关键词: L-天冬酰胺酶I型, 地衣芽孢杆菌, 酶学性质, 丙烯酰胺抑制, 薯条

Abstract: The type I L-asparaginase (BlAase 1) gene from Bacillus licheniformis was cloned and expressed in Escherichia coli. The recombined L-asparaginase had an activity of (63.64 ± 3.18) IU/mL, and its specific activity was 945.79 IU/mg. BlAase I exhibited maximum catalytic activity at pH 10.0 and 45 ℃. The relative enzymatic activity was above 90% at 45 ℃ for 12 h. In addition to L-asparagine, BlAase I showed catalytic ability to D-asparagine, which represented 23.38% of L-asparaginase activity. The Km value of BlAase I was 12.19 mmol/L, and the Vmax value was 2.69 IU/mL. Moreover, BlAase I had the ability to mitigate acrylamide formation in French fries. Compared with the untreated group, the acrylamide content in samples treated with BlAase I was effectively decreased by 58.39%. These results indicate that the novel type I L-asparaginase BlAase I has the potential for application in the food processing industry.

Key words: L-asparaginase, Bacillus licheniformis, characterization, acrylamide mitigation, French fries