potassium-bicarbonate and catechol

3,4-Dihydroxybenzoate decarboxylase in Enterobacter cloacae P241 was induced by adding 3,4-dihydroxybenzoic acid, 3-hydroxybenzoic acid, 3,4,5-trihydroxybenzoic acid or 4-acetamidobenzoic acid to the culture medium. After stabilizing the enzyme activity by adding 5 mM dithiothreitol and 20 mM Na(2)S(2)O(3) to a cell-free extract, catechol at 50 mM was carboxylated in the presence of 3 M KHCO(3) to 3,4-dihydroxybenzoic acid with a molar conversion ratio of 28% after 14 h at 30 degrees C.

Topics: 4-Aminobenzoic Acid; Bacterial Proteins; Bicarbonates; Carboxy-Lyases; Catechols; Coenzymes; Culture Media; Enterobacter cloacae; Gallic Acid; Hydroxybenzoates; para-Aminobenzoates; Potassium Compounds; Stereoisomerism

We found a bacterium, Pandoraea sp. 12B-2, of which whole cells catalyzed not only the decarboxylation of 2,6-dihydroxybenzoate but also the regioselective carboxylation of 1,3-dihydroxybenzene to 2,6-dihydroxybenzoate. The whole cells of Pandoraea sp. 12B-2 also catalyzed the regioselective carboxylation of phenol and 1,2-dihydroxybenzene to 4-hydroxybenzoate and 2,3-dihydroxybenzoate, respectively. The molar conversion ratio of the carboxylation reaction depended on the concentration of KHCO(3) in the reaction mixture. Only 5 or 48 % of 1,3-dihydroxybenzene added was converted into 2,6-dihydroxybenzoate in the presence of 0.1 M or 3 M KHCO(3), respectively. The addition of acetone to the reaction mixture increased the initial rate of the carboxylation reaction, but the final molar conversion yield reached almost the same value. When the efficient production of 2,6-dihydroxybenzoate was optimized using the whole cells of Pandoraea sp. 12B-2, the productivity of 2,6-dihydroxybenzoate topped out at 1.43 M, which was the highest value so far reported. No formation of any other products was observed after the carboxylation reaction.

Topics: Acetone; Bicarbonates; Burkholderiaceae; Carboxy-Lyases; Catechols; Hydroxybenzoates; Parabens; Phenol; Potassium Compounds