CURRENT APPLIED SCIENCE AND TECHNOLOGY

Bioremediation of Heavy Metal-Contaminated Soils: A Systematic Review of Applied Technologies in the Philippines

2025-07-10T12:40:17+07:00

Heavy metal contamination in soils poses a severe environmental and agricultural challenge, jeopardizing ecosystem health, food safety, and public health on a global scale. In the Philippines, where industrial and mining activities intensify these risks, sustainable remediation strategies are urgently needed. Contaminants such as copper, nickel, and lead are by-products of mining and industrial activities, posing risks to public health and agriculture. This study aims to systematically review bioremediation technologies applied to these contaminants, examining their effectiveness and limitations in the Philippine context. A systematic review methodology was employed, drawing data from relevant studies screened for relevance, quality, and applicability to the country’s environmental conditions, and focusing on quantitative results in contaminated soil areas, especially those impacted by mining. Key findings indicate that phytoremediation is the most commonly applied technique, with significant use of hyperaccumulator plants for copper and arsenic. Mycoremediation and microbial methods also show potential, although their effectiveness varies based on biological, environmental, and soil characteristics. Limitations such as limited bioavailability of metals and high variability in plant uptake capacity were noted, emphasizing the need for integrated, site-specific approaches. Hence, while bioremediation shows promise as a sustainable, cost-effective solution for heavy metal contamination, further research into plant-microbe combinations and natural chelants is essential for optimizing remediation in diverse soil and environmental contexts in the Philippines.

Bacterial Endophytes: A Versatile Factory for Producing Indole-3-acetic Acid, Recent Advances and Development

2025-03-10T17:40:18+07:00

The growing scientific interest and exploration of endophytes from plants have shown vital plant health promotion, and are attracting scientific interest. The endophytes, including bacteria, significantly strengthen the host plants' growth and resilience, fortifying the plants’ ability to combat pathogens and adapt to environmental stresses. Previous studies have investigated the pivotal role of endophytic bacteria in modulating the synthesis of secondary metabolites with medicinal properties and diverse biological effects. Endophytic bacteria are well-known sources of metabolites with notable medicinal potential and ability to boost plant growth, fortifying invulnerability to abiotic stress and biotic stress on plants. The catalog of primary and secondary metabolites that are produced by different endophytes indole-3-acetic acid (IAA) is an eminent constituent of the auxin in the indole derivatives family. IAA governs nearly every facet of botanical growth and progression, making it among the most significant phytohormones for plants. Notably, the endophyte bacteria deliver IAA which holds significance in growth and progression interactions with plants. Delving into the mechanisms underlying the biological synthesis and functions of IAA in endophytic bacteria can boost the production and application of IAA in agriculture and allied sectors. This review unifies recent research advancements in the production of IAA from bacterial endophytes and explains the pathway analysis for the biological synthesis of IAA.

Impact of Herbal Mixed Tisanes on Antioxidant Property and Sensory Emotion of Relaxation and Calmness

