Full Length Research Paper

Purification profile of b-amylase from Bacillus species

Ajayi A. O¹* and Fagade O. E

¹Department of Microbiology, Adekunle Ajasin University, P.M.B 01, Akungba-Akoko, Ondo State, Nigeria.

²Department of Botany and Microbiology, University of Ibadan, Ibadan, Nigeria.

Corresponding author. E-mail: jidet02@yahoo.com.

Accepted 8 February, 2008

The purified b-amylase had more enzymatic activity than crude samples from Bacillus species as shown in this study whereby the activity of crude enzyme from Bacillus subtilis (WBS) and Bacillus licheniformis (WBL) were 6.24 and 4.2 unit/ml while the purified enzymes had an improved activity of 18 and 18.60 unit/ml, respectively. The protein concentration of the enzyme samples ranged from 264.639 mg in Bacillus macerans (MBM) to 627.627 mg in B. subtilis (WBS) enzyme filtrates and relatively lower values of 6.418 mg in B. licheniformis (WBL) to 77.702 mg in B.coagulans (MBC) was observed for the purified enzymes samples. Similarly, the purification process improves the specific activity of the enzyme samples during the study. The crude enzyme samples precipitated by salting with known quantity of Ammonium sulphate [(NH₄)₂SO₄] at the range of 50 and 80% fraction improved the activity of the enzyme samples whereby the strains of B. subtilis (WBS) and B. licheniformis (WBL) had their specific activity improved from the original value of 0.596 and 0.488 U/mg to 2.012 and 2.062 U/mg, respectively. It was also observed that the protein concentration of the enzyme samples decreases gradually with the increase in the specific activity. 570.945 mg of protein was detected in the crude enzyme of B. coagulans (MBC) and this value decreases to 92.216 on precipitation with 80% Ammonium sulphate. The use of Sephadex Gel Chromatography further enhances the purification of the enzyme.

Key words: Activity, amylase, Bacillus, concentration, purification, starch. substrate.