Screening for Streptomyces hygroscopicus strains with high production of agricultural antibiotics by streptomycin resistance.

摘要

The research aimed to screen Streptomyces hygroscopicus strains with high production of agricultural antibiotics. A strain of S. hygroscopicus was screened from the soil of Hainan Island. After natural screening and consecutive ultraviolet induced mutation twice, 86-7 strain was obtained as the original strain then treated by UV irradiation and streptomycin resistance screening, and finally rescreened through shake-flask fermentation. Seven 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%. 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.