POLYESTER BIOSYNTHESIS CHARACTERISTICS OF PSEUDOMONAS-CITRONELLOLIS GROWN ON VARIOUS CARBON-SOURCES, INCLUDING 3-METHYL-BRANCHED SUBSTRATES

Forty-two different carbon sources were tested for the polyester synthesis of a citronellol-utilizing bacterium, Pseudomonas citronellolis (ATCC 13674). These included linear C-2 to C-10 monocarboxylic acids, C-2 to C-10 dicarboxylic acids, saccharides, alpha,omega-diols, hydrocarbons, and 3-methyl-branched substrates such as 3,7-dimethyl-6-octen-ol (citronellol), 3-methyl-n-valerate, 3-methyl-1-butanol, and 3-methyladipate. Isolated polymers were characterized by gas chromatography, infrared spectroscopy, H-1- or C-13-nuclear magnetic resonance spectroscopy, H-1-C-13 heteronuclear correlation spectroscopy (H-1-C-13 COSY), H-1-H-1 homonuclear COSY, and differential scanning calorimetry. Polyesters from nine monocarboxylic acids and two related carbon sources could be metabolically divided into three groups. The first group of C-2 to C-4 carbon sources resulted in copolyesters composed of 61 to 70 mol% 3-hydroxydecanoate, 23 to 33 mol% 3-hydroxyoctanoate, 3.6 to 9.0 mol% 3-hydroxy-5-cis-dodecenoate, and 1.8 to 2.6 mol% 3-hydroxy-7-cis-tetradecenoate. Carbon sources in group II (C-7 to C-10) produced copolyesters composed of 3-hydroxyacid monomer units with the same number of carbon atoms as the substrate (major constituent) and monomer units with either two less or two more carbons. Negligible amounts of 3-hydroxy-5-cis-dodecenoate and 3-hydroxy-7-cis-tetradecenoate were detected in copolyesters from this group. Copolyesters from group III (C-5 and C-6) had a monomer unit distribution that could be said to be between those of groups I and II. In addition, a novel copolyester, poly(3-hydroxy-7-methyl-6-octenoate-co-3-hydroxy-5-methylhexnoate), was synthesized when grown on citronellol. The H-1-C-13 heteronuclear COSY spectrum for monomer unit II revealed that both methylene and isopropyl groups, proximately connected in series to a single chiral center, had magnetically diastereotopic natures.