Excretion of metabolites by hydrogen bacteria II. Influences of aeration, pH, temperature, and age of cells

Vollbrecht, D.; Schlegel, Hans G.

doi:10.1007/bf00504427

Cited by 24 publications

(7 citation statements)

References 5 publications

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“…The excretion of succinate and fumarate by cells growing photosynthetically on malate has been detected using I H-NMR (D.J. Richardson [138][139][140]. In A. eutrophus, the excretion of metabolites was greater in a PHB-mutant than in the wild-type [138].…”

Section: H 2 Photoproduction and The Excretion Of Carbon Compoundsmentioning

confidence: 99%

“…Richardson [138][139][140]. In A. eutrophus, the excretion of metabolites was greater in a PHB-mutant than in the wild-type [138]. Identification of the pathways of metabolite excretion by photosynthetic bacteria, and understanding of the interaction of these pathways with other pathways for the dissipation of reducing equivalents will require a detailed knowledge of the carbon metabolism of these organisms, as well as the use of specific mutants.…”

Section: H 2 Photoproduction and The Excretion Of Carbon Compoundsmentioning

confidence: 99%

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Biochemical genetics revisited: the use of mutants to study carbon and nitrogen metabolism in the photosynthetic bacteria

Willison¹

1993

FEMS Microbiology Letters

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The biochemical genetics approach is defined as the use of mutants, in comparative studies with the wild‐type, to obtain information about biochemical and physiological processes in complex metabolic systems. This approach has been used extensively, for example in studies on the bioenergetics of the photosynthetic bacteria, but has been applied less frequently to studies of intermediary carbon and nitrogen metabolism in phototrophic organisms. Several important processes in photosynthetic bacteria—the regulation of nitrogenase synthesis and activity, the control of intracellular redox balance during photoheterotrophic growth, and chemotaxis—have been shown to involve metabolism. However, current understanding of carbon and nitrogen metabolism in these organisms is insufficient to allow a complete understanding of these phenomena. The purpose of the present review is to give an overview of carbon and nitrogen metabolism in the photosynthetic bacteria, with particular emphasis on work carried out with mutants, and to indicate areas in which the biochemical genetics approach could be applied successfully. In particular, it will be argued that, in the case of Rhodobacter capsulatus and Rb. sphaeroides, two species which are fast‐growing, possess a versatile metabolism, and have been extensively studied genetically, it should be possible to obtain a complete, integrated description of carbon and nitrogen metabolism, and to undertake a qualitative and quantitative analysis of the flow of carbon and reducing equivalents during photoheterotrophic growth. This would require a systematic biochemical genetic study employing techniques such as HPLC, NMR, and mass spectrometry, which are briefly discussed. The review is concerned mainly with Rb. capsulatus and Rb. sphaeroides, since most studies with mutants have been carried out with these organisms. However, where possible, a comparison is made with other species of purple non‐sulphur bacteria and with purple and green sulphur bacteria, and recent literature relevant to these organisms has been cited.

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Section: H 2 Photoproduction and The Excretion Of Carbon Compoundsmentioning

confidence: 99%

Section: H 2 Photoproduction and The Excretion Of Carbon Compoundsmentioning

confidence: 99%

Biochemical genetics revisited: the use of mutants to study carbon and nitrogen metabolism in the photosynthetic bacteria

Willison¹

1993

FEMS Microbiology Letters

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“…Metabolic engineering is a powerful tool to solve defined biotechnological problems, such as enhancing intermediate concentrations or broadening the range of precursors. Vollbrecht et al have reported to use a double mutant of Ralstonia eutropha ( Hydrogenomonas eutropha, Alcaligenes eutropha, Wautersia eutropha, Cupriavidus necator ) , which is unable to synthesize PHB and to utilize 3-hydroxybutanoate as a substrate, to produce R-3HB (Vollbrecht et al 1978 ; Vollbrecht and Schlegel 1978 , 1979 ). About 3.4 g/L of R-3HB was produced under optimum conditions (Vollbrecht and Schlegel 1979 ).…”

