一株纤维素分解菌的鉴定及对两种草坪草凋落物分解活性的研究

摘要

A fungal isolate (strain F1) was isolated from east part of grassland soil in Qilian alpine. Taxonomic status and decomposition activity to two kinds of lawn grass litter were studied in this study. Combinated morphology with rDNA-ITS molecular biology methods, the fungus was Microdochium bolleyi. The dynamics of lignocellulolytic enzymes secreted by M. Bolleyi and cell wall material (CWM) decomposition of perennial ryegrass (Lolium perenne) and white clover (Trifolium repens) litter were investigated for 42 d at 25 ℃ on a rotary shaker at 150 r/min in flask liquid fermentation method. 1) Insoluble cell wall material(ICWM) of two kinds of lawn grass litter significantly reduced after inoculation strain F1 (P<0. 05); 2) When two kinds of lawn grass litter acts as substrate respectively, the laccase secreted by strain F1 appears first, followed by the cellulase enzyme and xylanase, catechol oxidase and guaiacol oxidase occurs at the latest; 3) Perennial ryegrass compared with white clover, the insoluble cell wall material (ICWM) and cell wall material (CWM) degradation rate of perennial ryegrass litter was higher (P<0.05); 4) The FPAase, CMCase, xylanase, pycocatechol oxidase and guaiacol oxidase activity except for the laccase secreted by M. Bolleyi in perennial ryegrass litter were higher than those in white clover litter (P<0.05).%对1株分离筛选自东祁连山高寒草地土壤真菌菌株F1的分类学地位及对多年生黑麦草和白三叶凋落物的分解活性进行了研究.采用形态学和rDNA-ITS分子生物学相结合的方法,对菌株F1的分类学地位进行了确定,初步鉴定为Microdochium bolleyi；应用摇瓶液体发酵法,通过接种和不接种处理,分别以2种草坪草凋落物为底物,于25℃,150r/min震荡培养42 d,测定了2种草坪草凋落物诱导真菌分泌木质纤维素酶活力动态变化和草坪草凋落物细胞壁物质(CWM)的降解率.结果表明,1)接种处理后,2种草坪草细胞壁非水溶性物质(ICWM)的量显著减少(P＜0.05)；2)漆酶出现最早,其次是纤维素酶和木聚糖酶,邻苯二酚氧化酶和愈创木酚氧化酶出现最晚；3)与白三叶凋落物为底物的发酵体系相比,黑麦草凋落物ICWM和CWM降解率高,且差异显著(P＜0.05)；4)除漆酶之外,以黑麦草凋落物诱导菌株F1分泌的滤纸酶、羧甲基纤维素酶、木聚糖酶、邻苯二酚氧化酶和愈创木酚氧化酶活力比白三叶诱导相应的酶活力高(P＜0.05).