Laccase-catalyzed treatment of ketoconazole, identification of biotransformed metabolites, determination of kinetic parameters, and evaluation of micro-toxicity

Publication date: Available online 27 July 2016 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Aliakbar Yousefi-Ahmadipour, Maryam Bozorgi-Koshalshahi, Mehdi Mogharabi, Mohsen Amini, Mahmoud Ghazi-Khansari, Mohammad Ali Faramarzi Ketoconazole is widely used in human and veterinary medicine; however, residual amounts of this antifungal agent have potential adverse effects on ecological health. The present study describes the use of laccase from Trametes versicolor for biotransformation and detoxification of ketoconazole. The substrate was removed at optimum conditions of 45°C, pH 4.5, incubation time 6h, ketoconazole concentration 0.3mgml−1, 1-hydroxybenzotriazole (HBT) concentration 1mM, and laccase activity 1Uml−1. The use of HBT (1mM), a laccase mediator, enhanced the yield of elimination. A micro-toxicity study with Pseudokirchneriella subcapitata, Candida albicans, Cryptococcus neoformans, and Saccharomyces cerevisiae showed a decrease in the toxicity of laccase-treated ketoconazole and its isolated metabolites. The kinetic parameters K m and V max of laccase-catalyzed removal of the substrate were determined as 0.099μM and 4.43μmolh−1 mg−1, respectively. Two major bioconverted metabolites were also purified and identified. Graphical abstract
Source: Journal of Molecular Catalysis B: Enzymatic - Category: Biochemistry Source Type: research