he brewing industry is one of the largest in the world, from this was obtained large quantity of co products such as brewer`s spent grain (BSG). This is a material rich in cellulose, hemicellulose, protein, lignin, among others. Due to its composition has great potential as a raw material in various industries and production processes such as biotechnological processes, using BGS as a substrate for the generation of value-added products like xylitol. In this work, the temperature, pH, hydrolysis time, endoxylanase enzyme dose and percentage of BSG were determined to obtain the highest xylose concentration from the hydrolysis of the material with the enzyme extract obtained from Penicillium sp. HC1. For this, extract endoxylanase activity was evaluated under different pH and temperature values, obtaining the highest activity at pH 4 and 40°C. The influence of endoxylanases dose and BSG percentage in the release of reducing sugars was determined using a composite central design (CCD), where these two factors were evaluated. All treatments were evaluated at 2, 4, 6, 8, 10 and 24 hours. Statistical analysis showed that both BGS percentage, endoxylanase dose and the interaction between both factors significantly affect the release of reducing sugars (p-value <0.05), in a positive way. However, the term that most affects the response variable is the BGS percentage.