The effects of phosphorus and nitrogen limitation on polyhydroxyalkanoate (PHA) production and accumulation by activated sludge biomass with acetate as a carbon source were investigated. Pre-selected influent carbon-phosphorus (C:P, W/W) of 100, 160, 250, 500 and 750, and carbon-nitrogen (C:N, W/W) of 20, 60, 100, 125 and 180 were applied in the phosphorus limitation experiments and the nitroge...

Herbaspirillum seropedicae is a diazotrophic ß-Proteobacterium found associated with important agricultural crops. This bacterium produces polyhydroxybutyrate (PHB), an aliphatic polyester, as a carbon storage and/or source of reducing equivalents. The PHB polymer is stored as intracellular insoluble granules coated mainly with proteins, some of which are directly involved in PHB synthesis, deg...

Unloaded microspheres were prepared from polyhydroxybutyrate (PHB) and polyhydroxybutyrateco-valerate (PHB-HV) polymers using an oil-in-water emulsion solvent evaporation method. The study was conducted to evaluate how the polymer and some process parameters affect properties of the final microspheres such as particle size, superficial area, zeta potential, surface morphology and microsphere de...

Polyhydroxybutyrate [P(3HB)] was produced in the transgenic tobacco harboring the genes encoding acetoacetyl-CoA reductase (PhaB) and polyhydroxyalkanoate synthase (PhaC) from Ralstonia eutropha (Cupriavidus necator) with optimized codon usage for expression in tobacco. P(3HB) contents in the transformants (0.2mg/g dry cell weight in average) harboring the codon-optimized phaB gene was twofold ...

We investigated the effects of different feeding regimens (1-pulse, stepwise, and continuous) of fermented food-waste liquid on polyhydroxybutyrate (PHB) production. The fermentation liquid was filtered with a membrane filter (pore size, 0.45 μm) to remove anaerobic microorganisms and solids and used as a carbon source for Cupriavidus necator. One-pulse feeding yielded the highest cell concentr...

Polyhydroxyalkanoates (PHAs) is reported as polyesters of hydroxyalkanoates (HAs) which is generally synthesized by numerous bacteria and it is stored in the cytoplasm of cells as an intracellular carbon and energy sources compound. It has been considered as a replacement for conventional plastics. Microbial cell such as Alcaligenes, Pseudomonas, recombinant Escherichia coli and methylotrophs a...

We report here that gemfibrozil (GFZ) inhibits axenic and intracellular growth of Legionella pneumophila and of 27 strains of wild-type and multidrug-resistant Mycobacterium tuberculosis in bacteriological medium and in human and mouse macrophages, respectively. At a concentration of 0.4 mM, GFZ completely inhibited L. pneumophila fatty acid synthesis, while at 0.12 mM it promoted cytoplasmic a...

Because cyanobacteria directly harvest CO2 and light energy, their carbon metabolism is important for both basic and applied sciences. Here, we show that overexpression of the sigma factor sigE in Synechocystis sp. PCC 6803 widely changes sugar catabolism and increases production of the biodegradable polyester polyhydroxybutyrate (PHB) during nitrogen starvation. sigE overexpression elevates th...

Recovery of biodegradable plastics from activated sludge is a promising sustainable technology. In this study, polyhydroxybutyrate (PHB) – a biodegradable plastics material was produced by activated sludge performing enhanced biological phosphorus removal (EBPR) in batch experiments under anaerobic, aerobic and anaerobic/aerobic conditions. Under anaerobic conditions, the PHB content of 28.8% o...

Ultra-structural studies were conducted on root nodules of Samanea saman (Jacq.) Merr. collected from trees growing under natural conditions. Nodules were distributed singly as well as in clusters on the main and lateral roots. Mature nodules were elongated, branched and coralloid. Root hair curling was found but infection threads could not be observed. Rhizobia entered through the epidermis an...