Mutants of the strain producing natamycin, Streptomyces gilvosporeus, were obtained after space-flight mutation. With respect to the sand spores and slant spores, the mutation ratios were up to 67.6% and 78.3% and the...Mutants of the strain producing natamycin, Streptomyces gilvosporeus, were obtained after space-flight mutation. With respect to the sand spores and slant spores, the mutation ratios were up to 67.6% and 78.3% and the survival ratio was 43.1% and 3.0%, respectively. An improved mutant producing natamycin, S. gilvosporeus LK-45, was screened, which showed natamycin productivity of 1420mg·L^-1. A mutant resistant to 2-deoxy glucose, S.gilvosporeus LK-119, was further obtained using a＇rational screening procedure. The natamycin productivity of 1940mg·L^-1 was achieved when glucose was used as the carbon source.展开更多
[Objective] The research aimed to screen Streptomyces hygroscopicus strains with high production of agricultural antibiotics. [ Method] A strain of S. hygroscopicus was screened from the soil of Hainan Island. After n...[Objective] The research aimed to screen Streptomyces hygroscopicus strains with high production of agricultural antibiotics. [ Method] A strain of S. hygroscopicus was screened from the soil of Hainan Island. After natural screening and consecutive ultraviolet induced mutation twice, S6-7 strain was obtained as the original strain then treated by UV irradiation and streptomycin resistance screening, and finally rescreened through shake-flask fermentation. [Result] 7 better strains were selected by primary screening from 62 single colonies which were picked out randomly. After 3 generations of consecutive cultivation on slant media and rescreening, 5 strains presented obvious forward mutation. The forward mutation rate reached 8.06%, and the largest production increasing rate came up to 25.11%. [Conclusion] By combining streptomycin resistance screening and conventional ultraviolet induced mutation, both the antibiotic-producing capacity and forward mutation screening efficiency of the original strain were greatly enhanced.展开更多
[Objective] This study aimed to explore the mutagenesis effects of N＋ ion beam implantation on Streptomyces a/bus and obtain high-yield salinomycin- producing mutant strain. [ Method ] Streptomyces a/bus strain S-11-...[Objective] This study aimed to explore the mutagenesis effects of N＋ ion beam implantation on Streptomyces a/bus and obtain high-yield salinomycin- producing mutant strain. [ Method ] Streptomyces a/bus strain S-11-04 was mutated with different doses of N ＋ implantation. The effects of low energy N ＊ implantation on the survival rate, colony morphology and salinomycin-producing ability were investigated. [ Result] The results showed that low energy N ＋ implantation can efficiently improve the positive mutation rate of Streptomyces albus; 13 mutant strains with high yield of salinomycin were isolated; to be specific, mutant strain N3- 6 has relatively good genetic stability with four continuous generations, and the titres of salinomycin were increased by 41% in the shake-flask culture and 20.5% in mass production compared with the control. [ Conclusion ] N ＋ ion beam irradiation is an effective method to obtain high-yield salinomycin-producing Streptomy- ces albus strain.展开更多
文摘Mutants of the strain producing natamycin, Streptomyces gilvosporeus, were obtained after space-flight mutation. With respect to the sand spores and slant spores, the mutation ratios were up to 67.6% and 78.3% and the survival ratio was 43.1% and 3.0%, respectively. An improved mutant producing natamycin, S. gilvosporeus LK-45, was screened, which showed natamycin productivity of 1420mg·L^-1. A mutant resistant to 2-deoxy glucose, S.gilvosporeus LK-119, was further obtained using a＇rational screening procedure. The natamycin productivity of 1940mg·L^-1 was achieved when glucose was used as the carbon source.
基金Supported by Basic Research Fund for Central Nonprofit Institutes(Agro-environmental Protection Institute of Ministry of Agriculture)~~
文摘[Objective] The research aimed to screen Streptomyces hygroscopicus strains with high production of agricultural antibiotics. [ Method] A strain of S. hygroscopicus was screened from the soil of Hainan Island. After natural screening and consecutive ultraviolet induced mutation twice, S6-7 strain was obtained as the original strain then treated by UV irradiation and streptomycin resistance screening, and finally rescreened through shake-flask fermentation. [Result] 7 better strains were selected by primary screening from 62 single colonies which were picked out randomly. After 3 generations of consecutive cultivation on slant media and rescreening, 5 strains presented obvious forward mutation. The forward mutation rate reached 8.06%, and the largest production increasing rate came up to 25.11%. [Conclusion] By combining streptomycin resistance screening and conventional ultraviolet induced mutation, both the antibiotic-producing capacity and forward mutation screening efficiency of the original strain were greatly enhanced.
文摘[Objective] This study aimed to explore the mutagenesis effects of N＋ ion beam implantation on Streptomyces a/bus and obtain high-yield salinomycin- producing mutant strain. [ Method ] Streptomyces a/bus strain S-11-04 was mutated with different doses of N ＋ implantation. The effects of low energy N ＊ implantation on the survival rate, colony morphology and salinomycin-producing ability were investigated. [ Result] The results showed that low energy N ＋ implantation can efficiently improve the positive mutation rate of Streptomyces albus; 13 mutant strains with high yield of salinomycin were isolated; to be specific, mutant strain N3- 6 has relatively good genetic stability with four continuous generations, and the titres of salinomycin were increased by 41% in the shake-flask culture and 20.5% in mass production compared with the control. [ Conclusion ] N ＋ ion beam irradiation is an effective method to obtain high-yield salinomycin-producing Streptomy- ces albus strain.
