Azlin Suhaida Azmi

Growing interest in starch‐based bioplastics has increased the need to understand how material functionality, processing, and environmental performance shape research priorities. This study presents a Scopus‐based bibliometric analysis of 766 articles published between 2010 and 2025, using performance analysis, science mapping, and citation analysis. The findings identify interconnected research themes encompassing mechanical reinforcement, barrier properties, active food packaging, biodegradability, and end‐of‐life management. Plasticization, polymer blending, crosslinking, and nanoscale reinforcement are important strategies for tailoring material properties, while functional additives introduce antimicrobial activity and ultraviolet shielding. Despite these advances, moisture sensitivity, competing performance requirements, production costs, and inadequate disposal infrastructure continue to constrain practical implementation. A key processing priority is to extend development beyond laboratory‐scale solution casting toward scalable manufacturing, including melt compounding and extrusion‐based granulation or pelletization. The production of granular feedstocks and application‐specific beads should be accompanied by assessments of storage stability, bulk handling, and transportability to support subsequent processing and distribution. Further research should integrate waste‐derived and non‐food starch resources with standardized evaluation of mechanical, barrier, and biodegradation performance under realistic application and disposal conditions. Comprehensive life cycle and techno‐economic assessments are also needed to determine whether improvements in material functionality translate into environmentally and economically viable products.

Assessing hydrodynamic parameters in photobioreactors (PBR) is essential for optimised operation, yet computational fluid dynamics studies specifically evaluating shear stress properties remain scarce. This study utilises COMSOL Multiphysics® to provide novel quantitative insights into the hydrodynamic performance of a 15 L conventional flat-panel photobioreactor. A 2D time-dependent turbulent bubbly-flow model based on the Euler-Euler approach was implemented and validated against an airlift PBR (ALR) system, with a margin of error of less than 3%. Fluid flow, shear stress, and mixing behaviour were systematically investigated under aeration rates ranging from 0.1 to 1.0 vvm. Results demonstrated that while increasing aeration improved hydrodynamic parameters, average liquid velocities consistently remained below 0.02 m/s, indicating the persistent presence of dead zones near the vessel walls. Crucially, simulated shear stress remained below the 1.2 Pa critical threshold for microalgal cell damage. However, the 0.2 Pa threshold required to inhibit biofilm formation was only exceeded at aeration levels above 0.4 vvm. While higher aeration increased average turbulent kinetic energy and turbulent energy dissipation, their distribution remained non-uniform, with peak turbulence concentrated near the sparger and upper sections. These findings suggest an optimal aeration range of 0.2 to 0.6 vvm to balance mixing efficiency and shear control. Ultimately, this work delivers novel quantitative mapping of critical hydrodynamic regions, advancing the predictive basis for reactor scale-up and design optimisation.

Microalgae, known for their high photosynthetic efficiency, offer a promising approach for CO? sequestration and the production of high-value products such as single-cell proteins (SCP). However, low CO? solubility in water and strain-specific tolerance limit CO2 fixation efficiency. This study aimed to optimise CO? fixation and SCP production in freshwater Chlorella vulgaris using the Taguchi Orthogonal Array method. Key parameters, namely light (5-15 kLx), CO? concentration (1–5%), and nitrogen content (0–1 g/L), were investigated in a 2-L Schott glass bottle. Process validation was performed within the same system, and a comparative assessment was subsequently conducted against a 2-L flat-panel photobioreactor (FPPBR) to determine any differences in cultivation performance. Results showed that biomass productivity had a greater influence on CO? fixation (9.049%) and protein yield (45.78%) than CO? concentration or nitrogen content. Notably, the flat-panel PBR achieved superior growth performance (47.67%), highlighting the importance of reactor design. Logistic growth modelling with the Taguchi growth rate equation provided the best fit for the experimental data (R2 between 0.6-0.93). These findings provide valuable insights for enhancing microalgae CO? capture and SCP production, although further refinement of cultivation systems and kinetic models is necessary.

