Microorganisms polyhydroxyalkanoates

Steinbuchel, A. and Lutke-Eversloh, T. 2003. Metabolic engineering and pathway construction for biotechnological production of relevant polyhydroxyalkanoates in microorganisms. Biochemical Engineering Journal 16 81-96. 

Biochemical and Molecular Basis of Microbial Synthesis of Polyhydroxyalkanoates in Microorganisms... 

Polyhydroxyalkanoates (PHAs) are polyesters that were first isolated and characterized in 1925 by French microbiologist Maurice Lemoigne. They are produced by microorganisms (e.g. Alcaligenes eutrophus mdBacillus megaterium) in response... 

Various procaryotic microorganisms can produce polyhydroxyalkanoates using regenerable carbon sources. This polymer is a storage material and can make up to 90 % of the dried cell weight. The most widely researched material in this group up till now is the poly-D(-)-3-hydroxybutyric acid (PHB). 

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. 

Polymers derived from renewable resources (biopolymers) are broadly classified according to the method of production (1) Polymers directly extracted/ removed from natural materials (mainly plants) (e.g. polysaccharides such as starch and cellulose and proteins such as casein and wheat gluten), (2) polymers produced by "classical" chemical synthesis from renewable bio-derived monomers [e.g. poly(lactic acid), poly(glycolic acid) and their biopolyesters polymerized from lactic/glycolic acid monomers, which are produced by fermentation of carbohydrate feedstock] and (3) polymers produced by microorganisms or genetically transformed bacteria [e.g. the polyhydroxyalkanoates, mainly poly(hydroxybutyrates) and copolymers of hydroxybutyrate (HB) and hydroxyvalerate (HV)] [4]. 

PolyhydroxyaUcanoate (PHA) is a biodegradable and biocompatible thermoplastic that can be synthesized in many microorganisms from almost all genera of the microbial kingdom. Many microorganisms 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... 

Keywords Bio-based Biodegradable Microorganism Palm oil PHA Plastics Polyhydroxyalkanoate Polymer... 

Sunada K, Watanabe T, Hashimoto K (2003) Studies on photoktUing of bacteria on Ti02 thin film. J Photochem Photohiol A Chem 156 227-233 Suriyamongkol P, Weselake R, Narine S, Moloney M, Shah S (2007) Biotechnological approaches for the production of polyhydroxyalkanoates in microorganisms and plants - A review. Biotechnol Adv 25 148-175... 

Polyhydroxyalkanoates (PHAs) are polyesters formed by many prokaryotic micro-organisms-when unbalanced nutritional conditions are chosen for die (Hoducing cells Up to more than 90% of the cell dry weight can be accounted for as polymer. Besides the homopolyester poly-R-3-hydroxybutanoate, consisting of 3-hydroxybutanoate (3HB) only, two main types of copolyesters can be formed by different microorganisms. The first type of PHAs always contains C3 units in the polymer backbone, but the... 

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). 

Steinbuchel A, Hein S (2001) Biochemical rmd molecular basis of microbial synthesis of polyhydroxyalkanoates in microorganisms. Adv Biochem Eng Biotechnol 71 81-123... 

Abstract Polyhydroxyalkanoates (PHAs) are natural polyesters that accumulate in numerous microorganisms as a carbon- and energy-storage material under the nutrient-limiting condition in the presence of an excess carbon source. PHAs are considered to be one of the potential alternatives to petrochemically derived plastics owing to their versatile material properties. Over the past few decades, extensive detailed biochemical, molecular-biological, and metabolic studies related to PHA... 

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