RESUMO
The effect of varying cultural conditions was assessed on the production of polygalacturonase [PG] in Aspergillus niger NRRL3. The effect of different types of media and growth techniques [stationary and agitation cultures] on production of PG from A. niger was examined. The optimum activity of PG was recorded for potato dextrose broth medium with 0.1% citrus pectin as carbon source in agitation culture. There were variations in enzyme levels produced in culture filtrate with age of culture, the highest levels being in 3-day-old culture. The temperature and pH also had marked effects on the production of PG with the best conditions being 30°C and pH 5.0, respectively. The effect of different carbon sources on pH production showed that citrus pectin was the best carbon source. The addition of the different examined nitrogen sources and mineral salts decreased the productivity of PF enzyme compared to the PDB medium in absence of them