Poly-3-hydroxydecanoate

Qi, Q., Steinbtichel, A., and Rehm, B.H.A. (2000) In vitro synthesis of poly(3 -hydroxydecanoate) purification of type II polyhydroxyalkanoate synthases PhaCl and PhaC2 from Pseudomonas aeruginosa and development of an enzyme assay. Appl. Microbiol. Biotechnol., 54, 37-43. 

To date, various block copolymers have been produced using biological systems. This includes poly(3HB-fo-4HB) [17], P(3HB)-f>-poly(3-hydroxyvalerate-co-3-hydroxyheptanoate) [18], PHB-f -poly(hydroxyhexanoate) [19], poly 3HB-fc-poly(3-hydroxyheptanoate) [P(3HP)] [20], P(3HP)-f -poly(4-hydroxybutyrate) [P(4HB)] [21], poly(3-hydroxyhexanoate)-fe-poly(3-hydroxydecanoate)-co-[3-hydroxydodecanoate (3HDD)] [22] and poly[3-HDD-f -poly(3-hydroxy-9-decanoate)] [23]. These studies were motivated by the fact that although random copolymers, such as poly(3HB-co-3HV) and poly(3HB-co-4HB), exhibit useful mechanical and thermal properties they suffer from a deterioration of polymer properties due to the effect of ageing. It was found that all block copolymers exhibited improved properties compared with the two relative homopolymers, random and blend polymers. Various... 

Liu Q, Luo G, Zhou XR, Chen GQ. Biosynthesis of poly(3-hydroxydecanoate) and 3-Hydroxydo-decanoate dominating polyhydroxyalkanoates by p-oxidation pathway inhibited Pseudomonas putida. Metah Eng 2011 13 11-7. 

Block terpolymers of poly(hydroxyoctanoic acid), poly(hydroxyhexanoic acid) and poly(hydroxydecanoic acid), and the so-called bacterial elastomers , produced by bacteria [124] also belong to the polyester thermoplastic elastomer family (see also Chapter 2). 

Block copolymers were synthesized by a combination of fipase-catalyzed polymerization and atom transfer radical polymerization (ATRE). " " At first, the polymerization of 10-hydroxydecanoic acid was carried out by using lipase CA as catalyst. The terminal hydroxy group was modified by the reaction with a-bromopropionyl bromide, followed by ATRP of styrene using CuCE2,2 -bipyridine as catalyst system to give the polyester-polystyrene block copolymer. Trichloromethyl-terminated poly(e-CL), which was synthesized by lipase CA-catalyzed polymerization with 2,2,2-trichloroethanol initiator, was used as initiator for ATRP of styrene. 

A new pathway was recently engineered in vitro employing purified His6-tag-ged PhaCl and PhaC2 from P. aeruginosa plus a commercially available acyl-CoA synthetase allowing in vitro de novo PHA granules and in vitro synthesis of poly(3HD) from 3-hydroxydecanoate [74]. 

Lageveen et al. [41] showed that the monomer composition of aliphatic saturated poly(3HAMCL) produced by P. oleovorans is depended on the type of n-alkane used. It appeared that the n-alkanes were degraded by the subsequent removal of C2-units and it was therefore proposed that the /1-oxidation pathway was involved in poly(3HAMCL) biosynthesis. Preusting et al. [42] confirmed these results but also showed that with hexane as substrate some 3-hydroxyoctanoate and 3-hydroxydecanoate were produced, indicating that additional pathways were involved in poly(3HAMCL) biosynthesis (Table 1). 

When cells are grown on non-aliphatic substrates, such as glucose, fructose, acetate, or glycerol, these are converted to appropriate precursors that can be incorporated into poly(3HAMCL)s via fatty acid synthesis. The resulting PHAs have a monomer composition that is similar to that seen after growth on alkanes, often with 3-hydroxydecanoic acid as the major monomer. ( -Oxidation does not seem to play a role in the conversion of these substrates into poly(3HAMCL) since the addition of a -oxidation inhibitor did not affect the monomer composition [47]. 

In 1985, a lipase-catalyzed polymerization of 10-hydroxydecanoic acid was reported. The monomer was polymerized in benzene using poly(ethylene glycol) (PEG)-modified lipase soluble in the medium [12]. The degree of polymerization (DP) of the product was more than 5. PEG-modified esterase from hog Ever and lipase from Aspergillus niger (lipase A) induced the oligomerization of glycolic acid [13]. 

Pseudomonas citronellolis was found to produce mcl-PHA on many different substrates (Choi and Yoon 1994). Similar to P. fluorescens, this strain also produced unsaturated monomers from unrelated C -C acids up to 9 mol% 3-hydroxy-c -5-dodecenoate and up to 2.6 mol% 3-hydroxy-CM-7-tetradecenoate, with the largest content being (7 )-3-hydroxydecanoate. A novel copolyester, poly(3-hydroxy-7-methyl-6-octenoate-co-3-hydroxy-5-methylhexanoate), was synthesized when P. citronellolis was grown on citronellol (Choi and Yoon 1994). 

Poly(3-hydroxybutyrate-co-6mol% Has), HAs (hydroxyalkanoates) = 3% 3-hydroxydecano-ate, 3% 3-hydroxydodecanoate, <1% 3-hydroxyoctanoate, <1% 5-hydroxy-dodecanoate, ng = negligible. 

Typical SCL PHA include poly(lactide) (PLA), poly(3-hydroxybutyrate) (P3HB), poly(4-hydroxybutyrate) (P4HB),poly(3-hydroxyvalerate) (P3HV) and their random or block copolymers such as P3HB4HB, PHBV, PLAHB, etc. Typical MCL PHA are homopolymers of 3-hydroxyhexanoate (PHHx), 3-hydroxyheptanoate (PHHp), 3-hydroxyoctanoate (PHO), 3-hydroxynonanoate (PHN), 3-hydroxydecanoate (PHD),... 

UHMW P(3HB) [43] P(3HB-co-3HD) Poly(3-hydroxybutyrate-co-3-hydroxydecanoate) P(3HB-co-3HHx) Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) Tgt Glass transition temperature Tmt Melting temperature ... 

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