Two strains of the fungus Aspergillus niger were screened for their ability to produce citric acid on corn distillers` dried grains with solubles. It was determined that citric acid production by A. niger ATCC 9029 after 240 h was higher on untreated grains than on autoclaved grains or acid-hydrolyzed grains. In contrast, citric acid production by A. niger ATCC 12846 after 240 h was higher on autoclaved grains than on untreated grains or acid-hydrolyzed grains. Methanol or phosphate supplementation to the grains failed to stimulate citric acid production by either A. niger strain. Biomass production by both strains after 240 h was higher on the treated grains than the untreated grains. The highest citric acid yields were observed following growth of both strains on the untreated grains.
Gang Xie and Thomas P. West , 2006. Comparison of Citric Acid Production by Aspergillus niger ATCC 9029 and ATCC 12846 on Corn Distillers` Grains with Solubles. Research Journal of Microbiology, 1: 540-545.