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Two systems, one using an (R)-(-)-3-hydroxybutyrate dehydrogenase (BDH) null mutant of Ralstonia eutropha and the other using a recombinant Escherichia coli strain containing a synthetic poly[(R)-(-)-3-hydroxybutyrate] (PHB) operon and an extracellular PHB depolymerase gene, were used for the fermentative production of (R)-(-)-3-hydroxybutyrate (3HB). The(More)
Polyhydroxybutyrate is a microbial polyester that can be produced from renewable resources, and is degraded by the enzyme polyhydroxybutyrate depolymerase. The crystal structures of polyhydroxybutyrate depolymerase from Penicillium funiculosum and its S39 A mutant complexed with the methyl ester of a trimer substrate of (R)-3-hydroxybutyrate have been(More)
Poly(3-hydroxybutyrate) (PHB) granules isolated in native form (nPHB granules) from Ralstonia eutropha catalyzed formation of PHB from (14)C-labeled acetyl coenzyme A (CoA) in the presence of NADPH and concomitantly released CoA, revealing that PHB biosynthetic proteins (acetoacetyl-CoA thiolase, acetoacetyl-CoA reductase, and PHB synthase) are present and(More)
An intracellular 3-hydroxybutyrate (3HB)-oligomer hydrolase (PhaZ2(Reu)) of Ralstonia eutropha was purified from Escherichia coli harboring a plasmid containing phaZ2(Reu). The purified enzyme hydrolyzed linear and cyclic 3HB-oligomers. Although it did not degrade crystalline poly(3-hydroxybutyrate) (PHB), the purified enzyme degraded artificial amorphous(More)
The recently finished genome sequence of Ralstonia eutropha H16 harbors nine genes that are thought to encode functions for intracellular depolymerization (mobilization) of storage poly(3-hydroxybutyrate) (PHB). Based on amino acid similarities, the gene products belong to four classes (PhaZa1 to PhaZa5, PhaZb, PhaZc, and PhaZd1/PhaZd2). However, convincing(More)
An intracellular D(-)-3-hydroxybutyrate (3HB)-oligomer hydrolase gene from Ralstonia eutropha (formerly Alcaligenes eutrophus) H16 was cloned, sequenced, and characterized. As a hybridization probe to screen restriction digests of chromosomal DNA, an extracellular 3HB-oligomer hydrolase gene from Ralstonia pickettii strain (formerly Pseudomonas sp. strain)(More)
Mutational analysis of the poly(3-hydroxybutyrate) (PHB) depolymerase A of Pseudomonas lemoignei and of the poly(3-hydroxybutyrate) depolymerase of Alcaligenes faecalis revealed that S138 (P. lemoignei) and S139 (A. faecalis) are essential for activity. Both serines are part of a strictly conserved pentapeptide sequence which is present in all(More)
A novel intracellular poly(3-hydroxybutyrate) (PHB) depolymerase (PhaZd) of Wautersia eutropha (formerly Ralstonia eutropha) H16 which shows similarity with the catalytic domain of the extracellular PHB depolymerase in Ralstonia pickettii T1 was identified. The positions of the catalytic triad (Ser190-Asp266-His330) and oxyanion hole (His108) in the amino(More)
Two D-(-)-3-hydroxybutyrate (3HB) dehydrogenases, BDH1 and BDH2, were isolated and purified from a poly(3-hydroxybutyrate) (PHB)-degradable bacterium, Ralstonia pickettii T1. BDH1 activity increased in R. pickettii T1 cells grown on several organic acids as a carbon source but not on 3HB, whereas BDH2 activity markedly increased in the same cells grown on(More)
Enzymatic degradability has been investigated for a series of bacterial poly(3-hydroxybutyrate-co-3-hydroxypropionate)s (P(3HB-co-3HP)s) with 3-hydroxypropionate (3HP) unit contents from 11 to 86 mol % as well as poly(3-hydroxybutyrate) (P(3HB)) and chemosynthesized poly(3-hydroxypropionate) (P(3HP)). The behavior of degradation by two types of(More)