(360f) Engineering Production of Monomers from the Lysine Pathway

There is great interest in developing bio-based aromatic chemicals to replace phthalates, one of the highest volume monomers used in industrial and consumer products. We envision dipicolinic acid (DPA) could be a useful phthalate analog. In addition, the nitrogen atom in the aromatic ring confers new possibilities, as a metal chelator leading to its recent use in specialty polymers, with applications in heavy metal detection¹, catalysis², and even as the primary functional component of a self-repairing polymers³. DPA is naturally produced in Bacillus subtilis cells during sporulation. The biosynthetic pathway, however, has not yet been well-characterized. We have successfully identified the relevant genes for production of DPA in E. coli, including two uncharacterized genes spoVFA and spoVFB which are instrumental for production⁴. Initial fermentations yielded up to 1.4 g/L production of DPA in 48 hours. The productivity was also examined for E. coli where threonine and lysine production was reduced. Finally, engineered wild-type E. coli was able to produce DPA at maximum of 4.3 g/L with minimal media optimization. DPA production for all fermentations was monitored by HPLC and verified using LC-MS fragmentation. LC-MS of unpurified fermentation media also show production of several by-products, including homoserine and HTPA.

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