Figure 3

Astaxanthin production by engineered strains overexpressing single mevalonate synthetic pathway genes. a cell concentration (OD₆₀₀); b intracellular astaxanthin content (mg/g-cell); c volumetric astaxanthin concentration (mg/L). Diamond (black), Circle (blue), Square (red) and Triangle (yellow) symbols represent values of the vector control strain, acaT overexpressing strain, hmgS overexpressing strain and hmgR overexpressing strain, respectively. The values are means and the error bars show the SD (n = 3). Student's t-test; asterisks indicate significant differences compared to the vector control strain (*P < 0.05, **P < 0.01).