Fig. 4

3D surface plots for the response lipid yield of C. tropicalis ASY2 grown in ALB. a Effect of starch vs. yeast extract; b Effect of starch vs. airflow rate; c Effect of yeast extract vs. airflow rate. The interactive effect is represented with the color ranging from blue to red (blue, green, red); blue is least significant, green is moderately significant, and red is highly significant