Resumo

Tannase enzyme, primarily produced by the microorganisms to outline the toxic of the tannins, catalyzes the hydrolysis of the esters connections of tannins hydrolysable, producing gallic acid and glucose. Tannases are widely used in food industries, helping to reduce the adverse effects of tannins, removing insoluble precipitates in beverages such as wines and beers, as well as being applied to the bioremediation of tannic effluents. In this study, we evaluated the influence of carbon and nitrogen source over tannase production in submerged fermentation by fungi isolated from cocoa. Tannase activity was assayed by the spectrophotometric method of methanolic rhodanine, and one tannase unit was defined as the enzyme amount able to release 1 μmol of gallic acid per ml per min. The fungi was grown in submerged fermentation in a Czapeck minimal medium using 1% of tannic acid as a sole carbon source for up to 120 hours at 28 °C and 120 rpm. Cultures containing 1% of gallic acid and glucose after 72 h was done. The nitrogen source ammonium sulfate, urea, ammonium nitrate, ammonium phosphate and sodium nitrate at different concentrations (0.2%, 0.6% and 1%) added 1% tannic acid were also conducted. Tannic acid without the nitrogen source was used as control. The higher productivity of tannase by the fungi occurred at 72 h of cultivation (8.37 U / ml) in the presence of 1% of tannic acid. The fungus did not produce significant amounts of the enzyme when in medium containing 1% glucose (0.039 U / ml) and 1% gallic acid (0.116 U / ml), corroborating with published results which show that a strong end product inhibition with gallic acid or glucose and the inducible characteristic of the enzyme only in the presence of tannins. The supplementation of the cultures with ammonium nitrate at 0.6% (12.37 U / ml) showed the highest induction while ammonium sulfate and ammonium phosphate had a negative effect. The present fungi was unidentified yet, but presents biotechnological and industrial potential in comparison with the others fungus in the literature, considering it presented high tannase activity in a shorter time, even in not optimized growing conditions, it can further increase enzyme production after optimization process.