The functionalization of bio‐based chemicals is essential to allow valorization of natural carbon sources. An atom‐efficient biocatalytic oxidative cascade was developed for the conversion of saturated fatty acids to α‐ketoacids. Employment of P450 monooxygenase in the peroxygenase mode for regioselective α‐hydroxylation of fatty acids combined with enantioselective oxidation by α‐hydroxyacid oxidase(s) resulted in internal recycling of the oxidant H₂O₂, thus minimizing degradation of ketoacid product and maximizing biocatalyst lifetime. The O₂‐dependent cascade relies on catalytic amounts of H₂O₂ and releases water as sole by‐product. Octanoic acid was converted under mild conditions in aqueous buffer to 2‐oxooctanoic acid in a simultaneous one‐pot two‐step cascade in up to >99 % conversion without accumulation of hydroxyacid intermediate. Scale‐up allowed isolation of final product in 91 % yield and the cascade was applied to fatty acids of various chain lengths (C6:0 to C10:0).

Chemical and biocatalytic synthesis of non‐canonical α‐amino acids (ncAAs) from renewable feedstocks and using mild reaction conditions has not efficiently been solved. Here, we show the development of a three‐step, scalable and modular one‐pot biocascade for linear conversion of renewable fatty acids (FAs) into enantiopure l‐α‐amino acids. In module 1, selective α‐hydroxylation of FAs is catalyzed by the P450 peroxygenase P450_CLA. By using an automated H₂O₂ supplementation system, efficient conversion (46 to >99%; TTN>3300) of a broad range of FAs (C6:0 to C16:0) into valuable α‐hydroxy acids (α‐HAs; >90% α‐selective) is shown on preparative scale (up to 2.3 g L⁻¹ isolated product). In module 2, a redox‐neutral hydrogen borrowing cascade (alcohol dehydrogenase/amino acid dehydrogenase) allowed further conversion of α‐HAs into l‐α‐AAs (20 to 99%). Enantiopure l‐α‐AAs (e.e. >99%) including the pharma synthon l‐homo‐phenylalanine can be obtained at product titers of up to 2.5 g L⁻¹. Based on renewables and excellent atom economy, this biocascade is among the shortest and greenest synthetic routes to structurally diverse and industrially relevant ncAAs. magnified image

A three-step one-pot biocatalytic cascade was designed for the enantioselective formal α-amination of hexanoic acid to L-norleucine. Regioselective hydroxylation by P450_CLA peroxygenase to 2-hydroxyhexanoic acid was followed by oxidation to the ketoacid by two stereocomplementary dehydrogenases. Combination with final stereoselective reductive amination by amino acid dehydrogenase furnished L-norleucine in >97% ee.