Statistical optimization of endo-polygalacturonase production by overproducing mutants of Aspergillus niger in solid-state fermentation

Statistically based experimental designs were applied for endopolygalacturonase production by mutated strains of Aspergillus niger using apple pomace waste in solid-state fermentation (SSF). The Plackett-Burman design was used to search for the main factors. Urea was found to be the most significant factor (p<0.05) among these variables. To study the mutual interactions between variables and find the optimum medium, Doehlert design was performed to investigate the effect of the medium components, apple pomace, glucose and urea. Using the optimized medium, the maximal activity of endo-polygalacturonase production was found to be 4.26672 U. The Plackett-Burman design coupled with Doehlert design were proved to be the potent tools in optimizing medium composition for producing endo-polygalacturonase. Keywords: Doehlert design, Plackett-Burman design, solidstate fermentation Received: 18 November 2009 / Received in revised form: 18 December 2009, Accepted: 31 December 2009, Published online: 10 January 2010