Poly 3-hydroxybutyrate-co-3-hydroxyvalerate

The easiest way to control the content of 3HV units in the P(3HB-co-3HV) copolymer is by changing the concentration of the carbon source which contributes to the formation of 3HV units. Doi and co-workers found that by using a combination of butyric and pentanoic acids, R. eutropha (NCIB 11599) can be made to produce P(3HB-co-3HV) copolymers containing a wide range (0-85 mol%) of 3HV units (Table 7.1). 

Carbon source (g/1) Cell dry weight m PHA content (wt%) PHA composition (mol%)  

P(3HB-co-3HV) is commercialised by Tianan Biopolymer (i.e., Enmat YIOOOP) and Shenzhen Ecomaim Biotechnology (i.e., EM5231A). 

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Lannace, S., Ambrosio, L., Huang, S.J. and Nicolais, L. 1994. Poly(3- hydroxybutyrate)-co-(3-hydroxyvalerate)/poly-l-lactide blends thermal and mechanical properties. Journal of Applied Polymer Science 54 1525-35. 

Y Doi, Y Kanesawa, M Kunioka, T Saito. Biodegradation of microbial copolyesters Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and poly(3-hydroxybutyrate-co-4-hydroxybutyrate). Macromolecules 23 26-31, 1990. 

Poly(3-hydroxybutyrate), Poly(3-hydroxybutyrate-co-3-hydroxyvalerate), and Poly(3-hydroxyvalerate)... 

The copolymer poly-(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHB-co-PHV) produced by A eutrophus has generated more interest than poly-(R)-3-hydroxybutyrate (PHB) homopolymer. Since these bacterial polyesters are biodegradable thermoplastics, their mechanical and physical properties have received much attention. PHB is a relatively stiff and brittle material because of its high crystallinity. However, the physiochemi-cal and mechanical properties of [P(HB-HV)] vary widely and depend on the molar percentage of 3-hydroxyvalerate (HV) in the copolymer (4,5) as shown inTable 1. Propionic acid is converted by a synthetase to propionyl-CoA, and the biosynthetic P-ketothiolase catalyzes the condensation of propionyl-CoA with acetyl-CoA to 3-ketovaleryl-CoA by the acetoacetyl-CoA reductase. The hydroxyvaleryl moiety is finally covalently linked to the polyester by the PHA synthase (6). 

Kim, B. S., Lee, S. C.,Lee, S. Y., Chang, H. N, Chang, Y. K., and Woo, S. 1.1994b. Production of poly(3-hydroxybutyric-co-3-hydroxyvaleric acid) by fed-batch culture of Alcaligenes eutrophus with substrate control using on-line glucose analyzer. Enz. Microbial Technol., 16, 556-561. 

Biopol, produced by Metabolix, is a leading example of an improved poly(3-hydroxybutyrate-co-3-hydroxyvalerate), P(3HB-3HV), heteropolymer. Compared to PHB, P(3HB-3HV) is less stiff, tougher, and easier to process, making it more suitable for commercial production. It is also water resistant and impermeable to oxygen, increasing its value. 

F. S., Ultrasound characterization of coronary artery wall in vitro using temperature-dependent wave speed, IEEE Trans Ultrason. Ferroelectr. Ereq. Control 50,1474-1485, 2003 Bhardwaj, R Mohanty, A.K., Drzal, L.T. et al.. Renewable resource-based composites from recycled cellulose liber and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) bioplastic. Biomacromolecules 7, 2044-2051, 2006. 

Choe, S., Cha, Y, Lee, H., Yonn, Y, and Choi, H. 1995. Miscibility of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and polyfvinyl chloride) blends. Polymer 36, 4977 982. 

Mergaert, J. Webb, A. Anderson, C. Wouters, A. and Swings, J. Microbial degradation of poly(3-hydroxybutyrate) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) in soils.Environ. Microbiol. 1993, 59(10), 3233-3238. 

Spyros, A. Kimmich, R. Briese, B. H. and Jendrossek, D. IH NMR Imaging Study of Enzymatic Degradation in Poly(3-hydroxybutyrate) and Poly(3-hydroxybutyrate-co-3-hydroxyvalerate). Evidence for Preferential Degradation of the Amorphous Phase by PHB Depolymerase B Irom Pseudomonas lemoignei. Macromole. 1997,... 

Suwantong, O. Waleetomcheepsawat, S. Sanchavanakit, N. Pavasant, R Cheep-sunthom, P Bunaprasert, T Supaphol, R In vitro biocompatibility of electrospun poly(3-hydroxybutyrate) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) fiber mats. Int. J. BiolMacromol. 2007, 40(3), 217-23. 

Gursel, L Yagmurlu, F. Korkusuz, F. and Elasirci, V. In vitro antibiotic release from poly(3-hydroxybutyrate-co-3-hydroxyvalerate) tods. J. Microencapsul. 2002, 19,153-164. 

Riekes, M. K. Junior, L. R. Pereira, R. N. Borba, P. A. Fernandes, D. and Stulzer, H. K. Development and evaluation of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and polycaprolactone microparticles of nimodipine. Curr Pharm Des. 2013 March 12. [Epub ahead of print]. 

Choi, G. G. Kim, H. W. and Rhee, Y. H. Enzymatic and non-enzymatic degradation of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) copolyesters produced by Alcalig-enes sp. MT-16. J. Microbiol 2004, 42(4), 346-352. 

This result agrees with the slight shift toward higher temperatures of Ta (measured by DMA) in biodegradable poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBHV) with HAp, as evidenced by an increase in the activation energy for glassy relaxation [Chen et al., 2007]. 

Hameed, N.G. Qipeng, T. Feng, H.K. Sergei, G. Blends of cellulose and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) prepared from the ionic liquid l-butyl-3-methylimidazolium chloride. Carbohydr. Polym. 2011, 86 (1), 94-104. 

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