Malaysian Journal of Science

Purification and Characterization of Bromelain from Pineapple Variety Josapine

MUHAMMAD YAZID ABD HALIM — 2025-06-30

Pineapple (Ananas comosus (L) Merr) is a plant that contains bromelain enzymes in almost all parts of the plant, such as fruit, leaves, crown, and the stem with different amounts. Bromelain is included in the protease enzyme group that can break down the molecular structure of proteins into amino acids. Pineapple peel is one of the waste products from pineapple processing that has not been used optimally. This study aimed to purify and characterize bromelain enzyme from pineapple variety Josapine peel. The production of bromelain powder in this study was done in four steps, the extraction of crude bromelain from pineapple peel extracts, the purification of bromelain using ammonium sulphate precipitation, desalting using the diafiltration process and finally, freeze drying using a freeze dryer. The protease activity was determine using casein digestion unit (CDU) meanwhile the protein content was determine using Lowry’s Method. Result showed that the highest bromelain activity was observed in maturity index 5 in powder form with 2132.78±18.01 CDU/ml, the highest protein content was observed in maturity index 5 in crude extract form with 4.19±0.17 mg/ml and the highest specific enzyme activity was observed in maturity index 5 in powder form with 15234.14 CDU/mg protein. The agroindustry waste product, Josapine pineapple peel, has potential as a future alternative bromelain source.

Reproductive Biology of Pokea Clams (Batissa violacea var. celebensis, von Martens 1897) at Langkumbe River, Southeast Sulawesi, Indonesia

Bahtiar — 2025-06-30

Pokea clams (Batissa violacea) are bivalves that possess different reproductive patterns depending on the location. However, their reproductive pattern in Langkumbe River (Southeast Sulawesi, Indonesia) is unknown. This study aims to determine the sex ratio, gonad maturity level (GML), gonadosomatic index (GSI), fecundity and size of the first gonad maturity of the clams. The samples were collected randomly using iron baskets in all parts of the river and were combined together. The sex ratio, GML, GSI and size at first maturity were calculated using a standard formula, each of which was analyzed using the Chi-Square test, quantitative descriptive analysis as well as simple and non-linear regression. The results showed that the clams were gonochoric with more males than females. Male clams were relatively smaller and ranged from 3.28-3.75 cm in size. Furthermore, gonadal early and late development occurred in February through March and final gonad maturation occurred in April. Gonadal maturation and spawning occurred over a long period from March to October with a pattern of 1 peak spawning marked by an increase in the GSI value in the particular month. The GSI values in males and females were relatively the same, i.e., 36.47±16.79 and 34.80±17.71 as well as 18.37±9.46 and 18.57±8.86, respectively. Male pokea clams matured earlier than female with sizes of 1.4 cm or 0.23% and 2 cm or 0.50%, respectively. The reproductive potential of pokea clams in the Langkumbe River is high.

Assessing Bacterial Communities in Bulk Soil and Rhizosphere Associated with NPK Fertilizer in Oil Palm Seedlings via Amplicon Sequencing

Mohamad Khairil bin Radzali — 2025-06-30

Malaysia's palm oil industry relies heavily on chemical fertilizers, leading to significant environmental concerns such as nutrient loss and declining biodiversity. This study aims to evaluate the impact of post-fertilizer application on bacterial communities in soil, particularly focusing on bulk soil and rhizosphere. Through amplicon sequencing, we investigated the response of bacterial diversity to unfertilized and NPK-fertilized soil treatments. Fertilizer application increased soil phosphorus, potassium, and magnesium levels, enhancing seedlings’ growth but reducing bacterial diversity, particularly sensitive groups such as Acidobacteria and Verrucomicrobia. Candidatus Solibacter and Acidothermus were consistent biomarkers for unfertilized soil, while Mizugakiibacter and Castellaniella were for fertilized treatment. For the inferred bacterial community functions, the unfertilized bulk soil demonstrated enhanced function related to carbohydrate metabolism, and the unfertilized rhizosphere exhibited functions related to energy metabolism, stress tolerance, bioremediation, and plant defense. During fertilized treatment, functions related to secondary metabolites were enriched in the bulk soil, and bacterial colonization functions were enriched in both compartments. For network analysis, the fertilizer application reduced bacterial network interactions and complexity. Environmental drivers, namely, pH and soil total phosphorus (TP), influenced the bacterial biomarkers' abundance in the bulk soil and rhizosphere. These findings demonstrate the need to optimize chemical fertilizer applications and identify beneficial bacterial taxa to foster sustainable agricultural practices in the palm oil industry.

