Metabolic inhibitors as stimulating factors for citric acid production

The effect of some metabolic inhibitors on citric acid production by Aspergillus niger in cane molasses medium was investigated. Addition of 0.01-0.1 iodoacetic acid and sodium arsenate, 0.05 -1.0 sodium malonate, 0.01 sodium azide , 0.01-0.05 sodium fluoride , 0.1-1.0 EDTA stimulated citric acid production (5-49%), but not necessary total titratable acids. Higher concentrations 10mM of iodoacetic acid , sodium malonate and 0.5 mM sodium azide caused a complete inhibition of fungal growth. 0.2 mM of iodoacetic acid, sodium arsenate and sodium fluoride caused a remarkable inhibition of citric acid production. The implications of those preliminary functions was discussed.