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 Pseudomonas strains are able to accumulate mcl-PHA. In previous studies, ...

BACKGROUND Block polyhydroxyalkanoates (PHA) were reported to be resistant against polymer aging that negatively affects polymer properties. Recently, more and more attempts have been directed to make PHA block copolymers. Diblock copolymers PHB-b-PHHx consisting of poly-3-hydroxybutyrate (PHB) block covalently bonded with poly-3-hydroxyhexanoate (PHHx) block were for the first time produced su...

The gasification of organic waste materials to synthesis gas (syngas), followed by microbial fermentation, provides a significant resource for generating bioproducts such as polyhydroxyalkanoates (PHA). The anaerobic photosynthetic bacterium, Rhodospirillum rubrum, is an organism particularly attractive for the bioconversion of syngas into PHAs. In this study, a quantitative physiological analy...

By Erik Robert Coats, Ph.D. Washington State University December 2005 Chairs: Michael P. Wolcott, Frank J. Loge Biologically-derived polyesters known as polyhydroxyalkanoates (PHAs) represent a potentially sustainable replacement to fossil fuel-based thermoplastics. However, current production practices do not achieve this objective. Herein we report on the production of PHA with a mixed microb...

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...

Polyhydroxyalkanoates (PHAs) are aliphatic polyesters that biosynthesized and accumulate in bacterial cells. Among PHAs, poly(3-hydroxybutyrate-co‑3-hydroxyhexanoate)s [P(3HB‑co‑3HHx)s] known to be practical PHA copolymers with an appropriate degree of flexibility. In the biosynthesis PHA, ethanol induces chain transfer (CT) reaction, resulting low-molecular-weight PHA. this study, P(3HB‑co‑3HH...

Polyhydroxyalkanoates (PHA) are biodegradable bioplastics of interest as potential substitutes petroleum-derived plastics that can be produced starting from lignocellulosic-derived residues. This study presents the combined solid-state enzymatic hydrolysis (SSEH) and fermentation (SSF) a sustainable approach for obtaining PHA using leftovers brewer's spent grain (BSG), grape pomace (GP) olive-m...

Anaerobic sludge digestion is the main technology for sludge reduction and stabilization prior to sludge disposal. Nevertheless, methane production from anaerobic digestion of waste activated sludge (WAS) is often restricted by the poor biochemical methane potential and slow hydrolysis rate of WAS. This work systematically investigated the effect of PHA levels of WAS on anaerobic methane produc...