2025-07-20T13:01:19+07:00

Traditional tisanes have gained more interest as functional dietary sources of antioxidants and represent a class of bioactive compounds. This research aimed to develop mixed herbal tisanes with high antioxidant activity and impact on consumer acceptance and emotions (relaxation and calmness). The study explored the antioxidant properties of five herbal mixtures; lavender (Lavandula angustifolia Mill.), mimosa (Mimosa pudica Linn.), stevia (Stevia rebaudiana Bertoni), chamomile (Chamaemelum nobile (L.) All.) and rose (Rosa damascene). The analysis of raw materials found stevia exhibited the highest total phenolic content (768.92±30.19 µmol GE/100g) and highest nitric oxide scavenging (54.63±1.37%), followed by chamomile and mimosa. Sensory emotions, measured on a 5-point scale, indicated moderate to high levels of relaxation (3.94±0.69) and calmness (3.62±0.67). The mixture design employed varying proportions of three herbs: lavender (10-30%), mimosa (10-35%), and stevia (5-20%), with chamomile (30%) and rose (20%) as fixed components. Regression models demonstrated that various formulations of the herbs significantly affected consumer acceptance, calmness emotion and total flavonoid content (p<0.05). The optimized formulation of 23% lavender, 10% mimosa, and 17% stevia exhibited high consumer acceptance, emotions and antioxidant activities. The optimized herbal tea was analyzed for amino acid profile, and contained phenylalanine (86.13±0.08 µg/mL), tyrosine (7.67±0.04 µg/mL), serine (13.47±0.02 µg/mL), glutamic acid (8.36±0.21 µg/mL), all of which contributed to mood regulation and calmness. The phenolic compounds identified in tisanes were as follows; chlorogenic acid, catechin, ferulic acid, myricetin, and quercetin at 2967.66±46.19; 2089.45±0.68, 1025.35±1.87, 987.06±19.16, and 470.69±0.98 (µg/g), respectively, which may support relaxation and mental well-being. These findings highlight the promising role of herbal tisanes as a natural, functional beverage for oxidative stress reduction and emotional balance, with potential applications in the health and wellness industries.

Development of a Biofertilizer from Indigenous PGPR and Leonardite Residues for Sustainable Lettuce Cultivation and Soil Restoration

2025-08-13T12:25:07+07:00

Plant growth-promoting rhizobacteria (PGPR) are beneficial microbes that can enhance crop yield and soil fertility. In this study, we developed a biofertilizer using an indigenous PGPR strain, Microbacterium maritypicum R4-3, isolated from leonardite-associated rhizosphere at the Mae Moh lignite mine in Thailand. The strain showed strong phosphate solubilization (index = 3.81), siderophore production (1.43), and IAA synthesis (3.76 µg/mL). Its identity was confirmed by 16S rRNA sequencing and phylogenetic analysis, placing it with M. maritypicum type strains. Lettuce (Lactuca sativa var. crispa) was used as a test crop. In laboratory experiments using Leonard’s jar systems, R4-3 significantly increased plant biomass, yielding 18.58 g fresh weight (FW) and 1.97 g dry weight (DW) per plant, compared to 12.62 g FW and 1.36 g DW in uninoculated controls. In pot trials with amended soils, the highest yield was obtained from 25% leonardite plus R4-3, reaching 48.68 g FW and 2.92 g DW, outperforming both controls (1.94 g FW, 0.18 g DW) and two commercial biofertilizers. Soil analysis revealed improvements in total nitrogen (0.41%), exchangeable potassium (448 ppm), and organic matter (7.89%) under R4-3 treatment. These findings highlight the potential of native PGPR combined with leonardite to enhance plant growth and restore soil fertility in degraded soils. Therefore, this study offers a sustainable and low-cost strategy for converting mining waste into effective biofertilizer inputs for organic farming and land rehabilitation.

Evaluation of Biosaka Spray for Enhancing Physiological Traits and Improving Fruit Quality in Inodorus Melon

2025-09-11T10:27:40+07:00

Melon is an economically important horticultural crop, yet its productivity and fruit quality are often constrained by suboptimal cultivation practices. Biosaka, a biostimulant containing natural elicitors, has the potential to enhance physiological performance and fruit traits, but its effective concentration remains unclear. This study evaluated the optimal concentration of biosaka spray for improving physiological traits and fruit quality of Inodorus melon. A non-factorial completely randomized design was applied with six concentrations (0, 10, 20, 30, 40, and 50 mL L^-1), each with four plants and replications, totaling 96 experimental units. Biosaka application did not have significant effect on chlorophyll content, chlorophyll a/b ratio, stomatal density, biomass, net assimilation rate, or harvest index. In contrast, it significantly increased leaf area index (LAI) and fruit quality attributes. Polynomial regression predicted an optimal concentration of 26.5 mL L^-1 for LAI (0.845). Concentrations between 31.0 and 50.7 mL L^-1 produced optimal fruit traits, including fruit weight, diameter, total soluble solids, and edible portion. Correlation analysis indicated weak relationships between LAI and physiological parameters, while strong positive associations were found between biomass and NAR, and negative associations between HI and biomass. Overall, biosaka at 26.5 - 50.7 mL L^-1 is optimal for enhancing melon fruit quality, though further studies are required to characterize its elicitor compounds.

