Polyhydroxyalkanoates structure

Other blends such as polyhydroxyalkanoates (PHA) with cellulose acetate (208), PHA with polycaprolactone (209), poly(lactic acid) with poly(ethylene glycol) (210), chitosan and cellulose (211), poly(lactic acid) with inorganic fillers (212), and PHA and aliphatic polyesters with inoiganics (213) are receiving attention. The different blending compositions seem to be limited only by the number of polymers available and the compatibility of the components. The latter blends, with all natural or biodegradable components, appear to afford the best approach for future research as property balance and bio degradability is attempted. Starch and additives have been evaluated in detail from the perspective of structure and compatibility with starch (214). 

Figure 7.2. Chemical structures of poly-3-hydroxybutyrate (PHB A), PHB-co-3-hydroxyvalerate (PHB/V B), PHB-co-4-hydroxybutyrate (PHB/4HB C), Medium-chain-length polyhydroxyalkanoate (mcZ-PHA D), NODAX (E). Note The Rx side chain is generally composed of a straight chain aliphatic hydrocarbon from 3 to 11 carbons in length (mc/-PI IA) or 3, 5,7 or 9 carbons in length (NODAX ).

Potter, M., and Steinbtichel, A. (2006) Biogenesis and structure of polyhydroxyalkanoate granules, in Inclusions in Prokaryotes, Volume 1 of Microbiology Monographs (ed. M. Shively), Springer, Heidelberg, pp. 109-136. 

Madkour, M.H., Mayer, F., Pieper-Fiirst, U., Pries, A., Valentin, H.E., and Wieczorek, R. (1995) Considerations on the structure and biochemistry of bacterial polyhydroxyalkanoic acid inclusions. Can. J. Microbiol., 41 (Suppl. 1),... 

Kenmoku T, Sugawa E, Yano T, Imamura T (2002) Polyhydroxyalkanoate with (methylsulfanyl) phenoxy structure in side chain. EP 1275727B1... 

K. Grage, A.C. Jahns, N. Parlane, R. Palanisamy, LA. Rasiah, J.A. Atwood, B.H. Rehm, Bacterial polyhydroxyalkanoate granules biogenesis, structure, and potential use as nano-/micro-beads in biotechnological and biomedical applications. Biomacromolecules 10 (4) (2009) 660-669. 

Koller, M., Horvat, P., Hesse, P.l. et al. (2006) Assessment of formal and low structured kinetic modeling of polyhydroxyalkanoate synthesis from complex substrates. Bioprocess and Biosystems Engineering, 29(5-6), 367-377. 

In addition to bio-based polyesters such as poly(lactic acid) (PLA), polyhydroxyalkanoates (PHAs), and poly(ethylene furanoate) (PEE), all based upon biomass-derived building blocks that have a structure different from today s commercial petrochemical-based polyesters, biobased polyesters can be developed having an identical structure to well-known petrochemical based polyesters. A very important class of such drop-in type bio-based polyesters are represented by polyesters based upon either isophthalic acid or terephthalic acid, such as PET,... 

Polyhydroxyalkanoate(s) (PHA) have gained rapid interest worldwide. The structural diversity of hydroxyalkanoates has resulted in materials with a wide range of physical and thermal characteristics. In addition, the variety of characteristics are significantly impacted by every aspect of upstream processing, as well as recovery during downstream processing. The diversity and versatility of PHA have opened up various opportunities for exploitation as many possibilities are yet to be discovered and evaluated in various applications. 

Polyhydroxyalkanoates (PHA), a family of biopolyesters with diverse structures, are the only bioplastics completely synthesized by microorganisms. PHA can be synthesized by over 30% of soil-inhabiting bacteria (Wu et al. 2000). Many bacteria in activated sludge, in high seas, and in extreme environments are also capable of making PHA. In the last 10 years, PHA have been developed rapidly to find applications in various fields (Fig. 1) (Chen 2009a). 

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