Poly- -Hydroxy Alkanoates

Weusthuis RA, Huijberts GNM, Eggink G (1997) Production of mcl-poly(hydroxy-alkanoates) (review). In Eggink G, Steinbiichel A, Poirier Y, Witholt B (eds) 1996 International Symposium on Bacterial Polyhydroxyalkanoates. NRC Research Press, Ottawa... 

The discussion of the influence of the interphase need not be limited to just linear polyethylenes. Interphases of several nm have been reported in polyesters and poly-hydroxy alkanoates. One major difference between the interphase of a flexible polymer like polyethylene and semi-flexible polymers like PET, PEN and PBT is the absence of regular chain folding in the latter materials. The interphase in these semi-flexible polymers is often defined as the rigid amorphous phase (or rigid amorphous fraction, RAF) existing between the crystalline and amorphous phases. The presence of the interphase is more easily discerned in these semi-flexible polymers containing phenylene groups, such as polyesters. 

Composites of granular starch with poly(hydroxy alkanoates) (PHAs) have been extensively studied. PHAs are produced as energy storage polymers by a wide range of microorganisms. Poly(hydroxy butyrate-co-valerate) (PHBV) copolymers have been commercialized. These copolymers are completely biodegradable, but currently are several times more costly than commodity polymers such as PE and PS. Because of its low cost, starch is an attractive filler for these materials. 

HYDROGEN AND POLY- (HYDROXY) ALKANOATE PRODUCTION FROM ORGANIC ACIDS BY PHOTOSYNTHETIC BACTERIA... 

Hydrogen and Poly- (hydroxy) Alkanoate Production from Organic Acids by Photosynthetic. .. 

Xppip pp o poly-hydroxy-alkanoates stored as a cell-internal energy storage pool in phosphate-... 

Poly(hydroxy alkanoate), PHA, [poly(hydroxy butyrate) PHB, poly(hydroxyl valerate) PHV]... 

Poly(lactic acid) (PL A) is a renewable resource-based bioplastic with many advantages, compared to other synthetic polymers. PL A is eco-friendly, because, apart from being derived from renewable resources such as corn, wheat, or rice, it is recyclable and compostable [1, 2]. PLA is biocompatible, as it has been approved by the Food and Drug Administration (FDA) for direct contact with biological fluids [3] and has better thermal processability compared to other biopolymers such as poly(hydroxy alkanoate)s (PHAs), poly(ethylene glycol) (PEG), or poly(e-caprolactone) (PCL) [4]. Moreover, PLA requires 25-55% less energy to be produced than petroleum-based polymers, and estimations show that this can be further reduced by 10% [5]. 

Han X, Satoh Y, Satoh T, Matsumoto K, Kakuchi T, Taguchi S, Dairi T, Munekata M, Tajima K. (2011) Chemo-enzymatic synthesis of poly hydroxy alkanoate (PHA) incorporating 2-hydroxybutyrate by wild-type class I PHA synthase from Ralstonia eutropha. Appl Microbiol Biotechnol, 92, 509-517. 

Optically active polymers are important functional materials for several industrial and bio-m ical applications and are extensively used as chiral catalysts for asymmetric synthesis, packing materials of chromatographic columns and chiral materials for the preparation of liquid crystal polymers (7). Polymers such as poly hydroxy alkanoates (PHAs), naturally occurring microbial optically active polyesters, are important materials in biomedical applications owing to their biodegradability (2). In synthetic polymer chemistry, synthesis of optically active polymers has been one of the most challenging tasks. Most synthetic chiral polymers are prepared from optically pure starting materials which are, except when isolated from nature, in limited supply and difficult to prepare (7, 3). 

PHB is the most elementary representative of the poly(hydroxy alkanoates) (PHA) high degree of crystallinity, very brittle material ... 

Doi,Y., Kumagai, Y., Tanahashi, N. and Mukai, K. (1992) Structural effects on biodegradation of microbial and synthetic poly (hydroxy alkanoates), in Biodegradable Polymers and Plastics (eds M. Vert et al.). Royal Society of Chemistry, Cambridge, pp. 139-48. 

Eggink G, de Waard P and Huijberts GNM, Formation of novel poly(hydroxy-alkanoates) from long-chain fatty acids. Can. J. Microbiol. 1995, 41(Suppl. 1) 14-21. 

Abe H, Doi Y (2002), Molecular and material design of biodegradable poly(hydroxy-alkanoate)s , in Doi Y and Steinbiichel A, Biopolymers 3b, Polyesters II, Weinheim, Wiley-VCH, 105-132. 

Interestingly, it was in a different context that both Seebach and Gellman approached the field of yS-peptides. Seebach s initial interest in yS-peptides stemmed from their resemblance to poly(yS-hydroxy alkanoates) (PHA), an ubiquitous class of biopolymers of which poly[(P)-3-hydroxybutanoic acid] (8, PHB) is the most common (for reviews see [37, 38]). 

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