The Taguchi design of experiments was used to test the relative importance of medium components and environmental factors on poly(β-hydroxybutyrate)(PHB) production by Ralstonia eutropha. The optimum condition was obtained as: fructose concentration, 15 g/L; C/N ratio, 7.4; agitation speed 200 rpm; culture time, 40 h; temperature, 25 ° C; seed age, 15 h. At optimu...

Several DNA regions containing genes involved in poly-beta-hydroxybutyrate (PHB) biosynthesis and degradation and also in fatty acid degradation were identified from genomic sequence data and have been characterized in the serine cycle facultative methylotroph Methylobacterium extorquens AM1. Genes involved in PHB biosynthesis include those encoding beta-ketothiolase (phaA), NADPH-linked acetoa...

Poly(3-hydroxybutyrate) (PHB) depolymerase from Alcaligenes faecalis T1 is composed of three domains: the catalytic (C) domain, the fibronectin type III-like (F) domain, and the substrate-binding (S) domain. We constructed domain deletion, inversion, chimera, and extra-F-domain mutants and examined their enzyme activity and PHB-binding ability. In addition, we performed substitution of 214Asp a...

Cyanobacteria have many unexploited potential for natural products with a huge variability in structure and biological activity. Under stress conditions they are reported to produce biopolymers like poly-β-hydroxybutyrate (PHB), which can be produced intracellularly.Cyanobacteria are capable of synthesizing small amount of poly-β-hydroxybutyrate (PHB) under nitrogen and phosphorous starvation c...

Poly(3-hydroxybutyrate) (PHB) has been proposed to be a potential candidate used as biomaterial. However, its poor processability, high brittleness and rigidity have limited applicability. Transesterification reactions with poly(e-caprolactone) (PCL), one of the most promising biomedical materials, emerge an attractive alternative improve mechanical properties. In this work, poly(3-hydroxybutyr...

Genes responsible for the synthesis of poly(3-hydroxybutyrate) (PHB) in Azotobacter sp. FA8 were cloned and analyzed. A PHB polymerase gene (phbC) was found downstream from genes coding for beta-ketothiolase (phbA) and acetoacetyl-coenzyme A reductase (phbB). A PHB synthase mutant was obtained by gene inactivation and used for genetic studies. The phbC gene from this strain was introduced into ...

Poly-(R)-3-hydroxybutyrate (PHB), a linear polymer of R-3-hydroxybutyrate (R-3HB), is a fundamental constituent of biological cells. Certain prokaryotes accumulate PHB of very high molecular weight (10,000 to >1,000,000 residues), which is segregated within granular deposits in the cytoplasm; however, all prokaryotes and all eukaryotes synthesize PHB of medium-chain length (~100-200 residues) w...

New amorphous amphiphilic triblock copolymers of poly(3-hydroxybutyrate)-poly(ethylene glycol)-poly(3-hydroxybutyrate) (PHB-PEG-PHB) were synthesized using the ring-opening copolymerization of beta-butyrolactone monomer. They were characterized by fluorescence, SEM and (1)H NMR. These triblock copolymers can form biodegradable nanoparticles with core-shell structure in aqueous solution. Compari...

Ilyobacter delafieldii produced an extracellular poly-[3-hydroxybutyrate (PHB) depolymerase when grown on PHB; activity was not detected in cultures grown on 3-hydroxybutyrate, crotonate, pyruvate or lactate. PHB depolymerase activity was largely associated with the PHB granules (supplied as growth substrate), and only 16 % was detected free in the culture supernatant. Monomeric 3-hydroxybutyra...