Maximization of Xylanase Production by Aureobasidium Pullulans Using a By-Product of Rice Grain Milling As Xylan Source

The aim of this paper was to maximize xylanase production by Aureobasidium pullulans CCT 1261 using rice bran as xylan source. To achieve this goal, two statistical designs and additional cultivations were performed. The medium composition and cultivation conditions were evaluated by a 2(6-2) Fractional Factorial Design (FFD), and a 2(3) Central Composite Design (CCD) was used to model and maximize xylanase production. Sequentially, the model was validated, and some additional cultivations were performed to enhance xylanase production. Maximum xylanase production (82.2 U/mL) was obtained using 3.6 g/L of (NH4)(2)SO4, 1.5 g/L of yeast extract, 61.9 g/L of rice bran, initial pH 7.0, and 28 degrees C. After the experimental designs and additional cultivations, xylanase activity was 7-fold higher than at the initial cultivation conditions. In conclusion, this study allowed the sustainable use of a by-product of rice grain milling, which could also contribute to reduce the costs of submerged cultivation.