In vitro microbial production of citric acid by Aspergillus niger NCIM-1270 exposed to 6-fluoro-4-hydroxycoumarin

The current world production of citric acid is estimated to be 1.6 million tonnes per year whereof 99% is produced by microbial fermentation. The impact of 6-fluoro-4-hydroxycoumarin on microbial bioproduction of citric acid by Aspergillus oryzae NCIM -949, Aspergillus fumugatus NCIM - 902, Aspergillus awamori NCIM - 861, Aspergillus candidus NCIM - 883 and Aspergillus niger NCIM - 1270 has been assessed. It has been observed that the fungal strain Aspergillus niger NCIM - 1270 has been found most potential and effective for the citric acid fermentation process. It has been found that the micelles, i.e., 6-fluoro-4-hydroxycoumarin at molar concentration, i.e., 3.0×10-5M has stimulatory effect on production of citric acid by Aspergillus niger NCIM - 1270 and enhances the yield of citric acid to an extent of 4.915% higher in comparison to control fermentor flasks, i.e., 3.006 g/100 mL under the optimized conditions, viz. 290C temperature, 2.1 pH, 12 days of incubation period with 24% (w/v) molasses solution.