Polyhydroxybutyrate biodegradability

Polyhydroxybutyrate Biodegradable polyester used in degradable plastic products. 

Unverdorben, M. et al. Polyhydroxybutyrate biodegradable stent preliminary experience in the rabbit. Cardiovasc. Intervent. Radiol. 2002,25,127-132. 

If the homopolymer decomposes at the fabrication temperature another approach is to make a copolymer that can be melt processed at a lower temperature. For example, polyhydroxybutyrate decomposes at the processing temperature (190°C), whereas the copolymer with valeric acid can be processed at 160°C without decomposition. These aliphatic polyesters are biodegradable and most importantly, the decomposition products are not toxic, hence their use in medical applications (e.g., sutures). 

Nawrath C, Poirier Y, Somerville CR (1994) Plastid targeting of the enzymes required for the production of polyhydroxybutyrate in higher plants. In Doi Y, Fukuda K (eds) Biodegradable plastics polymers. Elsevier, Amsterdam, p 136... 

POIRIER, Y., DENNIS, D.E., KLOMPARENS, K., SOMMERVILLE, C., Polyhydroxybutyrate, a biodegradable thermoplastic, produced in transgenic plants, Science, 1992, 256, 520-523. 

Polyhydroxybutyric acid (PHB) is a bacterial biopolymer which has gained much interest because of its potential use as a biodegradable plastic material. This compound is produced by various terrestrial bacteria and serves as an energy reservoir. PHB is usually highly polymeric (10,000 monomer units) and is stored in the bacteria as an insoluble material in inclusion bodies that are visible with an electron microscope 1111]. Although PHB has been inten-... 

Polyesters have played a prominent part in the development of biodegradable polymers. One of the first products developed as a biodegradable plastic in the early 1970s was based on a polyester belonging to the polyhydroxyalknoates (PHA) group, called polyhydroxybutyrate (PHB). 

Though the interest for synthetic biodegradable polymers is still increasing, few of them are currently available. The best known products are polyhydroxybutyrate, poly(e-caprolactone), poly(glycolic acid), poly(lactic acid) and their copolymer. 

Polyhydroxyalkanoic acids (PHAs) have been extensively researched since the 1970s because of the potential applications of these compounds as biodegradable substitutes for synthetic polymers. The most successful PHA products are the polyhydroxybutyrates (PHBs). The bacterium... 

Hydrogenation of the C=0 bond in diketene to its chiral lactone, followed by its polymerization into a polyhydroxybutyrate-t5q)e biodegradable pol mier (Scheme 7.16.) is a prospective process for the preparation of plastics that are produced by ICI with a process involving fermentation of glucose It was found that over the complex [RhCl((S)-BINAP) (benzene)]Cl Nets in THF at 50 °C and 100 bar the product were produced with ee s of 90-92%... 

The polymer polyhydroxybutyrate (PHB), a polyester of 3-hydroxy-butanoic acid, is completely biodegradable as it is an ideal food for microbes. By copolymerization with another hydroxyacid, such as 3-hydroxypentanoic acid, the polymer can be tailored to take it suitable either for molded articles such as shampoo bottles or thin films for plastic envelopes or carrier bags. PHB is tradenamed Biopol by ICI. Most of the polymer that the company makes is used for packaging, agricultural products, and items of personal hygiene. Wella, the German hair-care company, sells its Sanara brand of shampoo in bottles made of Biopol and has reported increased sales as a result. 

Commodities organic acids, acrylamide, detergents, biopolymers, for example, biodegradable PLA and polyhydroxybutyrate (PHB), and enzymes... 

In synthetically produced polymers, biodegradability is achieved by reducing the stabilizer content and/or addition of initiators that accelerate biodegradation. Materials in this group include, for example, PHB (polyhydroxybutyrate) and PLA (polylactic acid) [9]. Other polymers use a blend of both types, for example a combination of polyethylene and starch. 

Barak, P., Coquet, Y., Halbach, T.R.. and Molina, J.A.E., 1991, Biodegradability of polyhydroxybutyrate (co-hydroxyvalerate) and starch-incorporated polyethylene plastic films in soils. J. Environ. Qual. 20 173-179. 

In the presence of limited nutrients, bacteria can be induced to make polyhydroxybutyrates and valerates, which are processed into a copolymer known as BiopoP. BiopoP has properties similar to polypropylene, but it is biodegradable and obtained from nonpetroleum sources. 

Polyhydroxybutyrate (PHB) is a polyhdroxyalkmioate polymer with pl tic-like properties that is synthesized by some soil bacteria (e.g. Alcaligenes eutrophus). The genes for the pathway have been cloned and inserted into plants with successful production of PHB. Additional research is required to optimize the properties the butyrate-valerate copolymer has superior functionality but it remains more difficult to express this material in plants compared to the pure polymer (75). Improved expression levels and localization would also assist in separations and in the economic cost to produce this renewable biodegradable plastic. 

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