Environmental Sustainability Projects

Environmental Sustainability Projects

      Environmental Sustainability Publications

Xanthine oxidase (XO) plays an important role in purine degradation in humans. The study aimed to determine the XO inhibitory potential of Chrysanthemum morifolium dried flower ethyl acetate sub-fractions and its anti-hyperuricemic effect in rat models. Bioassay-guided fractionation based on XO inhibitory assay was employed to obtain bioactive fractions and sub-fractions. In vitro cytotoxicity and cellular antioxidant capacity of the sub-fraction and its mode of XO inhibition were also investigated. The anti-hyperuricemic effect of the bioactive sub-fraction was investigated using rat models via oral consumption, and followed by an XO mRNA gene expression study. The compounds in the bioactive sub-fractions were identified putatively using HPLC-Q-TOF-MS/MS. Ethyl acetate (EtOAc) fraction exhibited the highest XO inhibition among the fractions. It was further fractionated into 15 sub-fractions. F10 exhibited high XO inhibitory activity, cellular pro-proliferative effect, and intracellular antioxidant activity among the sub-fractions tested. This sub-fraction was non-cytotoxic at 0.1–10 µg/mL, and very effective in lowering serum and urine uric acid level in rat models upon oral consumption. A total of 26 known compounds were identified and seven unknown compounds were detected via HPLC-Q-TOF–MS/MS analysis. The possible mechanisms contributing to the anti-hyperuricemic effect were suggested to be the non-competitive inhibition of XO enzyme, XO gene expression down-regulation, and the enhancement of uric acid excretion.

2.  Wong, K. K., Chiew F.J., Ong, G. H., Wong, R. R., & Loh, K. E. (2022). Safeness and effectiveness of entomopathogenic fungi for use as bioinsecticide: A mini review. Journal of Biological Control, 36(1).

Usage of conventional synthetic insecticide to control insect pests has increased to improve crops yield and production to meet the global food demands of a growing population. However, it should not be neglected that synthetic insecticide causes negative impacts on humans, livestock as well as the environment. This review aims to provide data on entomopathogenic fungi species that can be developed into bioinsecticide to control insect pests, in order to reduce the usage of synthetic insecticide. The fungi are discussed based on two criteria, its effectiveness in controlling the targeted pests, and its safety level to humans, non-targeted organisms, and the environment. Relevant data and information on entomopathogenic fungi from various research tools including Google Scholar, NCBI, Science Direct and Researchgate were compiled into tables for comparison and analysed. Six entomopathogenic fungi namely Beauveria bassiana, Metarhizium anisopliae, Verticillium lecanii, Metarhizium (Nomuraea) rileyi, Paecilomyces fumosoroseus and Hirsutella thompsonii are proposed as having the required criteria having potential to control targeted insects by means of producing various toxins or metabolites with insecticidal properties. Five out of the six species, B. bassiana, M. anisopliae, V. lecanii and N. rileyi are safe to humans, non-targeted organisms, and the environment. Furthermore, all these fungi can be mass produced to ensure their availability to be used as a biocontrol agents. However, future studies are required for further justification for harmful metabolites produced and their impact on environment.

3. Quah, Y., Tong, S. R., Tan, S.-A., Chow, Y. L. and Chai, T. T. (2022). ‘Phytochemicals and biological activities of Stenochlaena palustris’, in Murthy, H. N. (ed.) Reference series in phytochemistry. Bioactive compounds in bryophytes and pteridophytes. Switzerland: Springer Nature. https://doi.org/10.1007/978-3-030-97415-2_26-1

Stenochlaena palustris (family Blechnaceae) is a fern species that occurs in the tropics and subtropics. They have been used as edible wild vegetables and folk medicine by the indigenous people in the Asian region. Phytochemical analyses revealed the presence of flavonoids, phenolics, tannins, saponins, gums, steroids, glycosides, terpenoids, and alkaloids in S. palustris. Nonetheless, the main secondary metabolites identified from the fern are kaempferol glycosides, fatty acids and phytosterols. Phytocompounds and solvent extracts derived from the fern were demonstrated to have antioxidant, antiglucosidase, cytotoxic, antimicrobial, anti-butyrylcholinesterase, anti-metalotoxic, antipyretic, and termiticidal activities. In nursing mothers, the juice of the fern stimulated breast milk production. The antioxidant and antimicrobial potentials of the fern also contributed to their applications in food, cosmetics, and food packaging material. Thus, current literature indicates that S. palustris is a promising source of phytochemicals with potential applications in health promotion, food, and cosmetics, which deserves future research attention. This review presents an overview of the current knowledge pertaining to the biological activities of phytocompounds and extracts of S. palustris.

