Selection of Fermentation for Citric Acid in Bioreactor

Twenty-five strains of Aspergillus niger, isolated from different soil samples were evaluated for citric acid production. Shake flask technique was employed for screening of the isolated. The best citric acid producing strain, GCB-14, was selected for further studies using a laboratory scale stirred fermentor. Cane-molasses medium and sucrose salt medium were tested for the basal fermentation medium. The results indicated that maximum amount of citric acid i.e. 55.43 gl-1 was produced 144 h after incubation using cane-molasses medium. The maximum amount of sugar consumed and dry cell mass produced were 126 and 27.49 gl-1, respectively. Therefore, cane-molasses was optimized as the basal fermentation medium for maximal citric acid production.