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A novel alpha-amylase from Bacillus mojavensis A21: purification and biochemical characterization.

Research paper by Noomen N Hmidet, Hana H Maalej, Anissa A Haddar, Moncef M Nasri

Indexed on: 29 Jan '10Published on: 29 Jan '10Published in: Applied Biochemistry and Biotechnology



Abstract

alpha-Amylase from Bacillus mojavensis A21 (BMA.2) was purified to homogeneity by ultrafiltration, Sephadex G-75 gel filtration and Sepharose mono Q anion exchange chromatography, with a 15.3-fold increase in specific activity and 11% recovery. The molecular weight of the BMA.2 enzyme was estimated to be 58 kDa by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and gel filtration. The optimum temperature and pH were 80 degrees C and 6.5, respectively. BMA.2 belonged to the EDTA-sensitive alpha-amylase, but its activity was not stimulated by the presence of Ca2+ ions. The major end-products of starch hydrolysis were maltohexaose, maltopentaose and maltotriose. The N-terminal amino acid sequence of the first ten amino acids of the purified alpha-amylase was ASVNGTLMQY. Compared to sequences of other amylases, the ten amino acid sequence contains Val at position 3, while amylases from Bacillus licheniformis NH1 and Bacillus sp. SG-1 have Leu and Thr at position 3, respectively.