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  • Synthesis and characterization of poly(3-hydroxyalkanoates) from Brassica carinata oil with high content of erucic acid and from very long chain fatty acids.

Synthesis and characterization of poly(3-hydroxyalkanoates) from Brassica carinata oil with high content of erucic acid and from very long chain fatty acids.

International journal of biological macromolecules (2010-11-03)
Giuseppe Impallomeni, Alberto Ballistreri, Giovanni Marco Carnemolla, Salvatore P P Guglielmino, Marco Sebastiano Nicolò, Maria Grazia Cambria
ABSTRACT

Pseudomonas aeruginosa produced medium chain length poly(3-hydroxyalkanoates) (mcl-PHAs) when grown on substrates containing very long chain fatty acids (VLCFA, C>20). Looking for low cost carbon sources, we tested Brassica carinata oil (erucic acid content 35-48%) as an intact triglyceride containing VLCFA. Oleic (C18:1), erucic (C22:1), and nervonic (C24:1) acids were also employed for mcl-PHA production as model substrates. The polymers obtained were analyzed by GC of methanolyzed samples, GPC, 1H and 13C NMR, ESI MS of partially pyrolyzed samples, and DSC. The repeating units of such polymers were saturated and unsaturated, with a higher content of the latter in the case of the PHA obtained from B. carinata oil. Statistical analysis of the ion intensity in the ESI mass spectra showed that the PHAs from pure fatty acids are random copolymers, while the PHA from B. carinata oil is either a pure polymer or a mixture of polymers. Weight-average molecular weight varied from ca. 56,000 g/mol for the PHA from B. carinata oil and oleic acid, to about 120,000 g/mol for those from erucic and nervonic acids. The PHAs from erucic and nervonic acids were partially crystalline, with rubbery characteristics and a melting point (Tm) of 50°C, while the PHAs from oleic acid and from B. carinata oil afforded totally amorphous materials, with glass transition temperatures (Tg) of -52°C and -47°C, respectively.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Erucic acid, technical, ~90% (GC)
Supelco
Erucic acid, analytical standard
Sigma-Aldrich
Erucic acid, ≥99% (capillary GC)
Sigma-Aldrich
Nervonic acid, ≥99% (capillary GC)
Supelco
Nervonic acid, analytical standard