Oxidizes aldehydes to the corresponding carboxylic acids with a preference for aromatic aldehydes. It might play a role in the detoxification of aldehydes to avoid cell damage. A + an aldehyde + H2O = a carboxylate + AH2 + H(+) Binds 2 [2Fe-2S] clusters. Heterotrimer composed of PaoA, PaoB and PaoC. Exported by the Tat system (By similarity). The position of the signal peptide cleavage has not been experimentally proven (Probable).