d-Galacturonic acid catabolism in microorganisms and its biotechnological relevance

Richard, Peter; Hilditch, Satu

doi:10.1007/s00253-009-1870-6

Cited by 127 publications

(120 citation statements)

References 43 publications

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“…S. flexneri does not use exogenous gluconate as a carbon source, but carbon could enter this pathway from glucose or glucose-phosphate. In E. coli, the EntnerDoudoroff pathway is necessary for colonization initiation and maintenance in a mouse model (45). The Entner-Doudoroff pathway also contributes to colonization and production of disease by Vibrio cholerae, as an edd mutant strain failed to colonize in a mouse model or to induce fluid accumulation in ligated rabbit ileal loops (53).…”

Section: Discussionmentioning

confidence: 99%

“…5), indicating a lack of metabolism of these compounds or inhibition by their metabolic product. In E. coli, these substrates are ultimately converted to 2-keto-3-deoxy-D-gluconic acid, which is phosphorylated by ATP to yield 2-keto-3-deoxy-6-phosphogluconic acid (KDPG), the substrate of Eda (44,45). Accumulation of KDPG would be toxic to the bacteria.…”

Section: Figmentioning

confidence: 99%

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Role of Intracellular Carbon Metabolism Pathways in Shigella flexneri Virulence

et al. 2014

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Shigella flexneri, which replicates in the cytoplasm of intestinal epithelial cells, can use the Embden-Meyerhof-Parnas, EntnerDoudoroff, or pentose phosphate pathway for glycolytic carbon metabolism. To determine which of these pathways is used by intracellular S. flexneri, mutants were constructed and tested in a plaque assay for the ability to invade, replicate intracellularly, and spread to adjacent epithelial cells. Mutants blocked in the Embden-Meyerhof-Parnas pathway (pfkAB and pykAF mutants) invaded the cells but formed very small plaques. Loss of the Entner-Doudoroff pathway gene eda resulted in small plaques, but the double eda edd mutant formed normal-size plaques. This suggested that the plaque defect of the eda mutant was due to buildup of the toxic intermediate 2-keto-3-deoxy-6-phosphogluconic acid rather than a specific requirement for this pathway. Loss of the pentose phosphate pathway had no effect on plaque formation, indicating that it is not critical for intracellular S. flexneri. Supplementation of the epithelial cell culture medium with pyruvate allowed the glycolysis mutants to form larger plaques than those observed with unsupplemented medium, consistent with data from phenotypic microarrays (Biolog) indicating that pyruvate metabolism was not disrupted in these mutants. Interestingly, the wild-type S. flexneri also formed larger plaques in the presence of supplemental pyruvate or glucose, with pyruvate yielding the largest plaques. Analysis of the metabolites in the cultured cells showed increased intracellular levels of the added compound. Pyruvate increased the growth rate of S. flexneri in vitro, suggesting that it may be a preferred carbon source inside host cells.

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Section: Discussionmentioning

confidence: 99%

Section: Figmentioning

confidence: 99%

Role of Intracellular Carbon Metabolism Pathways in Shigella flexneri Virulence

et al. 2014

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“…At present, these residues are mainly used as cattle feed. However, since energy-consuming drying and pelletizing of the residues is required to prevent them from rotting, it is not always economical to process the residues, and it is desirable to find alternative uses.Various microbes which live on decaying plant material have the ability to catabolize D-galacturonate using various, completely different pathways (19). Eukaryotic microorganisms use a reductive pathway in which D-galacturonate is first reduced to L-galactonate by an NAD(P)H-dependent reductase (12,17).…”

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confidence: 99%

“…Various microbes which live on decaying plant material have the ability to catabolize D-galacturonate using various, completely different pathways (19). Eukaryotic microorganisms use a reductive pathway in which D-galacturonate is first reduced to L-galactonate by an NAD(P)H-dependent reductase (12,17).…”

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confidence: 99%

Metabolic Engineering of Fungal Strains for Conversion of d -Galacturonate to meso -Galactarate

