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Yoong Kit Aw

Bio: Yoong Kit Aw is an academic researcher from Monash University Malaysia Campus. The author has contributed to research in topics: Tropical peat & Swamp. The author has an hindex of 3, co-authored 5 publications receiving 270 citations.

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TL;DR: Pectin bionanocomposite films filled with various concentrations of two different types of halloysite nanotubes were prepared and characterized in this paper as potential films for food packaging applications.
Abstract: Pectin bionanocomposite films filled with various concentrations of two different types of halloysite nanotubes were prepared and characterized in this study as potential films for food packaging applications. The two types of halloysite nanotubes were long and thin (patch) (200–30 000 nm length) and short and stubby (Matauri Bay) (50–3000 nm length) with different morphological, physical, and dispersibility properties. Both matrix (pectin) and reinforcer (halloysite nanotubes) used in this study are considered as biocompatible, natural, and low-cost materials. Various characterization tests including Fourier transform infrared spectroscopy, field emission scanning electron microscopy, release kinetics, contact angle, and dynamic mechanical analysis were performed to evaluate the performance of the pectin films. Exceptional thermal, tensile, and contact angle properties have been achieved for films reinforced by patch halloysite nanotubes due to the patchy and lengthy nature of these tubes, which form a b...

243 citations

Journal ArticleDOI
TL;DR: It can be concluded that this strain represents a novel species within the Bcc, for which the name Burkholderia paludis sp.
Abstract: A novel Gram negative rod-shaped bacterium, designated strain MSh1T, was isolated from Southeast Pahang tropical peat swamp forest soil in Malaysia and characterized using a polyphasic taxonomy approach. The predominant cellular fatty acids (>10.0%) were C16:0 (31.7%), C17:0 cyclo (26.6%) and C19:0 cyclo w8c (16.1%). The polar lipids detected were phosphatidylglycerol, phosphatidylethanolamine and diphosphatidylglycerol. The predominant ubiquinone was Q-8. This revealed that strain MSh1T belongs to the genus Burkholderia. The type strain MSh1T can be differentiated from other Burkholderia cepacia complex (Bcc) species by phylogenetic analysis of 16S rRNA gene sequence, multilocus sequence analysis (MLSA), average nucleotide identity (ANI) and biochemical tests. DNA-DNA relatedness values between strain MSh1T and closely related type strains were below the 70% threshold value. Based on this polyphasic study of MSh1T, it can be concluded that this strain represents a novel species within the Bcc, for which the name Burkholderia paludis sp. nov. is proposed. The type strain is MSh1T (=DSM 100703T =MCCC 1K01245T). The dichloromethane extract of MSh1T exhibited antimicrobial activity against four Gram positive bacteria (Enterococcus faecalis ATCC 29212, Enterococcus faecalis ATCC 700802, Staphylococcus aureus ATCC 29213, Staphylococcus aureus ATCC 700699) and a Gram negative bacteria (Escherichia coli ATCC 25922). Further purification work has led to the isolation of Compound 1, pyochelin. Pyochelin demonstrated antimicrobial activity against four S. aureus strains and three E. faecalis strains with MIC values of 1.57 µg/ml and 3.13 µg/ml respectively. SEM analysis showed that the cellular morphology of E. faecalis ATCC 700802 was not affected by pyochelin; suggesting that it might target the intracellular components. Pyochelin, a siderophore with antimicrobial activity might be useful in treating bacterial infections caused by S. aureus and E. faecalis, however further work has to be done.

59 citations

Journal ArticleDOI
TL;DR: The isolate of a Gram variable, rod shaped, endospore forming, facultative anaerobic novel strain MSt1T that exerts potent and broad spectrum antimicrobial activity was isolated and proposed that it represents a novel species within the genus of Paenibacillus.
Abstract: Emergence of antimicrobial resistance coupled with the slowdown in discovery of new antimicrobial compounds points to serious consequences in human health. Therefore, scientists are looking for new antimicrobial compounds from unique and understudied ecosystem such as tropical peat swamp forests. Over the course of isolating antimicrobial producing bacteria from North Selangor tropical peat swamp forest, Malaysia, a Gram variable, rod shaped, endospore forming, facultative anaerobic novel strain MSt1T that exerts potent and broad spectrum antimicrobial activity was isolated. Phylogenetic analysis using 16S rRNA gene sequences showed that strain MSt1T belonged to the genus Paenibacillus with the highest similarity with Paenibacillus elgii SD17T (99.5%). Whole genome comparison between strain MSt1T with its closely related species using average nucleotide identity (ANI) revealed that similarity between strain MSt1T with Paenibacillus elgii B69 (93.45%) and Paenibacillus ehimensis A2 (90.42%) was below the recommended threshold of 95%. Further analysis using in silico pairwise DDH also showed that similarity between strain MSt1T with P. elgii B69 (55.4%) and P. ehimensis A2 (43.7%) was below the recommended threshold of 70%. Strain MSt1T contained meso-diaminopilemic acid in the cell wall and MK-7 as the major menaquinone. The major fatty acids of strain MSt1T were anteiso-C15:0 (48.2%) and C16:0 (29.0%) whereas the polar lipid profile consisted of phosphatidylglycerol, phosphatidylethanolamine, diphosphatidylglycerol, one unknown lipid, two unknown glycolipids and one unknown phospholipid. Total DNA G+C content of strain MSt1T was 51.5 mol%. Extract from strain MSt1T exerted strong antimicrobial activity against Escherichia coli ATCC 25922 (MIC = 1.5 µg/mL), MRSA ATCC 700699 (MIC = 25 µg/mL) and Candida albicans IMR (MIC = 12.5 µg/mL). Partially purified active fraction exerted strong effect against Escherichia coli ATCC 25922 resulting in cell rupture when viewed with SEM. Based on distinctive taxonomic differences between strain MSt1T when compared to its closely related type species, we propose that strain MSt1T represents a novel species within the genus of Paenibacillus, for which the name Paenibacillus tyrfis sp. nov. (= DSM 100708T = MCCC 1K01247T) is proposed.

