Mealworm larvae (Tenebrio molitor) have emerged as a promising biological agent for degrading synthetic plastics. This study aimed to establish a non-invasive method to monitor plastic biodegradation by linking oxygen consumption to metabolic activity and to investigate microbial and chemical changes associated with plastic degradation. Larvae were maintained under controlled conditions (25 ± 0.5 °C; 75 ± 5% relative humidity) and fed expanded polystyrene (EPS) or polypropylene (PP) for 28 days. Survival rates, daily plastic consumption, and oxygen uptake were recorded. Frass was analyzed for molecular weight changes, while GC–MS, FTIR, and NMR were used to detect chemical modifications in degraded polymers. Gut microbiota composition was assessed by sequencing to identify taxa associated with plastic diets. Survival exceeded 80% in plastic-fed groups compared to 44.2% in unfed controls. Mean daily plastic consumption per 100 larvae was 15.7 ± 2.2 mg (EPS) and 16.4 ± 1.5 mg (PP). Frass analysis revealed significant depolymerization, while GC–MS, FTIR, and NMR confirmed oxidative modifications and the formation of shorter-chain alkanes. Microbiome profiling showed consistent presence of Spiroplasma, Lactococcus, and Enterococcus, with enrichment of Staphylococcus and Providencia in EPS-fed groups. Oxygen uptake correlated with plastic degradation, validating it as a real-time metabolic indicator. This study demonstrates that oxygen uptake can serve as a real-time proxy for plastic degradation in vivo, providing higher temporal resolution than endpoint assays. The findings highlight the dual role of larvae and their gut microbiome in polymer breakdown, offering new insights into sustainable bioconversion strategies for plastic waste.

Waste streams, leachates, and wastewater often contain high-strength ammonia, which can be challenging to manage. Microbial fuel cells (MFCs) offer a promising solution for treating such a nuisance of high-strength ammonia. However, optimizing MFC operating conditions, at lower technology readiness levels, is crucial to achieve a sustainable and economically viable application. This study investigates the factors affecting ammonia nitrogen removal in MFCs. MFCs with a cation exchange membrane (CEM) exhibit a higher diffusion rate of ammonium ions from the anode to the cathode compared to those with a proton exchange membrane (PEM). In close circuit mode (CCM), MFCs with a Pt-coated cathode electrode achieved an ammonium removal efficiency of 96% in the cathode chamber. Moreover, a plain carbon cathode electrode yielded an 87.1% removal efficiency. These results indicate that the combination of a catalyst (Pt) and oxygen in the cathode chamber can effectively remove or recover ammonia nitrogen from wastewater. Simultaneously, the removal of ammonia nitrogen in a microbial electrolysis cell (MEC) was studied. At an applied potential of 1.0 V, an ammonium removal efficiency of 87.5% was achieved. It was concluded that ammonium losses in MFCs can occur through electron migration, volatilization, and biological processes such as nitrification and denitrification.

Mealworm larvae ( Tenebrio molitor ) exhibit the potential for biodegrading synthetic plastics, providing a sustainable strategy to reduce plastic waste.

Aquaponic systems are the integration of aquaculture and hydroponic systems to enhance productivity, reduce land use, and improve sustainability. This review focused on commonly used life cycle assessment (LCA) methodologies, system boundaries, and functional units used in aquaponics, standard impact categories, and identified hotspots. The scope is worldwide and encompasses a variety of aquaponic designs, fish species, and crops, illustrating the diversity of the systems examined. The analysis indicates that aquaponics provides the considerable environmental advantages of decreased fertilizer consumption and water conservation in comparison with aquaculture and hydroponic system. However, aquaponics systems are characterized by high energy consumption and may produce greater greenhouse gas (GHG) emissions compared to traditional farming methods when reliant on fossil fuel energy sources. Studies show that fish feed production, system infrastructure, and electricity usage for pumps, lights, heating, and other controls are hotspots. Harmonized comparisons of previous studies show methodological differences, especially in fish–plant co-production. Despite these variations, most believe that energy efficiency, renewable energy, feed optimization, and waste reuse may make aquaponics more sustainable. The study recommends the inclusion of broader environmental and social impacts. Also, future focus might be on making a standard functional unit or specifying system boundaries which might provide different accurate outcomes.

Heavy metal and cyanide contamination in soil presents serious environmental and ecological concerns due to their persistence, bioavailability, and toxicity to soil biota. In this study, a novel solid-phase direct contact bioassay kit was developed using immobilized Chlorella vulgaris spheres to evaluate the toxicity of soils contaminated with mercury (Hg²⁺), silver (Ag⁺), copper (Cu²⁺), and cyanide (CN⁻). The assay was designed using 25 mL glass vials in which algal spheres were directly exposed to spiked soils for 72 h without the need for pollutant extraction. Oxygen evolution in the headspace was measured as the primary endpoint, alongside optical density and chlorophyll a fluorescence (OJIP) to assess photosynthetic inhibition. The assay demonstrated high sensitivity and reproducibility, with strong correlations (R² > 0.93) between oxygen evolution and optical density. EC₅₀ values based on oxygen evolution were 4.43, 4.18, 3.10, and 61.3 mg/kg for Hg²⁺, Ag⁺, CN⁻, and Cu²⁺, respectively, and 7.8, 7.4, 2.9, and 29.7 mg/kg based on optical density. The relatively higher EC₅₀ for copper was attributed to its biological role as an essential micronutrient. OJIP transient profiles supported the observed photosynthetic inhibition, particularly under Hg²⁺, Ag⁺, and CN⁻ exposure. The present study overcomes the limitations of conventional chemical analyses by providing a rapid, low-cost, and ecologically relevant tool for direct soil toxicity assessment, with potential applications in environmental monitoring and contaminated site evaluation.