Once the glucose concentration exceeded this limit, a level off in cell dry weight was observed (Figure 3B). Similarly, the lipid content increased from 10.8% to 16.5% when the glucose concentration increased from 4.5 to 18 g/l,corresponding to an increase of the C/N ratio from 100 to 400. The lipid content reached the maximum value of 18.8% when the glucose concentration was at 28 g/l or C/N molar ratio was at 600.