title: Transformation Pathways of the Recalcitrant Pharmaceutical Compound Carbamazepine by the White-Rot Fungus Pleurotus ostreatus: Effects of Growth Conditions.
abstract: The widely used anticonvulsant pharmaceutical carbamazepine is recalcitrant in many environmental niches and thus poses a challenge in wastewater treatment. We followed the decomposition of carbamazepine by the white-rot fungus Pleurotus ostreatus in liquid culture compared to solid-state fermentation on lignocellulosic substrate where different enzymatic systems are active. Carbamazepine metabolites were identified using liquid chromatography-high-resolution mass spectrometry (LC-Q-TOF-MS). In liquid culture, carbamazepine was only transformed to 10,11-epoxy carbamazepine and 10,11-dihydroxy carbamazepine as a dead-end product. During solid-state fermentation, carbamazepine metabolism resulted in the generation of an additional 22 transformation products, some of which are toxic. Under solid-state-fermentation conditions, 10,11-epoxy carbamazepine was further metabolized via acridine and 10,11-dihydroxy carbamazepine pathways. The latter was further metabolized via five subpathways. When (14)C-carbonyl-labeled carbamazepine was used as the substrate, (14)C-CO2 release amounted to 17.4% of the initial radioactivity after 63 days of incubation. The proposed pathways were validated using metabolites (10,11-epoxy carbamazepine, 10,11-dihydroxy carbamazepine, and acridine) as primary substrates and following their fate at different time points. This work highlights the effect of growth conditions on the transformation pathways of xenobiotics. A better understanding of the fate of pollutants during bioremediation treatments is important for establishment of such technologies.
authors.forename: Naama
authors.initials: N
authors.lastname: Golan-Rozen
authors.affiliation: Department of Analytical Chemistry, Helmholtz Centre for Environmental Research - UFZ , Permoserstrasse 15, 04318 Leipzig, Germany.
authors.forename: Bettina
authors.initials: B
authors.lastname: Seiwert
authors.affiliation: Department of Analytical Chemistry, Helmholtz Centre for Environmental Research - UFZ , Permoserstrasse 15, 04318 Leipzig, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Riemenschneider
authors.affiliation: Department of Analytical Chemistry, Helmholtz Centre for Environmental Research - UFZ , Permoserstrasse 15, 04318 Leipzig, Germany.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Reemtsma
authors.forename: Benny
authors.initials: B
authors.lastname: Chefetz
authors.forename: Yitzhak
authors.initials: Y
authors.lastname: Hadar
mesh_terms: D000166:Acridines / Q000378:metabolism; D001673:Biodegradation, Environmental; D002220:Carbamazepine / Q000378:metabolism* / Q000493:pharmacokinetics; D002250:Carbon Radioisotopes / Q000032:analysis / Q000378:metabolism; D002853:Chromatography, Liquid / Q000379:methods; D004785:Environmental Pollutants / Q000378:metabolism* / Q000493:pharmacokinetics; D005285:Fermentation; D013058:Mass Spectrometry; D020076:Pleurotus / Q000254:growth & development* / Q000378:metabolism*; D062065:Wastewater / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000378:metabolism* / Q000493:pharmacokinetics
chemical_list: D000166:Acridines; D002220:Carbamazepine; D002250:Carbon Radioisotopes; D004785:Environmental Pollutants; D062065:Wastewater; D014874:Water Pollutants, Chemical