A Three-Enzyme-System to Degrade Curcumin to Natural VanillinReport as inadecuate




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Institut für Lebensmittelchemie im Zentrum Angewandte Chemie, Gottfried Wilhelm Leibniz Universität Hannover, Callinstraße 5, D-30167 Hannover, Germany





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Academic Editor: Luca Forti

Abstract The symmetrical structure of curcumin includes two 4-hydroxy-3-methoxyphenyl substructures. Laccase catalyzed formation of a phenol radical, radical migration and oxygen insertion at the benzylic positions can result in the formation of vanillin. As vanillin itself is a preferred phenolic substrate of laccases, the formation of vanillin oligomers and polymers is inevitable, once vanillin becomes liberated. To decelerate the oligomerization, one of the phenolic hydroxyl groups was protected via acetylation. Monoacetyl curcumin with an approximate molar yield of 49% was the major acetylation product, when a lipase from Candida antarctica CAL was used. In the second step, monoacetyl curcumin was incubated with purified laccases of various basidiomycete fungi in a biphasic system diethyl ether-aqueous buffer. A laccase from Funalia trogii LccFtr resulted in a high conversion 46% molar yield of curcumin monoacetate to vanillin acetate. The non-protected vanillin moiety reacted to a mixture of higher molecular products. In the third step, the protecting group was removed from vanillin acetate using a feruloyl esterase from Pleurotus eryngii PeFaeA 68% molar yield. Alignment of the amino acid sequences indicated that high potential laccases performed better in this mediator and cofactor-free reaction. View Full-Text

Keywords: vanillin; curcumin; lipase; laccase; esterase vanillin; curcumin; lipase; laccase; esterase





Author: Vida Esparan * , Ulrich Krings, Marlene Struch and Ralf G. Berger

Source: http://mdpi.com/



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