D-(-)-3-Hydroxybutyrate (DHB), the immediate depolymerization product of the intracellular carbon store poly-3-hydroxybutyrate (PHB), is oxidized by the enzyme 3-hydroxybutyrate dehydrogenase to acetoacetate (AA) in the PHB degradation pathway. Externally supplied DHB can serve as a sole source of carbon and energy to support the growth of Sinorhizobium meliloti. In contrast, wild-type S. melil...

The thermal degradation behavior of poly[(R)-3-hydroxybutyrate-co-16 mol%-4-hydroxybutyrate] (P(3HB-co-16 mol%-4HB)) was investigated based on spectroscopic analysis its pyrolyzates and two kinetic modeling approaches. Pyrolyzate revealed that trans-crotonic acid, cis-crotonic γ-butyrolactone, their oligomers (dimers trimers) were produced following P(3HB-co-16 mol%-4HB). analyses confirmed the...

BACKGROUND Biodegradable polyesters are candidates for the development of environmental friendly plastics. Poly-β-hydroxybutyrate (PHB) is a type of polyester from the hydroxyalkanoates family, synthesized by bacteria as an intracellular material and accumulated as granules in the cytoplasm. OBJECTIVES The aim of this study was to isolate Poly β-hydroxybutyrate over producing bacteria and opt...

BACKGROUND Microbial polyhydroxyalkanoates (PHA) are biopolyesters consisting of diverse monomers. PHA synthase PhaC2Ps cloned from Pseudomonas stutzeri 1317 is able to polymerize short-chain-length (scl) 3-hydroxybutyrate (3HB) monomers and medium-chain-length (mcl) 3-hydroxyalkanoates (3HA) with carbon chain lengths ranging from C6 to C12. However, the scl and mcl PHA production in Escherichi...

The main objective of the present study is to assess and improve fermentation conditions produce polyhydroxyalkanoates (PHAs), such as homopolymer poly(3-hydroxybutyrate) (PHB) copolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), from renewable inexpensive industrial waste by wild type Cupriavidus necator. Untreated residual glycerol, a byproduct generated biodiesel industry, was used...

The microbial degradation of tensile test pieces made of poly(3-hydroxybutyrate) [P(3HB)] or a copolymer of 90% 3-hydroxybutyric acid and 10% 3-hydroxyvaleric acid was studied in soils incubated at a constant temperature of 15, 28, or 40 degrees C for up to 200 days. In addition, hydrolytic degradation in sterile buffer at temperatures ranging from 4 to 55 degrees C was monitored for 98 days. D...