs are featured, which contain a variety of polymers and non-polymers, as well as inorganic fillers and materials. The binary filler approach is also explained, which combines two filler materials to achieve synergistic improvements in MMMs. The development of new robust, high-performance materials is one type of revolutionary membrane preparation approach for harsh and inconsiderate environments. In comparison to pristine polymeric membranes, blended mixed matrix membranes with polymer, solvent, and additives are believed for efficient performance. In addition, fabrication strategies for MMMs preparation are addressed. The fabrication technique can be used to improve membrane performance in a number of ways, including resilience to extremes in process conditions and higher mixture resolution when separating gases and liquids. After that, membrane characterization is performed to analyze the membrane's structural and morphological properties. Based on that, critical evaluation of the performances of the MMMs based on the characterization of the membrane is evaluated in context. Finally, the opportunities, as well as future prospects for the integration of MMMs units for process intensification in various sectors, are also significant of the review.
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PublicationSynthesis of zinc oxide nanoparticles via cellar spider extract for enhanced functional properties in antimicrobial activities( 2024-06)This study explores the green synthesis of zinc oxide nanoparticles (ZnO NPs) using cellar spider extracts as a sustainable alternative to traditional methods involving hazardous chemicals and radiation. The spider extracts effectively reduced zinc acetate dihydrate, yielding white precipitates indicative of ZnO NPs. Characterization through SEM revealed diverse morphologies, including spherical, rod-like, hexagonal, and uneven particles forming platelet-like aggregates. Further analyses, such as HPM, 3D nanoprofiler, and EDS, provided insights into size, shape, morphology, surface chemistry, thermal stability, and optical characteristics, quantifying the intended properties of the synthesized ZnO NPs. Antibacterial assays against E. coli and B. subtilis demonstrated significant antibacterial activity, affirming the nanoparticles' potential for antimicrobial applications. This green synthesis approach, validated through comprehensive characterization and quantitative measurements, offers a promising and environmentally friendly route for producing functional ZnO NPs.
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PublicationInhibition Study on the Growth of Clostridium Saccharoperbutylacetonicum N1-4 (ATCC 13564) for the Production of Biobutanol in ABE Fermentation( 2023-01-01)In this present study, the inhibition effect of different concentrations of sugar degradation products in upstream processing (Hydroxymethylfurfural (HMF) and Furfural) and butanol as product inhibition in downstream processing on the growth of Clostridium saccharoperbutylacetonicum N1-4 (ATCC 13564) for the production of biobutanol in ABE Fermentation has been investigated. It was found that the presence of HMF and Furfural is non-toxic to cell growth and biobutanol production at concentrations below 3 g/L in the fermentation medium. The specific growth rate for both HMF and furfural was 0.067 h−1 and 0.066 h−1 respectively which is very close to the control medium without any inhibitor addition (0.068 h−1). Surprisingly, the addition of 1 g/L HMF has improved the yield of biobutanol from 0.020 g/g (control) to 0.034 g/g and the addition of 1 g/L Furfural has improved the yield of biobutanol to 0.042 g/g. Butanol inhibition study on the growth of C. saccharoperbutylacetonicum N1-4 (ATCC 13564) shows the decrease of specific growth rate from 0.071 to 0.065 h−1 when 5 g/L butanol was added. 15 g/L of butanol addition has caused a significant drop in the specific growth rate to 0.011 h−1 with an inhibitory effect of 85.7%. This result reveals that sugar degradation product has an inhibitory effect on the growth of microorganisms and biobutanol production at a certain concentration, and this ABE fermentation suffers from product inhibition. Therefore, the development of a robust strain is necessary to make this biobutanol industrially competitive even in the presence of the inhibitory compound.
