An Aryl Alcohol Oxidase-Peroxygenase Catalyst System Enables Efficient Alcohol to Aldehyde Transformation

We describe a scalable aryl alcohol oxidase-based alcohol oxidation platform using multiphase and microaqueous reaction formats. Using trans-2-hexen-1-ol as a model substrate, a 9:1 n-dodecane/buffer two-liquid-phase system (100 mL, 0.55 M substrate) delivered up to ∼0.42 M trans-2-hexen-1-al with initial space-time yields up to 33 mM h^-1 and exceptionally high TTN (up to 3.6 × 10⁶). Unexpectedly, catalase did not improve productivity, whereas replacing catalase with a peroxygenase enabled direct utilization of H₂O₂ and increased the initial rate by >67% without compromising selectivity. Celite immobilization afforded a highly productive microaqueous system and enabled semipreparative operation in a rotating-bed reactor (120 mL, ∼1.5 M substrate), reaching 1.2 M aldehyde (≈120 g L^-1) with near-linear accumulation for ∼48 h. Overall, the titers, space-time yields, and TTN achieved here clearly rival chemical oxidation processes, highlighting strong potential for preparative-scale aldehyde manufacture.