Figure 3

The influence of the pH of fermentation on the rate of ethanol production from a combined sucrose/watermelon juice feedstock. The initial concentrations of fermentable sugars were nominally 25% (w/v). The 2007 Hinton, OK, USA watermelon crop was the source of the juice. The juice was processed to remove chromoplasts before its use in the fermentations. The nitrogen content for all fermentations was 1,177 mg N/L (33.0 μmol amino N/ml). All fermentations were essentially completed (that is, all sugars consumed) after 48 h. Other conditions for the fermentations are given in the text, and the approach used to estimate d(%)/d(h) is given in Methods.