Development of Carboxymethyl Cellulose/Starch Film Composites Using Cellulose from Sugarcane Bagasse and Titanium Dioxide for Active Food Packaging Applications

2025-09-29T14:22:43+07:00

The development of an active food packaging film from carboxymethyl cellulose (CMC), starch, glycerol, and microcrystalline cellulose (MCC) to enhance mechanical strength and moisture resistance, which was synthesized from sugarcane bagasse (SCB), and titanium dioxide (TiO₂) was investigated. The MCC was chemically extracted from SCB via alkaline treatment, hydrogen peroxide oxidation, and acid hydrolysis, resulting in 92% cellulose purity, as confirmed by Fourier Transform Infrared (FT-IR) spectroscopy and X-ray diffraction (XRD). The biofilms were prepared using the solution casting method with 3 conditions: CMC/starch, CMC/starch/MCC, and CMC/starch/MCC/TiO₂. Incorporating MCC and TiO₂ significantly improved tensile strength (21.57 MPa to 42.79 MPa) and Young’s modulus (1258 MPa to 1568 MPa). These additions decreased water solubility from 22.1% to 0.7%. FT-IR analysis of the films showed enhanced CH bonding of CMC in high content without any reaction. Biodegradability tests showed complete degradation within 7 days. Shelf-life extension tests demonstrated that bananas wrapped with CMC/starch/MCC/TiO₂ film lasted up to 12 days, compared to 5-6 days for unwrapped samples, with the addition of TiO₂ effectively scavenging ethylene without compromising film integrity. These results demonstrate the feasibility of SCB-derived MCC for sustainable, high-performance food packaging.

LC-MS Analysis and Intracellular and Extracellular Indole 3 Acetic Acid Production under Different Media by Endophytic Bacteria Associated with Humulus lupulus

2025-09-30T12:02:06+07:00

Recently, there has been a worldwide call to explore nature-friendly metabolites, which could enhance plant growth and substitute for chemically synthesized products. Indole-3-acetic acid (IAA) is one of the versatile metabolites that has a potential role for plant growth, anti-inflammatory, hepatoprotective, and anticancer properties. Furthermore, IAA is commonly synthesized chemically; the majority of reagents used pose environmental pollution. In contrast, biosynthesis through controlled cultivation of endophytes from medicinal plants offers an environmentally sustainable approach. The current study investigates the endophytic bacterium Bacillus licheniformis SKAM1 isolated from the leaves of Humulus lupulus for IAA production. The identification and characterization of endophytic bacterium was carried out using biochemical and molecular methods. Furthermore, LC-MS analysis of the dried extract of Bacillus licheniformis SKAM1 identified multiple bioactive compounds, including IAA, with potential therapeutic and agricultural applications. Additionally, the IAA quantification was performed using ultra-performance liquid chromatography (UPLC) across different media. UPLC analysis reveals that Bacillus licheniformis SKAM1 produces IAA in Luria broth medium; the extracellular IAA concentration was determined to be 1.16 mg/mL, whereas the intracellular level reached 1.11 mg/mL. Similarly, culture in minimal medium with extracellular IAA produced at 0.11 mg/mL and intracellular IAA at 0.06 mg/mL. The current study paves the way for exploring the role of abiotic conditions for cost-effective IAA production.