Mojžita

Wiebe

Hilditch

et al. 2010

Appl Environ Microbiol

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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- D-Galacturonate is the main component of pectin, an abundant and cheap raw material. Sugar beet pulp and citrus peel are both rich in pectin residues. At present, these residues are mainly used as cattle feed. However, since energy-consuming drying and pelletizing of the residues is required to prevent them from rotting, it is not always economical to process the residues, and it is desirable to find alternative uses.Various microbes which live on decaying plant material have the ability to catabolize D-galacturonate using various, completely different pathways (19). Eukaryotic microorganisms use a reductive pathway in which D-galacturonate is first reduced to L-galactonate by an NAD(P)H-dependent reductase (12,17). In the following steps a dehydratase, aldolase, and reductase convert the L-galactonate to pyruvate and glycerol (9,11,14).In Hypocrea jecorina (anamorph Trichoderma reesei) the gar1 gene codes for a strictly NADPH-dependent D-galacturonate reductase. In Aspergillus niger a homologue gene sequence, gar2, exists; however, a different gene, gaaA, is upregulated during growth on D-galacturonate containing medium (16). The gaaA codes for a D-galacturonate reductase with different kinetic properties than the H. jecorina enzyme, having a higher affinity toward D-galacturonate and using either NADH or NADPH as cofactor. It is not known whether gar2 codes for an active protein.Some bacteria, such as Agrobacterium tumefaciens or Pseudomonas syringae, have an oxidative pathway for D-galacturonate catabolism. In this pathway D-galacturonate is first oxidized to meso-galactarate (mucate) by an NAD-utilizing D-galacturonate dehydrogenase. Galactarate is then converted in the following steps to ␣-ketoglutarate. This route is sometimes called the ␣-ketoglutarate pathway (20). Galactarate can also be catabolized through the glycerate pathway (20). The products of this pathway are pyruvate and D-glycerate. These pathways have been described in prokaryotes, and it is not certain whether similar pathways also exist in fungi, some of which are able to metabolize galactarate.D-Galacturonate dehydrogenase (EC 1.1.1.203) has been described in Agrobacterium tumefaciens and in Pseudomonas syringae, and the enzymes from these organisms have been purified and characterized (3,6,22). Recently, the corresponding genes were also identified (4, 24). Both enzymes are specific for NAD as a cofactor but are not specific for the substrate. They oxidize D-galacturonate and D-glucuronate to meso-galactarate (mucate) and D-glucarate (saccharate), respectively. The reaction product is probably the hexaro-lactone which spontaneously hydrolyzes. The reverse reaction can only be observed at acidic ...

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“…Pectin is found in the cell wall of plants and is often discarded as waste in sugar-beet pulp, apple pomace and citrus peel (Richard & Hilditch, 2009). A number of research groups are interested in redirecting this biomass waste stream for the production of fuel and bulk chemicals (Benz et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Purification, crystallization and structural elucidation ofD-galactaro-1,4-lactone cycloisomerase fromAgrobacterium tumefaciensinvolved in pectin degradation

et al. 2016

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Pectin is found in the cell wall of plants and is often discarded as waste. A number of research groups are interested in redirecting this biomass waste stream for the production of fuel and bulk chemicals. The primary monomeric subunit of this polysaccharide is d-galacturonate, a six-carbon acid sugar that is degraded in a five-step pathway to central metabolic intermediates by some bacteria, including Agrobacterium tumefaciens. In the third step of the pathway, d-galactaro-1,4-lactone is converted to 2-keto-3-deoxy-l-threo-hexarate by a member of the mandelate racemase subgroup of the enolase superfamily with a novel activity for the superfamily. The 1.6 Å resolution structure of this enzyme was determined, revealing an overall modified ( / ) 7 TIM-barrel domain, a hallmark of the superfamily. d-Galactaro-1,4-lactone was manually docked into the active site located at the interface between the N-terminal lid domain and the C-terminal barrel domain. On the basis of the position of the lactone in the active site, Lys166 is predicted to be the active-site base responsible for abstraction of the proton. His296 on the opposite side of the active site is predicted to be the general acid that donates a proton to the carbon as the lactone ring opens. The lactone ring appears to be oriented within the active site by stacking interactions with Trp298.

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d-Galacturonic acid catabolism in microorganisms and its biotechnological relevance

Cited by 127 publications

References 43 publications

Role of Intracellular Carbon Metabolism Pathways in Shigella flexneri Virulence

Role of Intracellular Carbon Metabolism Pathways in Shigella flexneri Virulence

Metabolic Engineering of Fungal Strains for Conversion of d -Galacturonate to meso -Galactarate

Purification, crystallization and structural elucidation ofD-galactaro-1,4-lactone cycloisomerase fromAgrobacterium tumefaciensinvolved in pectin degradation

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