一株高活性纤维二糖酶真菌的筛选与鉴定

Screening and Identification of Filamentous Fungus with Higher Cellobiase Activity

纤维二糖酶在食品、农业、医疗和生物能源等领域有着广泛的应用,尤其在木质纤维素的降解反应中能够显著提高纤维素转化为葡萄糖的效率。利用纤维二糖作为唯一营养碳源的筛选方法,从唐山曹妃甸湿地土壤样品中筛选到一株高产纤维二糖酶的真菌,编号为CB21,通过观察其形态学特征和基于18S rDNA的系统发育进化分析,鉴定菌株CB21为桔青霉。检测该菌株发酵液中纤维二糖酶活力最高为342.5 U/ml,在中性pH 6~7的条件下表现出较好的催化活性,最适反应温度为60℃,且在50~80℃的高温范围内仍然能够保持80%以上的活性。桔青霉菌株CB21在研究纤维二糖酶的生化特性及木质纤维素的高效降解等方面具有一定的应用价值。

Cellobiase is widely used in food,agriculture,medicine and biofuel,which could significantly improve the efficiency of cellulose conversion to glucose in the lignocellulosic degradation reaction.An isolate(named CB21)of filamentous fungus with higher cellobiase activity was screened from the soil samples taken from Caofeidian Wetland in Tangshan,it was selected on the minimal media with cellulose as the sole carbon source.The strain CB21 was identified as penicillium citrinum based on its morphological characteristics and 18S rDNA sequence analysis by comparison with other sequences in the GenBank database.In a shake flask,the enzyme activity of CB21 reached 342.5 U/ml.The optimum pH range is neutral 6~7 and the optimum temperature is 60℃,and more than 80%of maintenance and enzyme activities are still reactive with the range from 50~80℃.The fungus species penicillium citrinum CB21 found in this study can be applied for efficient degradation on natural cellulose.