Enhancing fluoroglucocorticoid defluorination using defluorinated functional strain Acinetobacter. pittii C3 via humic acid-mediated biotransformation

Green synthesis of magnetic azo-linked porous organic polymers with recyclable properties for enhanced Bisphenol-A adsorption from aqueous solutions

Porous organic polymers (POPs) present superior adsorption performance to steroid endocrine disruptors. However, the effective recovery and high cost have been a big limitation for their large-scale applications. Herein, magnetic azo-linked porous polymers (Fe3O4@SiO2/ALP-p) were designed and prepared in a green synthesis approach using low-price materials from phloroglucinol and pararosaniline via a diazo-coupling reaction under standard temperature and pressure conditions, which embedded with Fe3O4@SiO2 nanoparticles to form three-dimensional interlayer network structure with flexible-rigid interweaving. The saturated adsorption capacity to bisphenol-A (BPA) was 485.09 mg/g at 298 K, which increased by 1.4 times compared with ALP-p of relatively smaller mass density. This enhanced adsorption was ascribed to increment from surface adsorption and pore filling with 2.3 times of specific surface area and 2.6 times of pore volume, although the total organic functional groups decreased with Fe3O4@SiO2 amendment. Also, the adsorption rate increased by about 1.1 and 1.5-fold due to enhancement in the initial stage of surface adsorption and subsequent stage pore diffusion, respectively. Moreover, this adsorbent could be used in broad pH (3.0-7.0) and salinity adaptability (<0.5 mol/L). The loss of adsorption capacity and magnetic recovery were lower than 1.1% and 0.8% in each operation cycle because of the flexible-rigid interweave. This excellent performance was contributed by synergistic effects from physisorption and chemisorption, such as pore filling, electrostatic attraction, π-π stacking, hydrogen bonding, and hydrophobic interaction. This study offered a cost-effective, high-performing, and ecologically friendly material along with a green preparation method.

Insight into the enhancement effect of humic acid on microbial degradation of triclosan in anaerobic sediments

Humic acid (HA) as one class of macromolecular substances plays important roles in mediating environmental behaviors of pollutants in sediments, but its effect on microbial degradation of triclosan (TCS), a common antibacterial drug, remains unclear. In this study, the effects of HA addition with different dosages (0-5%) on TCS degradation in anaerobic sediment slurries and the underlying microbial mechanisms were investigated. The results showed that HA addition significantly accelerated the TCS removal and the maximum removal percentage (30.2%) was observed in the sediment slurry with 5% HA addition. The iron reduction rate, relative abundances of the genera Comamonas, Pseudomonas and Geobacter, and bacterial network complexity in sediment slurry were significantly enhanced due to HA addition. Based on the partial least squares path modeling analysis, the enhancement effect of HA on TCS degradation was mainly explained by Fe(II):Fe(III) ratio with the highest influence on TCS removal (total effect: 0.723), followed by dominant genera abundances (total effect: 0.391), module relative abundance (total effect: 0.272), and network topological features (total effect: 0.263). This finding enhanced our understanding of the role of HA in TCS biodegradation in contaminated sediments for bioremediation purposes.

Detoxification of fluoroglucocorticoid by Acinetobacter pittii C3 via a novel defluorination pathway with hydrolysis, oxidation and reduction: Performance, genomic characteristics, and mechanism

Biological dehalogenation degradation was an important detoxification method for the ecotoxicity and teratogenic toxicity of fluorocorticosteroids (FGCs). The functional strain Acinetobacter pittii C3 can effectively biodegrade and defluorinate to 1 mg/L Triamcinolone acetonide (TA), a representative FGCs, with 86 % and 79 % removal proportion in 168 h with the biodegradation and detoxification kinetic constant of 0.031/h and 0.016/h. The dehalogenation and degradation ability of strain C3 was related to its dehalogenation genomic characteristics, which manifested in the functional gene expression of dehalogenation, degradation, and toxicity tolerance. Three detoxification mechanisms were positively correlated with defluorination pathways through hydrolysis, oxidation, and reduction, which were regulated by the expression of the haloacid dehalogenase (HAD) gene (mupP, yrfG, and gph), oxygenase gene (dmpA and catA), and reductase gene (nrdAB and TgnAB). Hydrolysis defluorination was the most critical way for TA detoxification metabolism, which could rapidly generate low-toxicity metabolites and reduce toxic bioaccumulation due to hydrolytic dehalogenase-induced defluorination. The mechanism of hydrolytic defluorination was that the active pocket of hydrolytic dehalogenase was matched well with the spatial structure of TA under the adjustment of the hydrogen bond, and thus induced molecular recognition to promote the catalytic hydrolytic degradation of various amino acid residues. This work provided an effective bioremediation method and mechanism for improving defluorination and detoxification performance.

Post-Global Pandemic Challenges and improvements in advanced detection and removal processes of toxic pollutants: Editorial

Every two years, the Pollutant Toxic Ions and Molecules Conference, PTIM, meets the environmentalist, biologist, chemists and health researchers in Costa de Caparica, Portugal, to showcase the latest technologies, methodologies and research advances in pollution detection, contamination control, remediation, and related health issues, as well as policy implications.