Polyhydroxyalkanoates bacterial fermentation

Lee, S. Y., Choi, J., and Wong, H. H. 1999b. Recent advances in polyhydroxyalkanoate production by bacterial fermentation mini-review. Int. J. Bio. Macromol., 25, 31-36. 

Polyhydroxyalkanoates Linear aliphatic polyesters produced in nature by bacterial fermentation... 

Choi J, Lee SY (1999) Eactors affecting the economics of polyhydroxyalkanoate production by bacterial fermentation. Appl Microbiol Biotechnol 51 13-21... 

Lee SY, Choi JI (1998) Effect of fermentation performance on the economics of poly(3-hydroxy-butyrate) production by Alcaligenes latus. Polym Degrad Stab 59 387-393 Lee SY, Choi J, Wong HH (1999) Recent advances in polyhydroxyalkanoate production by bacterial fermentation mini-review. Int J Biol Macromol 25 31-36 Lee SY, Lee KM, Chan HN, Steinbiichel A (1994) Comparison of recombinant Escherichia coli strains for synthesis and accumulation of poly(3-hydroxybutyric acid) and morphological changes. Biotechnol Bioeng 44 1337-1347... 

Polyhydroxyalkanoates The Natural Polymers Produced by Bacterial Fermentation... 

AMyama M, Tsuge T, Doi Y (2003) Environmental life cycle comparison of polyhydroxyalkano-ates produced from renewable carbon resources by bacterial fermentation. Polym Degrad Stab 80 183-194... 

Examples of microbial polyesters are the so-called polyhydroxyalkanoates (PHA), which are produced by bacterial fermentation of sugars and lipid, in order to store carbon and energy. There are about 100 different monomers that had been included into PHA polymers (Rehm and Steinbuchel, 2005) this list comprises hydroxyalkanoate units with a substituted group (alkyl, aryl, alkenyl, halogen, cyano, epoxy, ether, acyl, ester, and acid groups) (Fig. 1.2). 

Polyhydroxyalkanoates (PHAs, e.g. poly(3-hydroxybutyrate) (PHB), linear polyesters produced in nature by bacterial fermentation of sugar or lipids),... 

Polyhydroxyalkanoates (PHAs) are a family of polyesters produced by bacterial fermentation, with the potential to replace conventional hydrocarbon-based polymers. PHAs occur naturally in a variety of organisms, but the microorganisms can be employed to tailor their production in cells. Polyhydroxybutyrate (PHB), the simplest PHA, was discovered in 1926 by Maurice Lemoigne as a constituent of the bacterimn Bacillus megaterium [31]. 

Polyhydroxyalkanoates can be made from over 100 monomers based onpoly(3-hydroxyalkanoates) (P3HB), poly(4-hydroxybutyrate) P4HB, PHB, and PHV. PHA is produced in the cells of bacteria from at least five different PHA biosynthetic pathways (Park and Lee 2005 Madison and Huisman 1999). PHA is harvested from the cells and made into plastic pellets. Poly(3-hydroxyalkanoates) are the most common PHA and are the basis of PHAs produced by Metabolix Company and Tianjin Company. The P3HB can be copolymerized with P4HB to produce a flexible polymer based on PHAs. Polyhydroxyalkanoates have hydroxy-acid repeat units that are produced by bacterial fermentation with sugars or lipids to create linear polyesters. 

The polyhydroxyalkanoates represents a range of polyesters produced from renewable resources by bacterial fermentation. The class includes the 3-hydroxybutyrate-co-3-hydroxyvalerate polymers marketed under the Biopol trademark. 

Polyhydroxyalkanoates or PHA are thermoplastics produced by bacterial fermentation of sugars or lipids. Maurice Lemoigne, Director of the Fermentation Laboratory of the Pastenr Institnte in Lille, France, first isolated and characterized the simplest and most commonly occnrring polyester of PHA, poly-3-hydroxybu-tyrate, PHB or poly(3HB) represented in Figure 8.16, in the 1920s [13]. 

An additional advantage of the polyhydroxyalkanoates is that the polymers can be produced by fermentation. Certain types of bacteria produce PHAs for energy storage when they are grown in glucose solution in the absence of specific nutrients. The polymer forms as discrete granules within the bacterial cell, and it is then removed by extraction to give a white powder that can be melted and modified into a variety of different products. 

Abstract Polyhydroxyalkanoate (PHA) is a plastic-like material synthesized by many bacteria. PHA serves as an energy and carbon storage componnd for the bacteria. PHA can be extracted and purified from the bacterial cells and the resulting product resembles some commodity plastics such as polypropylene. Because PHA is a microbial product, there are natural enzymes that can degrade and decompose PHA. Therefore, PHA is an attractive material that can be developed as a bio-based and biodegradable plastic. In addition, PHA is also known to be biocompatible and can be used in medical devices and also as bioresorbable tissue engineering scaffolds. In this chapter, a brief introduction about PHA and the fermentation feedstock for its production are given. 

Abstract Polyhydroxyalkanoates (PHA) are intracellular polymers stored by many bacterial species. Presently PHA arc industrially produced by pure cultures fermentation where high quality substrates are used. Mixed cultures using raw substrates are able to produce PHA when submitted to transient conditions like oscillations on substrate feeding or on oxygen supply. The yield on PHA produced by activated sludge submitted to these dynamic conditions reach values comparable to those obtained by the pure cultures, being the first process less cost intensive than die last one. The chain length of the polymer produced in both processes is similar. 

Industrial Production of Bacterial Polyhydroxyalkanoates PHAs via Fermentation... 

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