The search for eco-friendly alternatives to conventional petroleum-based materials has intensified in an era marked by a growing global awareness of environmental sustainability. This study addresses the critical need for molecular identification and characterization of fungi sourced from a tempeh commercial starter culture for their potential role in fungal-based polymer production. The problem is the limited knowledge and understanding of the genetic composition of these fungi and their suitability for lactic acid (LA) production, which is a crucial component of fungal-based polymer manufacturing. This research examined the tempeh starter culture fungi to identify suitable strains for LA production. The fungi were genotyped by DNA sequencing of the ITS region. The study revealed that the Ragi tempeh commercial starter culture contained only one strain of Rhizopus (R. microsporus), which was verified through ITS rRNA sequencing with 99.8% similarity to the GenBank database, simplifying control over fungal growth and potentially leading to consistent biomaterial yields. The method employed, involving DNA PCR (and sequencing of the ITS region, proved to be accurate, straightforward, and not excessively labor-intensive. The PCR conditions were as follows: initial denaturation at 98°C for 2 min, followed by 25 cycles of denaturation (98°C for 15 seconds), annealing (60°C for 30 seconds), and elongation (72°C for 30 seconds), with a final extension at 72°C for 10 min. Consequently, the consistent presence of only one Rhizopus species in commercial starter cultures of tempeh presents a promising avenue for sustainable biomaterial production, particularly in LA production. The pilot flask setup at 1 × 10? spores/mL was inoculated into 150 mL shake flasks with 1.2 g/mL glucose, incubated at 37°C for 1 to 7 days with 100 rpm shaking, yielding 1.037 g/g after 5 days, demonstrating the feasibility of using this strain for industrial applications. ABSTRAK: Dalam era yang semakin menekankan kesedaran global terhadap kelestarian alam sekitar, pencarian alternatif mesra alam kepada bahan berasaskan petroleum konvensional semakin giat dijalankan. Kajian ini menangani keperluan kritikal untuk mengenal pasti dan mencirikan kulat secara molekul daripada kultur pemula komersial tempeh bagi potensi penggunaannya dalam penghasilan asid laktik (LA), komponen penting dalam pembuatan polimer berasaskan kulat. Masalah utama yang dibincangkan ialah kekurangan pengetahuan dan pemahaman mengenai komposisi genetik kulat ini serta kesesuaiannya untuk sintesis LA. Kajian ini menumpukan kepada pemeriksaan kulat dari kultur pemula tempeh bagi mengenal pasti strain yang sesuai untuk pengeluaran LA. Penjujukan DNA kawasan internal transcribed spacer (ITS) digunakan untuk mengenal pasti genotip kulat tersebut. Hasil kajian menunjukkan bahawa kultur pemula komersial Ragi tempeh hanya mengandungi satu strain sahaja, iaitu Rhizopus microsporus (disahkan melalui penjujukan ITS rRNA dengan 99.8% kesamaan dengan pangkalan data GenBank). Kehadiran satu spesies ini memudahkan kawalan pertumbuhan kulat dan berpotensi meningkatkan konsistensi hasil pengeluaran. Kaedah yang digunakan melibatkan PCR DNA dan penjujukan kawasan ITS, yang terbukti tepat, mudah, serta tidak terlalu memerlukan tenaga kerja yang banyak. Keadaan PCR adalah seperti berikut: penyahdenaturan awal pada suhu 98°C selama 2 minit, diikuti 25 kitaran yang terdiri daripada penyahdenaturan (98°C, 15 saat), pengannealan (60°C, 30 saat), dan pemanjangan (72°C, 30 saat), dengan pemanjangan akhir pada 72°C selama 10 minit. Kehadiran spesies Rhizopus yang konsisten dalam kultur pemula tempeh komersial membuka peluang yang menjanjikan untuk pengeluaran asid laktik yang mampan. Penggunaan susunan flask perintis pada suhu 30°C menghasilkan 1.037 g/g selepas 5 hari, membuktikan potensi strain ini untuk aplikasi industri.

