Production of Polyhydroxyalkanoates (PHAs) in Transgenic Plants

Abstract

Introduction Historical Perspective Synthesis of PHA in Plants Synthesis of Poly(3HB) in Arabidopsis thaliana Synthesis of Poly(3HB) in Other Plants Synthesis of Poly(3HB‐ co ‐3HV) Copolymer in Plants Synthesis of MCL‐PHA in Plants Novel Uses for PHA in Plants PHA to Modify Fiber Properties PHA as a Feed Supplement PHA as a Tool to Study Plant Metabolic Pathways Patents on PHA in plants Perspective on PHA Production in Agricultural Crops

Production of renewable polymers from crop plants

“…Such highlevel PHA accumulation leads to easier recovery of the polymer than is likely to be possible in plants. Although several methods for PHA extraction in plants are found in the (largely prophetic) patent literature, actual experimentation on PHA extraction from plants is very limited and clearly deserves more attention (Poirier and Gruys, 2001). An outstanding feature of bacterial PHAs is the enormous flexibility with regard to properties as a function of the nature and ratio of the various monomers.…”

High Levels of Bioplastic Are Produced in Fertile Transplastomic Tobacco Plants Engineered with a Synthetic Operon for the Production of Polyhydroxybutyrate

“…Tobacco has historically been a difficult host plant for PHB production, with nucleusencoded expression of genes fused to sequences encoding plastid targeting signals yielding only 0.3% dry weight PHB (Bohmert et al, 2002). For comparison purposes, similar nucleus-encoded, plastid-targeting strategies have yielded up to approximately 40% dry weight PHB in leaf tissue of Arabidopsis (Bohmert et al, 2000) and up to 5.7% and 3.7% dry weight PHB in corn stover (Poirier and Gruys, 2002) and switchgrass leaves (Somleva et al, 2008), respectively. Previous attempts at plastid-encoded production in tobacco yielded up to approximately 1.7% dry weight PHB in young leaf tissue, a number that dropped to an average of 20 ppm upon subsequent growth of the plants (Lö ssl et al, 2003).…”

“…PHB synthesis in biomass crops of industrial interest such as switchgrass (Panicum virgatum; Somleva et al, 2008), sugarcane (Saccharum spp. hybrids; Petrasovits et al, 2007;Purnell et al, 2007), and corn stover (leaves and stock of Zea mays; Poirier and Gruys, 2002) have also been reported. Further work, however, is needed to increase levels in these crops for commercial purposes.…”

“…In the model plant Arabidopsis (Arabidopsis thaliana), PHB has been produced in leaf tissue samples at levels up to 4% of the tissue's fresh weight (equivalent to approximately 40% dry weight PHB) in plants engineered with nucleus-encoded expression cassettes for plastid-targeted enzymes (Bohmert et al, 2000). In other plants, PHB levels ranging from trace amounts to 7.7% of the dry weight of the leaf or seed sample have been achieved depending on the plant host (Poirier and Gruys, 2002;Suriyamongkol et al, 2007;Snell and Peoples, 2009). PHB synthesis in biomass crops of industrial interest such as switchgrass (Panicum virgatum; Somleva et al, 2008), sugarcane (Saccharum spp.…”

Expression of bacterial genes in transgenic tobacco: methods, applications and future prospects

“…Recombinant bacteria were originally used to produce PHB, but production costs were too high compared to production of synthetic plastics (Choi and Lee, 1999). As an alternative, researchers have attempted to produce PHB in transgenic plants including Arabidopsis thaliana (Poirier et al 1992;Bohmert et al 2000), Brassica napus (Houmiel et al 1999), corn (Poirier and Gruys, 2002), potato (Bohmert et al 2002), sugarcane Purnell et al 2007), andtobacco (Bohmert et al 2002;Lössl et al 2003;Arai et al 2004).…”