Chemical Eng., BNUT
Environmental science, Tarbiat Modares University, Mazandaran, Noor, Iran
Biochemical & Chemical Engineering, Noshirvani University of Technology, Babol
Among enzymes, lipases have been widely investigated because of the 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 with the aid of central composite design (CCD) under response surface methodology (RSM) were obtained. 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/gdss), respectively. 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°C and pH value of 6.87.