Enhanced citric acid production via aconitase co-inhibition strategy using L-cysteine HCl-resistant <i>Aspergillus niger</i> NA-CYS3.

ABSTRACT: The present study presents a new approach to boost citric acid production by combining genetic improvement and enzyme inhibition in the fungus Aspergillus niger. A mutant strain, named NA-CYS3, was developed by chemically treating the wild-type strain to make it resistant to L-cysteine HCl, a chemical that normally limits growth. This mutant showed better tolerance and higher productivity. Optimal fermentation conditions including medium volume (50 mL), acidity (pH: 4.5), inoculum size (10%), incubation time (144 h), and temperature (30 °C) were optimized to maximize citric acid yield. Under these conditions, NA-CYS3 produced 26.35 g/L, a 2.7-fold increase in substrate use and higher yield compared to the wild-type strain. To further increase production, the activity of aconitase, a

SUBMITTER: Jabeen N 

PROVIDER: S-EPMC13310209 | biostudies-literature | 2026 Jul

REPOSITORIES: biostudies-literature