التعبير الجينى المتباين و تنقية و تسكين و توصيف انزيم الألفا أميليز AmyLa المؤتلف من لسيلا DS3

AmyLa α-amylase gene from Laceyella sp. DS3 was heterologously expressed in E. coli BL21. E. coli BL21 maximally expressed AmyLa after four hours of adding 0.02 mM IPTG at 37°C. The recombinant AmyLa α-amylase was purified 2.19-fold through gel filtration and ion exchange chromatography. We immobilized the purified recombinant AmyLa α-amylase on four carriers; chitosan had the best efficiency. The recombinant free and the immobilized AmyLa α-amylase showed optimum activity in the pH ranges of 6.0-7.0 and 4.0-7.0, respectively and possessed an optimum temperature of 55°C. The free enzyme had activation energy, Km, and Vmax of 291.5 kJ, 1.5 mg/mL, and 6.06 mg/min., respectively. The immobilized enzyme had activation energy, Km, and Vmax of 309.74 kJ, 6.67 mg/mL, and 50 mg/min., respectively. The immobilized enzyme was calcium-independent and insensitive (relative to the free enzyme) to metals. It could also be reused for seven cycles.