The paper examines effects of different inorganic salts in an apple pulp base on the production of pectinolytic enzymes with the aim of optimizing the medium for maximal enzyme production. The apple pulp combined with corn flour and simple mineral salts was used as a nourishing base in submerged production of pectinolytic enzymes by the fungus Aspergillus niger MK-15. The growth of the microorganism (dry weight) on different sources of nitrogen showed maximum dry weight with (NH4)2HPO4. The growth of the microorganism (dry weight) on different concentration of (NH4)2HPO4 (by 0.2% to 0.8%) provided maximal dry weight with 0.7% (NH4)2HPO4. The different inorganic salts (sources of nitrogen) on base stimulated the production of pectinolytic enzymes and enhanced by up to twofold the growth of Aspergillus niger in submerged fermentation. The best source of nitrogen on base was (NH4)2HPO4 with optimal concentration of 0.7%. The obtained results represent practical importance for using apple pulp as a carbon source for production of pectinolytic enzymes in submerged fermentation.