Figure 3

Production of epothilone B in the M. xanthus transformants (a) and HPLC–MS detection (b, c). a The epothilone productions, assayed after 7-days fermentation. ZE-, KE- and SE- series strains are termed for those recombinants from M. xanthus DZ2, DK1622 and SW504 strains, respectively. b HPLC results of the ion chromatograms of HPLC–MS runs. The upper row, a negative control form the wild type M. xanthus DZ2. The middle and the lower rows demonstrate the results from ZE-5 and ZE-9, respectively. c The fragmentation patterns of epothilone A and epothilone B produced in the isolate no. 9 with the correct molecular weight minus the H⁺ (epothilone A = 493; epothilone B = 507).