全基因组重排育种技术提高产豆豉纤溶酶菌产酶量

枯草芽孢杆菌DC-12 是从豆豉里面筛选出来的，具有纤溶酶活性的菌株。本论文采用了全基因组重排技术提高DC－12的产酶量，首先通过对DC－12进行紫外诱变和亚硝酸诱变构建重组突变库，在研究其原生质体制备和再生的基础上，以其中4株诱变菌株作为直接亲本，采用电融合的方法进行两次多亲本的全基因组重排，结合双灭活的筛选方法，共筛选出2株酶活大大提高并能稳定遗传的菌株，使亲本菌株的酶活提高了4~5倍，最高达2710 IU/ml。

Whole genome shuffling to enhance activity of fibrinolytic enzyme-producing strains

DC-12 is a Bacillus strain with strong fibrinolytic activity was screened from Douchi. A novel breeding technology, whole genome shuffling was applied to enhance the production of fibrinolytic enzyme First of all , a candidate mutant library was constructed by treating DC-12 with ultraviolet rays andhNO2, respectively. Based on studying the optimum conditions for protoplast preparation and regeneration of DC-12 ,multi -parental whole genome shuffling with 4 strains was conceded by p the screening method of double -inactive protoplast , two strains rotoplasts electrical fusion , then combines with withhigher yield of fibrinolytic enzyme were obtained effectively,which can descend stably after five generations , and their enzyme production reached 2710 IU/ml ,which was increased by 4 -5 fold compared with the mutants , respectively.