Production, purification and immobilization of pectinase from Aspergillus ibericus onto functionalized nanoporous activated carbon (FNAC) and its application on treatment of pectin containing wastewater

•The citrus pectin obtained from citrus peels were used as a substrate for the production of pectinase.•Optimization of pectinase production conditions was analyzed using RSM.•The maximum activity of pectinase was observed 69UmL−1 by A. ibericus it is 2 folds higher than other reports.•The purified pectinase was immobilized onto FNAC and increased stability of enzyme were seen.•The PIFNAC was packed on column reactor for the treatment of pectin containing citrus processing wastewater.