Fig. 4

Enhancement of armeniaspirol production. A LCMS spectra comparison of notonesomycin A and armeniaspirol production between Streptomyces sp. A793 wild type strain (A793 WT) and edited strains A793-2, A793-3 and A793-4. B Comparison of the production of armeniaspirols (1–3) between A793 WT and edited strains A793-2, A793-3 and A793-4. C Comparison of the production of armeniaspirols intermediates 4–6, 7–8, 10–12 and 16–18 between A793 WT and edited strains A793-2, A793-3 and A793-4. 9, 13–15 were not observed in our analyses. Mean values in three independent experiments are presented and error bars refer to standard deviation. Significance of differences to A793 WT was calculated with Student’s t-test (* P-values < 0.05)