Of the 10 M  m² of raw hides produced annually in Bangladesh only a fifth is tanned by 175 odd tanneries, using imported tanning materials. Vegetable tannins can be extracted from roughly 10,000 tors of mangrove barks available annually at the felling coupes in the Sundarbans. Amelioration of the properties of these tannins is, however, a precondition to their use as tanning materials.

Tannins were extracted by various methods from goran (Ceriops decandra), kankra (Brugiera gymnorrhiza) and passur (Xylocarpus molluccensis) barks collected from the Sundarbans. The percentages of tannins obtained were 24, 21 and 17 respectively. A method was developed for overall purification and improvement of colour and quality of tannin. Chemical analysis indicates that the tannin is of catechol group and quantitative analysis of the extractives shows that the production of mangrove tannins would be an economically viable proposition. Tanning experiments with goat skin show that light coloured and fine-grained uppers and soles can be made with the purified tannins.