[ Objective ] To enhance amylase, protease and cellulase activities of Bacillus licheniformis LCB-8 by ultraviolet mutagenasis. [ Method ] Ultraviolet light was used to mutate this strain. The activities of amylase, p...[ Objective ] To enhance amylase, protease and cellulase activities of Bacillus licheniformis LCB-8 by ultraviolet mutagenasis. [ Method ] Ultraviolet light was used to mutate this strain. The activities of amylase, protease and cellulase were determined to get high-yielding strains. [ Resalt] The best time for ultraviolet mutation was 30 s, and the mortality rate reached 72.4%. After primary screening and rascraening, two better strains were obtained. After mutagenasis, the activities of amylase, protease and cellulase of DY-97 strain were enhanced by 150%, 78% and 17% respectively. After mutagenesis, the activities of cellulase, amylase and protease of DY-34 strain were enhanced by 31%, 46% and 64% respectively. [ Conclusion] The DY-97 strain is suitable for fermentation of feed rich in protein and amylum, whereas the DY-34 strain is suitable for fermentation of feed rich in cellulose.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
Fifteen mutant isolates were obtained by ultraviolet mutation from parent isolate Botrytis cinerea BC-4. Among them three mutant isolates, BC4-1, BC4-2, and BC4-15, showed strong herbicidal activity. BC4-1 showed maxi...Fifteen mutant isolates were obtained by ultraviolet mutation from parent isolate Botrytis cinerea BC-4. Among them three mutant isolates, BC4-1, BC4-2, and BC4-15, showed strong herbicidal activity. BC4-1 showed maximum herbicidal activity for inhibition of germination and growth of Digitaria sanguinalis L. and Arnaranthus retroflexus L. The results also showed that herbicidal activity was influenced by differing pH of PD media, with pH value of 4.0 being the optimum. The crude toxin was extracted using chloroform, petroleum ether, and ethyl acetate, respectively, and the ethyl acetate extracts showed the strongest inhibitory activity on the germination and growth of D. sanguinalis L. and A. retroflexus L. Using HPLC, one fraction with an absorption peak at 271 nm was separated from the crude toxin. This fraction could strongly inhibit the growth of D. sanguinalis L. at a concentration of 100 mg L^-1 and could completely inhibit the seed germination of D. sanguinalis L. and A. retroflexus L. at a concentration of 50 mg L^-1 .展开更多
基金supported by the grants from Initial Scientific Research Foundation for Doctors in Liaocheng University
文摘[ Objective ] To enhance amylase, protease and cellulase activities of Bacillus licheniformis LCB-8 by ultraviolet mutagenasis. [ Method ] Ultraviolet light was used to mutate this strain. The activities of amylase, protease and cellulase were determined to get high-yielding strains. [ Resalt] The best time for ultraviolet mutation was 30 s, and the mortality rate reached 72.4%. After primary screening and rascraening, two better strains were obtained. After mutagenasis, the activities of amylase, protease and cellulase of DY-97 strain were enhanced by 150%, 78% and 17% respectively. After mutagenesis, the activities of cellulase, amylase and protease of DY-34 strain were enhanced by 31%, 46% and 64% respectively. [ Conclusion] The DY-97 strain is suitable for fermentation of feed rich in protein and amylum, whereas the DY-34 strain is suitable for fermentation of feed rich in cellulose.
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Fifteen mutant isolates were obtained by ultraviolet mutation from parent isolate Botrytis cinerea BC-4. Among them three mutant isolates, BC4-1, BC4-2, and BC4-15, showed strong herbicidal activity. BC4-1 showed maximum herbicidal activity for inhibition of germination and growth of Digitaria sanguinalis L. and Arnaranthus retroflexus L. The results also showed that herbicidal activity was influenced by differing pH of PD media, with pH value of 4.0 being the optimum. The crude toxin was extracted using chloroform, petroleum ether, and ethyl acetate, respectively, and the ethyl acetate extracts showed the strongest inhibitory activity on the germination and growth of D. sanguinalis L. and A. retroflexus L. Using HPLC, one fraction with an absorption peak at 271 nm was separated from the crude toxin. This fraction could strongly inhibit the growth of D. sanguinalis L. at a concentration of 100 mg L^-1 and could completely inhibit the seed germination of D. sanguinalis L. and A. retroflexus L. at a concentration of 50 mg L^-1 .
