Elham Jahandar - Department of Chemical Engineering, Sharrood Branch, Islamic Azad University, Shahrood, Iran
Maryam Khavarpour - Department of Chemical Engineering, Ayatollah Amoli Branch, Islamic Azad University, Amol, Iran
Habibollah Younesi - Department of Environmental Sceinces, College of Natural Resources& Marine Sceinces, Tarbiat Modares

Among enzyme, study on lipase production has been widely increased because of its numerous industrial applications. In the present work, optimization of lipase production by Aspergillus niger in submerged fermentation from wheat bran as solidsubstrate was evaluated. Design Expert 7.01 (Stat-Ease Inc., Minneapolis, MN, USA) software was used for the regression and graphical examination of experimental results parameters. Central composite design (CCD) under response surfacemethodology (RSM) was applied to obtain the optimal conditions.The analysis of variance (ANOVA) demonstrates that the modelwas highly significant. Three dimensional (3D) plots were illustrate to depict the interaction between all factors. Experimental results indicated that the optimal conditions for the desired object were o.42 g/l, 10.46 g/l, 9.32 g/l and 7.09 w/w%, for yeast, oliveoil, glucose concentration and wheat bran, respectively. Use of regression model, maximal lipase activity of 4759.97 U/l wasachieved with consideration of the optimal condition for the parameters. The experiment was carried out under optimal condition resulted in lipase activity of 4751 U/l which was Similar to the value predicted by the model. According to these results, the responsesurface methodology not only applied to determine the significance information on interaction between the factors but also conducted at optimal conditions for the desired objective

Lipase Production, Wheat Bran, Submerged Fermentation, Asperjillus niger, Response Surface Methodology