Polyhydroxyalkanoates degradation

Ruiz JA, L6pez NI, Mendez BS (1999) Polyhydroxyalkanoates degradation affects survival of Pseudomonas oleovorans in river water microcosms. Rev Argent Microbiol 31 201-204 Ruiz JA, L6pez NI, Fernandes R, Mendez B (2001) Polyhydroxyalkanoate degradation is associated with nucleotide accumulation and enhanced stress resistance and survival of Pseudomonas oleovorans in natural water microcosms. Appl Environ Microbiol 67 225-230 Ruiz JA, Lopez NL, Mendez BS (2004) rpoS gene expression in caibon-starved cultures of the polyhydroxyalkanoate-accumulating species Pseudomonas oleovorans. Curr Microbiol 48 396 00... 

Polyesters offer multiple options to meet the complex world of degradable polymers. All polyesters degrade eventually, with hydrolysis being the dominant mechanism. Degradation rates range from weeks for aliphatic polyesters (e.g. polyhydroxyalkanoates) to decades for aromatic polyesters (e.g. PET). Specific local environmental factors such as humidity, pH and temperature significantly influence the rate of degradation. 

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). 

These environmentally degradable polyolefins, because of their cost/ performance profiles are very competitive for the growing markets for such plastics. They will be strong competition for the polyester types such as poly(lactic acid) and polyhydroxyalkanoates so frequently publicized as the innovative solution to plastic waste management. 

Within this context, the search for a material that is durable while in use and degradable after its disposal has led to the emergence of biodegradable plastic— materials that decompose into carbon dioxide and water as the final result of the action of microorganisms such as bacteria and fungi [5]. Polyhydroxyalkanoates (PHAs) constitute examples of such materials. 

AKI03] Akiyama M., Tsuge T., Doi Y., Environmental lifecycle comparison of polyhydroxyalkanoates produced from renewable carbon resources by bacterial fevme n L iorC Polymer Degradation and Stability, o. 80, no. l,p. 183,2003. 

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 Polyhydroxyalkanoate (PHA) is an attractive material because it can be produced from renewable resources and because of its plastic-like properties. In addition, PHA can be degraded by the action of microbial enzymes. Although PHA resanbles some commodity plastics, the performance and cost of PHA are not yet good enough for widespread applications as plastic materials. Therefore, the PHA commercialization attempts by many industries for bulk applications have been challenging. However, PHA also possesses interesting properties that can be developed for non-plastic applications. This chapter describes some new niche applications for PHA in cosmetics and wastewater treatment. 

Jendrossek D, Handrick R (2002) Microbial degradation of polyhydroxyalkanoates. Annu Rev Microbiol 56 403-432... 

Lee SY, J-i Choi (1999) Production and degradation of polyhydroxyalkanoates in waste environment. Waste Manag 19 133-139... 

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... 

Matavulj M, Mohtoris HP (1992) Fungal degradation of polyhydroxyalkanoates and a semi-quantitative assay for screening their degradation by terrestrial fungi. FEMS Microbiol Lett 103 323-331... 

Papaneophytou CP, Velah EE, Pantazaki AA (2011) Purification and characterization of an extracellular medium-chain length polyhydroxyalkanoate depolymerase from Thermus thermophilus HB8. Polym Degrad Stab 96 670-678... 

Sudesh K, Loo CY, Goh LK, Iwata T, Maeda M (2007) The dl-absoibing property of polyhydroxyalkanoate films and its practical application a refreshing new outlook for an old degrading material. Macromol Biosci 7 1199-1205... 

Wang YW, Mo W, Yao H, Wu Q, Chen J, Chen GQ (2004) Biodegradation studies of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate). Polym Degrad Stab 85 815-821 Wang YW, Wu Q, Chen GQ (2003) Reduced mouse fibroblast cell growth by increased hydro-philicity of microbial polyhydroxyalkanoates via hyaluronan coating. Biomaterials 24 4621 629... 

Among all biodegradable polymers, unlike number of biopolymerslimitedto industrial compositing, polyhydroxyalkanoate is known to have the potential to degrade in every environment [10],... 

Bordes, R, Hablot, E., Pollet, E., Averous, L, Effect of clay organomodifiers on degradation of polyhydroxyalkanoates. Polymer Degradation and 5, 789-796 (2009), DOl http //dx.doi.0rg/lO.lOl6/j.polym degradstab.2009.01.027. 

Some synthetic polymers like, polyurethanes, specifically polyether-polyurethanes, are likely to be degraded by microbes but not completely. However, several polymers such as, polyamides, polyfluorocarbons, polyethylene, polypropylene, and polycarbonate are highly resistant to microbial degradation. Natural polymers are generally more biodegradable than synthetic polymers specifically, polymers with ester groups like aliphatic polyesters [1]. Therefore, several natural polymers such as cellulose, starch, blends of those with synthetic polymers, polylactate, polyester-amide, and polyhydroxyalkanoates (PHAs) have been the focus of attention in the recent years [3]. 

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