Fig. 2. Schematic representation of the P. aeruginosa arginine and pyruvate fermentation systems. The gene organisation of the pyruvate and arginine fermentation pathways
as well as involved regulators are shown. Pyruvate fermentation produces 2 main products, acetate and lactate. Acetate is formed in 3 steps involving a pyruvate dehydrogenase
(not shown for the sake of clarity as well as the reductive TCA cycle), a phosphotransacetylase (pta), and an acetate kinase (ackA). Lactate is formed via a lactate dehydrogenase
encoded by ldhA. Only the ackA-pta operon of the pyruvate fermentation pathway is activated by Anr. The arginine fermentation requires 4 proteins encoded by the arcDABC
operon. An arginine/ornithine antiporter (arcD), the arginine deiminase (arcA), the ornithine carbamoyltransferase (arcB), and the carbamate kinase (arcC). The NarL represses
the additional activation of the arcDABC operon mediated by the ArgR regulator. Regulators and proteins are shown as ellipses.