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PublicationEfficiency of Fabricated Adsorptive Polysulfone Mixed Matrix Membrane for Acetic Acid Separation( 2023-06-01)The ultrafiltration mixed matrix membrane (UF MMMs) process represents an applicable approach for the removal of diluted acetic acid at low concentrations, owing to the low pressures applied. The addition of efficient additives represents an approach to further improve membrane porosity and, subsequently, enhance acetic acid removal. This work demonstrates the incorporation of titanium dioxide (TiO2) and polyethylene glycol (PEG) as additives into polysulfone (PSf) polymer via the non-solvent-induced phase-inversion (NIPS) method to improve the performance of PSf MMMs performance. Eight PSf MMMs samples designated as M0 to M7, each with independent formulations, were prepared and investigated for their respective density, porosity, and degree of AA retention. Morphology analysis through scanning electron microscopy elucidated sample M7 (PSf/TiO2/PEG 6000) to have the highest density and porosity among all samples with concomitant highest AA retention at approximately 92.2%. The application of the concentration polarization method further supported this finding by the higher concentration of AA solute present on the surface of the membrane compared to that of AA feed for sample M7. Overall, this study successfully demonstrates the significance of TiO2 and PEG as high MW additives in improving PSf MMM performance.
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PublicationCyclic voltammetry studies of bioanode microbial fuel fells from batch culture of Geobacter sulfurreducens( 2021-05-24)The present study aims to investigate the performance of batch culture of Geobacter sulfurreducens (G. sulfurreducens) for electrical current generation via cyclic voltammetry (CV) method. The CV study was performed with an applied voltage in the range of -0.1 to 0.1 V against the standard calomel electrode (SCE) during the cell growth and attachment of G. sulfurreducens on graphite felt and initial acetate concentration of 20 mM. The kinetics of electrode reaction was investigated by conducting CV experiments at different scanning rates of 5, 10, 20, 50 and 100 mVs-1. The diffusion coefficients (D) and heterogeneous electron transfer rate constant (ko) of both anodic and cathodic process were 1.04 x10-5 cm2.s-1, 1.73x10-6 cm2.s-1, 0.0004 cm.s-1 and 0.0011 cm.s-1, respectively. The obtained results showed that the anode exhibits high bioeletrocatalytic activity due to the attachment of G. sulfurreducens on the anode surface.
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PublicationBibliometric Analysis on Biobutanol Production Research Trends from 2010-2022 using Scopus Database( 2024-03-01)The global demand for biofuels as an alternative energy source is on the rise due to the anticipated decline in fossil fuel (gasoline). Biobutanol, among various biofuels, has garnered significant attention for its advanced features and suitability as an alternative to fossil fuels. Recognizing the importance of understanding research issues and fostering collaborative networks, this bibliometric analysis focuses on synthesizing research trends in biobutanol production over the past 12 years. Examining 357 Scopus-indexed documents, the study shows that over 80% of relevant articles were published after 2010, indicating the recent emergence of literature in this field. Citation analysis identifies publishing trends dating back to 2010, highlighting leading scholars. In 2016, 47 publications in Chemical Engineering were attributed to the field, with Professor Sahaid authoring 12 publications, primarily affiliated with UKM. Chemical Engineering comprised the predominant subject area, with articles constituting 75.07% of total publications. Bioresource Technology was the primary source title, and the keyword Biobutanol was frequently associated with the research (92.16%). UKM led in institutional contributions with 12 publications, while India had the highest total publications at 17.65%, and Malaysia contributed 6.44%. The majority of publications (88.24%) originated from journal publications, and English was the predominant language, accounting for 96.64% of the publications. This paper underscores the recent surge in biobutanol research and the importance of collaborative efforts for further advancements.
