Journal of Environmental Microbiology and Toxicology

Optimization of Sugarcane Bagasse for Whey Adsorption: A Sustainable Approach to Enhancing Nutrient-Rich Animal Feed

2025-12-14T17:26:07+00:00

Waste agricultural biomass is often environmentally hazardous when released to the environment, and some residues are toxic to the surrounding ecosystems. These biomasses, when properly valorized, can be a sustainable source of green adsorbents. The ever-increasing need for nutrient-fortified animal feed has become a real challenge for the animal feed industry. In this study we focus on a method of improving the nutrient content of the agricultural waste biomass sugarcane bagasse through the adsorption of whey, a byproduct of the cheese industry. The potential of sugarcane bagasse and spent cheese whey as sustainable adsorbent and adsorbate, respectively, is explored. We first use a one-factor-at-a-time approach to maximize the adsorption capacity of sugarcane bagasse. The factors examined include bed height, pH, temperature, and whey concentration. RSM was successfully used to further improve the optimal conditions. A fixed-bed column packing method was utilized in the adsorption experiments. Parameters optimized include the effects of different bed heights (1 cm to 3 cm), pH levels (4 to 8), temperatures (20 °C to 30 °C), and whey concentrations (0.01% to 0.05%). The optimal conditions include a bed height of 3 cm, pH of 8.0, temperature of 25 °C, and whey concentration of 0.01%. These optimal conditions improve the nutrient content of the agro-industrial waste. The Modified Dose Response (MDR) Model was utilized to analyze the breakthrough curves of the design parameters, which include bed height, flow rate, and initial solute concentration. The results show that a 3 cm bed height yields a qm value of 79.487 mg/g, pH 8 gives a qm value of 82.797 mg/g, and a 0.05% whey concentration results in a qm value of 95.274 mg/g. To the best of our knowledge, this research is the first, and it has the potential to contribute to a sustainable novel approach for whey supplementation in animal feed.

Toxicity and Bioaccumulation of Lead (Pb) in the Marine Bivalve Geloina expansa

2025-12-17T11:00:16+00:00

Heavy metal pollution is a major environmental concern due to its persistence, toxicity, and ability to bioaccumulate in aquatic ecosystems. In Malaysia, increasing attention has been given to monitoring heavy metals in local marine organisms, as their accumulation in sediments and biota threatens ecosystem health and food safety. Bivalves serve as effective bioindicators, and LC50 provides essential insight into the acute toxicity of heavy metals across species. This study investigated the effects of lead (Pb) exposure on the bivalve Geloina expansa through a 96-hour acute toxicity assay. Mortality increased with rising Pb concentrations, accompanied by higher Pb accumulation in soft tissues. The 96-hour LC50 for G. expansa was calculated as 218.23 mg/L. Exposure to 250 mg/L Pb resulted in substantial Pb accumulation (1653 ± 177.51 mg/kg) compared to controls (13.00 ± 1.04 mg/kg), confirming effective uptake. These findings highlight Geloina expansa sensitivity to Pb and its suitability for pollution monitoring.

Multifunctional Applications of Bacterial Cellulose: Bridging Food, Cosmetic and Environmental Sectors