As an eco-friendly and technically feasible method for physical modification of materials, bead-milling has been extensively used in many industrial applications ranging from chemicals, nanomaterials, foods, and pharmaceuticals with impacts on particle size, surface morphology, stability, and overall products’ performance. Apparently, there have been limited studies conducted on sulfur curative dispersion using this technology, necessitating a thorough investigation of its performance. The objectives of the present study were to explore the influence of the bead-milling process parameters, particularly rotational speed and flow rate, on the sulfur curative dispersion characteristics and to analyze its behavior within the rubber elastomer matrix. Taguchi’s L9 orthogonal array experimental design was employed to identify the optimal rotational speed and flow rate of a 60-L bead-milling machine on the sulfur curative dispersion. The stability and morphology of the resulting sulfur curative dispersion were characterized, along with its mechanical properties in rubber elastomers. It was found that higher rotational speed (800 rpm) and lower flow rate (350 L/h) of the bead-milling process resulted in smaller sulfur particle sizes, leading to improved tensile strength of the rubber elastomer. This research may provide valuable insights to determine the ideal bead-milling process for sulfur curative, enhancing the mechanical properties and overall performance of elastomeric rubber composites as well as across various fields. ABSTRAK: Sebagai sebahagian kaedah mesra alam dan secara teknikal dapat mengubah suai bentuk fizikal bahan, mesin pengisaran manik telah digunakan secara meluas dalam kebanyakan aplikasi industri termasuk kimia, nanomaterial, makanan, dan farmaseutikal dengan kesan pada saiz zarah, morfologi permukaan, kestabilan, dan prestasi keseluruhan produk. Namun, terdapat kurang kajian terhadap taburan kuratif sulfur menggunakan teknologi ini, menyebabkan penyelidikan menyeluruh diperlukan bagi menilai prestasinya. Objektif kajian ini adalah bagi mengkaji pengaruh parameter proses pengisaran manik, terutamanya pada kelajuan putaran dan kadar aliran, iaitu terhadap ciri-ciri taburan kuratif sulfur dan mengkaji tindak balasnya pada matriks elastomer getah. Reka bentuk eksperimen Taguchi L9 bersusunan ortogonal telah digunakan bagi mengenal pasti kelajuan putaran dan kadar aliran optimal mesin pengisaran manik 60 liter terhadap taburan kuratif sulfur. Kestabilan dan morfologi taburan kuratif sulfur yang terhasil telah dicirikan, bersama sifat mekanikal dalam elastomer getah. Dapatan mendapati bahawa proses pengisaran manik pada kelajuan putaran lebih tinggi (800 rpm) dan kadar aliran lebih rendah (350 L/j) menyebabkan saiz zarah sulfur lebih kecil, membawa kepada peningkatan kekuatan regangan elastomer getah. Kajian ini mungkin memberikan pengetahuan penting bagi menentukan proses pengisaran manik yang ideal untuk kuratif sulfur, meningkatkan sifat mekanikal dan prestasi keseluruhan komposit getah elastomerik serta pelbagai bidang lain.

Polymer encapsulation is commonly adopted in drug delivery systems to form encapsulation that can assist in delivering active compounds to the targeted area. Acalypha indica (AI) crude extract was obtained from AI plants through ultrasound-assisted extraction. It is naturally unstable in the external environment and, thus, needs to be encapsulated to protect against volatility. Herein, this study emphasized the development of the encapsulations of AI extracts using a chitosan-polycaprolactone (PCL) blend by emulsion-solvent evaporation and freeze-dried methods. Four parameters for Al encapsulation were studied by fixing one parameter at a time. The percentage of encapsulation efficiency (EE%) was recorded as a response for each parameter. The study proceeded with central composite design (CCD) as the response surface methodology (RSM) optimization tool to study the interactions between the factors. Central points were taken from the preliminary data obtained in one-parameter experiments. The validation was carried out with two data of the highest and lowest EE% suggested by CCD. The highest EE% recorded was 98.70%, and the lowest EE% was 87.80%. The results showed a difference between predicted and experimental values at a percentage lower than 7.5%. Fourier Transform Infrared Spectroscopy (FTIR), scanning electron microscopy (SEM), particle size analyzer, and zeta potential were used to analyze the properties of selected microencapsulated samples. Overall, the encapsulation of AI extracts was successful and has the potential to be used in drug delivery.

Food-waste (FW) has a high content of fermentable sugar which can be exploited to generate an alternative source of fuel that could replace fossil fuels. Anaerobic digestion (AD) is an approach to convert organic-waste into high-value products like biomethane and hydrogen. However, hydrolysis is deemed to be a rate-limiting process in the AD process, limiting biogas production. This study seeks to improve the hydrolysis process through pre-treating FW with chemical and biological treatments. We show that the enzymatic treatment substantially improved the hydrolyzation and solubilization of food waste, resulting in a three folds increase in biogas production compared to untreated food waste. A co-treatment of biological and enzymatic treatments significantly improved the hydrolysis process, solids reduction, and solubilization of the substrate. The soluble chemical oxygen demand (SCOD) and reducing sugar were increased by 50% and 25% respectively, compared to enzymatically treated only. However, the inhibitory effect of accumulated salts from the treatment has limited the application of anaerobic digestion. Our results reveal that using enzymatic and acidic pre-treatment can significantly enhance hydrolysis of FW to increase biogas production, highlighting the potential of AD.