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PublicationMicrobial Fuel Cell Technology as Advanced Sewage Sludge Treatment( 2023-01-01)The microbial fuel cell (MFC) has emerged as an innovative and sustainable renewable energy technology, offering a potential alternative to address the global energy crisis. Operating through electrochemical processes, MFCs harness the power of electrogenic bacteria (EB) as biocatalysts to generate electricity. This chapter highlights the untapped potential of sewage sludge, derived from wastewater treatment, as a valuable fuel source within the MFC system. Extensive research has demonstrated the abundance of organic components present in sewage sludge, making it highly amenable to degradation through microbiological pathways within the MFC. Despite the lack of large-scale commercial utilization of MFC technology in wastewater treatment plants, the significant progress and promising findings indicate its effectiveness in addressing the challenges associated with sewage sludge management. The MFC system not only facilitates the simultaneous generation of energy but also contributes to bioremediation efforts. The redox potential inherent in MFCs enables this dual functionality, effectively integrating energy production with the treatment of sewage sludge. This chapter sheds light on the potential of MFC technology as an advanced approach for sewage sludge treatment. By harnessing the capabilities of electrogenic bacteria and capitalizing on the rich organic composition of sewage sludge, MFCs offer a sustainable solution that can simultaneously address energy needs and promote efficient waste management in wastewater treatment plants. The abundant and promising data accumulated thus far underscore the viability and potential of MFCs in mitigating the challenges associated with sewage sludge waste.
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PublicationFormulation of selective hydrophobic deep eutectic oil-in-water nanoemulsion as green fungicides for mitigating anthracnose fungus Colletotrichum gloeosporioides( 2023-12-01)Hydrophobic deep eutectic nanoemulsions derived from fatty acids and terpenes (referred to as HyDEN) were introduced as potential nano-coating to effectively combat anthracnose during the postharvest preservation of fruits. Anthracnose primarily caused by the Colletotrichum gloeosporioides species is known for causing substantial damage to fruits. Synthetic fungicides have proven to be effective but come with environmental, health, and safety concerns. In this study, hydrophobic deep eutectic solvents (HDESs) were evaluated for their physical properties to identify the most suitable HDES for the formulation of HyDEN. Menthol-Thymol (MT) at 1:1 and 2:1 ratio met the criteria and was chosen for the formulation of HyDEN. HyDEN (MT-N 1:1) displayed a higher zeta potential value and smaller mean droplet diameter and then tested for its antifungal properties against C. gloeosporioides compared with selected antifungal agents. HyDEN (MT-N 1:1) exhibited strong antifungal activity against C. gloeosporioides and was attributed to its potent mode of action, binding affinity, and rapid onset compared to HDES and fungicide (Globus 5.5). This study also investigated how HyDEN (MT-N 1:1) affects mycelial growth, cell membrane permeability, and cellular leakage of C. gloeosporioides, highlighting its superior disruption of cell membranes compared to HDES and Globus 5.5. This research presents an eco-friendly alternative to the use of toxic chemicals and showcases an innovative and sustainable approach to controlling anthracnose in postharvest fruit preservation.
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PublicationGreen Renewable Energy: Microbial Fuel Cell Technology( 2023-01-01)Microbial fuel cells (MFCs) are a bio-electrochemical system designed to generate energy by using electrons obtained from biological processes catalyzed by microorganisms. In MFCs, electrons are transmitted from the anode compartment (the negative terminal) to the cathode compartment (the positive terminal) via a conductive substance. Electrons are mixed with oxygen at the cathode, while protons diffuse via a proton exchange membrane. MFCs need continuous electron release from the anode and electron consumption from the cathode. Using microorganisms for effective conversion, MFC technology promises to produce clean energy from waste products produced by civilization. This technology, in contrast to renewable energy sources, recycles trash and energy created by our civilization and returns them to us, therefore reducing the adverse side effects of environmental degradation. This article examines the historical pattern of energy usage in Malaysia. In conjunction with that, this paper will review the principles of MFCs. Several designs of microbial fuel cells are utilized in this study. There has been variation in power density outcomes. Single-chamber, double-chamber, tubular, and flat-plate MFCs are examples of MFCs. Nonetheless, double-chamber and single-chamber MFCs are the focus of this paper. The substrate utilized affects the performance of MFCs; thus, several widely used substrates are also examined.