Could be involved in the degradation of the Pseudomonas aeruginosa quorum sensing signal molecule HHQ (2-heptyl-4-quinolone) to anthranilic acid. May catalyze the hydroxylation of HHQ to PQS (2-heptyl-3-hydroxy-4-quinolone). 2-heptyl-4(1H)-quinolone + H(+) + NADH + O2 = 2-heptyl-3-hydroxy-4(1H)-quinolone + H2O + NAD(+) Up-regulated by PQS. Belongs to the 3-hydroxybenzoate 6-hydroxylase family.