Resumo

Tannase or tannin acyl hydrolase is an inducible enzyme produced by variety of microorganisms. It catalyses the breakdown of hydrolysable tannins and gallic acid esters. Tannase is applied commercially in the food industry where it is used as clarifying agent in some wines, fruit juices and in the production of instantant tea. In the pharmaceutical industry, it is used in the production of gallic acid, a substrate applied in the chemical or enzymatic synthesis of the propylgallate, a potent antioxidant and in the manufacture of Trimethoprim. Tannase is also used to treat tannery effluents and to reduce the non nutritional effects of tannins in animal feed. Hence, the objective of this work was optimization of the medium conditions for tannase production by Aspergillus sp. GM4 under solid-state fermentation (SSF). Surface response methodology was applied to the optimization of the laboratory scale production these enzyme using jamun leaves in SSF for Aspergillus sp. GM4. The Plackett-Burman design was conducted to evaluate the effects of variables, including temperature (^oC), moisture level (tap water: substrate), tannic acid (%), glucose (%), gallic acid (%), potassium nitrate (%), yeast extract (%), ammonium sulfate (%), substrate quantity (g), inoculum concentration (spores.g^-1 of substrate), incubation time (days) and pH on the production of tannase. Among these variables, incubation time, potassium nitrate and tannic acid had significant effects on enzyme production. The best incubation time was studied and others variables were optimized using the Central Composite Design (2²) and surface response methodology. The best conditions for tannase production were: incubation time of 2 days; tannic acid 1.53% (w/w) and potassium nitrate 2.71% (w/w). After the optimization process, the tannase activity increased 4.65-fold.