一株耐冷玫红假裸囊菌HD1031的鉴定及其所产纤维素酶的研究

Identification of a psychrotroph Pseudogymnoascus roseus HD1031 and the properties of its producing cellulase

摘要:

【目的】以纤维素为唯一碳源, 从四川省阿坝自治州黄龙沟的高山低温环境中分离筛选产纤维素酶的耐冷菌, 并研究菌株的产酶特征。【方法】根据菌株的ITS序列分析及形态特征, 对菌株进行鉴定。利用DNS法测定纤维素酶酶活性。【结果】从四川省阿坝自治州黄龙沟的高山腐殖土中筛选出一株产纤维素酶的耐冷菌HD1031, 经鉴定该菌为玫红假裸囊菌(Pseudogymnoascus roseus)。该菌可在4 °C?25 °C生长, 最适生长温度为16?°C?17 °C。该菌在以微晶纤维素和玉米芯粉为碳源、硫酸铵和Tryptone为氮源的培养基中, 17 °C、160 r/min摇瓶发酵8 d后产生纤维素酶, 其中内切葡聚糖酶酶活为366.67?U/mL, 滤纸酶酶活87.6 U/mL, β-葡萄糖苷酶酶活90.8 U/mL, 酶最适反应pH为6.0, 最适反应温度为50 °C。【结论】筛选获得一株产纤维素酶的耐冷菌HD1031, 此菌株所产纤维素酶在20 °C?40 °C下活性较高, 对热敏感, 具有低温纤维素酶的特点。

关键词:玫红假裸囊菌, 耐冷菌, 低温纤维素酶

Abstract:

[Objective] To screen a psychrotolerant cellulase-producing strain from the decayed soil of Huanglong Mountain, Sichuan, China, and determine the properties of the cellulase. [Methods] The strain was identified by the morphology and ITS sequence analysis. The DNS method was used to determine the activity of cellulases. [Results] A psychrotolerant cellulase-producing strain HD1031 was screened from the decayed soil of Huanglong Mountain. It was identified as Pseudogymnoascus roseus by the morphology and ITS sequence analysis. The strain could grow between 4 °C and 25 °C and its optimum growth temperature is 16 °C?17 °C. In the medium containing Avicel, corn cob powder, (NH4)2SO4 and Tryptone, the strain HD1031 produced cellulases. After cultivating under the conditions of 17 °C and 160 r/min for 8 days, the cellulases activities in the fermentation broth were CMCase activity 366.67 U/mL, FPA 87.6 U/mL and the β-glucosidase activity 90.8 U/mL. The optimum pH value and temperature of the CMCase was pH 6.0 and 50 °C, respectively. [Conclusion] A psychrotolerant cellulase-producing strain HD1031 was screened and identified. The cellulase possessed the characters of cold-active cellulase.

Key words:Pseudogymnoascus roseus, Psychrotroph, Cold-active cellulase