Production of tannase and gallic acid by Aspergillus tamarii in submerged and solid state cultures

Abstract

The hydrolytic enzyme, tannase and the antioxidant phenolic compound, gallic acid are useful in many biotechnological processes especially in food and pharmaceutical areas. The purpose of this study was to evaluate the production of tannase and gallic acid by Aspergillus tamarii developed in submerged and solid state cultures using tannic acid as substrate. In submerged cultures, maximal tannase activity (20,400 ± 2,900 U/L) was obtained after 2 days of cultivation using 2% tannic acid as substrate. In solid state cultivation using polyurethane foam as inert support, maximal tannase activity was obtained after 4 days of cultivation in 15% tannic acid cultures (25,470 ± 1,600 U/L). In both types of cultures, high accumulation of gallic acid was found in the two day-culture filtrates, 0.36±0.05 and 0.67±0.08 g of gallic acid per g of tannic acid, in submerged and solid state cultures, respectively. The accumulation of gallic acid in the cultures is, however, a transitory phenomenon, considering that the fungus slowly absorbs and metabolizes gallic acid.\tKey words: Aspergillus tamari, gallic acid, inert support, solid-state cultures, submerged cultures, tannase.