Lipase Production in Solid State Fermentation Using Aspergillus niger: Response Surface Methodology

Among enzymes, lipases have been widely investigated because of their numerous industrial applications. In this study, optimization of lipase production by Aspergillus niger in solid state fermentation from rice bran as solid substrate was investigated. The optimal conditions were obtained with the aid of central composite design (CCD) under response surface methodology (RSM). In the analysis of 20 experimental runs, effects of three variables such as olive oil concentration, glucose concentration and humidity ratio on lipase activity were evaluated. The interaction between lipase activity and independent paired parameters were illustrated by three-dimensional diagrams while other factors were set at zero level. The optimum values of oil concentration, glucose concentration and humidity ratio were 1.78, 2.54 and 1.95% (g/g sub(dss)), respectively and the enzyme activity for optimum conditions was 121.53 (U/g sub(dss)). Also, the effect of temperature and pH on the relative lipase activity in enzyme reaction was evaluated. The lipase produced was highly active at 30.3 degree C and pH value of 6.87.