24 citations

Journal ArticleDOI
TL;DR: The draft genome sequences of two antimicrobial-producing isolates, Burkholderia sp.
Abstract: We report the draft genome sequences of two antimicrobial-producing isolates, Burkholderia sp. strains MSh1 and MSh2, which were isolated from tropical peat swamp forest soil. Putative genes related to different antimicrobial production have been annotated in both genome sequences.

3 citations

Journal ArticleDOI
TL;DR: Genes involved in antimicrobial biosynthesis are found in this genome of Paenibacillus sp.
Abstract: We report the draft genome sequence of Paenibacillus sp. strain MSt1, which has broad-range antimicrobial activity, isolated from tropical peat swamp soil. Genes involved in antimicrobial biosynthesis are found to be present in this genome.

2 citations


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3,734 citations

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TL;DR: The potential of nanoparticles for their uses in the food industry is summarized in order to provide consumers a safe and contamination free food and to ensure the consumer acceptability of the food with enhanced functional properties.
Abstract: Recent innovations in nanotechnology have transformed a number of scientific and industrial areas including the food industry. Applications of nanotechnology have emerged with increasing need of nanoparticle uses in various fields of food science and food microbiology, including food processing, food packaging, functional food development, food safety, detection of foodborne pathogens and self-life extension of food and/or food products. This review summarizes the potential of nanoparticles for their uses in the food industry in order to provide consumers a safe and contamination free food and to ensure the consumer acceptability of the food with enhanced functional properties. Aspects of application of nanotechnology in relation to increasing in food nutrition and organoleptic properties of foods have also been discussed briefly along with a few insights on safety issues and regulatory concerns on nano-processed food products.

368 citations

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TL;DR: Antibiotic‐free antibacterial strategies enabled by advanced nanomaterials are presented and practical antibacterial applications employing these antibiotic‐free strategies are introduced.
Abstract: Bacterial infection is one of the top ten leading causes of death globally and the worst killer in low-income countries. The overuse of antibiotics leads to ever-increasing antibiotic resistance, posing a severe threat to human health. Recent advances in nanotechnology provide new opportunities to address the challenges in bacterial infection by killing germs without using antibiotics. Antibiotic-free antibacterial strategies enabled by advanced nanomaterials are presented. Nanomaterials are classified on the basis of their mode of action: nanomaterials with intrinsic or light-mediated bactericidal properties and others that serve as vehicles for the delivery of natural antibacterial compounds. Specific attention is given to antibacterial mechanisms and the structure-performance relationship. Practical antibacterial applications employing these antibiotic-free strategies are also introduced. Current challenges in this field and future perspectives are presented to stimulate new technologies and their translation to fight against bacterial infection.

364 citations

Journal ArticleDOI
TL;DR: Halloysite is natural tubular clay suitable as a component of biocompatible nanosystems with specific functionalities as discussed by the authors, and the selective modification of halloysite inner/outer surfaces can be achieved by exploiting supramolecular and covalent interactions resulting in controlled colloidal stability adjusted to the solvent polarity.
Abstract: Halloysite is natural tubular clay suitable as a component of biocompatible nanosystems with specific functionalities. The selective modification of halloysite inner/outer surfaces can be achieved by exploiting supramolecular and covalent interactions resulting in controlled colloidal stability adjusted to the solvent polarity. The functionalized halloysite nanotubes can be employed as reinforcing filler for polymers as well as carriers for the sustained release of active molecules, such as antioxidants, flame-retardants, corrosion inhibitors, biocides and drugs. The tubular morphology makes halloysite a perspective template for core-shell metal supports for mesoporous catalysts. The catalysts can be incorporated with selective and unselective metal binding on the nanotubes' outer surface or in the inner lumens. Micropatterns of self-assembled nanotubes have been realized by the droplet casting method. The selective modification of halloysite has been exploited to increase the nanotubes' ordering in the produced patterns. Pickering emulsions, induced by the self-assembly of halloysite nanotubes on oil-water interface, can be used for petroleum spill bioremediation and catalysis.

305 citations

Journal ArticleDOI
TL;DR: An up-to-date overview of polymer-nanoclay composites along with their synthesis routes and applications is presented in this article, which highlights potential future directions for this emerging field of research.
Abstract: Recent advancements in material technologies have promoted the development of various preparation strategies and applications of novel polymer–nanoclay composites. Innovative synthesis pathways have resulted in novel polymer–nanoclay composites with improved properties, which have been successfully incorporated in diverse fields such as aerospace, automobile, construction, petroleum, biomedical and wastewater treatment. These composites are recognized as promising advanced materials due to their superior properties, such as enhanced density, strength, relatively large surface areas, high elastic modulus, flame retardancy, and thermomechanical/optoelectronic/magnetic properties. The primary focus of this review is to deliver an up-to-date overview of polymer–nanoclay composites along with their synthesis routes and applications. The discussion highlights potential future directions for this emerging field of research.

199 citations