Yves Poirier

Polyhydroxybutyrate, a Biodegradable Thermoplastic, Produced in Transgenic Plants

Polyhydroxybutyrate (PHB), a high molecular weight polyester, is accumulated as a storage carbon in many species of bacteria and is a biodegradable thermoplastic. To produce PHB by genetic engineering in plants, genes from the bacterium Alcaligenes eutrophus that encoded the two enzymes required to convert acetoacetyl—coenzyme A to PHB were placed under transcriptional control of the cauliflower mosaic virus 35S promoter and introduced into Arabidopsis thaliana. Transgenic plant lines that contained both genes accumulated PHB as electron-lucent granules in the cytoplasm, nucleus, and vacuole; the size and appearance of these granules were similar to the PHB granules that accumulate in bacteria.

Perspectives on the production of polyhydroxyalkanoates in plants

Poly-β-hydroxybutyrate (PBH) was recently shown to be produced in genetically engineered plants which expressed the genes from Alcaligenes eutrophus responsible for the formation of PHB from acetoacetyl-CoA. The transgenic plants accumulated PHB as granules which were similar in size and appearance to the bacterial PHB granules. These observations suggest that large scale production of PHB and other polyhydroxyalkanoates in genetically altered crop plants may be feasible.

Plant polymers for biodegradable plastics: Cellulose, starch and polyhydroxyalkanoates

Christiane Nawrath 1.., Yves Poirier 2 and Chris Somerville Carnegie Institution of Washington, Department of Plant Biology, 290 Panama Street, Stanford, CA 94305-1297, USA; ~ Current address: Institut de Biologie V@dtale et de Phytochimie, Universitd de Fribourg, 3 rue Albert Gockel, CH1700 Fribourg, Switzerland (* author for correspondence, fax: 3 72 99 740); 2 Current address. Institut de Biologie et Physiologie Vdgdtales, B6timent de Biologie, Universit~ de Lausanne, CH-IO15 Lausanne, Switzerland

Synthesis of high-molecular-weight poly([r]-(-)-3-hydroxybutyrate) in transgenic Arabidopsis thaliana plant cells

High-molecular-weight poly([R]-(-)-3-hydroxybutyrate) (PHB), a biodegradable thermoplastic, was produced from a suspension culture of transgenic Arabidopsis thaliana plant cells expressing two genes from the bacterium Alcaligenes eutrophus involved in the synthesis of PHB. The molecular structure of the plant-produced polymer was analysed by gas chromatography, mass spectrometry, proton nuclear magnetic resonance spectroscopy, infra-red spectroscopy, spectropolarimetry, differential scanning calorimetry, X-ray diffraction and size exclusion chromatography. The results indicate that the polymer from transgenic plants appears to have a chemical structure identical to that of PHB produced by bacteria. However, the molecular weight distribution of the plant-produced PHB was much broader than that of typical bacterial PHB.