2025-12-17T11:15:04+00:00

In recent years, with increasing demand for sustainable, environmentally friendly materials, bacterial cellulose (BC) has attracted significant attention as a promising biomaterial. BC possesses excellent mechanical strength, good biocompatibility, extremely high water-holding capacity (more than 100 times its own weight), and can be easily modified. These unique properties make BC superior to plant cellulose in many applications. This review summarizes recent progress in BC across several important fields. In the food industry, BC has been widely used as edible films and coatings, enhancing the shelf life of fresh products. Moreover, when natural antimicrobial agents or pH indicators were incorporated, active and intelligent packaging were developed. As a food additive, BC acts as a high-quality dietary fiber that can adsorb cholesterol and bile salts in the gastrointestinal tract. BC also improves the texture of low-calorie foods and protects probiotic bacteria during storage. In the cosmetic field, BC is well-suited for facial masks because its three-dimensional structure can hold a large amount of active compounds and conform well to the skin surface. When BC was combined with propolis or other natural extracts, the antioxidant and anti-aging effects were greatly enhanced. In wastewater treatment, the abundant hydroxyl groups and large surface area enable heavy metal ions and organic dyes to be removed effectively. Besides, BC has been used as a reinforcement material in the paper and textile industries. The addition of BC greatly increases tensile strength and provides hydrophobicity while maintaining complete biodegradability. Although BC has numerous excellent properties and great potential in many fields, large-scale production still faces some challenges, mainly high costs and low yields. The use of agro-industrial waste as a substrate and the development of new bioreactors can significantly reduce production costs. Based on the above-mentioned research, it is clear that BC will play an important role in the future sustainable industry.

Biodecolorization of Metanil Yellow by Serratia marcescens MM06 Under Variable Environmental Conditions for Soil and Water Remediation

2025-12-17T18:23:08+00:00

Metanil Yellow is a common pollutant coming from the dyeing industry. Its removal using decolorizing bacteria offers a sustainable approach to remediate polluted soils and water bodies. This research examines the impact of several parameters, such as initial dye concentration, temperature, pH, and NaCl concentration, on the decolorization efficacy of Serratia marcescens strain MM06 for the dye Metanil Yellow. The percentage of decolorization studied across different dye concentrations from 100 to 700 mg/L shows the highest decolorization at dye concentrations of between 100 and 300 mg/L. The decolorization was highest at 25°C. The effect of pH on the decolorization showed that the best decolorization occurred between pH 7 and 8. The effect of salinity on the decolorization for future coastal areas remediation showed that the best decolorization (90–100%) happened at NaCl levels up to 15 g/L. The decolorization effectiveness decreased as the NaCl concentration increased, reaching 10% at 30 g/L. Decolorization was severely inhibited by mercury, silver, and copper at 1 mg/L, which shows that chelating or sequestering agents may need to be added to the contaminated soil or water bodies before decolorization can take place. Gaining a thorough understanding of the decolorization characteristics is an important preliminary study before field studies are carried out to understand the limitations of the decolorization bacterium.

Growth Modeling of a γ-Hexachlorocyclohexane-degrading Microbial Consortium Based on Chloride Release Kinetics

2025-12-19T07:11:38+00:00

Nonlinear growth modeling can offer a more robust approach in curve fitting exercises compared to the traditional linear regression for modelling microbial growth processes. The models utilized include Huang, Baranyi-Roberts, modified Gompertz, Buchanan-3-phase, modified Richards, modified Schnute, modified Logistics, von Bertalanffy, MMF (Morgan Mercer Flodin), and the study evaluated these primary growth models to describe a bacterial consortium growth on lindane, with growth measured indirectly by chloride release. The results show that choosing the best model using visual inspection is inadequate for distinguishing between models, as all evaluated models demonstrated acceptable fits. A statistically and information-criterion-based discriminatory approach demonstrated distinct performance disparities. The Huang model consistently demonstrated superior performance compared to competing models, characterized by the lowest error values, the highest explanatory power, favorable information criteria, and minimal systematic bias. However, the modified Richards and modified Logistics models also exhibited competitive performance under specific criteria. The MOORA multi-criteria decision-making approach was utilized to mitigate the uncertainty associated with the majority voting approach. MOORA demonstrates that the Huang model is the most robust overall, with the modified Richards and modified Logistics models following closely behind. The parameters obtained from the Huang model for the chloride release kinetics at 10 μM lindane were Lag period (d or day), Ymax, and μm values of -3.132 (d), 9.235, and 0.934 (d-1), respectively. The utilization of the modelling exercise yielded important parameters for future secondary modelling exercises and preliminary prediction of performance and limitations in field studies.

