新型常压室温等离子体-紫外复合诱变选育埃莎霉素I高产菌株#br#

目的 通过对埃莎霉素Ⅰ产生菌WSJ-IA进行诱变选育研究，以期获得埃莎霉素Ⅰ高产菌株。方法 使用多功能等离子体诱变系统(multifunctional plasma mutagenesis system, MPMS)对出发菌株的孢子进行等离子体和紫外复合诱变，设定不同的诱变时间处理孢子悬液，通过致死率确定合适的诱变条件，利用突变株摇瓶发酵效价筛选出正突变菌株。结果 在MPMS射频功率为100W，处理距离5mm，气体流量12.5SLM，等离子体-紫外辐射时间为50s时，菌株致死率为96.08%。在此诱变条件下，以突变株的初筛效价为指标的突变率、正突变率分别达到63.96%和22.52%，复筛效价是出发菌株1.5倍以上的有5株，占复筛菌株的9%。最终筛选出一株发酵单位比出发菌株提高221%、埃莎霉素Ⅰ组分含量提高192%的正突变株IA-425。42L自动发酵罐发酵结果表明，该菌株埃莎霉素Ⅰ产量达到(2000±200)μg/mL左右。结论 新型等离子体复合紫外诱变方式，可有效提高菌株的埃莎霉素Ⅰ发酵产量和组分含量。这为埃莎霉素Ⅰ的大规模发酵和临床前研究奠定了良好基础。

Breeding of high isomycin-I-producing strain by MPMS compositemutagenesis with plasma and UV#br#

Objective To obtain the high-yield isomycin-I-producing strain by means of mutation breeding of WSJ-IA strain. Methods The spores from the original strain were treated by the composite mutagenesis of Plasma and UV in multifunctional plasma mutagenesis system (MPMS). We determined the operating parameters for plasma jet and UV irradiation time by appropriate lethality rates. The positive mutants were screened out by comparison of the titers in shake flask fermentation. Results When the radio frequency power of MPMS was 100W, with the handling distance of 5mm, the working flow of 12.5SLM, and the Plasma-UV irradiation time of 50s, the lethality rate of strains reached 96.08%. Under these conditions, the total mutation rate was 63.96% and the positive mutant rate was 22.52% based on the fermentation titers of the mutants and WSJ-IA strain in the preliminary screening. Five high-yield isomycin-producing strains were obtained by the shake flask fermentation, and their yields of isomycin I were 1.5 times higher than that of WSJ-IA strain, about 9% in the total rescreening mutants. After several rounds of screening, ultimately, IA-425 strain displayed the excellent feature of high yield. The fermentation titer and proportion of the isomycin I component in IA-425 were 221% and 192% higher than that in WSJ-IA strain respectively. The titer of IA-425 in the 42L fermenter was (2000±200)μg/mL. Conclusion Through the composite mutagenesis of plasma and UV, the yield and proportion of isomycin I were significantly increased compared to WSJ-IA strain. IA-425 strain paved the road for isomycin I research of large scale fermentation and clinical