热凝胶多糖产生菌株的复合诱变选育

Mutation and Screening of Curdlan-producing Strain by Combined Mutation Methods

[目的]提高热凝胶多糖产量和凝胶特性。[方法]采用紫外线和亚硝基胍对土壤杆菌714进行诱变;通过平板-摇瓶筛选方法,得到2株高产菌。[结果]突变菌株0.6-45和0.5-50的热凝胶多糖粗提得率分别为26.5和26.4 g/L,分别是出发菌株粗提得率(3.8 g/L)的7.0和6.9倍,热凝胶多糖精提得率分别为19.4和18.0 g/L。凝胶特性分析表明,突变菌株热凝胶多糖凝胶的破裂强度、破裂位移、弹性、内聚性、恢复性较好,均高于市售样品,而凝胶强度、硬度、胶着性和咀嚼性低于市售样品。GPC测定菌株0.6-45和菌株0.5-50产热凝胶多糖的MW分别为1.57×10~6和1.27×10~6Da。[结论]复合诱变提高了热凝胶多糖的产量并改善了多糖的凝胶特性。

[Objective] In order to improve the yield and quality of curdlan. [Method] Agrobacterium sp. 714 was mutated by UV and NTG. Two high-yleld strains were selected by plate spreading and shaking-flask fermentation. [ Result] The crude yield of curdlan from the strain O. 6 -45 and tarain 0. 5 -50 were 26.4 and 26.5 g/L,and were 6.9 and 7.0 times higher than the crude yield of parent strain （3.8 g/L）. The refined yield of curdlan from the strain O. 6-45 and strain 0.5 -50 were 19.4 and 18.0 g/L. The characteristics of gel showed that the fracture strength, fracture .distance, springiness, cohesiveness and resilience were higher than the sample from market, and the gel strength,hardness,gumminess and chewiness were 10wer than sample from market. GPC results showed the molecular weights were respectively 1.57 x 106 and 1.27 x l0s Da for curdtan fram the Strain O. 6- 45, and 0. 5 -50. [ Conclusion ] Combined mutation improves the yield of curdlan and changes the characteristics of gel.