Optimization of Xylanase production from Aspergillus niger using Central Composite Design (CCD)

Abstract

Xylanase is a hydrolytic enzyme which has broad industrial application and can be produce via Aspergillus niger. In this study, four factors: incubation temperature, medium pH, incubation time, and agitation speed were screened by performing Onefactor- at-a-time (OFAT) analysis. The first factor manipulated was the incubation temperature (25-37oC, pH 5.0, 5 days, 150 rpm), followed by medium pH (pH 3.0-9.0, 32oC, 5 days, 150 rpm), incubation time (3-9 days, 32oC, pH 5.0, 150 rpm), and agitation speed (50-200 rpm, 32oC, pH 5.0, 5 days). Xylanase production with the maximal enzyme activity was successfully obtained from OFAT analysis under condition of 32oC, pH 5.0, 5 days, and 150 rpm. From these significant factors, incubation temperature and medium pH were then statistically optimized using Response Surface Methodology (RSM) in order to improve the xylanase production. Central Composite Design (CCD) was implemented in the process of xylanase production optimization based on OFAT analysis. Two coded factor (X1= Incubation temperature and X2= Medium pH) under OFAT analysis range of 28-37oC and pH 3.0-7.0, respectively were carried out of a total 11 experimental runs with 3 centre points. A triplicate was done for each running in order to increase the optimization accuracy. From the data analyzed by Design of Experiment (DoE), maximal xylanase production with enzyme activity of 0.5118 U/mL was predicted to produce under condition of 32.67oC and pH 4.56 with desirability of 0.936. A validation test with triplicate was done to verify the predicted result, enzyme activity from the validation test was obtained is 0.5638 U/mL.