Metabolic Engineering\nof High L‑Lysine-Producing Escherichia\ncoli for de Novo Production of L‑Lysine-Derived\nCompounds

5-Aminovalerate\n(5-AVA), 5-hydroxyvalerate (5-HV), and\n1,5-pentanediol (1,5-PDO) are l-lysine derivatives with extensive\napplications in the production of materials such as polyesters, polyurethane,\nplasticizers, inks, and coatings. However, their large-scale production\nis limited by the lack of efficient synthetic pathways. Here, we aimed\nto construct multiple synthetic pathways by screening the key enzymes\ninvolved in the synthesis of these compounds in Escherichia\ncoli. The engineered pathway utilizing RaiP demonstrated\na superior catalytic efficiency. The LER strain that overexpressed\nonly <i>raiP</i> successfully synthesized 9.70 g/L 5-HV\nand 8.31 g/L 5-AVA, whereas the strain LERGY that overexpressed <i>raiP</i>, <i>gabT,</i> and <i>yahK</i> accumulated\n9.72 g/L 5-HV and 7.95 g/L 5-AVA from 20 g/L glucose. The introduction\nof exogenous transaminases and dehydrogenases enhanced cell growth\nand fermentation efficiency with respect to 5-HV synthesis, albeit\nwithout significantly impacting the yield. Strain LE05, incorporating\nonly two exogenous enzymes, RaiP and CaR, produced 1.87 g/L 1,5-PDO,\n3.85 g/L 5-HV, and 4.78 g/L 5-hydroxyglutaraldehyde from 20 g/L glucose\nafter 6 days. The strain LE02G, fortified with transaminase, dehydrogenase,\nand NADPH regeneration system, accumulated 7.82 g/L 1,5-PDO, whereas\nthe <i>aldp</i>-knock out LE02G2 synthesized 10.98 g/L 1,5-PDO\nfrom 50 g/L glucose in fed-batch fermentation after 6 days, yielding\n0.22 g/g glucose (0.37 mol/mol). Introducing the NADPH regeneration\npathway and deleting the NADPH-consuming pathways increased the 1,5-PDO\nyield and decreased the precursor concentration. The proposed pathways\nand engineering strategies presented in this study can prove instrumental\nin developing biological routes for the practical production of 5-AVA,\n5-HV, and 1,5-PDO.