Production and Characterization of Tannase By Bacillus subtilis in Solid State Fermentation of Corn Leaves

Tannase (tannin acyl hydrolase EC3.1.1.20) is an industrially important enzyme with extensive applications. The current study aimed to optimize the tannase production employing corn leaves as substrate and characterize tannase activity. Tannase producing bacterial strains were isolated from Catla catla fish gut. The highest enzyme-producing bacterial strain was identified as Bacillus subtilis using 16S rDNA sequencing. Fermentation parameters and additional medium components were optimized with the application of one variable at a time and enhanced tannase was obtained with 50% substrate moisture, acetate buffer (pH 4.0) as enzyme extraction medium with 2 ml volume, 45 °C incubation temperature, pH 5, 2% inoculum size, 24 h incubation time, 150 rpm agitation, large-sized substrate particles (4.0 mm), enzyme extraction without centrifugation and medium components (MgSO4, 4% tannic acid and yeast extract). The central composite design was employed to optimize the concentrations of optimal medium components, which were found as 4.0% tannic acid, 0.5% MgSO4 and 1.5% yeast extract for the highest tannase production (211.97±0.08 U/ml). Tannase characterization revealed the maximum tannase activity at pH 8, 30 °C (with 30 min incubation period and 0.35% substrate concentration). The results of the present study revealed the potential of utilization of agricultural resources (corn leaves) as a low-cost substrate to reduce the production cost of tannase.