Development of a Hybrid Model for Rainfall Forecasting in Northeastern Thailand: Integration of Seasonal Autoregressive Integrated Moving Average, Support Vector Regression, and Variational Mode Decomposition

2025-09-04T09:23:30+07:00

This study presents a hybrid model integrating Seasonal Autoregressive Integrated Moving Average (SARIMA), Ensemble Variational Mode Decomposition (EVMD), and Support Vector Regression (SVR) to improve monthly rainfall forecasting in Northeastern Thailand. The approach addresses the challenges posed by the non-stationary and nonlinear nature of rainfall data. SARIMA is first applied to extract linear components, while EVMD is used to decompose residuals into Intrinsic Mode Functions (IMFs). Each IMF and the remaining residuals are forecasted using SVR. A dataset comprising 496 months of rainfall records (January 1983 to April 2024) from 12 meteorological stations under the Thai Meteorological Department was used. Model performance was evaluated using five statistical metrics: RMSE, PRMSE, RPD, MAE, and R². The hybrid SARIMA-EVMD-SVR model consistently outperformed SARIMA and SVR standalone models, achieving R² values above 0.84 and RPD values greater than 2.5 in most stations. The hybrid model improved forecasting accuracy by up to 39.26% over SVR and 36.11% over SARIMA. The results highlight the model’s ability to effectively capture complex rainfall dynamics. Its adaptability offers potential for application in other time series forecasting tasks, contributing to enhanced decision-making in water resource planning and climate-related policy development.

Diagnosis of Mango Leaf Diseases Using Deep Learning Techniques

2025-08-04T00:36:07+07:00

Mango cultivation is a cornerstone of Thailand's agriculture and economy, but diseases such as anthracnose, algal leaf spot, and gall midge present significant challenges as they can reduce crop yield and quality. In this study, we developed a machine learning-based system to diagnose mango leaf diseases using a dataset of 1,900 images collected from mango orchards in Phitsanulok province. The data underwent preprocessing and augmentation to optimize model training. Five deep learning models—Convolutional Neural Network (CNN), VGG16, DenseNet121, ResNet50, and InceptionV3—were trained and evaluated. Among these, ResNet50 demonstrated the best performance, with an accuracy of 99.8%, a precision of 0.998, a recall of 0.998, and an F1-score of 0.998. Leveraging its superior performance, the ResNet50 model was integrated into a mobile application designed for real-time disease diagnosis. This user-friendly application enables mango farmers to upload images of affected leaves and receive instant disease identification and treatment recommendations. The findings highlight the potential of deep learning models in agricultural applications, offering a reliable and efficient tool for early disease detection and management. By enabling timely intervention, this innovation enhances crop health, reduces losses, and boosts productivity, contributing significantly to sustainable farming practices and improving farmers' livelihoods.

Combination of Biological and Coagulation Treatments for Sludge Landfill Leachate: A Case Study in Hanoi, Vietnam

2025-10-10T14:51:53+07:00

Similar to other developing countries, Hanoi, the capital of Vietnam disposes of urban sludge, including sludge from water and wastewater treatment plants, drainage systems, at a landfill. With increasing population growth and urbanization, the volume of generated sludge continues to rise, necessitating proper treatment of the resulting sludge landfill leachate. This study assessed the characteristics of sludge landfill leachate and investigated appropriate treatment methods. The results indicate that the leachate contained high turbidity and TSS levels, along with a substantial organic content, as reflected by an average COD of 222 mg/L and BOD₅ of 110 mg/L. Nitrogen levels were also high, with NH₄⁺ at 102 mg/L and TN at 108 mg/L. Based on these characteristics, the study implemented a combined coagulation and biological treatment approach. The pretreatment of the leachate by coagulation led to COD reduction, thereby reducing the efficiency of the subsequent biological treatment. Therefore, the selected treatment process involved an initial AO (anoxic-oxic) biological treatment using biofilm carriers to remove organic matter and nitrogen, followed by coagulation using PAC at a dosage of 200 mg/L. The treated sludge landfill leachate met local discharge standard of Hanoi. This study provides essential data for designing sludge landfill leachate treatment system in Hanoi, Vietnam.

