Effect of various pollutants and soil-like constituents on laccase from Cerrena unicolor

• Published in: Journal of environmental quality Vol. 28; no. 6; pp. 1929 - 1938
• Main Authors: Filazzola, M.T., Sannino, F., Rao, M. A., Gianfreda, L.
• Format: Journal Article
• Language: English
• Published: Madison, WI American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America 01-12-1999; Crop Science Society of America; American Society of Agronomy
• Subjects: Adsorption; Applied sciences; Bioassay; BIODEGRADATION; Biological and physicochemical phenomena; BIOLOGICAL EFFECTS; BIOLOGY AND MEDICINE, APPLIED STUDIES; Catalyst activity; Catalyst deactivation; Cerrena unicolor; Decontamination. Miscellaneous; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; ENVIRONMENTAL SCIENCES; ENZYME ACTIVITY; Enzymes; Exact sciences and technology; FUNGI; Herbicides; HYDROLASES; laccase; Natural water pollution; Oxidation; Pesticide effects; PHENOLS; Pollution; Pollution, environment geology; REMEDIAL ACTION; Soil and sediments pollution; Solubility; Wastewaters; Water treatment and pollution; Substituent effect; Reaction inhibitor; Enzyme; Pesticides; Soil pollution; Biological purification; Fungi; Enzymatic activity; Decontamination; Phenols; Aromatic compound; Oxidation; Water pollution; Oxidoreductases; Waste water purification; Performance; Catalyst activity; Thallophyta; Laccase
• ISSN: 0047-2425; 1537-2537
• DOI: 10.2134/jeq1999.00472425002800060032x

Laccase from Cerrena unicolor catalyses the oxidation of a wide range of aromatic compounds, either xenobiotic or naturally occurring phenols, leading to the formation of polymeric products. These are characterized by their low solubility and often may form precipitates or aggregates. The oxidizing efficiency of the enzyme is strictly dependent on the number of hydroxyl groups and the position of substituents on the phenolic molecules. During the reaction with some substrates, the enzyme is inactivated, because of possible adsorption of laccase molecules on newly formed polyphenols. By contrast, the oxidation of humic precursors (i.e., resorcinol, gallic acid, and pyrogallol) does not influence greatly the residual laccase activity. The triazinic herbicides, triazine and prometryn (2,4-bis(isopropylamino)-6-methylthio-s-triazine), are not substrates of laccase. They, however, inhibit laccase activity assayed with 2,4-dichlorophenol (2,4-DCP) or catechol as substrates. The reduction of substrate oxidation rates is usually accompanied by the retention of higher levels of residual enzymatic activity. These results, together with the slight recovery in laccase activity following dialysis of the assay mixture, provide further evidence that the enzyme may be incorporated into or adsorbed onto polyphenolic products, with a consequent reduction in the concentration of active forms of laccase.