METABOLISM OF AROMATIC COMPOUNDS BY BACTERIA,

1. m-Hydroxybenzoic acid hydroxylase A which catalizes m-hydroxybenzoic acid to potocatechuic acid was obtained as cell-free enzyme from the cells of Ps. dacunhae A-7-2 and R-10-2 and m-hydroxybenzoic acid hydroxylase B which catalyzes m-Hydroxybenzoic acid to gentisic acid was obtained from the cells of Ps. sp. 15-1A and strain 23-1A, 42-1A. Each enzyme requires TPN, probably TPNH, as a cofactor.2. The constitutive enzymatic pathway via protocatechuic acid in the cells of Ps. ovalis S-5, was demonstrated, and its activity is strongest at the stationary phase during the growth of the cells. Shikimic acid is converted to protocatechuic acid by the incubation with the cells and this pathway is not inhibited by the addition of streptomycin 10-3M.3. From the incubation mixture of Ps. ovalis S-5 with shikimic acid, 5-dehydroshikimic acid was crystallized which is produced from shikimic acid and converted to protocatechuic acid. Thus, 5-dehydroshikimic acid was recognized as a precursor to protocatechuic acid.4. The pathway from m-hydroxybenzoic acid was examined among the one hundred and thirtythree strains isolated from the soil and sewages. It was concluded that one hundred and nine strains had protocatechuic acid path. And a new pathway from salicylic acid to gentisic acid was recognized in the cells of Ps. sp. 15-1A, 15-4A and 40-2A.