Fig. 4

Photosynthetic production of squalene from CO₂ in engineered S. elongatus PCC 7942 strains. a Cell pellets from engineered S. elongatus strains were extracted using a mixture of chloroform and methanol. Authentic squalene standard (peak 1) and extracted samples (peak 2) were analyzed with GC–MS. The internal standard (IS) is 1-phenyloctadecane. b Mass spectra and retention times of authentic squalene or the samples from engineered S. elongatus strains. RT retention time (in min). c Growth (OD₇₃₀) of wild-type (black square) and engineered S. elongatus strains: SeSC00S (red circle), SeSC33S (blue triangle) and SeSC41S (cyan upper triangle) strain. d Production (mg/L/OD₇₃₀) of squalene from wild-type and the engineered S. elongatus SeSC00S, SeSC33S, SeSC41S. All data are the mean ± standard deviation (SD) from the triplicated cultures. ND not detected