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Chemosphere Apr 2023Microbes play a dominant role for the transformation of organic contaminants in the environment, while a significant gap exists in understanding the degradation...
Microbes play a dominant role for the transformation of organic contaminants in the environment, while a significant gap exists in understanding the degradation mechanism and the function of different species. Herein, the possible bio-degradation of triclosan in microbial fuel cell was explored, with the investigation of degradation kinetics, microbial community, and possible degradation products. 5 mg/L of triclosan could be degraded within 3 days, and an intermediate degradation product (2,4-dichlorophen) could be further degraded in system. 32 kinds of dominant bacteria (relative intensity >0.5%) were identified in the biofilm, and 10 possible degradation products were identified. By analyzing the possible involved bioreactions (including decarboxylation, dehalogenation, dioxygenation, hydrolysis, hydroxylation, and ring-cleavage) of the dominant bacteria and possible degradation pathway of triclosan based on the identified products, biodegradation mechanism and function of the bacteria involved in the degradation of triclosan was clarified simultaneously. This study provides useful information for further interpreting the degradation mechanism of organic pollutants in mixed flora by combining analysis microbiome community and degradation pathway.
Topics: Triclosan; Bioelectric Energy Sources; Biodegradation, Environmental; Bacteria; Microbiota
PubMed: 36739987
DOI: 10.1016/j.chemosphere.2023.137983 -
Environmental Pollution (Barking, Essex... Sep 2019Increasing attention has been attracted in developing new technologies to remove chlorofene (CF) and dichlorofene (DCF), which were active agents in antimicrobials for...
Increasing attention has been attracted in developing new technologies to remove chlorofene (CF) and dichlorofene (DCF), which were active agents in antimicrobials for general cleaning and disinfecting. This study investigated the significant influences of bicarbonate (HCO) on the degradation of CF and DCF in the Cu(II)-mediated Fenton-like system Cu/HO. Our results indicate that HCO may play a dual role to act 1) as a ligand to stabilize Cu(II), forming soluble [Cu(HCO)(S)] species to catalyze HO producing hydroxyl radical (OH) and superoxide ion (O) and 2) as a OH scavenger. Furthermore, the reaction kinetics, mechanisms, and intermediates of CF and DCF were assessed. The apparent rate constants of CF and DCF were enhanced by a factor of 8.5 and 5.5, respectively, in the presence of HCO at the optimized concentration of 4 mM. Based on the intermediate identification and frontier electron densities (FEDs) calculations, the associated reaction pathways were tentatively proposed, including C-C scission, single or multiple hydroxylation, and coupling reaction. In addition, significant reduction in the aquatic toxicity of CF and DCF was observed after treatment with Cu/HO-HCO system, evaluated by Ecological Structure Activity Relationships (ECOSAR) program. These findings provide new insights into Cu(II)-mediated reactions to better understand the environmental fate of organic contaminants in carbonate-rich waters.
Topics: Anti-Bacterial Agents; Bicarbonates; Carbonates; Chlorophenols; Copper; Dichlorophen; Disinfectants; Environmental Restoration and Remediation; Hydrocarbons, Halogenated; Hydrogen Peroxide; Hydroxyl Radical; Iron; Kinetics; Oxidation-Reduction; Phenol
PubMed: 31227352
DOI: 10.1016/j.envpol.2019.05.148