高效纤维素降解菌Flavodon sp.x10的酶学活性

Enzyme activities of a high-efficiency cellulose degrading fungus Flavodon sp.x10

为了筛选高效纤维素降解真菌,本研究利用采集的江苏省盐城东台杨树人工林土壤凋落物作为分离样品,通过在纤维素为碳源的选择培养基上进行培养、结合刚果红染色筛选出透明圈较大的纤维素降解菌株。通过对筛选的菌株酶活测定和比较,发现了一株高效纤维素降解真菌。根据菌株形态和ITS序列分析将其鉴定为黄囊孔菌Flavodon的一个种,命名为Flavodon sp.x10。该菌株菌丝呈白色,无孢子产生,能利用自然界中的大部分碳源,适应能力较强。纤维素相关酶活测定结果表明Flavodon sp.x10的滤纸酶活为0.1388 U/mL,内切型-β-葡聚糖酶活为0.3592 U/mL,微晶纤维素酶活为0.1358 U/mL,β-葡萄糖苷酶活为0.1221 U/mL。在基础培养基中加入20.0 g/L葡萄糖,5.0 g/L蛋白胨,0.01 g/L维生素B1,1.0 g/L磷酸二氢钾,0.5 g/L七水硫酸镁,0.2 g/L碳酸钙,0.3 g/L七水硫酸锌,能够较大提高菌株产酶能力。根据酶活数据分析,纤维素降解过程中微晶纤维素酶起主导作用,β-葡萄糖苷酶起次要作用,内切型-β-葡聚糖酶对于纤维素降解作用最低。Flavodon sp.x10可作为潜在的开发菌种用于纤维素生物降解的研究。

A high-efficiency cellulose-degrading fungus was screened from soil litter of poplar plantation in Dongtai,Yancheng,Jiangsu Province.The fungus formed large transparent circles on a selective medium using cellulose as a carbon source.Based on the morphology and ITS phylogenetic analysis,the fungus was identified as a strain of the genus Flavodon,named Flavodon sp.x10.The mycelia of the strain were white and produced no spores.The activities of the filter paper enzyme,endo-β-glucanase,avicelase,andβ-glucosidase,were 0.1388,0.3592,0.1358,and 0.1221 U/mL,respectively.The addition of 20.0 g/L glucose,5.0 g/L protein,0.01 g/L vitamin B1,1.0 g/L potassium dihydrogen phosphate,0.5 g/L magnesium sulfate hetahydrate,0.2 g/L calcium carbonate,and 0.3 g/L zinc sulphate hetahydrate could greatly improve the enzyme production capacity of the strain.Comparative analysis of the enzyme activity data shows that,avicelase plays a leading role in cellulose degradation,andβ-glucosidase a secondary role,while endo-β-glucanase has a relatively low effect on cellulose degradation.Hopefully Flavodon sp.x10 can be used as a potential valuable strain for cellulose biodegradation.