Biosynthesis, biodegradable polymers

Including biodegradable polymers, hydrogen storage, nanomaterials, biosynthesis, conducting polymers, biomass fuel Source Caplus database... 

In the current industrial process, nisin is manufactured by fermentation of L. lactis subsp. lactis in a milk-based medium. Biosynthesis of nisin is coupled with the growth of lactic acid bacteria and the production of a significant amount of lactic acid (7). Lactic acid is an important chemical for food processing. It can also be used as a raw material in the production of the biodegradable polymer poly(lactic) acid (12). Unfortunately, lactic acid is not recovered in the current nisin process. 

Amass W, Amass A, Tighe BA (1998) Review of biodegradable polymers uses, current developments in the synthesis and characterization of biodegradable polyesters, blends of biodegradable polymers and recent advances in biodegradation studies. Polym Int 47 89-144 Anderson AJ, Dawes EA (1990) Occurrence, metabolism, metabolic role, and industrial uses of bacterial polyhydroxyalkanoates. Microbiol Rev 54 450-472 Anderson AJ, Haywood GW, Dawes EA (1990) Biosynthesis and composition of bacterial poly(hydroxyalkanoates). Int J Biol Macromol 12 102-105 Bowien B, Kusian B (2002) Genetics and control of CO(2) assimilation in the chemoautotroph Ralstonia eutropha. Arch Microbiol 178 85-93... 

Martin DP, Zhang S, Su L, Lenz RW (1999) Extracellular polymerization of 3-hydroxyal-kanoate monomers by the synthase from Alcaligenes eutrophus. In Steinbuchel A (ed) Biochemical principles and mechanisms of biosynthesis and biodegradation of polymers. Wiley-VCH, Weinheim, pp 168-175... 

Plant cell walls are complex, heterogeneous structures composed mainly of polymers, such as cellulose, hemicelluloses, and lignins. In spite of several decades of research, cell wall assembly and the biosynthesis and ultimate biodegradative pathways of individual polymers are still far from being fully understood. One simple example will suffice Even today, no enzyme capable of catalyzing cellulose formation in vitro has been obtained. 

As was pointed out in Chapter 10, routes of biosynthesis (anabolism) often closely parallel pathways of biodegradation (catabolism). Thus, catabolism begins with hydrolytic breakdown of polymeric molecules the resulting monomers are then cleaved into small two- and three-carbon fragments. Biosynthesis begins with formation of monomeric units from small pieces followed by assembly of the monomers into polymers. The mechanisms of the individual reactions of biosynthesis and biodegradation are also often closely parallel. However, in most instances, there are clear-cut differences. A first principle of biosynthesis is that biosynthetic pathways, although related to catabolic pathways, differ from them in distinct ways and are often catalyzed by completely different sets of enzymes. 

R. Steudel, A. Albertsen, in Biochemical Principles and Mechanisms of Biosynthesis and Biodegradation of Polymers. (A. Steinbiichel, ed.), Wiley-VCH, Weinheim, 1999, p. 17. 

Phanerochaete chrysosporium and the Biodegradation of Lignin. Lignin is an abundant, naturally occurring polymer whose function in nature is to provide structural support to woody plants (8). Its formation iji vivo is catalyzed by the free radical oxidative polymerization of clnnamyl alcohols (8). Because the type and quantity of clnnamyl alcohols may vary and because its biosynthesis occurs via a non-stereospeclfIc free radical mechanism, the lignin polymer is a racemic heteropolymer whose structure varies from species to species (8). The lack of an ordered and repeating structure coupled with the racemic nature of the polymer (8) combine to make lignin resistant to attack by most enzyme systems. 

USM2 for the production of biodegradable plastics. Ph.D dissertation. Universiti Sains Malaysia Bhubalan K, Lee W-H, Loo C-Y, Yamamoto T, Tsuge T, Doi Y, Sudesh K (2(X)8) Controlled biosynthesis and characterization of poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate) from mixtures of palm kernel oil and 3HV-precursors. Polym Degrad Stab 93 17-23... 

PROPERTIES OF SPECIAL INTEREST Natural resources basic polysaccharides nontoxic biodegradability bioactivity biosynthesis interesting derivatives (chitosan) toughness graft copolymerization chelating ability for transition metal cations immobilizes enzymes by chemical linking or adsorption chiral polymer. 

Kobayashi, G., SUotani, T., Shima, Y. and Doi, Y. (1994) Biosynthesis and characterization of poly-(3-hydroxybutyrate-co-3-hydroxyhexanoate) from oils and fats by Aeromonas sp. OL-338 and Aeromonas sp. FA-440, in Biodegradable Plastics and Polymers (eds Y. Doi and K. Fukuda), Elsevier, Amsterdam, pp. 410-416. 

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