The Potential of the Spatholobus littoralis Hassk Plant as an Antioxidant and Prediction of the Mechanism of Activity Against ROS1 Kinase Receptor in Silico

Sri Atun — 2025-06-30

Various phenolic compounds that exhibit antioxidant, anticancer, and anti-inflammatory activities are found in Spatholobus. Therefore, this study aimed to determine the antioxidant potential of Spatholobus littoralis wood in vitro and predict the mechanism of its activity against the ROS1 kinase receptor in silico. The ground-dried wood of S. littoralis was extracted with ethanol via maceration. The analysis of the total phenolic content (TPC) of extracts and fractions obtained from S. littoralis wood was determined by the Folin-Ciocalteu reagent. Similarly, the antioxidant activity was determined by the DPPH (2,2-diphenyl-1-picrylhydrazyl) and FRAP (The ferric reducing antioxidant power) method. The human ROS1 kinase enzyme (4UXL and 3ZBF) was used to determine the molecular mechanism of the interaction from the genus Spatholobus in silico. The total ethanol extract, chloroform, and ethyl acetate fraction of S. littoralis showed a high content of phenolic compounds and antioxidant activity. Phenolic compounds in plants of the genus Spatholubus also showed good activity against ROS1 kinase receptors (3ZBF and 4UXL). In conclusion, the S. littoralis plant has the potential to be developed for the discovery of new drugs.

Bogdanov-Takens Bifurcation in SIRI Model with Multiple Reinfection of COVID-19

Livia Owen — 2025-06-30

In the presence of cases of COVID-19 reinfection, we propose a SIRI (Susceptible-Infected-Recovery-Infected) spread model of two COVID-19 variants. This model considers the possibility of individuals becoming reinfected with the same or different variants, although the risk of reinfection with the same variant remains lower due to natural immunity from previous infections. Besides analyzing the stability of equilibrium points, we focus on codimension-one bifurcations. Our initial numerical simulations used parameters obtained from real data collected through a British government survey. Our analysis revealed unstable disease-free equilibria and stable endemic equilibria. By varying the Case Fatality Rate parameter, we identified all codimension-one bifurcations. To further investigate the model's dynamics, we introduced a new parameter, the reinfection rate, and utilized AUTO software. Our research led to the discovery of codimension-two bifurcations, specifically the Bogdanov-Takens bifurcation. We identified the parameter domain where a stable limit cycle and homoclinic orbit occur in the presence of the Bogdanov-Takens bifurcation. We also simulated parameter variations that could trigger a pandemic resurgence. This highlights the possibility of emerging variants causing a pandemic return.

Probing the Rotation Curve of NGC 4501 Galaxy using Two Different Models

Israa Abdulqasim Mohammed Ali — 2025-06-30

Rotation curves of spiral galaxies have become an important tool for investigating their physical properties and is usually used as evidence for dark matter presence in their haloes. This research aims to probe the rotation curve of the spiral galaxy NGC 4501. The HI data of this galaxy have been collected from Very Large Array (VLA) and nonlinear fitting techniques have been used in this research for different components: stars, gas and halo. Particularly, kinematic analysis of NGC 4501’s rotation curve has been carried out in this research using two different profile models: pseudo-isothermal profile and the Moore profile. The results of this study clearly showed that pseudo-isothermal model is better at reproducing the rotation curve of NGC 4501 than Moore model. The reduced chi-square, χ_"red " ^2 of pseudo-isothermal is found to be close to one whereas Moore model does not agree with observational data. This is due to the fact that the pseudo-isothermal model is characterized primarily by the linearity of its behavior within the inner region together with the flat profile at large radii. As a result, the dark matter distribution in NGC 4501 is one that may be represented by a core halo model.

