Mutagenicity screening of reaction products from the enzyme-catalyzed oxidation of phenolic pollutants

Journal Article · Tue Nov 01 00:00:00 EST 1994 · Environmental Toxicology and Chemistry; (United States)

DOI:https://doi.org/10.1002/etc.5620131105· OSTI ID:6809047

Massey, I J; Aitken, M D; Ball, L M; Heck, P E ^[1]

---

1. Univ. of North Carolina, Chapel Hill, NC (United States). Dept. of Environmental Sciences and Engineering

Phenol-oxidizing enzymes such as peroxidases, laccases, and mushroom polyphenol oxidase are capable of catalyzing the oxidation of a wide range of phenolic pollutants. Although the use of these enzymes in waste-treatment applications has been proposed by a number of investigators, little information exists on the toxicological characteristics of the oxidation products. The enzymes chloroperoxidase, horseradish peroxidase, lignin peroxidase, and mushroom polyphenol oxidase were used in this study to catalyze the oxidation of phenol, several mono-substituted phenols, and pentachlorophenol. Seventeen reaction mixtures representing selected combinations of enzyme and parent phenol were subjected to mutagenicity screening using the Ames Salmonella typhimurium plate incorporation assay; five selected mixtures were also incubated with the S9 microsomal preparation to detect the possible presence of promutagens. The majority of reaction mixtures tested were not directly mutagenic, and none of those tested with S9 gave a positive response. Such lack of mutagenicity of enzymatic oxidation products provides encouragement for establishing the feasibility of enzyme-catalyzed oxidation as a waste-treatment process. The only positive responses were obtained with reaction products from the lignin peroxidase-catalyzed oxidation of 2-nitrophenol and 4-nitrophenol. Clear positive responses were observed when strain TA100 was incubated with 2-nitrophenol reaction-product mixtures, and when strain TA98 was incubated with the 4-nitrophenol reaction mixture. Additionally, 2,4-dinitrophenol was identified as a reaction product from 4-nitrophenol, and preliminary evidence indicates that both 2,4- and 2,6-dinitrophenol are produced from the oxidation of 2-nitrophenol. Possible mechanism by which these nitration reactions occur are discussed.

• OSTI ID: 6809047
• Journal Information: Environmental Toxicology and Chemistry; (United States), Vol. 13:11; ISSN 0730-7268
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
CHLORINATED AROMATIC HYDROCARBONS
MUTAGEN SCREENING
PHENOLS
SALMONELLA TYPHIMURIUM
SENSITIVITY
ENZYME ACTIVITY
AROMATICS
BACTERIA
HALOGENATED AROMATIC HYDROCARBONS
HYDROXY COMPOUNDS
MICROORGANISMS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
SALMONELLA
SCREENING
560300* - Chemicals Metabolism & Toxicology