Ralstonia eutropha H16 degraded (mobilized) previously accumulated poly(3-hydroxybutyrate) (PHB) in the absence of an exogenous carbon source and used the degradation products for growth and survival. Isolated native PHB granules of mobilized R. eutropha cells released 3-hydroxybutyrate (3HB) at a threefold higher rate than did control granules of nonmobilized bacteria. No 3HB was released by n...

The gene loci ehyAB, calA, and calB, encoding eugenol hydroxylase, coniferyl alcohol dehydrogenase, and coniferyl aldehyde dehydrogenase, respectively, which are involved in the first steps of eugenol catabolism in Pseudomonas sp. strain HR199, were amplified by PCR and combined to construct a catabolic gene cassette. This gene cassette was cloned in the newly designed broad-host-range vector p...

Background Carbonic anhydrase (CA) enzymes catalyze the interconversion of CO2 and bicarbonate. These enzymes play important roles in cellular metabolism such as CO2 transport, ion transport, and internal pH regulation. Understanding the roles of CAs in the chemolithotropic betaproteobacteria Ralstonia eutropha is important for the development of fermentation processes based on the bacterium’s ...

BACKGROUND The chemoautotrophic bacterium Ralstonia eutropha can utilize H2/CO2 for growth under aerobic conditions. While this microbial host has great potential to be engineered to produce desired compounds (beyond polyhydroxybutyrate) directly from CO2, little work has been done to develop genetic part libraries to enable such endeavors. RESULTS We report the development of a toolbox for t...

Conversion of 3-hydroxypropionate (3HP) from 1,3-propanediol (PDO) was improved by expressing dehydratase gene (dhaT) and aldehyde dehydrogenase gene (aldD) of Pseudomonas putida KT2442 under the promoter of phaCAB operon from Ralstonia eutropha H16. Expression of these genes in Aeromonas hydrophila 4AK4 produced up to 21 g/L 3HP in a fermentation process. To synthesize homopolymer poly(3-hydro...

Cysteine dioxygenases (Cdos), which catalyze the sulfoxidation of cysteine to cysteine sulfinic acid (CSA), have been extensively studied in eukaryotes because of their roles in several diseases. In contrast, only a few prokaryotic enzymes of this type have been investigated. In Ralstonia eutropha H16, two Cdo homologues (CdoA and CdoB) have been identified previously. In vivo studies showed th...

Wautersia eutropha, formerly known as Ralstonia eutropha, a gram-negative bacterium, accumulates polyhydroxybutyrate (PHB) as insoluble granules inside the cell when nutrients other than carbon are limited. In this paper, we report findings from kinetic studies of granule formation and degradation in W. eutropha H16 obtained using transmission electron microscopy (TEM). In nitrogen-limited grow...

Intracellular poly[D-(-)-3-hydroxybutyrate] (PHB) depolymerases degrade PHB granules to oligomers and monomers of 3-hydroxybutyric acid. Recently an intracellular PHB depolymerase gene (phaZ1) from Ralstonia eutropha was identified. We now report identification of candidate PHB depolymerase genes from R. eutropha, namely, phaZ2 and phaZ3, and their characterization in vivo. phaZ1 was used to id...

The bacterium Ralstonia eutropha H16 synthesizes polyhydroxybutyrate (PHB) from acetyl coenzyme A (acetyl-CoA) through reactions catalyzed by a β-ketothiolase (PhaA), an acetoacetyl-CoA reductase (PhaB), and a polyhydroxyalkanoate synthase (PhaC). An operon of three genes encoding these enzymatic steps was discovered in R. eutropha and has been well studied. Sequencing and analysis of the R. eu...