Purification and Characterization of Recombinant Thermostable a-Amylase of Bacillus licheniformis SITH Expressed in Escherichia coli

• Main Author: AFFRIANA (NIM 10504062), RIAN
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/11257
• Institution: Institut Teknologi Bandung

Thermostable a-amylase is a starch hydrolyzing enzyme which is widely used in industry. A recombinant thermostable a-amylase of Bacillus licheniformis (recombinant BLA.SITH) has been expressed as an intracellular enzyme in Escherichia coli BL21/[pET-16-bla]. Expression of recombinant BLA.SITH was induced 4.75 fold by an addition of isopropyl B-D-1-thiogalactopyranoside (IPTG) 1 mM for 10 hours. Recombinant BLA.SITH was purified by nickel-nitriloacetic acid (Ni-NTA) affinity chromatography. The molecular weight of recombinant BLA.SITH was ~58 kDa based on sodium dodecyl sulphatepolyacrylamide gel electrophoresis (SDS-PAGE) analysis. The purified recombinant BLA.SITH maintains high activity at temperature 50-80 oC and has an optimum temperature of 70 oC. Thin Layer Chromatography analysis showed that the major end products of endoamylolytic activity of recombinant BLA.SITH were maltose (G2), maltotriose (G3) and maltopentaose (G5).