Pseudomonas sp. 61-3 accumulates a blend of poly(3-hydroxybutyrate) [P(3HB)] homopolymer and a random copolymer, poly(3-hydroxybutyrate-co-3-hydroxyalkanoate) [P(3HB-co-3HA)], consisting of 3HA units of 4-12 carbon atoms. Pseudomonas sp. 61-3 possesses two types of PHA synthases, PHB synthase (PhbC) and PHA synthases (PhaC1 and PhaC2), encoded by the phb and pha loci, respectively. The P(94 mol...

over the years, the use of plastics has complicated the problem of disposal of solid wastes. one strategy to reduce plastic waste is the use of biodegradable plastics. a group of these plastics are polyhydroxyalkanoates (phas). to date more than 250 different microorganisms are known to synthesize and accumulate pha. most pseu-domonas strains are able to accumulate mcl-pha. in previous studies,...

Medium-chain-length polyhydroxyalkanoates (PHAs) are polyesters having properties of biodegradable thermoplastics and elastomers that are naturally produced by a variety of pseudomonads. Saccharomyces cerevisiae was transformed with the Pseudomonas aeruginosa PHAC1 synthase modified for peroxisome targeting by the addition of the carboxyl 34 amino acids from the Brassica napus isocitrate lyase....

We have developed the conversion of glycerol into thermoplastic poly(3-hydroxypropionate) [poly(3HP)]. For this, the genes for glycerol dehydratase (dhaB1) of Clostridium butyricum, propionaldehyde dehydrogenase (pduP) of Salmonella enterica serovar Typhimurium LT2, and polyhydroxyalkanoate (PHA) synthase (phaC1) of Ralstonia eutropha were expressed in recombinant Escherichia coli. Poly(3HP) wa...

In order to scale up medium-chain-length polyhydroxyalkanoate (mcl-PHA) production in recombinant microorganisms, we generated and investigated different recombinant bacteria containing a stable regulated expression system for phaC1, which encodes one of the mcl-PHA polymerases of Pseudomonas oleovorans. We used the mini-Tn5 system as a tool to construct Escherichia coli 193MC1 and P. oleovoran...

To date, limited reports are available on the regulatory systems exerting control over bacterial synthesis of the biodegradable polyester group known as polyhydroxyalkanoates (PHAs). In this study, we performed random mini-Tn5 mutagenesis of the Pseudomonas putida CA-3 genome and screened transconjugants on nitrogen-limited medium for reduced PHA accumulation phenotypes. Disruption of a GacS se...

This study explored the potential of using Rhodosprillum rubrum as the biological vehicle to convert chemically simple carbon precursors to a value-added bio-based product, the biopolymer PHA. R. rubrum strains were bioengineered to overexpress individually or in various combinations, six PHA biosynthetic genes (phaC1, phaA, phaB, phaC2, phaC3, and phaJ), and the resulting nine over-expressing ...

Medium-chain-length polyhydroxyalkanoates (PHAs) are polyesters having properties of biodegradable thermoplastics and elastomers that are naturally produced by a variety of pseudomonads. Saccharomyces cerevisiae was transformed with the Pseudomonas aeruginosa PHAC1 synthase modified for peroxisome targeting by the addition of the carboxyl 34 amino acids from the Brassica napus isocitrate lyase....

Polyhydroxyalkanoates (PHAs) are biodegradable polyesters that have a wide variety of physical properties dependent on the lengths of the pendant groups of the monomer units in the polymer. PHAs composed of mostly short-chain-length (SCL) monomers are often stiff and brittle, whereas PHAs composed of mostly medium-chain-length (MCL) monomers are elastomeric in nature. SCL-MCL PHA copolymers can...