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Abstracto

The production of citric acid from shea nut shell (Vitellaria paradoxa) using Aspergillus niger

O. S. Kobomoje, A. O. Mohammed and P. F. Omojasola

The fungus Aspergillus niger was used to produce citric acid from the (shell) of Shea nut (Vitellaria paradoxa). The shea nut shell was dried, sieved to remove the dirt and then blended. The waste was pre-treated with acid and steam. The powdered was then used as substrate in separate shake-flasks which contained mineral salts medium (MSM) and inoculum of Aspergillus niger for citric acid production. Fermentations were carried out in flasks containing the MSM, waste substrate at pH 5.0, 5% substrate concentration, 1.5% inoculum size and at 29+10C for 5 days; the result obtained at day1 was (0.012mg/ml) and at day5 of the fermentation, the yield was (0.020mg/ml) for the citric acid production by Aspergillus niger. These fermentation parameters were combined in a single optimization experiment. The result obtained from the optimization experiment for citric acid was 0.028mg/ml.