Water Purification through Bioconversion of Phenol Compounds by Tyrosinase and Chemical Adsorption by Chitosan Beads

• Published in: Biotechnology progress Vol. 21; no. 3; pp. 823 - 829
• Main Authors: Yamada, Kazunori, Akiba, Yuji, Shibuya, Takashi, Kashiwada, Ayumi, Matsuda, Kiyomi, Hirata, Mitsuo
• Format: Journal Article
• Language: English
• Published: USA American Chemical Society 01.05.2005; American Institute of Chemical Engineers
• Subjects: Adsorption; Agaricales - enzymology; bioconversion; Biodegradation, Environmental; Biological and medical sciences; Biotechnology; chitosan; Chitosan - chemistry; Coated Materials, Biocompatible - chemistry; Enzymes, Immobilized - chemistry; Fundamental and applied biological sciences. Psychology; Hydrogen; Hydrogen peroxide; Hydrogen-Ion Concentration; Microspheres; Monophenol Monooxygenase - chemistry; Oxidation; p-Chlorophenol; p-Cresol; pH effects; Phenols; Phenols - chemistry; Phenols - isolation & purification; Protein Binding; Q1; Quinone; Temperature effects; tyrosinase; Waste water; Water Pollutants, Chemical - isolation & purification; Water purification; Water Purification - methods; Water; Phenol; Purification; Adsorption; Enzyme; Biotransformation; Phenols; Oxidoreductases; Chitosan; Monophenol monooxygenase
• ISSN: 8756-7938; 1520-6033
• DOI: 10.1021/bp0495668

Enzymatic removal of various phenol compounds from artificial wastewater was undertaken by the combined use of mushroom tyrosinase (EC 1.14.18.1) and chitosan beads as function of pH value, temperature, tyrosinase dose, and hydrogen peroxide‐to‐substrate ratio. Chitosan film incubated in a p‐crersol+tyrosinase mixture had the main peaks at 400–470 nm assigned to chemically adsorbed quinone derivatives, which increased over the immersion time. These results indicate that removal of phenol compounds is caused by their tyrosinase‐catalyzed oxidation to the corresponding quinone derivatives and the subsequent chemical adsorption on the chitosan film. The optimum conditions for quinone adsorption were determined to be pH 7 and 45 °C for p‐cresol. Some alkyl‐substituted phenol compounds were removed by adsorption of quinone derivatives enzymatically generated on the chitosan beads, and the % removal for p‐cresol, 4‐ethylphenol, 4‐n‐propylphenol, 4‐n‐butylphenol, and p‐chlorophenol went up to 93%. In addition, 4‐tert‐butylphenol underwent tyrosinase‐catalyzed oxidation in the presence of hydrogen peroxide. This procedure was applicable to removal of chlorophenols and alkyl‐substituted phenols.