Optimization of tannase biosynthesis from two local aspergilli using commercial green tea as solid substrate

Abstract

This study aimed to the production of tannase through SSF techniques by using some local fungal strain. Eleven fungal strains able to produce extracellular tannase (tannin acyl hydrolase; E.C.3.1.1.20) were isolated from tannins rich soil. On the basis of tannin degradation and tannase activity, two of them were selected and identified as Aspergillus aculeatus and Aspergillus awamori. Cultural fermentation conditions including; incubation time, culture pH, incubating temperature, initial moisture level, nitrogen source, minerals and tannin rich wastes substrate were evaluated to increase the yield of tannase production and tannin degradation. The results showed that A aculeatus produced the highest tannase level (41.4 IUg-1) compared with A awamori (27.6 IUg-1) under SSF using 1.0 g of fermentable green tea at 30°C andpH 6.0 in presence of CaCl2 and peptone with 80% initial moisture level. The results also revealed 2.52 and 2.04 folds increase in tannase biosynthesis from A. aculeatus and A. awamori respectively after fermentation conditions investigation. © 2011 Asian Network for Scientific Information.