Carbon-Based Materials/Latex Composite from Euphorbia Tirucalli Plant for Potential Bone Fracture Treatment

Supardi — 2025-06-30

This study aims to investigate the preparation and characterization of carbon-based materials (CMs)/latex composites from the Euphorbia tirucalli plant for potential bone fracture treatment. The primary objectives are to: i) determine the antibacterial property of the CMs/latex composites against Staphylococcus aureus bacteria; and ii) determine the tensile strength of the CMs/latex composites via chicken bones as the model. The CMs were prepared using a simple heating method, using an oven at a temperature of 250 ^oC. The CMs/latex composites were prepared by mixing 3 ml of the latex and CMs solutions with concentrations of 10%, 20%, and 40% in 10 ml of distilled water. The CMs were characterized using UV-Vis, PL, and FTIR spectroscopies. The antibacterial property and tensile strength of the CMs/latex composites were tested using the diffusion method and an ultimate testing machine, respectively. The results obtained demonstrate that the CMs had absorption and emission peaks at wavelengths of 287 nm and 499 nm, respectively, resulting in cyan luminescence. The FTIR test of the CMs indicated the existence of the C=C, O-H, and N=C=S functional groups. The CMs/latex composites produced the highest diameter of inhibition zone and tensile strength of 3.24 mm and 0.02 kN, respectively. These findings concern the potential application of CMs/latex composites for bone fracture treatment with antibacterial properties.

Effect of Cu and Si Wafer Substrates in Increasing Raman Signal Of Surface-Enhanced Raman Scattering-Based Au Nanoparticles

Affi Hidayah — 2025-06-30

Surface-enhanced Raman spectroscopy (SERS) has attracted considerable research interest over the last four decades because of its rapid vibrational spectroscopic detection, high sensitivity, and nondestructive technique for enhancing the generally weak signal from Raman scattering. Here, SERS substrates were fabricated by drop-casting Au nanoparticles (NPs) onto two substrates (Cu and Si wafers). The AuNPs (diameter = 7.3 nm) were synthesized from an Au metal ion solution with a concentration of 4.22 × 10⁻⁴ M via photochemical reduction using a femtosecond laser. The SERS substrates were tested for their ability to enhance the Raman signal of paraquat pesticides at 10 ppm. Six vibration peaks of the paraquat pesticides at 671, 838, 1187, 1294, 1530, and 1643 cm⁻¹ were successfully detected and enhanced. The results showed that the SERS substrate on the Si wafer increased the Raman signal more than the Cu wafer.

Exploring Fertilizer-Microbiome Interactions Through Next-Generation Sequencing (NGS): Insights for Sustainable Agriculture

Mohamad Khairil bin Radzali — 2025-06-30

With the global demand for food production escalating, concerns about the long-term sustainability and environmental impact of traditional farming practices, particularly the application of chemical fertilizers, have gained prominence. Recognizing the importance of addressing these issues, this review explores the evolving dynamic between fertilizers and microbial communities, emphasizing the need for a more profound understanding of these interactions. The transformative impact of next-generation sequencing (NGS) technologies in unraveling microbial intricacies within agricultural ecosystems is highlighted as a crucial tool for advancing this understanding. Investigation extends to discerning the nuanced effects of both chemical and non-chemical fertilizers on soil microbiomes, considering variations in soil type and crop specificity. Linking these findings to the Sustainable Development Goals (SDGs), the review highlights the critical connection between fertilizer use, microbial diversity, and the achievement of sustainability objectives. Despite the potential of NGS, the review acknowledges current limitations, sparking discussions on potential technological advancements and methodological improvements. Emphasizing the necessity for interdisciplinary collaboration, it advocates for comprehensive insights that bridge gaps between microbiology, agriculture, and sustainability. In conclusion, the article synthesizes historical perspectives, cutting-edge technologies, and sustainable development objectives to provide a holistic understanding of the intricate interplay between fertilizers, microbial diversity, and the imperative path toward a more sustainable agricultural future.

Study on Machinability Issues of Hard to Machining Inconel 718 - A Review

Kishor K Powar — 2025-06-30

In the aerospace and automobile industries, there has been a recent growing demand for tough and heat-resistant materials. Processing these materials is difficult, primarily due to their mechanical properties, which include strong wear resistance, abrasion resistance, and low heat conductivity. This results in short tool lifetimes and high cutting temperatures and forces. Variations in machinability may be brought on by changes in material microstructures brought on by changes in chemical composition, forging methods, casting, and heat treatment. Because of their remarkable greater efficiency and effectiveness, Inconel 718 nickel superalloys are employed in numerous automotive, marine, and aviation applications. In contrast, Inconel 718's poor thermal conductivity and quick strain hardening made fabrication difficult and compromised the surface's machining ability. This study examines Inconel 718 machining problems, and the issue of dry machining and machining with nanofluids, which demonstrates advancements in research on improving surface quality and material removal rate by reviewing the properties of alumina (Al₂O₃)-based nanofluids.