Method of preparing seeding material for production of citric acid

摘要

Disclosed is a method of preparing a seeding material for the production of citric acid by cultivating spores of a fungus on a nutrient medium containing carbon and nitrogen sources and mineral salts and by separating spores from the nutrient medium. The fungus used is the strain Aspergillus niger R-3 selected from the strain Aspergillus niger -119 by the stepwise action on it of ethyleneimine, N-nitrosomethylurea and ultraviolet radiation.