Chemosynthetic, described

Polyesters, such as microbially produced poly[(P)-3-hydroxybutyric acid] [poly(3HB)], other poly[(P)-hydroxyalkanoic acids] [poly(HA)] and related biosynthetic or chemosynthetic polyesters are a class of polymers that have potential applications as thermoplastic elastomers. In contrast to poly(ethylene) and similar polymers with saturated, non-functionalized carbon backbones, poly(HA) can be biodegraded to water, methane, and/or carbon dioxide. This review provides an overview of the microbiology, biochemistry and molecular biology of poly(HA) biodegradation. In particular, the properties of extracellular and intracellular poly(HA) hydrolyzing enzymes [poly(HA) depolymerases] are described. 

Weed competition for water and nutrients can have similar effects on fruit quality as described above for fertilisation. For example, if weed competition is completely prevented by chemosynthetic herbicides in conventional production, this can lead to excess supply of certain mineral nutrients, in particular nitrogen and potassium, which in turn results in reduced sensory quality and shelf-life (Section 16.2.2). On the other hand, excessive weed competition, in particular, during the pre-bloom phase and the end of the first shoot growth period (Gut and Weibel, 2005), can induce nutrient and/or water deficiency and a risk of quality loss. 

Figure 3 (a) Comparison of the turbidimetric profiles for a series of chemosynthetic elastin polypeptides based on random copolymers of the repeat sequence [(Val-Pro-Gly-Val-Gly)i x(Val-Pro-Gly-Xaa-Gly)J, where fx refers to the mole fraction of variant pentapeptides within the polymer sequence. " (b) Hydrophobicity scale based on ft values for the copolymers described above as a function of guest residue identity and mole fraction, f. Note that hydrophobic amino acids shift the position of 7 toward lower temperature and that more polar guest residues shift the position of 7i toward higher temperatures in a manner commensurate with the level of substitution within the polypeptide sequence. Reprinted from Uriy, D. W. Gowda, D. C. Parker, T. M. etal. Biopolymers 99Z, 32(9), 1243 20(b) Copyright 1992, with permission from Wiley. 

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