Environmental problems caused by fossil fuels use and the need for a new path based on renewable energy sources leads biomass fuels development. Biofuels are considered strategic option for power generation, among them stands out ethanol. In order to minimize the competition with the food chain, the starch sources are alternatives biofuel obtainment, including the Cyperus esculentus (CE). This work aimed to study the ideal conditions for obtaining ethanol from CE flour fermentation, using the enzymatic route for the hydrolysis reaction. The fatorial design used was 3, in order to verify the influence of independents variables: fermentation time (h) and yeast concentration (g L-1) in enzymatic route, and degree alcoholic as the response (°GL). The tests in the raw material were realized, humidity content determination, starch content, reducing sugars (AR), chemically analyzed and scanning electronic microscopy (SEM) and UV-vis to determine the °GL response. The samples presented values humidity content 55.05%, starch content 52.38% and AR 12.23%. The SEM images showed elements protoxilema and protofloema. With the factorial design were achieved optimal conditions (15 g L-1 yeast concentration and 30 hours for fermentation time) for the production of ethanol with 24.27 ° GL.8515101523