Solar-Energy Driven Simultaneous Saccharification and Fermentation of Starch to Bioethanol for Fuel-Cell Applications

A solar reactor was designed to perform the conversion of starch to ethanol in a single step. An aqueous starch solution (5wt%) was fed into the reactor bed charged with Baker's yeast (Saccharomyces cerevisiae) and amylase, resulting in approximately 2.5wt% ethanol collected daily (ca. 25mLday^-1). A significant amount of ethanol (38g) was collected over 63days, corresponding to 84% of the theoretical yield. The production of ethanol without additional energy input highlights the significance of this new process. The ethanol produced was also demonstrated as a potential fuel for direct ethanol fuel cells. Additionally, the secondary metabolite glycerol was fully reduced to a value-added product 1,3-propanediol, which is the first example of a fungal strain (Baker's yeast) converting glycerol insitu to 1,3-propanediol. All you need is sun: A solar reactor is designed for conversion of starch to bioethanol in a single step. An aqueous starch solution (5wt%) is fed into the reactor charged with Baker's yeast and amylase. Ethanol production with no additional energy input signifies the importance of this new process. The ethanol produced from starch is demonstrated as a potential fuel for direct ethanol fuel cells.