In this study, 17 L. brevis strains obtained from fermented products in previous studies were purified and these selected isolates were identified by the DuPont Qualicon RiboPrinter (R) system. Spectrophotometric and visual reading method indicated that isolate L. brevis A6X showed the highest activity. It was observed that pyrogallol product with the decarboxylase activity of gallic acid was composed of tannic acid using the thin layer chromatography. The proximate molecular weights of the enzyme produced by the selected isolate of L. brevis were determined by the SDS-PAGE method, and also the effect of different temperature, pH, substrate concentration, the concentration of tannic acid and various minerals on activity were all investigated. As a result of the test, it was found that the optimum temperature was 37 degrees C, pH 5.0, methyl gallate concentration used as the substrate 7 mM and tannic acid concentration 1.75 mM. While enzyme activity increased in the presence of Ca+, Zn+ and K+ ions, it did not show any changes in the presence of surfactant (Tween 80), inhibitor (DMSO), denaturing agent (urea). In addition, in presence of Mg+, Hg+ and Zn+ ions caused the tannase activity to decrease.