title: Enzymatic degradation of anthracene, dibenzothiophene and pyrene by manganese peroxidase in media containing acetone.
abstract: The high hydrophobicity of polycyclic aromatic hydrocarbons (PAHs) greatly hamper their degradation in liquid media. The use of an organic solvent can assist the degradative action of ligninolytic enzymes from white rot fungi. The enzymatic action of the enzyme manganese peroxidase (MnP) in media containing a miscible organic solvent, acetone (36% v/v), was evaluated as a feasible system for the in vitro degradation of three PAHs: anthracene, dibenzothiophene and pyrene. These compounds were degraded to a large extent after a short period of time (7, 24 and 24h, respectively), at conditions maximizing the MnP-oxidative system. The initial amount of enzyme present in the reaction medium was determinant for the kinetics of the process. The order of degradability, in terms of degradation rates was as follows: anthracene>dibenzothiophene>pyrene. The intermediate compounds were determined using gas chromatography-mass spectrometry and the degradation mechanisms were proposed. Anthracene was degraded to phthalic acid. A ring cleavage product of the oxidation of dibenzothiophene, 4-methoxybenzoic acid, was also observed.
authors.affiliation: Department of Chemical Engineering, School of Engineering, University of Santiago de Compostela, E-15782 Santiago de Compostela, Spain.
authors.forename: Gemma
authors.initials: G
authors.lastname: Eibes
authors.forename: Tomas
authors.initials: T
authors.lastname: Cajthaml
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Moreira
authors.forename: Gumersindo
authors.initials: G
authors.lastname: Feijoo
authors.forename: Juan M
authors.initials: JM
authors.lastname: Lema
mesh_terms: D000096:Acetone / Q000737:chemistry*; D000873:Anthracenes / Q000032:analysis; D001673:Biodegradation, Environmental; D003470:Culture Media; D004785:Environmental Pollutants / Q000032:analysis*; D015394:Molecular Structure; D010544:Peroxidases / Q000737:chemistry*; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis*; D020072:Polyporales / Q000201:enzymology*; D011721:Pyrenes / Q000032:analysis; D013876:Thiophenes / Q000032:analysis
chemical_list: D000873:Anthracenes; D003470:Culture Media; D004785:Environmental Pollutants; D011084:Polycyclic Aromatic Hydrocarbons; D011721:Pyrenes; D013876:Thiophenes; D000096:Acetone; C030984:pyrene; D010544:Peroxidases; C051129:manganese peroxidase; C034020:anthracene; C016366:dibenzothiophene