Producing of supercritical carbon dioxide-tolerant enzyme based on halo-tolerant enzyme and syntheses of chitin oligosaccharide

2014 Fiscal Year Final Research Report

• Project/Area Number: 23550177
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Environmental chemistry
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: YATSUNAMI Rie 東京工業大学, 生命理工学研究科, 助教 (90334531)
• Project Period (FY): 2011-04-28 – 2015-03-31
• Keywords: 耐塩化酵素 / 超臨界二酸化炭素 / オリゴ糖合成

Outline of Final Research Achievements

Genome sequencing of extremely halophilic archaeon Halobacterium salinarum NRC-1 was completed, and a chitinase-homolog (ChiN1) was found. The gene encoding ChiN1 was expressed in extremely halophilic archaeon Haloarcula japonica. The recombinant ChiN1 was most active at 1.0 M NaCl. Supercritical carbon dioxide (scCO2) is attracting as an environmentally friendly solvent since CO2 is an abundant resource. The scCO2 has been used as a solvent for enzyme-catalyzed organic synthesis. However, many enzymes are unstable in scCO2. In this study, some ChiN1 mutants with less lysines on its protein surface were prepared and characterized to find a category of enzymes with high tolerance toward CO2 pressurization. On the basis of the 3D structure model of ChiN1, more solvent-accessible lysines were replaced by alanines. The Ha. japonica-produced mutants were prepared and assayed for chitinase activity in scCO2. Two mutants showed higher activity than wild-type ChiN1 in 10 MPa scCO2 for 1 h.

Free Research Field

タンパク質工学