Some factors affecting production of pectic enzymes by Aspergillus niger

The effects of varying cultural conditions were assessed for the production of pectic enzymes in a strain of Aspergillus niger, isolated from decaying orange fruit. Polygalacturonase and pectinmethylesterase were found to be inducible by polygalacturonic acid and pectin in the medium, respectively. Ammonium sulphate was the best nitrogen source for the production of both enzymes. There were variations in enzyme levels produced in culture filtrates with age of the culture, the highest levels being in 4-day-old cultures. The temperature and pH also had marked effects on the production of pectic enzymes with the best conditions being 40°C and pH 5, respectively. Surface culture technique gave appreciable enzyme yield, while agitation had an inhibitory effect on enzyme production.