A esterase gene was characterized from a halophilic bacterium Chromohalobacter canadensis which was originally isolated from a salt well mine. Sequence analysis showed that the esterase, named as EstSHJ2, contained active site serine encompassed by a conserved pentapeptide motif (GSSMG). The EstSHJ2 was classified into a new lipase/esterase family by phylogenetic association analysis. Molecular weight of EstSHJ2 was 26 kDa and the preferred substrate was p-NP butyrate. The EstSHJ2 exhibited a maximum activity at 2.5 M NaCl concentration. Intriguingly, the optimum temperature, pH and stability of EstSHJ2 were related to NaCl concentration. At 2.5 M NaCl concentration, the optimum temperature and pH of EstSHJ2 were 65 ℃ and pH 9.0, and enzyme remained 81% active after 80 ℃ treatment for 2 h. Additionally, the EstSHJ2 showed strong tolerance to metal ions and organic solvents. Among these, 10 mM K⁺, Ca²⁺ , Mg²⁺ and 30% hexane, benzene, toluene has significantly improved activity of EstSHJ2. The EstSHJ2 was the first reported esterase from Chromohalobacter canadensis, and may carry considerable potential for industrial applications under extreme conditions.

从嗜盐菌加拿大色盐菌中表征酯酶基因它最初是从一个盐井矿中分离出来的。序列分析表明，命名为 EstSHJ2 的酯酶含有被保守五肽基序 (GSSMG) 包围的活性位点丝氨酸。通过系统发育关联分析，EstSHJ2 被归入一个新的脂肪酶/酯酶家族。EstSHJ2 的分子量为 26 kDa，优选的底物是 p-NP 丁酸盐。EstSHJ2 在 2.5 M NaCl 浓度下表现出最大活性。有趣的是，EstSHJ2 的最适温度、pH 值和稳定性与 NaCl 浓度有关。在 2.5 M NaCl 浓度下，EstSHJ2 的最适温度和 pH 为 65 ℃和 pH 9.0，80 ℃处理 2 h 后酶仍保持 81% 的活性。此外，EstSHJ2 对金属离子和有机溶剂表现出很强的耐受性。其中，10 mM K ⁺、Ca ²⁺  、Mg ²⁺ 和30%的己烷、苯、甲苯显着提高了EstSHJ2的活性。EstSHJ2 是第一个报道的来自加拿大色盐菌的酯酶，在极端条件下可能具有相当大的工业应用潜力。