Fig. 4

Alr5283 and Alr5284 are responsible for the heptadecane production in Anabaena 7120. GC/MS SIM chromatographs of the volatile metabolites from wildtype (a), DR935 (b), and DR935(pZR2239) (c) strains, respectively. Heptadecane naturally produced in wildtype Anabaena 7120 was not detected in DR935, but reemerged after the complement plasmid pZR2239 was transformed into DR935. Five μg mL⁻¹ tetracosane serves as an internal standard (IS, blue arrow). d Total heptadecane production mg⁻¹ chlorophyll of wildtype Anabaena 7120, DR935, and DR935(pZR2239) cultures from days 0 to 5. Heptadecane yield was calculated by measuring the total heptadecane produced from days 0 to 5 and dividing by total chlorophyll content of the 100 mL cultures measured on day 5. The culture density increased over days 0–5 but only day 5 chlorophyll content was used to make the calculation (the chlorophyll content of seed culture at day 0 is negligible). Therefore, the total heptadecane production mg⁻¹ chlorophyll calculation is an underestimate