Tannase of Enterobacter sp. was purified and characterized at molecular level. It was found to be 90 kDa in molecular weight. The purified enzyme showed maximum activity at 40 degrees C. The enzyme was also found to be active in acidic range of pH. The nucleotide and amino acid sequence of tannase exhibited resemblance with the other reported tannase sequences of bacteria, fungi and plants. Probably, this is the first report of tannase gene in Enterobacter sp. The investigation suggests that the purified enzyme can be useful to synthesize molecules of pharmaceutical interest. In addition to above, the enzyme tannase and the organism itself can also be employed to protect grazing animals and environment against the toxic effects caused by tannins in them. (C) 2010 Elsevier Ltd. All rights reserved.