Point mutation of the xylose reductase (XR) gene reduces xylitol accumulation and increases citric acid production in Aspergillus carbonarius

Citric Acid Production by Aspergillus Niger*

the Stokes' equation (4). The anomalous appearance of the curves might suggest that a non-random sample had been selected, but examination of the frequencies of cells appearing in different size ranges reveals a normal distribution indicating that a random sample had been selected. The diameters of cells and the correspondent frequencies are: 3.5-2; 4.0-7; 4.5-10; 5.0-20; 5.5-17; 6.0-8; 6.5-2; ...

Improving xylitol production through recombinant expression of xylose reductase in the white-rot fungus Phanerochaete

Production of xylitol from D-xylose by a xylitol dehydrogenase gene-disrupted mutant of Candida tropicalis.

Xylitol dehydrogenase (XDH) is one of the key enzymes in d-xylose metabolism, catalyzing the oxidation of xylitol to d-xylulose. Two copies of the XYL2 gene encoding XDH in the diploid yeast Candida tropicalis were sequentially disrupted using the Ura-blasting method. The XYL2-disrupted mutant, BSXDH-3, did not grow on a minimal medium containing d-xylose as a sole carbon source. An enzyme assa...

Production of citric acid by mutants of Aspergillus niger.

Development of methodology for the recovery of citric acid from the fermented broth involves standardization of the various parameters to achieve maximum performance in terms of recovery and optimum conditions. The present investigation was carried out to study the purification of citric acid from fermented broth by calcium carbonate precipitation and subsequent acid hydrolysis. The parameters ...

Overexpression of a C4-dicarboxylate transporter is the key for rerouting citric acid to C4-dicarboxylic acid production in Aspergillus carbonarius

BACKGROUND C4-dicarboxylic acids, including malic acid, fumaric acid and succinic acid, are valuable organic acids that can be produced and secreted by a number of microorganisms. Previous studies on organic acid production by Aspergillus carbonarius, which is capable of producing high amounts of citric acid from varieties carbon sources, have revealed its potential as a fungal cell factory. Ea...