The efficacy of DL-5-(4-hydroxyphenyl)-5-phenyl hydantoin on biotransformation of molasses to citric acid by fungal strains such as Aspergillus flavus NCIM-540, Aspergillus oxyzae NCIM - 553, Aspergillus niger NCIM - 501, Aspergillus foetidus NCIM - 937 and Aspergillus wentii NCIM-941 has been assessed. It has been observed that the fungal strain Aspergillus niger NCIM - 501 has been found most significant and effective for the citric acid fermentation process. It has been found that the compound, i.e. DL-5-(4-hydroxyphenyl)-5-phenyl hydantoin has stimulatory effect on production of citric acid by Aspergillus niger NCIM - 501 and enhances the yield of citric acid to an extent of 12.477% higher in comparison to control fermentor flasks, i.e., 7.989g/100 ml under the optimized conditions, viz. 30C temperature, 2.0 pH, 12 days of incubation period with 26% molasses solution