Optimization of oxidative bioconversions catalyzed by phenylacetone monooxygenase from Thermobifida fusca

By choosing properly the nature of the reaction medium and its ionic strength, biocatalytic properties of isolated phenylacetone monooxygenase from Thermobifida fusca can be improved, achieving the best results when working in Tris or phosphate buffers presenting moderate ionic strengths. The use of different enzymatic cofactor regenerating systems has been studied, resulting in the highest activities by using glucose or glucose-6-phosphate dehydrogenase. The cofactor concentration, key parameter when oxidizing with isolated Baeyer–Villiger monooxygenases, was optimized, being demonstrated that PAMO can perform its biocatalytic activity with the highest TTNs with low requirement of nicotinamide cofactor (2 μM).

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► Tris and phosphate buffers are optimal for PAMO activity and selectivity.
► PAMO is able to perform oxidative activity in high concentration media (2 M).
► Second enzymatic system affects PAMO properties, best results with GDH and G6PDH.
► Highest total turnover numbers were achieved at cofactor concentrations of 2 μM.