Fate of the Nitrilotriacetic acid -Fe(III) complex during photodegradation and biodegradation by Rhodococcus rhodochrous.

International audienceAminopolycarboxylic acids are ubiquitous in natural waters and wastewaters. They have the ability to form very stable water-soluble complexes with many metallic di- or trivalent ions. The iron complex nitrilotriacetic acid-Fe(III) (FeNTA) has been previously shown to increase drastically the rate of photo- and biodegradation of 2-aminobenzothiazole, an organic pollutant, by Rhodococcus rhodochrous. For this paper, the fate of FeNTA was investigated during these degradation processes. First, it was shown, using in situ 1H nuclear magnetic resonance, that the complex FeNTA was biodegraded by Rhodococcus rhodochrous cells, but the ligand (NTA) alone was not. This result indicates that FeNTA was transported and biotransformed inside the cell. The same products, including iminodiacetic acid, glycine, and formate, were obtained during the photo- and biodegradation processes of FeNTA, likely because they both involve oxidoreduction mechanisms. When the results of the different experiments are compared, the soluble iron, measured by spectrophotometry, was decreasing when microbial cells were present. About 20% of the initial iron was found inside the cells. These results allowed us to propose detailed mechanistic schemes for FeNTA degradation by solar light and by R. rhodochrou

Predictive toxicology using systemic biology and liver microfluidic "on chip" approaches: Application to acetaminophen injury

International audienceWe have analyzed transcriptomic, proteomic and metabolomic profiles of hepatoma cells cultivated inside a microfluidic biochip with or without acetaminophen (APAP). Without APAP, the results show an adaptive cellular response to the microfluidic environment, leading to the induction of anti-oxidative stress and cytoprotective pathways. In presence of APAP, calcium homeostasis perturbation, lipid peroxidation and cell death are observed. These effects can be attributed to APAP metabolism into its highly reactive metabolite. N-acetyl-p-benzoquinone imine (NAPQI). That toxicity pathway was confirmed by the detection of GSH-APAP, the large production of 2-hydroxybutyrate and 3-hydroxybutyrate, and methionine, cystine, and histidine consumption in the treated biochips. Those metabolites have been reported as specific biomarkers of hepatotoxicity and glutathione depletion in the literature. In addition, the integration of the metabolomic, transcriptomic and proteomic collected profiles allowed a more complete reconstruction of the APAP injury pathways. To our knowledge, this work is the first example of a global integration of microfluidic biochip data in toxicity assessment. Our results demonstrate the potential of that new approach to predictive toxicology

Photo- et biodégradation de dérivés du benzothiazole. Etude en système combiné

Thès

Photo-et biodégradation de dérivés du benzothiazole : étude en système combiné

Degradation in aqueous solution of 2-aminobenzothiazole (ABT) and benzothiazole (BT) has been studied by photochemical pathways, microbiological and combining the two approaches. The photochemically involved aqueous iron complexes or complex between iron and NTA (Fenta). The microbiologically using a bacterial strain of Rhodococcus rhodochrous. Degradation patterns were established for various tracks. We have shown that there is great similarity between the photochemical and microbiological degradation. In addition, two new degradation products were identified by NMR and HPLC coupled with UV-visible SM. This is the 4OH-ABT and an iron complex with a catechol derivative of ABT. We have shown the greatest efficiency of coupling the iron and microorganisms. The major role of iron has been demonstrated in the degradation process as photoinitiator and as an activator of bacterial enzymesLa dégradation en solution aqueuse du 2-aminobenzothiazole (ABT) et du benzothiazole (BT) a été étudiée par voies photochimique, microbiologique et en combinant les deux approches. La voie photochimique impliquait des complexes aqueux de fer ou le complexe entre le fer et l'acide nitrilotriacétique (FeNTA). La voie microbiologique utilisait une souche bactérienne de Rhodococcus rhodochrous. Les schémas de dégradation ont été établis pour les différentes voies. Nous avons montré qu'il existait une grande similitude entre la dégradation photochimique et microbiologique. De plus, deux nouveaux produits de dégradation ont été identifiés par RMN CLHP couplée SM et UV-visible. Il s'agit du 4OH-ABT et un complexe de fer avec un dérivé catéchol d'ABT. Nous avons montré la plus grande efficacité du système couplant le fer et les microorganismes. Le rôle majeur du fer a été mis en évidence dans les processus de dégradation comme photo-inducteur et comme activateur des enzymes bactérienne

Photo-et biodégradation de dérivés du benzothiazole (étude en système combiné)

La dégradation en solution aqueuse du 2-aminobenzothiazole (ABT) et du benzothiazole (BT) a été étudiée par voies photochimique, microbiologique et en combinant les deux approches. La voie photochimique impliquait des complexes aqueux de fer ou le complexe entre le fer et l'acide nitrilotriacétique (FeNTA). La voie microbiologique utilisait une souche bactérienne de Rhodococcus rhodochrous. Les schémas de dégradation ont été établis pour les différentes voies. Nous avons montré qu'il existait une grande similitude entre la dégradation photochimique et microbiologique. De plus, deux nouveaux produits de dégradation ont été identifiés par RMN CLHP couplée SM et UV-visible. Il s'agit du 4OH-ABT et un complexe de fer avec un dérivé catéchol d'ABT. Nous avons montré la plus grande efficacité du système couplant le fer et les microorganismes. Le rôle majeur du fer a été mis en évidence dans les processus de dégradation comme photo-inducteur et comme activateur des enzymes bactériennesCLERMONT FD-BCIU Sci.et Tech. (630142101) / SudocSudocFranceF

Photo-biodégradation du 2-aminobenzothiazole : rôle du fer

International audienc

Comparison of Microbial and Photochemical Processes and Their Combination for Degradation of 2-Aminobenzothiazole▿

The transformation of 2-aminobenzothiazole (ABT) was studied under various conditions: (i) a photodegradation process at a λ of >300 nm in the presence of an Fe(III)-nitrilotriacetic acid complex (FeNTA), (ii) a biodegradation process using Rhodococcus rhodochrous OBT18 cells, and (iii) the combined processes (FeNTA plus Rhodococcus rhodochrous in the presence or absence of light). The transformation of ABT in the combined system, with or without light, was much more efficient (99% degradation after 25 h) than in the separated systems (37% photodegradation and 26% biodegradation after 125 h). No direct photolysis of ABT was observed. The main result seen is the strong positive impact of FeNTA on the photodegradation, as expected, and on the biotransformation efficiency of ABT, which was more surprising. This positive impact of FeNTA on the microbial metabolism was dependent on the FeNTA concentration. The use of UV high-performance liquid chromatography, liquid chromatography-electrospray ionization mass spectrometry, and in situ 1H nuclear magnetic resonance provided evidence of the intermediary products and thus established transformation pathways of ABT in the different processes. These pathways were identical whether the degradation process was photo- or biotransformation. A new photoproduct was identified (4OH-ABT), corresponding to a hydroxylation reaction on position 4 of the aromatic ring of ABT

Complementarily of the photo- and biodegradation processes for pollutants removal from the aquatic compartments: application to benzothiazole derivatives

Communication oral