Whole‐Cell Production of Resolvin E2 and 17 R ‐Resolvin D5 by a Double‐Oxygenating 15 S ‐Lipoxygenase With 5 S ‐Lipoxygenase Activity From Pseudobdellovibrionaceae bacterium

ABSTRACT Resolvin E2 (RvE2; 5 S ,18 R ‐dihydroxyeicosapentaenoic acid) and 17 R ‐resolvin D5 (17 R ‐RvD5; 7 S ,17 R ‐dihydroxydocosahexaenoic acid) are specialized pro‐resolving mediators (SPMs) that actively promote the resolution of inflammation. However, their efficient biocatalytic production remains challenging because of the limited catalytic performance and poor stability of previously reported 5 S ‐lipoxygenases (5 S ‐LOXs). Here, we identified and characterized a novel double‐oxygenating 15 S ‐LOX from Pseudobdellovibrionaceae bacterium exhibiting 5 S ‐LOX activity and evaluated its potential as a whole‐cell biocatalyst for SPM production. Recombinant Escherichia coli cells expressing this enzyme stereoselectively converted 18 R ‐hydroxyeicosapentaenoic acid (18 R ‐HEPE) and 17 R ‐hydroxydocosahexaenoic acid (17 R ‐HDHA), prepared using engineered 18 R ‐ and 15 R ‐LOXs from Sorangium cellulosum , into RvE2 and 17 R ‐RvD5, respectively. Product identities were confirmed by chiral‐phase HPLC and LC–MS/MS analyses. Reaction conditions, including pH, temperature, and DMSO, cell, and substrate concentrations, were optimized to enhance biotransformation performance. Under optimized conditions, 4.0 mM 18 R ‐HEPE and 17 R ‐HDHA were converted into 0.57 mM (190.61 mg/L) RvE2 and 1.48 mM (533.5 mg/L) 17 R ‐RvD5 within 60 and 30 min, respectively. RvE2 production was 2.4‐fold higher than that obtained using a previously reported purified 5 S ‐LOX, and this study provides the first quantitative report of 17 R ‐RvD5 production. These findings establish a double‐oxygenating 15 S ‐LOX with 5 S ‐LOX activity as an efficient whole‐cell platform for SPM production.