P450Jα - A new, robust and α-selective fatty acid hydroxylase displaying unexpected 1-alkene formation.

: Oxyfunctionalization of fatty acids (FAs) is a key step in the design of novel synthetic pathways for bio-based/bio-degradable polymers, surfactants and fuels. Here, we show the isolation and characterization of a robust FA α-hydroxylase (P450 Jα ) which catalyses the selective conversion of a broad range of FAs (C6:0-C16:0) and oleic acid (C18:1) with H 2 O 2 as oxidant. Under optimized reaction conditions P450 Jα yields α-hydroxy acids all with >95% regioselectivity, high specific activity (up to 15.2 U mg -1 ) and efficient coupling of oxidant to product (up to 85%). Lauric acid (C12:0) turned out to be an excellent substrate with respect to productivity (TON = 394 min -1 ). On preparative scale, conversion of C12:0 reached 83% (0.9 g L -1 ) when supplementing H 2 O 2 in fed-batch mode. Under similar conditions P450 Jα allowed further the first biocatalytic α-hydroxylation of oleic acid (88% conversion on 100 mL scale) at high selectivity and in good yields (1.1 g L -1 ; 79% isolated yield). Unexpectedly, P450 Jα displayed also 1-alkene formation from shorter chain FAs (≤ C10:0) showing that oxidative decarboxylation is more widely distributed across this enzyme family than reported previously.