4. Agarwal, T., Tan, S.-A., Nie, L., Zahmatkesh, E., Ansari, A., Rad, N. K., Zarkesh, I., Maiti, T. K. and Vosough, M. (2022). ‘Electroconductive nanofibrillar biocomposite platforms for cardiac tissue engineering’, in Jegatheesan, V., Bandara, N., Sarkar, P., Sarkar, A., Pal., K. (eds.) Food, medical, and environmental applications of nanomaterials. Cambridge: Elsevier, pp. 305-330. https://doi.org/10.1016/B978-0-12-822858-6.00010-8

Over the last decade, cardiac tissue engineering has witnessed enormous developments. Integration of nano-topological features and electrical stimulation (via conductive materials/polymers) has been shown to promote cardiac tissue repair and regeneration. This chapter highlights the fabrication strategies and different electroconductive materials for developing electroconductive nanofibrillar biocomposite platforms. The discussion is further extended toward ascertaining cardiac cells’ response on these biocomposite platforms both in vitro and in vivo. On a concluding note, various challenges have also been discussed.

5. Yap, A.Y., Liew, CW. (2022). Structural, thermal, and electrochemical studies on PVA-LiTf-TiO2 nanocomposite polymer electrolyte and the performance on electric double layer capacitor application. Ionics 28, 4111–4128. https://doi.org/10.1007/s11581-022-04659-

Polymer electrolyte systems composed of poly(vinyl alcohol) (PVA) and lithium trifluoromethanesulfonate (LiTf, also known as LiCF3SO3) at 60:40 weight ratios with varying weight percentages (wt.%) of titanium (IV) oxide (TiO2) nanofiller were prepared by solution casting technique. The most conductive nanocomposite polymer electrolyte which was added with 10 wt.% of TiO2 nanofiller has an ionic conductivity of (1.08 ± 0.002) × 10−4 S cm−1 at room temperature. The ionic transport mechanism in the nanocomposite polymer electrolyte was found to obey Arrhenius relationship which is related to thermally activated principle. Fourier-transform infrared (FTIR) study confirmed complexation between the PVA, LiTf, and TiO2. TGA thermogram of the most conductive polymer electrolyte shows good thermal stability which can withstand high temperature. The increase in glass transition temperature (Tg) of PVA upon addition of 10 wt.% TiO2 nanofiller is attributed to the interaction between TiO2 nanofiller and polymer matrix that causes the polymeric backbone to become more rigid. Linear sweep voltammogram of the sample shows a wide potential window of 4.95 V. The ionic transference number was found to be close to unity which suggests that the charge carriers are mostly ionic species. A simple electrical double layer capacitor (EDLC) was fabricated using nanocomposite polymer electrolyte with 10 wt.% of TiO2 nanofiller and its performance was evaluated. The EDLC was found to have specific capacitance of 444.06 mF g−1 (or 3.87 mF cm−2) with good electrochemical stability.

6. Yue, C.S., You, K.Y., Tan, C.W. et al. (2022) Method development and determination of potassium and phosphorus in oil palm organic fertilizers by microwave plasma atomic emission spectrometry (MP-AES). J IRAN CHEM SOC 19, 4435–4443. https://doi.org/10.1007/s13738-022-02612-w

In this study, the suitability of the external and standard addition methods was evaluated by the determination of phosphorus (P) and potassium (K) in oil palm organic fertilizers produced in Kelang Valley, Malaysia. A Comparison of the calibration methods for the P and K analyses was conducted by microwave plasma atomic emission spectrometry. In the external method, deviation from linearity was significantly observed for the element effect, acid effect and fertilizer matrix effect on the P and K analyses. A stronger deviation was encountered for P compared to K for the parameters studied. On the other hand, the determination of both the concentrations of P and K was successfully carried out using the standard addition method. The matrix effect caused by the presence of polyatomic ions and other elements was found to be almost negligible.