Tailoring Structural, Optical, and Electrical Properties of ITO Thin Films via Thickness Control, Reactive Nitrogen, and Thermal Annealing

2025-10-23T20:42:50+07:00

In this study, indium tin oxide (ITO) and nitrogen-incorporated ITO (ITON) thin films with thicknesses of 57, 116, and 173 nm were deposited on glass substrates using DC magnetron sputtering. The effects of nitrogen incorporation, film thickness, and thermal annealing on the structural, optical, and electrical properties were investigated. X-ray diffraction (XRD) analysis revealed that ITON exhibited partial crystallization in the as-deposited state and influenced the preferred crystal orientation after annealing, with ITO favoring (400) and ITON favoring (222). Both materials demonstrated high optical transparency (>70%) in the visible range, with ITON exhibiting higher transmittance, particularly at thickness of 173 nm (84.79% after annealing). The optical bandgap decreased with increasing thickness but increased after annealing, with ITON maintaining consistently higher values. Electrical measures indicated a thickness-dependent resistivity trend. Un-annealed ITO showed a systematic sheet resistance decrease from 546.4 to 255.83 Ω/square, whereas annealed ITO exhibited a minimum sheet resistance of 208.5 Ω/square at 173 nm. ITON films initially displayed unmeasurable sheet resistance at lower thicknesses, but after annealing, sheet resistance decreased systematically from 1789.0 to 447.23 Ω/square. Despite the low nitrogen concentration (0.01%), its incorporation significantly influenced the structural and electrical properties of the films. These findings provide insights into optimizing ITON thin films for advanced optoelectronic applications.

Biogas Production from Co-Digestion of Cassava Residue and Wastewater: Effects of Substrate Ratios and Digestion System Configurations

2025-10-21T15:51:42+07:00

Agricultural waste from cassava processing poses significant environmental challenges globally. This study investigated optimal anaerobic co-digestion parameters using batch experiments with six cassava residue-to-wastewater ratios (1:1, 1:2, 1:3, 1:4, 1:5, 2:1) tested in 20-liter digesters under mesophilic conditions for 20 days. The 1:3 cassava residue-to-wastewater ratio achieved maximum cumulative biogas production (6,200±450 mL) with 55% methane content, significantly outperforming other ratios (p<0.001). Increasing stirring speed from 50 to 120 rpm enhanced biogas yield by 31.2%, while hybrid configuration combining horizontal pre-digestion with vertical digestion increased production by 14.6% compared to conventional systems. The optimized process achieved 84.6% COD removal and 81.8% VS reduction, with VFA concentrations decreasing from 1,899 to 96 mg/L, indicating stable methanogenesis. Microbial analysis revealed enrichment of Methanosarcina species under 120 rpm agitation, correlating with enhanced performance. The integrated optimization of substrate ratio, mixing intensity, and reactor configuration provides a practical framework for industrial-scale cassava waste valorization, contributing to sustainable waste management and renewable energy production.

Optimization of Aeration Strategies in Moving Bed Biofilm Reactor for Hospital Wastewater Treatment

2025-09-01T11:57:59+07:00

The growing complexity of hospital wastewater presents significant challenges for traditional treatment methods, highlighting the need for innovative and energy-efficient alternatives. This study investigated the effect of different aeration strategies on the biological removal efficiency of carbon and nitrogen in a laboratory-scale moving bed biofilm reactor (MBBR). The system was operated under three aeration conditions: continuous aeration and two intermittent aeration regimes. The results show that intermittent aeration enhanced nitrogen removal through simultaneous nitrification-denitrification (SND) while maintaining high organic matter degradation efficiency. In Phase I (continuous aeration), carbon removal efficiency reached 87.4%, whereas total nitrogen removal remained below 20% due to the absence of anoxic conditions. In contrast, intermittent aeration in Phases II and III significantly improved nitrogen removal to 82.5% and 87.8%, respectively, while achieving comparable carbon removal rates. The most effective operational mode involved a 40-min aeration period followed by 20 min without aeration, facilitating denitrification and minimizing energy consumption. Furthermore, the system maintained stable biofilm development, with mixed liquor suspended solids (MLSS) concentrations ranging from 1.9 to 3.3 g/L. Despite the low MLSS concentration, the system consistently exhibited high treatment performance, underscoring the robustness of biofilm-based processes in MBBR systems. These findings highlight the potential of optimized aeration strategies in MBBR systems to enhance treatment efficiency while reducing operational costs. This study provides valuable guidance for designing sustainable hospital wastewater treatment systems that meet stringent regulatory standards.

