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

Abstract

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.