Understanding how environmental conditions influence microbial functions is essential for optimizing biological wastewater treatment and bioelectrochemical systems. This study investigated the effects of carbon-to-nitrogen (C/N) ratio and nitrate availability on 3-oxo-C10-HSL accumulation and the functional responses of Pseudomonas aeruginosa 9027 under anoxic conditions using microbial fuel cells (MFCs). Initial C/N ratios of 1, 10, and 30 were established using sodium acetate and KNO3. After 240 h of operation, 3-oxo-C10-HSL concentrations were 18.9 ± 16.4, 91.1 ± 59.5, and 202.3 ± 51.3 nM at C/N ratios of 1, 10, and 30, respectively, while residual nitrate concentrations were 7.5 ± 1.5, 1.5 ± 0.4, and 0.8 ± 0.7 mM. 3-oxo-C10-HSL was not detected in the limited aerobic experiments conducted for comparison. 3-oxo-C10-HSL accumulation was associated with nitrate depletion and was greater at higher initial C/N ratios following nitrate depletion. COD and nitrate removal exceeded 89
The resistance of conventional plastic packaging to degradation causes severe environmental impacts, driving the development of sustainable alternatives. This study investigated the biodegradation of biopolymer-based films composed of bacterial cellulose/kappa-carrageenan (BC/KC) blends incorporated with natural extracts under controlled (ex situ) and natural semi-arid conditions in Pernambuco, Brazil (in situ). Soil microbial populations were characterized, and the films were evaluated as antimicrobial packaging for mozzarella cheese. The films showed high susceptibility to biodegradation, with mass losses of 50–100
Cephalexin (CPX), a widely used β-lactam antibiotic, is frequently detected in aquatic environments and poses risks to ecological and human health, yet the biodegradation pathways underlying its microbial removal remain incompletely characterized. In this study, a synthetic bacterial–fungal consortium (CPXS), comprising Achromobacter aegrifaciens, Citrobacter amalonaticus, Elizabethkingia anophelis, Bacillus wiedmannii, and Geotrichum pandrosion, was constructed and evaluated for CPX biodegradation. Following systematic single-factor and multivariable optimization (pH 8, 30 °C, 85 mg/L CPX), the consortium achieved 98.5
Hexavalent chromium [Cr(VI)] has emerged as a significant environmental pollutant because of its toxicity and long-term persistence. As a result, remediation of Cr(VI) is urgently needed to save the ecosystem and human health. There are several traditional remediation methods that are not sustainable. Therefore, the current work explores the green synthesis of iron oxide nanoparticles (BJ-IONPs) derived from Mustard (Brassica juncea) waste. The synthesized BJ-IONPs were characterized using X-ray Diffraction (XRD), Differential Scanning Calorimetry - Thermogravimetric Analysis (DSC-TGA), Fourier Transform Infrared Spectroscopy (FTIR), Zeta Potential, Field Emission Scanning Electron Microscopy (FESEM), and Transmission Electron Microscopy (TEM) techniques for the surface morphology, physical charge, and particle size. Additionally, batch studies were conducted to evaluate the efficiency of synthesized nanoparticles for Cr(VI) remediation by varying the pH, temperature, initial Cr(VI) concentration, adsorbent dose, and contact time. Following the experiments, maximum adsorption i.e. 99.66
Humic acid (HA) is an important component of natural organic matter and is widely present in soils, sediments, and wastewater. Due to its complex aromatic structure and high chemical stability, HA exhibits poor biodegradability and increases the difficulty of wastewater treatment. Microbial degradation has attracted increasing attention as an environmentally friendly approach for HA removal. However, functional HA-degrading microorganisms from natural organic matter-rich environments remain insufficiently explored. In this study, artificial lake sediment and humified soil beneath decayed ginkgo wood were selected as microbial sources for screening HA-degrading microorganisms. A total of 33 microbial isolates were obtained through enrichment culture, acclimation, and screening procedures. Among them, three representative strains, designated as HA-X1, HA-X4, and HA-Z3, exhibited relatively higher HA removal efficiencies. Based on morphological characteristics and molecular identification, HA-X1 and HA-X4 were assigned to Bacillus-related taxa, while HA-Z3 was affiliated with the genus Phoma. The growth characteristics and HA removal performances of the selected strains under different initial HA concentrations, pH conditions, and inoculum dosages were further investigated. The results showed that all selected strains could grow in HA-containing media and exhibited HA removal capability under the tested conditions. Among the three strains, HA-X4 showed the highest overall removal performance. The selected strains displayed different responses to environmental factors, indicating variations in their HA transformation characteristics. Scanning electron microscopy (SEM) analysis revealed the morphological characteristics of bacterial cells and fungal mycelial structures. This study provides functional microbial resources for further investigation of HA biodegradation and the development of biological treatment technologies for HA-containing wastewater.
