Reversibly catalyzes the regioselective carboxylation of phenol to form salicylic acid. Involved in a pathway for the degradation of salicylate via phenol. Also catalyzes the decarboxylation of beta-resorcylic acid (2,4-dihydroxybenzoic acid) into resorcinol (1,3-dihydroxybenzene), gamma-resorcylic acid (2,6-dihydroxybenzoic acid) into resorcinol, 2,3-dihydroxybenzoic acid into catechol (1,2-dihydroxybenzene), and 4-aminosalicylic acid into 3-aminophenol. H(+) + salicylate = CO2 + phenol Inhibited by AgNO(3), HgCl(2), p-chloromercuribenzoic acid and NiCl(2). Optimum pH is 5.5 for decarboxylase activity. Optimum temperature is 40 degrees Celsius for the decarboxylase activity and 30 degrees Celsius for carboxylase activity. Homotetramer. Belongs to the metallo-dependent hydrolases superfamily.