A new cold-adapted, alkali-stable and highly salt-tolerant esterase from Bacillus licheniformis

作者：Zhang, Weijia; Xu, Hui; Wu, Yingqiang; Zeng, Jie; Guo, Ziwei; Wang, Lu; Shen, Cheng; Qiao, Dairong^*; Cao, Yi^*

来源：International Journal of Biological Macromolecules, 2018, 111: 1183-1193.

DOI：10.1016/j.ijbiomac.2018.01.152

• Esterase
• Salt-tolerant
• Bacillus licheniformis

Bacterial esterases and lipases, especially extremozymes attract increasing attention due to various advantages both in good properties and wide applications. In the present study, a cold-adapted, alkali-stable and highly salt-tolerant esterase (Est700) was cloned from Bacillus licheniformis, expressed and purified with a molecular mass of 25 kDa. The optimal temperature of Est700 was 30 degrees C, with 35% maximal activity retaining at 0 degrees C. Its optimal pH was 8.0 and showed high stability at pH 5.0-11.0. Noticeably, Est700 was highly activated by 3.5 M NaCl and the extent of this activation is much stronger than that of currently reported halophilic ones. It was also stable in 5 M NaCl with no activity loss. High salt concentrations changed the secondary structure and folding properties of Est700 with formation of more alpha-helix and less beta-sheet domains. With salt incubation, its melting temperature was estimated to be 57.2 degrees C, which is 12.8 degrees C higher than that of native one. Interestingly, Est700 lacks the acidic surface that is considered essential for enzyme stability at high salinity. However, it has a mainly positive surface electrostatic potential, which is probably different from most reported halotolerant esterases. These multiple properties make Est700 a valuable candidate in both basic research and industrial applications.

• 出版日期2018-5
• 单位成都大学; 中国医药集团总公司四川抗菌素工业研究所; 四川大学