Effect of 5,7-dihydroxy-4-phenylcoumarin on bioproduction of citric acid by Aspergillus niger NCIM-1986

The efficacy of coumarin, i.e., 5,7-dihydroxy-4-phenylcoumarin on production of citric acid by fungal strains such as Aspergillus aculeatus NCIM - 1636, Aspergillus awamori NCIM -1645, Aspergillus foetidus NCIM-1765, Aspergillus wentii NCIM - 1789 and strain Aspergillus niger NCIM-1986 has been assessed. It has been observed that the fungal strain Aspergillus niger NCIM-1986 has been found most potential and effective for the citric acid fermentation process. It has been found that the coumarin, i.e.,5,7-dihydroxy-4-phenylcoumarin at molar concentration, i.e., 5.0 × 10-5M has stimulatory effect on production of citric acid by Aspergillus niger NCIM-1986 and enhances the yield of citric acid to an extent of 12.303% higher in comparison to control fermentor flasks, i.e., 8.640 g/100 ml under the optimized conditions, viz. 300C temperature, 1.8 pH, 11 days of incubation period with 32% (w/v) molasses solution.