Color and Toxicity Removal following Tyrosinase-Catalyzed Oxidation of Phenols

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• 作者：Keisuke Ikehata and James A. Nicell
• 刊名：Biotechnology Progress
• 出版年：2000
• 出版时间：August 2000
• 年：2000
• 卷：16
• 期：4
• 页码：533 - 540
• 全文大小：101K
• 年卷期：v.16,no.4(August 2000)
• ISSN：1520-6033

文摘

The products of phenol oxidation catalyzed by mushroom tyrosinase (polyphenoloxidase, EC 1.14.18.1) were assessed in terms of their residual color and toxicity. Theaddition of aluminum sulfate had little effect on the removal of colored products fromphenol solutions treated with tyrosinase. Although chitosan was used successfully toremove the color when added before the reaction initiation or after the reactioncompletion, the required dose of chitosan was lower when it was added after thereaction. In this case, the minimum doses of chitosan required to achieve 90% colorremoval were proportional to the logarithm of the initial concentration of phenol. Thecolor removal induced by chitosan addition appeared to be the result of chemicalinteraction followed by a coagulation mechanism. All treated solutions of phenol andchlorophenols, except 2,4-dichlorophenol, had substantially lower toxicities than theircorresponding initial toxicities, as measured using the Microtox assay. Chitosanaddition significantly enhanced the reduction in toxicity. The toxicities of the phenolsolutions treated with tyrosinase were markedly lower than previously reportedtoxicities of solutions treated with peroxidase enzymes.