SEQUENCE DISTRIBUTION OF BETA-HYDROXYALKANOATE UNITS WITH HIGHER ALKYL-GROUPS IN BACTERIAL COPOLYESTERS

Two different samples of copolyesters produced by Pseudomonas oleovorans when grown either on nonanoic acid alone or on an equimolar mixture of nonanoic and octanoic acids were evaluated for sequence distribution by controlled methanolysis to their oligomers, separation of the oligomers by HPLC, and analysis of the fractions so obtained by fast atom bombardment mass spectrometry (FAB-MS). The copolyesters contained primarily ß-hydroxyheptanoate and ß-hydroxynonanoate units, which showed no observable differences in their 1H and13C NMR spectra with changes in composition, so those analyses could not be applied. The observed oligomer composition and that calculated on the basis of Bernoullian statistics for sequence distributions in random copolymers of the compositions studied were in good agreement. © 1990, American Chemical Society. All rights reserved.