Microbial polyester

Doi et alP reported on the biodegradation of PHAs. The mechanism of biodegradation of these polymers has been studied and involves the enzyme, bacterial esterases, which depolymerizes the polymer to monomers, dimers, and trimers. Budwill et al reported the rapid mineralization of PHB and PHBV in anaerobic sewage sludge, and more than 90% metabolized to methane and 

PHB and PHBV is also receiving attention for potential biomedical applications such as controlled drug release and sutures. In vivo, PHB degrades to D-3-hydroxybutyric acid which is a normal constituent of human blood. Its application in non-medical use is doubtful given its high costs. PHAs remain the most characterized of all the biodegradable polyesters. Interested readers are directed to the reviews by Doi, Gross and Steinbuchel.  

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Keywords. Polyhydroxyalkanoic acids, Microbial polyesters, PHA, PHA synthase, Metabolic engineering, PHA granules, Ralstonia eutropha, Pseudomonas aeruginosa... 

Production of Microbial Polyesters Fermentation and Downstream Processes... 

Production of Microbial Polyester by Fermentation of Recombinant Microorganisms... 

Polyhydroxyalkanoate (PHA) is a biodegradable and biocompatible thermoplastic that can be synthesized in many microoiganisms from almost all genera of the microbial kingdom. Many microoiganisms synthesize polyhydroxyalkanoates (PHAs) as intracellular carbon and energy reserve materials [1]. These microbial polyesters materials are thermoplastics with biodegradable properties [2]. PHAs are usually accumulated... 

Several review articles on biodegradable polymers and polyesters have appeared in the literature [12-22]. Extensive studies have been carried out by Al-bertsson and coworkers developing biodegradable polymers such as polyesters, polyanhydrides, polycarbonates, etc., and relating the structure and properties of aliphatic polyesters prepared by ROP and polycondensation techniques. In the present paper, the current status of aliphatic polyesters and copolyesters (block, random, and star-shaped), their synthesis and characterization, properties, degradation, and applications are described. Emphasis is placed primarily on aliphatic polyesters derived by condensation of diols with dicarboxylic acids (or their derivatives) or by the ROP of cyclic monoesters. Polyesters derived from cyclic diesters or microbial polyesters are beyond the scope of this review. 

Ashby, R. D., Shi, F.-Y., and Gross, R. A. 1999. A tunable switch to regulate the synthesis of low and high molecular weight microbial polyesters. Biotechnol. Bioeng., 62,106-113. 

Electrospinning of PHA is still relatively new in scaffold fabrication. To date, P(3HB) and P(3HB-co-3HV) are the most common microbial polyesters to be electrospun into tissue-engineering scaffolds. Suwantong et al. (2007) prepared ultrafine electrospun fiber mats of P(3HB) and P(3HB-co-3HV) as scaffolding materials for skin and nerve generation, hi their study, they evaluated the in vitro biocompatibility of these fibers using mouse fibroblasts and Schwann cells... 

Dodd NJF, Jha AN (2009) Titanium dioxide induced cell damage a proposed role of the carboxyl radical. Mutat Res 660 79-82 DoiY (1990) Microbial polyesters. VCH, New York... 

Manna A, Paul AK (2000) Degradation of microbial polyester poly(3-hydroxybutyrate) in environmental samples and in culture. Biodegradation 11 323-329... 

Tian J, Sinskey AJ, Stubbe J (2005) Kinetic studies of polyhydroxybutyrate granule formation in Wautersia eutrvpha H16 by transmission electron microscopy. J Bacteriol 187 3814—3824 TokiwaY, CalabiaBP (2004) Degradation of microbial polyesters. Biotechnol Lett 26 1181-1189 Tokiwa Y, Ugwu CU (2007) Biotechnological production of (R)-3-hydroxybutyric add monomer. J Biotechnol 132 264—272... 

B. Kessler, R. Weusthuis, B. Witholt, G. Eggink, Production of microbial polyesters fermentation and downstream processes, in W. Babel, A. Steinbiichel (Eds.), Biopolyesters, Springer, Berlin, Heidelberg, 2001, pp. 159-182. 

K.M. Schreck, M.A. Hillmyer, Block copolymers and melt blends of polylactide with Nodax microbial polyesters preparation and mechanical properties, J. Biotechnol. 132 (3) (2007) 287-295. 

These data confirming the high discrimination power of the TG-FAB and HPLC-FAB methods applied to identification of the microbial polyester microstructure, because by NMR analysis it was not possible to establish... 

Ballistreri, A., Garozzo, D., Giuffrida, M., Impallomeni, G., and Montaudo, G., Analytical Degradation An Approach to the Structural Analysis of Microbial Polyesters by Different Methods, /. Anal. App. Pyrolysis, 16, 239,1989. 

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