低温纤维素降解菌假裸囊菌SDF-LT的分离、鉴定及其对玉米秸秆降解特性的研究

Isolation,identification and degradation characteristics of maize straw of low-temperature cellulose-degrading strain Pseudogymnoascus sp.SDF-LT

为筛选低温高效纤维素降解真菌,从河北省石家庄、邢台、唐山等地区的小麦-玉米轮作农田采集土壤39份作为分离样品。在10℃条件下,采用纤维素钠-刚果红培养基测定菌株透明圈大小;测定滤纸酶活性进行酶活性比较,最终筛选得到1株低温高效纤维素降解真菌SDF-LT,根据菌株形态学和ITS序列分析鉴定为假裸囊菌(Pseudogymnoascus)。采用自然低温条件下沙袋法测定菌株SDF-LT的秸秆降解能力,发现接种该菌株的玉米秸秆降解率在80 d时为42.67%,显著高于市售秸秆降解菌剂和空白对照。80 d时SDF-LT处理的玉米秸秆中纤维素、半纤维素和木质素含量最少,分别为26.79%、28.52%、4.41%,显著低于常温秸秆降解菌剂和空白对照;采用扫描电镜观察秸秆的纤维结构发现,SDF-LT处理的秸秆纤维束结构断裂,纤维结构高度破坏。筛得的菌株SDF-LT为玉米秸秆的降解提供了菌种资源。

In order to screen low-temperature and high-efficiency cellulose-degrading fungi,39 soil samples were collected from the wheat-maize double cropping fields in Shijiazhang,Xingtai,Tangshan in Hebei Province.The size of the transparent circle of the straw degradation fungi were screened by Cellulose sodium-Congo red medium at 10℃.By comparing the filter paper enzyme activities,a low temperature cellulose degrading fungi SDF-LT was found.Based on the morphology and ITS phylogenetic analysis,the fungi were identified as a strain of the genus Pseudogymnoascus.Sandbag method under natural low-temperature conditions was used to determine the straw degradation ability of the strains SDF-LT.The degradation rate of this strain was 42.67% at 80 days after inoculation,which was significantly higher than that of the normal temperature inoculants and control.At 80 days,the content of cellulose,hemicellulose,and lignin in maize straw treated with SDF-LT were 26.79%,28.52%,4.41% respectively,which were significantly lower than those of normal temperature straw degrading bacteria and control.Using scanning electron microscopy,it was found that the original fiber bundle structure of straw treated by SDF-LT was broken,and the fiber structure was highly damaged.The screened strain SDF-LT provided strain resources for the maize straw degradation.