Utilization of Orange Peel, Corn Steep Liquor, and Parboiled Rice Water in the Production of Polygalacturonase from <i>Aspergillus niger</i>

Abstract

The objective of this work was to optimize the process parameters of exo-polygalacturonase production from Aspergillus niger ATCC 9642 via submerged fermentation using agro-industrial residues such as orange peel, corn steep liquor, and parboiled rice water and to do partial enzyme characterization. A complete second-order design was used for screening the most important factors and to maximize exo-polygalacturonase production. The maximum exo-polygalacturonase activity in our work was 18.5 U/mL (specific activity of 195.6 U/mg) at 120 h with concentrations of 80 g/L orange peel, 60 g/L corn steep liquor, and 450 g/L parboiled rice water, at 180 rpm, 30°C, pHinitial 5.5, and spore concentration 5x106 spores/mL. The highest storage stability was obtained at 348 h for 55°C and 808 h for −80°C (pH 5.5). The activation energy (Ed) for deactivation reaction was 1.05 KJ/mol, with a half-life (t1/2) of 63 h.