Improvement of tylosin fermentation by mutation and medium optimization

Abstract

A tylosin-hyperproducing mutant of Streptomyces fradiae MNU20 was isolated from 3500 strains obtained from either MNNG- or u.v.-treated S. fradiae NRRL2702. With the optimal medium, S. fradiae MNU20 was able to produce 159 mg tylosin g biomass-1, indicating that tylosin productivity in S. fradiae NRRL2702 was increased 14-fold by mutation and medium optimization. When the effect of valine, succinate and natural zeolite on tylosin production was investigated using the optimal medium, these substances essentially enhanced tylosin production up to 349 mg g biomass-1; their time addition during the culture period appeared to be critical for the increase.