7. Ong, W., Yen, H. M., Kiew, P. L., Lim, T. H., Leong, K. L., Tan, S. Y., & Lim, J. X. (2022). In2O3/MoS2/ Reduced Graphene Oxide Nanostructure as Composite Electrodes for Supercapacitors. In Key Engineering Materials (Vol. 936, pp. 63–71). Trans Tech Publications, Ltd. https://doi.org/10.4028/p-bb4r2i

In this study, a novel reduced graphene oxide, indium (III) oxide, and molybdenum disulfide (rGO/In2O3/MoS2) ternary composite for supercapacitor electrode application was developed via green hydrothermal synthesis. The topography, surface morphology, crystalline structure, phase identification and molecular structure of the composites were examined by applying Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDX), Transmission Electron Microscopy (TEM), X-ray Diffraction Spectroscopy (XRD), X-Ray Photoelectron Spectroscopy (XPS), and Raman Spectroscopy. SEM and TEM reveal the uniform dispersion of In2O3 nanoparticles on the rGO and MoS2 sheets. EDX, XRD, and XPS analysis confirm the coexistences of rGO, In2O3, and MoS2, and hence the composite formation. The electrochemical performances of rGO/In2O3/MoS2 ternary composite were evaluated by cyclic voltammetry (CV) in two-electrode configuration in 1 M sodium sulfite (Na2SO3) aqueous electrolyte. The electrochemical results show that the rGO/In2O3/MoS2 composite electrodes possess improved specific capacitance of 77 F/g at a scan rate of 25 mV/s, a modest 29% enhancement over pure In2O3 and In2O3/MoS2 binary composite.

8. Chia, M.-R.; Ahmad, I.; Phang, S.-W. (2022) Starch/Polyaniline Biopolymer Film as Potential Intelligent Food Packaging with Colourimetric Ammonia Sensor. Polymers, 14, 1122. https://doi.org/10.3390/polym14061122

The use of petroleum-based plastics in food packaging leads to various environmental impacts, while spoilage of food and misinterpretation of food-date labelling account for food insecurity; therefore, a biopolymer capable of indicating food edibility is prepared to resolve these issues. In this research, starch/polyaniline (starch/PANI) biopolymer film was synthesised and investigated as an ammonia sensor for potential application as intelligent food packaging. FT-IR and XRD were used to confirm the composition of the biopolymer films, while UV-Vis spectrometry was applied to identify the oxidation state of PANI in emeraldine form. PANI was successfully incorporated into the starch matrix, leading to better thermal stability (TGA) but decreasing the crystallinity of the matrix (DSC). The performance of the polymer-film sensor was determined through ammonia-vapour sensitivity analysis. An obvious colour change from green to blue of starch/PANI films was observed upon exposure to the ammonia vapour. Starch/PANI 0.4% is the optimum composition, having the best sensor performance with good linearity (R2 = 0.9459) and precision (RSD = 8.72%), and exhibiting excellent LOD (245 ppm). Furthermore, the starch/PANI films are only selective to ammonia. Therefore, the starch/PANI films can be potentially applied as colourimetric ammonia sensors for intelligent food packaging.

9. Chia, M.-R.; Phang, S.-W.; Ahmad, I. (2022) Emerging Applications of Versatile Polyaniline-Based Polymers in the Food Industry. Polymers, 14, 5168. https://doi.org/10.3390/polym14235168

Intrinsically conducting polymers (ICPs) have been widely studied in various applications, such as sensors, tissue engineering, drug delivery, and semiconductors. Specifically, polyaniline (PANI) stands out in food industry applications due to its advantageous reversible redox properties, electrical conductivity, and simple modification. The rising concerns about food safety and security have encouraged the development of PANI as an antioxidant, antimicrobial agent, food freshness indicator, and electronic nose. At the same time, it plays an important role in food safety control to ensure the quality of food. This study reviews the emerging applications of PANI in the food industry. It has been found that the versatile applications of PANI allow the advancement of modern active and intelligent food packaging and better food quality monitoring systems.

10. Yue, C.S., Teh, G.B., Wong, P.Y. et al. Removal of Cu(II) from aqueous solution using a sol–gel derived strontium ferrite nanoparticle. (2022)  Int. J. Environ. Sci. Technol. https://doi.org/10.1007/s13762-022-04656-0

Strontium ferrite nanoparticles were prepared by sol–gel method at carbonization temperature of 800 °C for 96 h and characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy, X-ray diffraction (XRD) and thermogravimetric analysis. Adsorption of Cu(II) by the nanoparticles was conducted at aqueous medium under the optimum conditions in terms of pH, adsorbent dosage and contact time. Characterization results indicated that complete formation of the nanoparticles happened at temperature above 600 °C and it exists predominately as M-type SrFe12O19 nanoparticles. The adsorption results showed that Cu(II) adsorption onto the nanoparticles followed well the Langmuir isotherm model and pseudo-second-order. The adsorption, FTIR and XRD results indicated the adsorption mechanism may involve both the chemical and physical adsorptions at different stages. This was further confirmed by the presence of three different adsorption stages in the intraparticle model.