Acido-alcoholyzed Products of Polylactide (PLA) and Their Use in Enhancing Mechanical Properties, Hydrophilicity, and Cell Compatibility of PLA Nanofibers for Tissue Engineering Applications

2025-09-11T21:53:06+07:00

Alcoholysis and acidolysis effectively transesterify polylactide (PLA) resin into small or medium-sized lactate oligomers with tunable hydrophilicity. The products can then be used to prepare various functional materials. This work employed 2, 2-bis(hydroxymethyl) propionic acid (DMPA) to generate small-sized PLA oligomers with carboxylic and hydroxyl terminals. The chemical structures and compositions of the acido-alcoholyzed PLA (aPLA) were analyzed by proton nuclear magnetic resonance (¹H-NMR) and Fourier transform infrared (FTIR) spectroscopy. The optimum product was blended with PLA resin and fabricated into electrospun nanofibers to increase their mechanical properties, hydrophilicity, and biocompatibility. The surface morphology, chemical structures, crystallinity, and properties of the PLA/aPLA blends were characterized by scanning electron microscopy (SEM), FTIR, X-ray diffraction (XRD) spectroscopy, water contact angle (WCA) measurements, tensile tests, and biocompatibility tests. Nanofibers with a ragged surface morphology and a 900-1500 nm size range were generated. The fibers showed higher crystallinity due to the enhanced crystallization induction by the acid and hydroxyl chain ends. Incorporating aPLA increased the elongation at break and the toughness of the fiber mats due to the plasticizing effect and the higher compatibility of aPLA in the PLA matrix. The hydrophilicity of the fiber mats also improved due to the higher contents of the polar end groups, leading to high water absorption in a short time. The cell compatibility results confirmed that the fibers containing 20% aPLAs were suitable for incubating L929 fibroblast cells, which was reflected in the higher adhesion and growth on the cells on the fiber mats within 7 days. The materials have high potential for use in tissue engineering scaffolding and biomedical applications.

Effect of Growth Regulators on Calotropis gigantea (Linn.) Aiton f. Callus Formation and Its Phytochemical Content

2025-03-07T15:44:50+07:00

Crown flower (Calotropis gigantea (Linn.) Aiton f.) is a weed that has potential as a source of medical materials. In vitro culture through callus induction can be an alternative method for rapid multiplication and producing phytochemical compounds in a shorter time. The great potential of crown flower plants is still unutilized optimally in Indonesia. The research aimed to determine the effect of various concentrations of plant growth regulators on callus formation and the phytochemical contents of crown flower. Young stem explants of crown flower were cultured on Murashige and Skoog (1962) medium supplemented with 6-benzyl amino purine and 2,4-dichlorophenoxyacetic acid. The research used a completely randomized design and callus formation time, fresh callus weight, callus morphology, flavonoids, and phytochemical contents were observed. The data were analyed using ANOVA and DMRT with a 5% level test. Treatments with 0.5 mg/L BAP and 0.5 mg/L 2,4-D could induce faster and bigger calli than other treatments with 5.82 g callus weight, yellowish-green colour, and compact texture. The addition of BAP and 2,4-D into the culture medium was able to produce different compounds compared to the field grown plants. Based on the results, PGR’s combination are required for callus formation and the production of different phytochemical compounds. Therefore, crown flower can be more effectively utilized as a medicinal or industrial plant.