Submitted to: Annual Meeting and Expo of the American Oil Chemists' Society
Publication Type: Abstract Only
Publication Acceptance Date: 3/1/2004
Publication Date: 5/1/2004
Citation: Ashby, R.D., Solaiman, D., Nunez, A., Foglia, T.A. 2004. Tricylglycerol-based production of environmentally benign, value-added polymers and surfactants [abstract]. Annual Meeting of the American Oil Chemists' Society. p. 32.
Technical Abstract: Animal fats and vegetable oils are derived from renewable resources and can be utilized as carbon substrates in fermentation processes designed to produce value-added materials. Many species of bacteria and yeast are able to utilize triacylglycerols (TAGs) or their components (free fatty acids, FFA, and glycerol) to synthesize biopolyesters (polyhydroxyalkanotes; PHAs), and biosurfactants (sophorolipids; SLs). These biobased products could replace their synthetic equivalents provided their production costs can be minimized. Presently, there are over 100 different structural variations of PHA. These variations depend on the genetic makeup of the bacteria and the carbon substrate provided to the organism. By utilizing different bacterial strains we have produced from TAGs, FFAs and glycerol both short-chain PHA (scl-PHA), the most common of which is poly 3-hydroxybutyrate (PHB), a semicrystalline thermoplastic, and the amorphous medium-chain PHA (mcl-PHA), which contains monomers of 3-hydroxyalka(e)noates with 6 to 14 carbon atoms and exhibits elastomeric or adhesive-like properties. We have further modified the properties of the polymers by molar mass regulation, formation of natural polymer blends and crosslink formation through gamma irradiation and epoxidation and aging. SLs are amphipathic molecules produced by the yeast Candida bombicola from a number of TAGs and FFAs. Their primary structure is a disaccharide (sophorose; 2'-O-Beta-D-glucopyranosyl-Beta-D-glucopyranose) with a fatty acid (oleic acid is preferred) that can be in its free acid form attached at the 1' position or lactonized between the 1' and 4" positions of the glucose rings. These molecules are biosynthesized in acetylated or nonacetylated forms and are generally synthesized as mixtures containing up to 12 different compounds. Recently, we were successful in utilizing fatty acid methyl esters (FAMEs) and the waste stream from biodiesel production to produce SLs with increased ratios of FAMEs in their side chains. This allowed further structural modifications. In summary, our research efforts have demonstrated the possibility of synthesizing and modifying biomaterials using TAGs as feedstocks.