Fermentation of juice from sugarcorn, a new feedstock for the ethanol industry

The Brazilian ethanol industry enjoys some advantages over their North American counterpart.  This includes the sugarcane feedstock, which has high yields of readily fermentable sugar.  Sugarcorn was developed to produce fermentable sugars in the stalk for temperate and sub-temperate regions of the world where sugarcane cannot be cultivated.    Sugarcorn hybrids were grown at Ottawa Ontario (45°23'N, 75°43'W) and Ridgetown Ontario (42°26'N, 81°53'W).  Stalks were stripped of leaves and juice extracted using a three roller press.  Sugar content of the juice was found to range from 125 to 180 g/L.  This juice was then used as a fermentation substrate for Saccharomyces cerevisiae.  Sugarcorn juice was supplemented with 0, 3 or 9 g/L of yeast extract, inoculated with S. cerevisiae and monitored for 72 hours.  Supplemental nitrogen in the form of yeast extract at 3 g/L was the most beneficial for fermentation.  That is, ethanol yield and productivity were the highest in this medium at 0.466 g/g and 0.554 g/L·hr respectively.  Higher overall ethanol yield was observed when the fermentation experiment was repeated with the addition of 3 g/L yeast extract in the inoculation medium.  Under these conditions, S. cerevisiae consumed most of the reducing sugars within 24 hours and produced 45.62 g/L of ethanol in 72 hours, representing 90 % of theoretical ethanol yield.  Sugarcorn is a new feedstock that shows promise for reducing the cost of the energy and enzyme inputs currently used in the conventional starch to ethanol process.