High-yield whole cell biosynthesis of Nylon 12 monomer with self-sufficient supply of multiple cofactors

Abstract

Biosynthesis of Nylon 12 monomer using dodecanoic acid (DDA) or its esters as the renewable feedstock typically involves ω-hydroxylation, oxidation and ω-amination. The dependence of hydroxylation and oxidation-catalyzing enzymes on redox cofactors, and the requirement of L-alanine as the co-substrate and pyridoxal 5′-phosphate (PLP) as the coenzyme for transamination, raise the issue of redox imbalance and cofactor shortage, challenging the development of efficient biocatalysts. Simultaneous regeneration of the redox equivalents, PLP and L-alanine required in the artificial pathway was enabled by its interfacing with the native metabolism of the host using glucose dehydrogenase (GDH), L-alanine dehydrogenase (AlaDH) and an exogenous ribose 5-phosphate (R5P)-dependent PLP synthesis pathway as bridges. Further engineering of the host by blocking β-oxidation and enhancing substrate uptake improved the ω-aminododecanoic acid (ω-AmDDA) yield to 96.5%. This study offers a strategy to resolve the cofactor imbalance issue commonly encountered in whole-cell biocatalysis and meanwhile lays a solid foundation for Nylon 12 bioproduction.