Polyhydroxybutyrate plastic

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... 

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). 

Polyhydroxybutyrate Biodegradable polyester used in degradable plastic products. 

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. 

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. 

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. 

Polyhydroxyalkanoates, Polyhydroxybutyrate, History, Bacterial synthesis. Chemical synthesis. Genetic engineering. Mechanical properties. Thermal transitions. Crystallization, Plasticizers, Thermal degradation. Processing, Applications... 

PHA constitute a whole class of microbially synthesized polyesters [33], of which polyhydroxybutyrate (PHB) and the copolymer with valerate (PHBV) have attracted much attention as possible replacements of oil-based thermoplastics. To serve as a useful injection moldable plastic with reasonable ductility, PHA... 

Polyhydroxybutyric acid is a storage compound for excess carbon in many microorganisms (E 2.2). It may be used in the production of plastics (F 4). Acetoacetic acid, acetone, and /S-hydroxybutyric acid are excreted in the urine of people with a pathologically high blood sugar level (diabetes mellitus) (E 1). Their appearance is of diagnostic value. Butyric acid, butanol, and acetone are products of microbial fermentations. 

Yasin, M. and B.J. Tighe, Strategies for the design of biodegradable polymer systems Manipulation of polyhydroxybutyrate-based materials, Plastics, Rubber and Composites Processing and Applications, 19 (199,3) 15-27. 

Figure 8.1 Chemical formulae for the family of polyhydrojyalkanoates (a) and the two most common commercial plastic resins, polyhydroxybutyrate (b) and its copolymer with polyhydroxyvalerate (c).

Growth of Alcaligemes eutrophus H16 for the production of the biodegradable plastic, polyhydroxybutyrate (PHB) (Mackley and Harrison, 1992), where the biomass growth matched that of a conventional laboratory scale shake flask, but is considerably more scaleable. 

These materials are from renewable sources and are often made from plant materials that can be grown year after year and should come from agricultural nonfood crops. Biodegradable polymers are broken down into CO 2 and water by microorganisms. Although biopolymers may be able to help solve the disposal problems of current plastic packaging, it is not clear if they can really deliver on this promise and whether there is possible competition with the food chain. Cellulose is the most common biopolymer and organic compound on Earth. Other examples are starch, PHB (polyhydroxybutyrate), natural fibers, silk, and wood plastic composites (WPC). 

Biobased polymers are those made from natural or organic ingredients, such as starch from corn, potato, tapioca, rice, or wheat (Narayan 2006a, 201 lb). Biobased polymers can also be made from oils, such as palm seed, linseed, soy bean, or fermentation products, like polylactic acid (PEA), polyhydroxy alkanoate (PHA), and polyhydroxybutyrate (PHB). BPI World provides a listing of compostable plastic resins, bags, cutlery, and packaging (BPI World 2013). 

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