Immobilization of Microbial Consortium for Glutaric Acid Production from Lysine

Graphical Biocatalysis : In this study, an efficient synthetic microbial consortium for glutaric acid production was developed by dividing the cadaverine pathway into two engineered strains. Moreover, strategies of cofactor regeneration and colloidal chitin based-immobilization were implemented to provide a low-cost approach for glutaric acid biosynthesis under mild reaction conditions. Glutaric acid is an important C5 platform compound for the synthesis of nylon polymers. However, its production titer and cost are limited by the need for expensive cofactors addition as well as the difficulty of reusing microbial catalysts. Herein, to address these problems, two regeneration systems each for NAD(P) + and α-ketoglutaric acid were introduced into a five-enzyme cadaverine pathway for a whole-cell biocatalytic approach. We demonstrated the efficient conversion of lysine to glutaric acid in a synthetic microbial consortium manner, producing 73.2 g/L glutaric acid with a 74 % molar yield in a 5-L bioreactor scale. Moreover, with a colloidal chitin-based immobilization, the engineered microbial consortium exhibited good stability and reusability in a five-cycle bioconversion. This study provides an efficient microbial platform for glutaric acid production by developing a cheaper and universal cell immobilization approach.