AI Article Synopsis
- D-galacturonic acid can be derived from pectin, a low-cost raw material, through hydrolysis.
- Metabolic engineering was used to create fungal strains that convert D-galacturonate to galactarate (mucate), which has various applications in food, cosmetics, and pharmaceuticals.
- The study showed that deleting the gene for D-galacturonate reductase in fungi hindered growth on D-galacturonate, but introducing a bacterial gene for D-galacturonate dehydrogenase allowed the modified strains to successfully produce galactarate.
Article Abstract
D-galacturonic acid can be obtained by hydrolyzing pectin, which is an abundant and low value raw material. By means of metabolic engineering, we constructed fungal strains for the conversion of D-galacturonate to meso-galactarate (mucate). Galactarate has applications in food, cosmetics, and pharmaceuticals and as a platform chemical. In fungi D-galacturonate is catabolized through a reductive pathway with a D-galacturonate reductase as the first enzyme. Deleting the corresponding gene in the fungi Hypocrea jecorina and Aspergillus niger resulted in strains unable to grow on D-galacturonate. The genes of the pathway for D-galacturonate catabolism were upregulated in the presence of D-galacturonate in A. niger, even when the gene for D-galacturonate reductase was deleted, indicating that D-galacturonate itself is an inducer for the pathway. A bacterial gene coding for a D-galacturonate dehydrogenase catalyzing the NAD-dependent oxidation of D-galacturonate to galactarate was introduced to both strains with disrupted D-galacturonate catabolism. Both strains converted D-galacturonate to galactarate. The resulting H. jecorina strain produced galactarate at high yield. The A. niger strain regained the ability to grow on d-galacturonate when the D-galacturonate dehydrogenase was introduced, suggesting that it has a pathway for galactarate catabolism.
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| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2798651 | PMC |
| http://dx.doi.org/10.1128/AEM.02273-09 | DOI Listing |
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