Antibacterial Activity of Disinfectants Against Staphylococcus aureus Isolated from Healthcare Equipment in Some Kano Metropolitan Hospitals

2026-01-21T18:41:24+00:00

This study investigated the antibacterial activity of common hospital disinfectants, Dettol, Hypo, and Izal, against Staphylococcus aureus isolated from healthcare equipment in selected hospitals within Kano Metropolis, Nigeria. A total of 288 samples were collected from the hospital environment, including bed sheets, bed rails, toilet door handles, and Nurses' used gloves across Imam Wali General Hospital, Muhammad Abdullahi Wase Teaching Hospital, and Murtala Muhammad Specialist Hospital. Bacterial isolation and identification were conducted using standard microbiological methods, including culture on Mannitol Salt Agar and biochemical tests. Results showed that S. aureus was the predominant isolate (30.06%), followed by E. coli (27.27%), Klebsiella pneumoniae (22.02%), and Pseudomonas aeruginosa (8.39%). The antibacterial efficacy of the disinfectants was assessed using the disc diffusion method at varying concentrations (100%, 50%, 25%, and 12.5%). Statistical analysis (ANOVA, p < 0.05) revealed significant differences among the disinfectants. Hypo (sodium hypochlorite) demonstrated the highest mean zone of inhibition across all concentrations (21.26 mm at 100%), followed by Izal (18.06 mm) and Dettol (17.58 mm), while ethanol (control) exhibited the least activity (11.83 mm). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) results further confirmed Hypo's superior efficacy (MIC = 0.08 mL; MBC = 0.05 mL). These findings highlight Hypo as the most effective disinfectant against S. aureus isolated from hospital surfaces, likely due to its strong oxidative mechanism via hypochlorous acid production. The study underscores the importance of using highly effective disinfectants like Hypo in infection control protocols to reduce the risk of nosocomial infections and limit the spread of antimicrobial-resistant pathogens in healthcare facilities.

Physicochemical Characteristics of Anopheles Mosquito Breeding Sites in Azare, Bauchi State, Nigeria: Implications for Malaria Transmission and Control

2026-01-21T19:00:36+00:00

The physicochemical parameters of breeding sites of African malaria vector mosquitoes were investigated in Azare town, Bauchi State, Nigeria. A multiparameter pH meter was used to analyze water samples from various breeding sites for parameters such as temperature, pH, turbidity, dissolved oxygen, total dissolved solids, and conductivity. The results showed that the mean temperature (30.9°C and 31.1°C), pH (6.8 and 7.3), and dissolved oxygen (4.32 mg/L and 3.99 mg/L) were within the tolerable limits for mosquito breeding in Sudan and Sahel savannah regions, respectively. However, the levels of turbidity, total suspended solids, chloride, nitrate, nitrogen, and potassium exceeded the recommended limits in both regions, indicating potential anthropogenic influences. The study highlights the importance of understanding these parameters in developing targeted control strategies to reduce malaria transmission in Azare town and similar environments.

Response Surface Optimization of Acetylcholinesterase Extraction from Scomberomorus commerson for Toxicological Applications

2026-01-24T18:14:26+00:00

Cholinesterase, especially acetylcholinesterase, is often used in toxicology research in insecticide biomonitoring work from the environment or from agricultural products. One of the most utilized sources of acetylcholinesterase is from fish acetylcholinesterase, and the search for potentially sensitive sources of acetylcholinesterase is ongoing research. In this study, the extraction conditions of acetylcholinesterase (AChE) from Scomberomorus commerson, a novel source, were optimized using Response Surface Methodology (RSM). A Box-Behnken Design (BBD) was applied to evaluate the effects of three independent variables—pH (7.0-8.8), NaCl concentration (0.05-0.20 M), and Triton X-100 concentration (0.01-0.04% v/v)—on AChE activity as the response. Experimental data were fitted to a quadratic polynomial model, which demonstrated good agreement with the observed values (R² = 0.9081; Adj R² = 0.7898). Analysis of variance confirmed that pH was the most significant factor influencing extraction efficiency (p < 0.01), while NaCl and Triton X-100 showed weaker individual effects within the studied range. A significant interaction between pH and NaCl (p < 0.05), together with the quadratic effect of pH, contributed to the nonlinear extraction profile. Numerical optimization predicted maximum AChE activity at pH 8.79, 0.197 M NaCl, and 0.039% Triton X-100, yielding a predicted activity of 0.145 U (95% CI: 0.125-0.166 U). Experimental validation produced a similar value of 0.152 U, confirming the reliability of the model. Further kinetic characterization revealed substrate-dependent variations in catalytic parameters, with Vmax and Km values of 0.02238 U and 0.03387 mM for acetylthiocholine (ATC), 0.02135 U and 0.2177 mM for propionylthiocholine (PTC), and 0.01928 U and 0.2316 mM for butyrylthiocholine (BTC), respectively. These findings demonstrate that RSM is an effective approach for improving AChE extraction, with pH identified as the primary factor governing extraction performance.

