A reversible salicylic acid decarboxylase (Sdc), found in the yeast Trichosporon moniliiforme WU-0401, is applicable for the production of p-aminosalicylic acid (PAS) from m-aminophenol (m-AP). For the high-yield production of PAS, used as an antituberculous agent, we developed F195Y, a genetically engineered Sdc mutant. We succeeded in selectively producing PAS from,n-AP through an enzymatic Kolbe-Schmitt reaction in aqueous solution by using recombinant Escherichia coli cells expressing the gene encoding F195Y. We found that 70 mM PAS was produced at 30 degrees C in 15h with a conversion yield of 70% (mol/mol).