高产纤维素酶菌株筛选及诱变选育

为了得到高产纤维素酶的菌株，达到缓解纤维素酶活不高、纤维素酶供不应求现状的目的。从自然界中筛选出较优良的产纤维素酶菌株并对其进行紫外、60Co-γ射线诱变选育获得高产纤维素酶活的突变株。从自然界筛选出来的菌株通过菌落、菌丝体以及孢子丝的形态初步鉴定为放线菌并命名为XZ-33。对XZ-33进行复合诱变选育并根据致死率和诱变剂量以及正突变率的相互关系，得出合适的诱变剂量即：紫外照射7 min，辐照剂量为0.6 KGy的γ射线对产纤维素酶的出发菌进行诱变，得到高产纤维素酶的突变株UV-Co16，其CMCase酶活达到66.15 IU/mL，以及PFAase酶活2.91 IU/mL，分别是出发菌的3.17倍和2.42倍。该突变株的获得为微生物发酵生产乙醇奠定了基础。

Screening and Mutation breeding of the Strains of High-yielding Celluase

In order to get the strains of high-yielding cellulase,to alleviate the present bad situation：the activity of most cellulase is relatively low;the supply of cellulase has failed to keep pace with demand.Some higher cellulase-producing strain were picked from the nature and then carried them on mutation breeding under the UV light and 60 Co-γrays to obtained mutants of those high-produced.The original stains gained by screening had been preliminarily identified as the Actinomycete XZ-33 by observing the form of bacterial colony,mycelium and spores.According to the interrelation between the fatality rate,mutation doses and mutation rate,it could be deduced that the most appropriate conditions of induced mutation was that exposing them under UV-irradiation for 7 minute and γ rays-irradiation up to 0.6 KGy.After a series of mutation breeding a high cellulase-producing mutant stain have been obtained,named as mutant UV-Co16,its CMCase enzyme activity reached at the level of 66.15 IU/mL,and PFAase enzyme 2.91 IU/mL,it was respectively 3.17 times and 2.42 times higher than the original screened strains.The success to get a high cellulase-producing mutant stain laid the foundation of the technology that using special microorganism to ferment to produce ethanol.