Polyhydroxybutyrate microbial

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... 

Chiellini E, Solaro R (1996) Biodegradable polymeric materials. Adv Mater 8 305-313 Cyras VP, Commisso MS, Mauri AN et al (2007) Biodegradable double-layer films based on biological resources polyhydroxybutyrate and cellulose. J Appl Polym Sci 106 749-756 De Koning GJM (1993). Prospects of bacterial poly[(R)-3-hydroxyalkanoates]. Center for Polymers and Composites (CPC), Eindhoven University of Technology, Eindhoven Doi Y (1990) Microbial polyesters. Wiley, New York... 

PHA constitute a whole class of microbially synthesized polyesters [33], of which polyhydroxybutyrate (PHB) and the copolymer with valerate (PHBV) have attracted much attention as possible replacements of oil-based thermoplastics. To serve as a useful injection moldable plastic with reasonable ductility, PHA... 

Generally, polymers from renewable resources have different origins such as natural (e.g., polysaccharides - namely cellulose and starch, which are produced in large amounts protein gums), synthetic (e.g., polylactic acid, PLA) derived from natural monomers, and microbial (e.g., polyhydroxybutyrate, PHB) [1, 5] The main components of biomass are cellulose, lignin, hemicelluloses and extractives and, as a nonwood structural component, starch. 

A more recent biodegradable polymer is polyhydroxybutyrate-valerate copolymer (PHBV) from ICI Americas Inc.. These copolymers are produced through biochanical means. In fact, these natural thermoplastics are derived from bacteria. They are fully degradable in many microbial environments. Other biodegradable polymers include Konjac, a water-soluble polysaccharide produced by FMC Chitin, another polysaccharide that is insoluble in water and Chitosan, which is soluble in water. 

Polyhydroxybutyric acid is a storage compound for excess carbon in many microorganisms (E 2.2). It may be used in the production of plastics (F 4). Acetoacetic acid, acetone, and /S-hydroxybutyric acid are excreted in the urine of people with a pathologically high blood sugar level (diabetes mellitus) (E 1). Their appearance is of diagnostic value. Butyric acid, butanol, and acetone are products of microbial fermentations. 

JiangY, Marang L, Kleerebezem R, Muyzer G, van Loosdrecht MCM. Polyhydroxybutyrate production from lactate using a mixed microbial culture. Biotechnol Bioeng 2011 108 2022-35. 

Brigham CJ, Kurosawa K, Rha CK, Sinskey AJ (2011) Bacterial carbon storage to value added products. J Microbial Biochem Technol 83 83-002 Brigham CJ, Gai CS Lu J, Speth DR, Worden RM, Sinskey AJ (2012) Engineering Ralstonia eutwpha for production of isobutanol from CO, H, and Oy In Lee JW (ed) Advanced biofuels and bioproducts. Springer, New York, DOI 10.1007/978-l-4614-3348-4 39 Bruland N, Voss I, Bramer C, Steinbtichel A (2009) Unravelling the C(3)/C(4) carbon metabolism in Ralstonia eutropha H16. J Appl Microbiol 109 79-90 Budde CF, Mahan AE, Lu J, RhaC, Sinskey AJ (2010) Roles of multiple acetoacetyl coenzyme A reductases in polyhydroxybutyrate biosynthesis in Ralstonia eutropha H16. J Bacteriol 192 5319-5328... 

Cheap methanol may be used as a carbon source to replace carbohydrate in the microbial production of chemicals. For example, polyhydroxybutyrate (PHB), a biodegradable thermoplastic material, can be produced by microbial fermentation. However, its hi cost restricts large-scale application. The cost of the substrate is an important contributing factor to the overall cost of production. The use of methanol to produce PHB, if successfully developed without sacrificing the molecular weight, would significantly improve process economics and increase its practical application. Recent studies have shown promising results [58, 84, 85]. 

G. Biopolymere E biopolym res The term b. is used for all polymers occuring in living organisms, such as - proteins, - polysaccharides, nucleic acids or mostly biotechnologi-cally produced polymers (- microbial gums, - sucrose, biotransformation to biopolymers), that have structures and/or properties similar to natural polymers (- dextrans, - levans, - polyhydroxybutyric acid, - polylactic acid, - pullulan, -+xanthan). 

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