Abstract: The filamentous fungus, Aspergillus niger MTCC 282, was used to produce citric acid in submerged fermentation with Colocassia antiquorum (10% w/v) as the substrate. The maximum yield of citric acid (46.5 mg mL-1) was obtained with inoculum age (7 days), inoculum level (2% v/v), temperature (30°C), pH (4.0), sucrose (2.0% w/v) and ammonium nitrate (1.2% w/v). The addition of methanol to the fermentation medium resulted in substantial increase in the production of citric acid.