Standardization of Process Parameters for Production of Citric Acid from Mahua Flowers (Madhuca indica) by Surface Fermentation using Aspergillus niger NCIM-545 and NCIM-595

Madhuca indica commonly known as mahua, is a large tree which produces edible flowers rich in reducing sugars. In the present investigation suitability of mahua flowers as a substrate for production of citric acid was evaluated. The environmental parameters such as pH, temperature, incubation period, inoculum and nutritional parameters viz. initial sugar concentration, nitrogen source, and methanol contration affected the production of ciric acid using Aspergillus niger NCIM-545 and NCIM-595. The production of citric acid was optimum when fermentation was carried out at initial pH of 5.0, temperature of 30°C, incubation period of 168 h and inoculum level of 2.0 per cent for both the strains. Further it was observed that at sugar level of 14 per cent, yeast extract (0.07 per cent nitrogen level) and methanol (4 per cent), the citric acid production was optimum. At the optimised conditions the citric acid production was comparatively higher for Aspergillus niger NCIM-595 than NCIM-545.