长枝木霉菌M-1的突变株筛选以及纤维降解特性研究

Screening of mutant strains from T.Longibrachiatum M-1 and study on cellulose-degradation characteristics

本研究通过紫外(UV)诱变方法对纤维素降解菌长枝木霉(Trichoderma longibrachiatum)M-1进行诱变,对诱变菌株进行筛选、鉴定,并对其酶活力和玉米秸秆降解特性进行测定。结果表明:有5个菌株的水解圈直径/菌落直径(D/d)值较对照增大。ITS rDNA测序结果表明,5#菌株发生了突变。通过形态学观察和聚类分析,确定5#菌株也为长枝木霉。酶活力测定结果显示,5#菌株各酶活均有所提高,滤纸酶活(Fpase)提高了30.06 U/mL,外切酶活(CBH)提高了24.44 U/mL,内切酶活(EG)提高了19.01 U/mL。玉米秸秆粉降解结果表明,菌株5#的降解率、纤维素降解率及半纤维素降解率分别提高了10.01%(2.48倍)、6.46%(1.8倍)和3.03%(1.58倍)。经过电镜扫描发现,菌株5#对玉米秸秆的降解程度比对照更彻底。本研究为农作物秸秆得以大量利用提供了优良的菌株资源。

The cellulose degrading bacterium Trichoderma Longibrachiatum M-1 was mutagenized by UV.After being screened and identified,the enzyme activity and corn straw degradation characteristics of the mutant strains were measured.The results showed that there were five strains with higher value of hydrolytic circle diameter/bacterial colony diameter(D/d)than the control.The results of ITS rDNA sequencing showed that the strain 5#had mutated.Through morphological observation and cluster analysis,strain 5#was also identified as T.longicornis.The results of activity assay showed that the enzyme activities of strain 5#were improved,among which Fpase enzyme activity was increased by 30.06 U/mL,CBH enzyme activity was increased by 24.44 U/mL,and EG enzyme activity was increased by 19.01 U/mL.The degradation results of corn straw meal showed that the degradation rate,cellulose degradation rate and hemicellulose degradation rate of strain 5#was increased by 10.01%(2.48 times),6.46%(1.8 times)and 3.03%(1.58 times),respectively.Upon scanning electro microscope analysis,strain 5#degraded corn stover more thoroughly than the control.This study provided excellent strain resources for heavily utilization of crop straw.