The application of cassava starch in the biopolymers industry has been growing significantly due to its low cost, good oxygen barrier in the dry state, and biodegradability. Plant culture technology is an alternative to traditional propagation as it does not require large areas for production, has a higher rate of multiplication, and produces disease-free plants. However, the application of cassava callus culture for starch production is limited. This study focuses on identifying the significant culture parameters for a maximum Rayong cultivar cassava callus growth and evaluation of its starch content. Cassava stems petiole and leaf explants were cultured on MS medium containing different combinations of 2,4-D (8, 12, and 15 mg/L) and BAP (1, 3, and 5 mg/L) under three light conditions (0, 16, and 24 h). The screening of the most influential parameter was done using the 2-level Factorial Design in Design Expert v13 by analyzing the frequency of callus formation. All leaf explant turned brown with no callus induction. The highest frequency of callus formation derived from stem petiole explant was achieved by the combination of 8 mg/L 2,4-D and 1 mg/L BAP under the light condition (75%) followed by 8 mg/L 2,4 D + 1 mg/L BAP under the dark condition (50%). Based on the ANOVA analysis, the individual supply of 2,4-D and BAP respectively, have a negative effect on callus formation while the combination of 2,4-D and BAP has a positive effect. Light supply did not significantly affect cassava callus formation. The amount of starch in the cassava callus was then investigated using an iodine test which yielded 0.21% of the total weight of the callus (0.0101g). The amount of starch is relatively low considering that the callus was not grown under the optimum condition for starch production. The findings of this study open prospects for future research in cassava cultures in favor of starch production. ABSTRAK: Penggunaan kanji ubi kayu dalam industri biopolimer telah meningkat secara mendadak disebabkan oleh faktor kosnya yang rendah, rintangan oksigen yang baik dan sifat keterbiodegradasi. Teknologi kultur tisu tumbuhan merupakan alternatif kepada pembiakan secara tradisional yang mana teknologi ini tidak memerlukan kawasan penanaman yang luas, penghasilan yang lebih singkat dan menghasilkan tumbuhan bebas penyakit. Walau bagaimanapun, kajian mengenai penggunaan kanji dari kultur ubi kayu masih belum meluas. Kajian ini bertujuan mengenal pasti parameter penting dalam pertumbuhan maksimum kalus kultivar ubi kayu Rayong dan kandungan kanjinya. Eksplan dari tangkai petiol dan daun ubi kayu dikulturkan dalam medium MS yang mengandungi pelbagai kombinasi hormon tumbuhan 2,4-D (8, 12 dan 15 mg/L) dan BAP (1, 3 dan 5 mg/L) di bawah tiga tempoh masa pencahayaan (0, 16 dan 24 jam). Saringan parameter paling berpengaruh dilakukan menerusi reka bentuk faktorial 2-peringkat perisian Design Expert v13 melalui analisa frekuensi pembentukan kalus. Semua eksplan daun telah bertukar dari hijau ke perang dan tidak menunjukkan induksi kalus. Bagi eksplan batang daun, frekuensi pembentukan kalus tertinggi diperoleh dari kombinasi 8 mg/L 2,4-D dan 1 mg/L BAP di bawah pencahayaan 24 jam (75%) diikuti dengan 8 mg/L 2,4 D + 1 mg/L BAP di bawah pencahayaan malap (50%). Berdasarkan analisis ANOVA, medium 2,4-D dan BAP masing-masing menunjukkan kesan negatif kepada pembentukan kalus, sementara kombinasi 2,4-D dan BAP memberikan kesan positif. Dapatan ini menunjukkan bahawa pencahayaan tidak signifikan terhadap pembentukan kalus kultur ubi kayu. Kandungan kanji di dalam kalus ubi kayu kemudiannya diuji dengan larutan iodin, dan menunjukkan dapatan sebanyak 0.21% dari berat kalus (0.0101 g). Secara relatif, nilai ini adalah rendah memandangkan eksperimen ini bukan dihasilkan di bawah keadaan optimum bagi pembentukan kanji. Hasil kajian ini membuka peluang kepada kajian-kajian lain di masa hadapan dalam penghasilan kanji dari kultur tisu ubi kayu.

Banana fiber (BF) is a renewable resource which can be a good reinforcer to polylactic acid, enhancing the polymers stiffness and accelerating biodegradability rates. However, due to the difference in nature between banana fibers (hydrophilic) and polylactic acid (hydrophobic), a good adhesion between the fiber and the matrix cannot be achieved. To tackle the problem, the fibers were chemically treated using sodium hydroxide under three factors (temperature, concentration, and treatment time). The factors interactions were given by response surface methodology and the statistical interactions were observed by ANOVA. Alkaline effect on fiber’s morphology, composition, mechanical, and morphological properties of composites produced were observed. Young’s modulus values have increased substantially compared to untreated fiber’s composites, with a slight increase in the tensile strength values. However, the elongation at break values have slightly dropped with the fiber’s alkaline treatment. Scanning electron microscope observations had shown a successful removal of impurities (e.g. hemicellulose, wax) and between the fiber’s strands, and an improvement of surface structure. Fourier-transform infrared spectroscopy analysis showed the successful removal of impurities, and interaction between PLA and banana fibers.