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Showing 1 to 20 of 31 for “"polyhydroxybutyrate"”.
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Molecular weight modulation in polyhydroxybutyrate fermentations
Polyhydroxybutyrate (PHB) is a material with significant potential for commercial applications. It has material properties similar to isotactic polypropylene; it can be produced from renewable resources; it is biodegradable. Unfortunately, it is very brittle when compared to polypropylene. The …
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Isolation and characterization of bacterial polyhydroxybutyrate inclusions
Polyhydroxybutyrate (PHB) is a carbon reserve found in some bacteria, and under nutrient limiting conditions accumulates intracellularly in the form of inclusion bodies. These inclusions contain proteins, and the PHB within the inclusions exists in an amorphous state. In this study a procedure to …
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Design and synthesis of mechanistic probes for polyhydroxybutyrate synthases
Biodegradable polyhydroxybutyrates (PHBs) produced by a wide range of bacteria have been considered as an ideal alternative to petroleum-based plastics. Two types of mechanistic probes have been synthesized in order to understand the mechanism of PHB synthases (PhaCs). The first type is oxo analogs …
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Transcriptional profiling and flux measurements of polyhydroxybutyrate production in Synechocystis
(cont.) to determine the CO₂ uptake rates and PHB production rates of strains engineered for enhanced CO₂ fixation and PHB production respectively.
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Solution properties and molecular size of polyhydroxybutyrate from recombinant Escherichia coli
Polyhydroxybutyrate molecules produced by recombinant Escherichia coli were evaluated in terms of their size in solution to develop and test a hypothesis concerning the regulation of the molecular weight of PHB during in vivo polymer production. Two recombinant strains of E. coli were used to …
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Studies on the mechanism of polyhydroxybutyrate (PHB) granule formation in Ralstonia eutropha H16/
Polyhydroxybutyrates (PHBs) are biodegradable polymers produced by bacteria in the form of insoluble granules for carbon storage. Insights into the mechanisms of granule formation are important for improving commercial PHB production and engineering new alternatives to petroleum-based plastics. …
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Control of product molecular weight in the enzymatic synthesis of a biodegradable polyester, polyhydroxybutyrate
Polyhydroxybutyrate (PHB) is a polymer accumulated by many bacterial species to store carbon and reducing equivalents. PHB is packaged intracellularly in inclusions termed "granules" that contain the polymer in an amorphous state, surrounded by a protein coat. The molecular weight (Mw) of PHB is …
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The role of the phasin PhaP in promoting polyhydroxybutyrate (PHB) granule formation in Caulobacter crescentus
Polyhydroxybutyrate (PHB) is a biodegradable polymer produced by many microorganisms when they find themselves limited in an essential nutrient such as nitrogen or phosphorus but in the presence of an abundant carbon source. PHB and other related polymers are of interest because they have valuable …
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Mechanistic investigation of polyhydroxybutyrate (PHB) synthases and elucidation of PHB biosynthesis and degradation process in Wautersia eutropha H16
Polyhydroxyalkanoate (PHA) synthase from various bacterial organisms is able to catalyze the polymerization of (R)-hydroxyalkanoate-CoAs into high molecular weight PHAs under nutrient- limited conditions in the presence of a carbon source. PHA synthases are representative of enzymes involved in …
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Evaluation of factors affecting the performance of biological phosphorus removal in a full-scale wastewater treatment plant
… total and ortho-phosphorus, COD, acetic acid, polyhydroxybutyrate, glycogen, calcium, magnesium, potassium, ammonia, alkalinity, TSS, ORP, pH, and DO. Profiles of the aerobic and anaerobic zones, and secondary clarifier showed that the plant is operating as an actual EBPR system, with sporadic …
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Genetic and Environmental Modulation of the Chickpea - Mesorhizobium Symbiosis
… 1.5-fold, bacteroid size 1.4-fold and amount of polyhydroxybutyrate 1.4-fold. Plant biomass was negatively correlated with bacteroid size and the amount of polyhydroxybutyrate under well-watered conditions. Symbiotic efficiency was negatively correlated with both bacteroid size and the amount of …
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The delivery of bioactive proteins using biodegradable microspheres
… was demonstrated. Preparations produced with polyhydroxybutyrate and poly(DTH carbonate) polymers were also shown to be more hydrophobic than PLA microspheres, which may enhance particle uptake by antigen presenting cells and Peyer's patches. Systematic immunisation with microspheres with a …
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Valorization of wastewater-derived biomass via integrated aqueous systems
… of such systems; and (b) wastewater-derived polyhydroxybutyrate-accumulating bacteria (WW-PHB) systems, where pilot-scale production of the biopolymer PHB has been demonstrated with no impact to effluent discharge quality, yet critical barriers remain in identifying competent technologies for …
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The bacterial synthesis and characterisation of polyhydroxyalkanoates using waste plastics as carbon sources for novel applications
… Cupriavidus necator H16 was used to generate polyhydroxybutyrate (PHB) and other PHAs with differing polyester compositions, depending on the type of waste carbon source used in 48 hour fermentations in nutrient rich media. These products were then chemically analysed to assess their …
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Production of biopolymer using a membrane-based bioreactor
… methanotrophic bacteria produce intracellular polyhydroxybutyrate (PHB) in the absence of nitrogen and presence of methane and oxygen. In this study, Colorado School of Mines (CSM) and Mango Materials (MM) collaborated on a Phase I NASA grant, investigating the production of PHB in a novel …
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Biodegradable polymers for the sustained release of antisense nucleic acids
… Polymers such as polylactide, polyglycolide, polyhydroxybutyrate and polyhydroxyvalerate were used due to their biocompatability and non toxic degradation products. Release profiles of antisense nucleic acids from films over 28 days was biphasic, characterised by an initial burst release …
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Evolution of energy storage traits in symbiotic rhizobia
… nitrogen-fixation into storage compounds like polyhydroxybutyrate (PHB). Although the conflict-of-interest between PHB accumulation and nitrogen-fixation has been discussed as a driving factor in the evolution of legume-rhizobia interactions, its role in natural populations is unclear. …
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Improved production of poly(hydroxybutyrate) and related enzymes
… aims to address both of these problems, using polyhydroxybutyrate as a simple model. To simplify the purification of the polymer and to broaden the range of potential monomers, PHA can be produced in vitro. To achieve this on a commercial scale would require the production of large quantities …
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The Utilization of Activated Sludge Polyhydroxyalkanoates for the Production of Biodegradable Plastics
… amounts of the PHA copolymers formed, i.e., polyhydroxybutyrate (PHB) and polyhydroxyvalerate (PHV) were different under different operating conditions, even though the types and amounts of volatile fatty acids (VFAs) in the feed were the same. It was determined that high total phosphorus …
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