Medium optimization for solid state fermentative production of xylanase by Aspergillus terreus using central composite design

Abstract

Response surface methodology (RSM) was employed for the optimization of the composition of medium for the production of xylanase by Aspergillusterreus under solid state fermentation (SSF). The effect of twelve medium components was tested using Plackett-Burman designand the variables namely, peptone, soybean meal, (NH₄)₂SO₄, and CoSO₄ were found to be significant on the production of xylanase. These variables were selected for further optimization studies using central composite (CCD) design. The steepest ascent method was used to access the optimal region of the medium composition, followed by an application of response surface. The optimum values of the tested variables were peptone - 0.0161 g/gds or (g/gram dry substrate), soybean meal – 0.0429 g/gds, (NH₄)₂SO₄ – 0.0161 g/gds, and CoSO₄ – 0.0031 g/gds. Under the final optimized conditions, the predicted response for xylanase production was 356.56 IU/gds (International units of xylanase activity per gram of dry substrate), and the observed validated experimental value was 355.73 IU/gds.