关键词: Pseudomonas stutzeri, 过氧化氢酶, 酶学特性, 异源表达

Abstract: At present, the commercial catalases mostly come from animal liver and Aspergillus niger fermentation, but these enzymes usually have poor thermal stability, low enzyme activity and high price. In order to solve this problem, a strain of Pseudomonas Stutzeri S12 with the high-level activity of catalase was isolated from landfill leachate. Through whole genome sequencing and gene identification, the gene katE encoding catalase in this strain was found, and it was heterologously expressed and purified in E. coli BL21 (DE3). KatE’s optimal temperature was 35 ℃, the optimal pH was 8.0, and its activity couldreach to 1 349 U·mg-1. The enzyme had a wide range of temperature adaptability in the range of 10 ～ 40 ℃. KatE had good thermal stability. After being treated at 50 ℃ for 5 h, 70% enzyme activity was remained, and after being incubated at 60 ℃ for 2 h, 50% enzyme activity was remained. The Km and Vmax values were 100.5 mmol·L-1 and 16 666 μmol·L-1·min-1, respectively. The enzyme activity was better under medium and low temperature conditions, showed good thermal stability and high enzyme activity, which provided a new material for the development of new commercial catalase.

Key words: Pseudomonas Stutzeri, catalase, catalase characterization, heterologous expression