P-Hydroxydecanoate

Rhamnolipids, in which one or two molecules of rhamnose are linked to one or two moleeules of 3-hydroxydecanoic acid, are the best-studied glycolipids. Production of rbamnose-containing glycolipids was first described by Jarvis and Johnson [10]. The main glycolipids produced by P. aeruginosa are rhamnolipids of the types 1 and 2, L-rhamnosyl-(3-hydroxydecanoyl-p-hydroxydecanoate and L-ihamnosyl-L-rhamnosyl- 3-hydroxydecanoyl- 3-hydroxydecanoate. Their structures can be seen in Fig. 1. The formation of rhamnolipid types 3 and 4 containing one 3-hydroxydecanoic acid with one and two rhamnose units, methyl ester derivatives of rhamnoUpids 1 and 2, and rhanmolipids with alternative fatty acid chains have also been reported [5]. 

Figure 14.1 Structure of a rhamnolipid with two rhamnose and two p-hydroxydecanoic acid units.

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]. 

There is considerable interest in synthesizing copolymers. This is actually possible if organisms are confronted with mixtures of so-called related and unrelated substrates. Copolymers can also be synthesized from unrelated substrates, e.g., from glucose and gluconate. The 3-hydroxydecanoate involved in the polyester is formed by diversion of intermediates from de novo fatty-acid synthesis [41,42]. Related , in this context, refers to substrates for which the monomer in the polymer is always of equal carbon chain length to that of the substrate offered. Starting from related substrates, the synthesis pathway is closely connected to the fatty-acid /1-oxidation cycle [43]. In Pseudomonas oleovor-ans, for example, cultivated on octane, octanol, or octanoic acid, the synthesized medium chain length polyester consists of a major fraction of 3-hydroxyoc-tanoic acid and a minor fraction of 3-hydroxyhexanoic acid. If P. oleovorans is cultivated on nonane, nonanol, or nonanoic acid, the accumulated polyester comprises mainly of 3-hydroxynonanoate [44]. 

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). 

Natural y-decalactone is produced biotechnologically starting from ricinoleic acid, which is degraded by P-oxidation to 4-hydroxydecanoic acid, which lactonizes at lower pH to yield y-decalactone [197a], [197b],... 

NMR and MS/MS spectroscopy. Fellutamide A is composed of leucinal, P-hydroxyglutamine and asparagine esterified by 3-hydroxydecanoic acid. In fellutamide B, glutamine replaces P-hydroxyglutamine. P. fellutanum was previously isolated in the land environment [69]. 

In order to determine which one of the two routes is responsible for the formation of 3-hydroxydecanoate constituents, we cultivated P. putida on a combination of octanoate and [2- C] acetate. The resulting PHA consisted of the monomers 3-hydroxyhexanoate (8%), 3-hydroxyoctanoate (89%) and 3-hydroxydecanoate (3%). The labeling pattern of this polymer gives information on the origin of the monomers. 

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... 

The production of PHA using residual oil from biotechnological rhamnose production as a carbon source for growth of C. necator H16 (the nomenclature in the article was "Ralstonia eutropha") andP. oleovorans-was described by Fiichtenbusch et al. (2000). The strains accumulated PHA at 41.3 and 38.9%, respectively, of the cell dry mass when they were cultivated in defined media with oil from the rhamnose production as the sole carbon source. The accumulated PHA isolated from C. necator was identified as PHB homopolyester, whereas the PHA isolated from P. oleovorans consisted, typically for this type of PHA-accumulating organism, of (P)-3-hydroxyhexanoicacid, (P)-3-hydroxyoctanoicacid, (/ )-3-hydroxydecanoic acid and (P)-3-hydroxydodecanoic acid. Approximately 20-25% of the carbon components of the residual oil were converted into PHA. Up to 80% of cell dry mass of PHB homopolyester from different plant oils was produced by C. necator DSM 545 (Fukui and Doi 1998). 

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). 

Hydroxy acids, like p-hydroxyethoxybezoic acid or co-hydroxydecanoic acid, are capable of selfcondensation to form polyesters [10] ... 

The chemical structure of lipid A of lipopolysaccharide isolated from Comamonas testosteroni was recently determined by lida et al. (1996) by means of methylation analysis, mass spectrometry and NMR. The lipid A backbone was found to consist of 6-0-(2-deoxy-2-amino-P-D-glucopyrano-syl)-2-deoxy-2-amino-alpha-D-glucose which was phosphorylated in positions 1 and 4. Hydroxyl groups at positions 4 and 6 were unsubstituted, and position 6 of the reducing terminal residue was identified as the attachment site of the polysaccharide group. Fatty acid distribution analysis and ES/MS of lipid A showed that positions 2,2, 3 and 3 of the sugar backbone were N-acylated or O-acylated by R-3-hydroxydecanoic acid and that the hydroxyl groups of the amide-linked residues attached to positions 2 and 2 were further O-acylated by tetradecanoic and dodecanoic acids, respectively. 

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. 

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