Engineered Green Synthesized Silica-Oxide Nanoparticle for Enhanced Bioremediation of Petroleum Polluted Soil in the Niger Delta

2026-02-25T13:34:41+00:00

The most prevalent environmental contaminants in the Niger Delta zone are petroleum hydrocarbons, and their spillage poses a serious threat to life. So many techniques have been deployed over the years to reclaim soil perturbed with petroleum hydrocarbons using nanobioremediation. The use of these nanoparticles is drawing so much attention, which could be attributed to several qualities these nanoparticles possess. These engineered green synthesized silica-oxide nanoparticles (EGSSON) are used for the enhanced degradation of petroleum hydrocarbon-polluted agricultural farm soil, thereby restoring beneficial microorganisms to the ecosystem. With the manufacturing of these environmentally friendly (EGSSON), the industrial cost for decontaminating agricultural soil might be cut down due to the availability of the plant materials used, which are productive and more efficient than other methods, which have hazardous material manufacturing, inefficient cleanup techniques, and high capital needs. Therefore, using effective, eco-friendly, and financially feasible methods is essential to establishing and achieving environmental sustainability. Because of their large size, strong chemical reactions, and catalytic properties, these nanoparticles are employed to remediate hydrocarbon-polluted soil, which has led to an increase in their use in recent decades. After calcination of bamboo leaves to create white, powdery silica-oxide particles, the silica-oxide nanoparticle is further described and put through an ecotoxicity test on microbial cells. These green synthesized silica-oxide nanoparticles, when introduced with hydrocarbon-degrading microorganisms, exhibit a nanobioremediation strategy that is cost-effective, friendly to the environment and highly sustainable.

Evaluation of the Antimicrobial Activity of Selected Psychotropic Drugs Against Yeast Species

2026-02-25T13:49:44+00:00

The antimicrobial activity of psychotropic drugs forms the basis for their repurposing for antibiotic applications and concurrently requires care in their disposal due to their potential role in the evolution and spread of antimicrobial resistance. Four psychotropic drugs of the sedative class, namely barbiturate, benzodiazepine, non-benzodiazepine, and chloral hydrate, were tested for their antimicrobial activity against three different types of yeasts, viz, an ascomycetous non-pathogenic yeast Saccharomyces cerevisiae, an ascomycetous pathogenic yeast Candida tropicalis, and a basidiomycetous emerging pathogenic yeast Rhodotorula mucilaginosa; biofilm-forming ability was used as the parameter of pathogenicity. All drugs showed antibiofilm activity; chloral hydrate was more effective (causing 66.3%, 42.355 and 25.44% in S. cerevisiae, R.mucilaginosa and C. tropicalis respectively) at lower concentrations (MIC50), S. cerevisiae was the most resistant yeast except in the case of chloral hydrate, while R. mucilaginosa was the most sensitive yeast (up to 76.85% and 74.67% inhibition by benzodiazepine and non-benzodiazepine respectively) towards the selected sedative drugs. Some of these drugs may be repurposed for use as antibiotics, while care must be taken in their disposal, as they may contribute to the evolution and spread of antimicrobial resistance.