地衣芽孢杆菌L-天冬酰胺酶Ⅰ 型的克隆表达及其在降低薯条中丙烯酰胺的应用

Cloning, Expression and Characterization of a Novel Type Ⅰ L-Asparaginase from Bacillus licheniformis and Its Application in Reduction of Acrylamide in French Fries

将L-天冬酰胺酶Ⅰ型酶基因克隆并实现其在大肠杆菌中表达。重组酶活力为(63.64±3.18)IU/mL,比活力为945.79 IU/mg,最适催化反应条件为45℃、pH 10.0。45℃处理12 h后,重组酶的相对酶活力仍大于90%。该酶无谷氨酰胺催化能力,具有23.38%的D-天冬酰胺活性,其对L-天冬酰胺的Km值为12.19 mmol/L,最大反应速率Vmax为2.69 IU/mL。此外,将L-天冬酰胺酶Ⅰ型应用于油炸薯条中,处理后的样品中丙烯酰胺含量降低58.39%。研究表明,地衣芽孢杆菌L-天冬酰胺酶Ⅰ型具有应用于食品加工工业的潜力。

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.