Comparison of locally available carbon rich substrates for augmented microbial production of citric acid with mutant Aspergillus niger S-6 strain

Abstract

The aim of the present study was to compare three carbon sources for Citric acid (CA) production by using mutant strain of Aspergillus niger S-6. UV rays at a wavelength of 365 nm were used as the mutagen on a locally isolated Aspergillus niger strain, arbitrarily named as A. niger S-6. The fungus was exposed to 30 minutes of UV irradiation. Cane molasses, pumpkin and sweet potato were taken as the carbon sources for preparation of fermentation media. CA yield was quantitatively estimated by calculating total titrable acidity (TTA) of fermentation media. Mutagenesis with UV radiation led to more than twofold higher CA production in all fermentation media. Sweet potato medium showed higher CA production of 11.84 + 0.13 g% in comparison to cane molasses (11.37 + 0.11 g %) and pumpkin (10.15 + 0.06 g %) Sweet potato.