Microbial production of pyrogallol through decarboxylation of gallic acid.

Culturalconditions for the microbial production from gallic acid of pyrogallol were investigated with Citrobacter sp.The maximal formation of pyrogallol was observed when the bacterium was cultured at 28°C for 48hr in a medium containing 2.0% gallic acid, 0.5% maltose, 0.2% (NH4)2HPO4, 0.1% KH2PO4, 0.05% KC1, 0.05% MgSO4-7H2O and 0.05% yeast extract (pH 6.0).Under these conditions, 7.2g ofpyrogallol was formed from 20g of gallic acid added to one liter of the medium.Larger amounts of pyrogallol could be produced when gallic acid was further added to the broth after 16~24hr cultivation.The reaction was performed at pH 4.5 under anaerobic conditions using 1 mML-ascorbic acid and N2 gas.Seventy-five grams of gallic acid added to one liter of the broth was transformed to 54. 1 g ofpyrogallol under these conditions, with a yield of97.4%.Pyrogallol is a polyphenol widely used in industry.It is industrially produced by autoclaving gallic acid which is obtained from tannins under strong acidic conditions.However, studies on the microbial production