Elucidation of the trigonelline degradation pathway reveals previously undescribed enzymes and metabolites

Significance The experimental dissection of novel metabolic pathways, from genes and enzymes to metabolites, is a key issue for improving our knowledge of the enzymatic capabilities of the microbial world and providing accurate functional annotation of genomes. We used an integrative methodology combining the phenotyping of a complete genome-scale mutant collection ofAcinetobacter baylyi ADP1 with an untargeted liquid chromatography/MS-based approach to uncover the degradation pathway of trigonelline (TG), a widespread osmolyte. We provide extensive information about this unusualN- heterocyclic aromatic degradation route that expands the metabolite repertoire. The occurrence of conserved gene clusters for TG dissimilation in soil, plant-associated, and marine bacteria underlines its environmental abundance.