Two extracellular xylanases, denominated X2 and X3, were purified and characterized from the halotolerant bacterium Bacillus sp. Asc6BA isolated from “Salar de Ascotán” in the Atacama Desert. Xylanases were purified by anion exchange, cation exchange and size exclusion liquid chromatography. Xylanase X2 and X3 were purified ~ 690-fold and ~ 629-fold, respectively, compared to the concentrated extracellular fraction with a final specific activity of 169 and 154 u mg⁻¹, respectively. Optimal conditions of pH and temperature of xylanolytic activity were 6.0 and 60 °C for X2 and 7.0 and 60 °C for X3. Half-life of X2 xylanase was 30 min at 50 °C, while X3 xylanase was remarkably more thermostable, retaining more than 70% of its activity after 32 h of incubation at 50 °C. X2 exhibited K_m, V_max and k_cat values of 7.17 mg mL⁻¹, 1.28 mM min⁻¹ mg⁻¹ and 425.33 s⁻¹, respectively. X3 exhibited K_m, V_max and k_cat values of 6.00 mg mL⁻¹, 19.25 mM min⁻¹ mg⁻¹ and 82,515 s⁻¹, respectively. In addition to their thermal stabilities, these enzymes were shown to be resistant to freeze-drying. These stability properties, in addition to the ability of these enzymes to be active in a wide range of temperatures and pHs, make these xylanases good candidates for industrial applications.

从卤代细菌Bacillus sp。中纯化并表征了两种胞外木聚糖酶，分别命名为X2和X3 。Asc6BA与阿塔卡马沙漠中的“ Salar deAscotán”隔离。木聚糖酶通过阴离子交换，阳离子交换和尺寸排阻液相色谱法纯化。与浓缩的细胞外级分相比，木聚糖酶X2和X3分别纯化了约690倍和约629倍，最终比活性分别为169和154umg ^-1。X2的pH和木聚糖水解活性温度的最佳条件是X2为6.0和60°C，X3为7.0和60°C。X2木聚糖酶的半衰期在50°C时为30分钟，而X3木聚糖酶的热稳定性明显更高，在50°C孵育32小时后，其活性保持超过70％。X2展出ķ_米，V_最大和ķ_猫7.17毫克毫升值^-1，1.28毫分钟^-1 毫克^-1和425.33小号^-1，分别。X3显示ķ_米，V_最大和ķ_猫的6.00毫克毫升值^-1，19.25毫摩尔分钟^-1 毫克^-1和82515个小号^-1， 分别。除了其热稳定性外，这些酶还显示出抗冻干性。除了这些酶在广泛的温度和pH值下具有活性的能力以外，这些稳定性还使这些木聚糖酶成为工业应用的良好候选者。