从稻田土壤中快速筛选分离纤维素降解真菌

Rapid Screening of Cellulose Degradation Fungus from Paddy Soil

为了建立一种纤维素分解真菌的快速分离方法,将一种水不溶的,呈色基团与维晶纤维素交联的纤维素酶检测底物作为筛选指示剂,同时作为筛选培养基中的唯一碳源,通过测定培养液的OD值,快速从样品中分离筛选出纤维素分解菌。经酶活测定、形态学观察及16S r DNA基因序列分析及系统发育树分析结果表明,筛选出的3株真菌:J1为尖孢镰刀菌Fusarium sp,J5为青霉菌Penicillium sp,J7为枝顶孢霉菌Acremonium sp,它们的纤维素分解全酶活(FPase)、内切酶活(EG)、外切酶活(CBH)分别是:J1,3.07μ/m L,6.28μ/m L,3.92μ/m L;J5,2.28μ/m L,5.38μ/m L,3.08μ/m L;J7,5.86μ/m L,6.10μ/m L,5.47μ/m L。本研究采用的纤维素分解菌的筛选方法较以往的平板降解圈法更准确,更快捷。菌株J7可作为出发菌株,具有深度开发的潜力。

In this study,to establish a kind of fast separation methods of cellulose-decomposing fungus,a water insoluble（ crosslinked） chromogenic substrate is used. At the same time it was the only carbon source in acidic inorganic salt screening culture medium. Strains cellulose decomposing were isolated and screened rapidly by measuring the OD value of culture. Three strains of wild fungi were preliminarily identified,by determing of enzyme activity,observing morphology and analysing 16 S r DNA gene sequence and phylogenetic tree. Strain J1 was Fusarium sp. Strain J5 was Penicillium sp.Strain J7 was Acremonium sp. Cellulose decomposing enzyme activity of holoenzyme,endonuclease and exonclease for J1 were 3. 07 μ / m L,6. 28 μ / m L and 3. 92 μ / m L,and for J5 were 2. 28 μ / m L,5. 38 μ / m L and 3. 08 μ / m L,for J7 were 5. 86 μ / m L,6. 10 μ / m L and 5. 47 μ / m L. The method of separation is more accurate and more quick than the existing methods including tablet degradation ring method. Three strains of wild fungi,Strain J7 enzyme activity of holoenzyme and exonclease is relatively high. It can be used as a starting strain,has the depth development potential.