Section: Methods For R-ha Productionmentioning

confidence: 99%

Enatiomerically pure hydroxycarboxylic acids: current approaches and future perspectives

Ren

Ruth²,

Thöny‐Meyer

et al. 2010

Appl Microbiol Biotechnol

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The growing awareness of the importance of chirality in conjunction with biological activity has led to an increasing demand for efficient methods for the industrial synthesis of enantiomerically pure compounds. Polyhydroxyalkanotes (PHAs) are a family of polyesters consisting of over 140 chiral R-hydroxycarboxylic acids (R-HAs), representing a promising source for obtaining chiral chemicals from renewable carbon sources. Although some R-HAs have been produced for some time and certain knowledge of the production processes has been gained, large-scale production has not yet been possible. In this article, through analysis of the current advances in production of these acids, we present guidelines for future developments in biotechnological processes for R-HA production.Electronic supplementary materialThe online version of this article (doi:10.1007/s00253-010-2530-6) contains supplementary material, which is available to authorized users.

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“…It should be noted that it is not possible to achieve the theoretically maximum value of the HCE of 0.214 Hmol/Hmol due to the required energy (H 2 ) necessary for maintenance purposes. Larger deviations from the theoretical values might be caused by the synthesis of side products other than biomass, such as pyruvate [57,61], 3-hydroxybutyric acid, acetone, or 2-oxoglutarate [62,63] depending on the culture conditions applied. More detailed analyses, however, were not undertaken at this stage of the investigation.…”

Section: Experimental Data: Product Formationmentioning

confidence: 99%

Third-generation feed stocks for the clean and sustainable biotechnological production of bulk chemicals: synthesis of 2-hydroxyisobutyric acid

et al. 2012

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Background The synthesis of 2-hydroxyisobutyric acid (2-HIB), a promising building block for, e.g., Plexiglas® production, is described as an example for a clean and sustainable bioproduction. Methods A derivative strain of Cupriavidus necator H16, impaired in the poly-ß-hydroxybutyrate synthesis pathway and equipped with xenogenic 2-hydroxyisobutyryl-coenzyme A mutase from Aquincola tertiaricarbonis L108, was applied. Batch cultivation was performed in the presence of vitamin B12 by supplying a gas mixture comprising hydrogen, oxygen, and carbon dioxide. Results Exploiting the chemo-litho-autotrophic potential of this so-called knallgas bacterium, 2-HIB was synthesized and excreted into the cultivation broth under aerobic conditions when inorganic nitrogen-limited conditions allowed an overflow metabolism of carbon metabolites. 2-HIB synthesis proceeded at a rate of 8.58 mg/[(g bacterial dry mass)·h]. Approximately 400 mg/L in total was obtained. The results were subsequently compared to calculated model data to evaluate the efficiency of the conversion of the substrates into the product. To achieve overall yield data regarding the substrate conversion, the model describes an integral process which includes both 2-HIB synthesis and biomass formation. Conclusions This study has confirmed the feasibility of the microbial synthesis of the bulk chemical 2-HIB from hydrogen and carbon dioxide by exploiting the chemo-litho-autotrophic metabolism of C. necator H16 PHB−4, additionally expressing the foreign 2-HIB-coenzyme A mutase. The product synthesis was satisfying as a proof of principle but does not yet approach the maximum value as derived from the model data. Furthermore, the biosynthesis potential of an optimized process is discussed in view of its technical application.

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Excretion of metabolites by hydrogen bacteria II. Influences of aeration, pH, temperature, and age of cells

Cited by 24 publications

References 5 publications

Biochemical genetics revisited: the use of mutants to study carbon and nitrogen metabolism in the photosynthetic bacteria

Biochemical genetics revisited: the use of mutants to study carbon and nitrogen metabolism in the photosynthetic bacteria

Enatiomerically pure hydroxycarboxylic acids: current approaches and future perspectives

Third-generation feed stocks for the clean and sustainable biotechnological production of bulk chemicals: synthesis of 2-hydroxyisobutyric acid

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