Catabolic characterization of dipicolinic acid in Alcaligenes faecalis strain JQ135

Dipicolinic acid (DPA) is a widely distributed pyridine derivative containing two carboxylate groups. However, the catabolism of DPA mediated by microorganisms are rarely reported. Alcaligenes faecalis strain JQ135, previously isolated in our lab, was able to degrade various pyridine derivatives, including nicotinic acid (NA). In this study, it was found that strain JQ135 could utilize DPA as the sole carbon and nitrogen source for growth and degrade 1.8 mM (300 mg/L) DPA to a non-detectable level within 12 h. The catabolism of DPA by strain JQ135 extracted two intermediates, i.e., 3-hydroxy-2,6-dipicolinic acid and 4-imino-pent-2-enedioic acid. Moreover, deletion of the key genes essential for NA catabolism (such as moaCDEBmoeA and maiA ) did not affect DPA catabolism, indicating that the maleamate pathway and molybdenum cofactor are not involved in the DPA catabolism by strain JQ135. This study will provide insights into the bacterial catabolism of DPA.