Fig. 3.

Principal component analysis (PCA) of the final production of volatile compounds (Max), the maximal specific rate of production (SRmax), and the time at which this maximum was reached (PointSRmax). Each fermentation is identified by the labels X, Y, and Z, where X corresponds to the strain, Y to the initial nitrogen concentration in mg N/l and Z is the phytosterol content in mg/l. PR propanol, ISO isobutanol, IA isoamyl alcohol, EA ethyl acetate, ISO isobutyl acetate, IAA isoamyl acetate, EH ethyl hexanoate, EO ethyl octanoate