Novel erythromycins from a recombinant Saccharopolyspora erythraea strain NRRL 2338 pIG1. I. Fermentation, isolation and biological activity.

In a previous report, a plasmid, pIG1, which contained the loading domain from the Streptomyces avermitilis polyketide synthase (PKS), promoters from Streptomyces coelicolor and the DEBS1-TE truncated PKS from Saccharopolyspora erythraea, was integrated into the S. erythraea chromosome, effectively replacing the natural erythromycin loading domain with the avermectin loading domain. In this paper, we report the feeding of short-chained fatty acids to this recombinant strain, and its parent, NRRL 2338. Both strains incorporated exogenously supplied fatty acids to produce novel, biologically active, C-13 substituted erythromycins.