Production of citric acid by Aspergillus niger T-918 exposed to 6-Hydroxy-4-methylcoumarin

The efficacy of some coumarin compound, i.e., 6-Hydroxy-4-methylcoumarin on bioproduction of citric acid by Aspergillus foetidus T-501, Aspergillus fischeri T-611 6.968, Aspergillus geganticus T-715 , Aspergillus oryzae T-816, Aspergillus niger T-918 has been assessed. It has been observed that the fungal strain Aspergillus niger T-918 has been found most potential and effective for the citric acid fermentation process. It has been found that the coumarin, i.e., 6-Hydroxy-4-methylcoumarin on at molar concentration, i.e., 6.0 × 10-5M has stimulatory effect on production of citric acid by Aspergillus niger T-918 and enhances the yield of citric acid to an extent of 12.247% higher in comparison to control fermentor flasks, i.e., 9.757 g/100 ml under the optimized conditions, viz. 270C temperature, 2.0 pH, 13 days of incubation period with 30% (w/v) molasses solution.