The precipitated enzyme solution was loaded at a flow rate of 0.2 mL min-1 to (2x7 cm), pre-equilibrated with 1 mM Tris-HCl buffer of pH 8.0 and the eluted fractions (1 mL each) were collected. After loading the sample, column was washed with the same buffer until the reading of the eluted buffer at 280 nm was zero. The bound proteins were then eluted with a concentration gradient of sodium chloride (0-0.5 M NaCl) in the same buffer and fractions of 2 mL each were collected at a flow rate of 0.2 mL min-1. Protein concentration of each fraction was determined by measuring the absorbance at nm and each fractions were assayed for protease activity. Fractions with high specific activity were pooled and then concentrated by lyophilization