Search

Pseudomonas oleovorans was grown separately on 5-(4'-tolyl)valeric acid, 5-(4'-ethylphenyl)-valeric acid, 5-(4'-biphenyl)valeric acid, and 8-(4'-tolyl)octanoic acid either as the sole carbon source or as a coefeed with either nonanoic acid or 5-phenylvaleric acid. For polymer production, 5-(4'-tolyl)valeric acid was the most effective growth substrate of the five. It resulted in the production of poly-3-hydroxy-5-(4'-tolyl)valerate, a crystalline polymer with a glass transition temperature of 18 °C and a melting transition of 95 °C. This poly(3-hydroxyalkanoate) (PHA) is apparently the first example of a crystalline aromatic-containing bacterial PHA. When P. oleovorans was cofed an equimolar mixture of 5-phenylvaleric acid and 5-(4'-tolyl)valeric acid, the polymer produced contained 36 mol % of 3-hydroxy-5-phenylvalerate and 64 mol % of 3-hydroxy-5-(4'-tolyl)valerate, and it did not crystallize.

Lamellar single crystals of both natural poly[(R)-β-hydroxybutyrate], PHB, and synthetic poly[(R,S)-β-hydroxybutyrate] of various tacticities were degraded using enzymes isolated from the fungus Aspergillus fumigatus and the bacterium Pseudomonas lemoignei. Degradation was monitored by both turbidimetric and titrimetric assays. Despite their highly ordered state, single crystals of bacterial PHB were observed to degrade completely; no decrease in molecular weight was observed in the partly degraded polymer. By contrast, the single crystals of synthetic PHB showed only partial degradation, with some decrease in molecular weight; faster and more substantial degradation was observed for the most isotactic material, whereas single crystals from a nearly atactic sample were essentially inert. These results differ from those found for PHB films, implying that tacticity response is linear when crystallinity effects have been normalized. The observed results are consistent with preferential degradation from the c...

Propagation rate coefficient (k p ) values have been measured for monomers in the methacrylate family -ethyl (EMA), n-butyl (BMA), and isobutyl (i-BMA)- using pulsed-laser polymerization combined with gel permeation chromatography (GPC). Molecular weight calibrations were verified using both commercial polymer standards and GPC viscometry. Covering the temperature range of 10-90 o C, the k p results are well fit by the Arrhenius relationship and are compared to previous determinations for methyl methacrylate (MMA). A definite increase in k p is observed when progressing from MMA to EMA to BMA, with k p differences between BMA and i-BMA slight

Two different terpolyesters were obtained by fermentation of Rhodospirillum rubrum fed either with 4-pentenoic acid alone or with an equimolar mixture of 4-pentenoic and valeric acids. Sequence distributions of these two polyesters were determined by fast atom bombardment mass spectrometry (FAB-MS) of the oligomers prepared by partial methanolysis and separated by HPLC. The distributions in both polymers follow Bernoullian statistics, indicating that both are random terpolyesters

Pseudomonas oleovorans was grown on 2-methyl-3-hydroryoctane, ethyl 2-methyl-3-hydroxyoctanoate, ammonium 2-methyl-3-hydroryoctanoate, and methyl 2-methyl-3-hydroryoctanoate in attempts to obtain poly(3-hydroxyalkanoate)s (PHAs), with methyl branches at the 2-position. The microorganisms did not grow on these carbon sources alone but survived and could be reactivated later with organic substrates which could be used for good cell growth. Futhermore, bacterial growth on the branched carbon sources was observed when a cofeeding technique was applied, in which case cell growth showed no lag time and formed a biomass which contained a high percentage of PHAs. In this manner a variety of copolymers were obtained, and these were investigated by NMR, methanolysis-gas chromatography, and thermal analysis

Rhodospirillum rubrum was grown on 4-pentenoic acid (PEA) and on an equimolar mixture of PEA and pentanoic acid (PA). With both substrated the bacterium produced polymers containing 9-hydroxybutyrate (3HB), 9-hydroxyvalerate (3HV), and 3-hydroxy-4-pentenoate (HPE) repeating units. The poly(β-hydroxyalkanoates) (PHAs) obtained from PEA and from the PEA/PA mixture had molecular weight M n of 110000 and 155000, respectively. The polymers containing the unsaturated unit, HPE, possessed the same crystal structure as PHAs containing a high mole fraction of 3HV units

The crystallization kinetics of poly(β-hydroxyoctanoate) (PHO), a bacterially produced copolyester containing mostly β-hydroxyoctanoate repeating units was studied. The crystallization rate reached a maximum at 0-5°C. The equilibrium melting point was determined to be approximately 68°C. The long-term crystallization study on PHO crystallized from the melt at -20, +5, and +20°C revealed that stable but different levels of crystallinity were reached after 3-7 weeks. The melting endotherm peak continued to change shape for up to 19 weeks. The thermal history greatly affected the mechanical properties of the polymer

The sequence distributions of microbial copolyesters produced by Pseudomonas oleovorans grown with (a) nonanoic acid (NA) (b) an equimolecular mixture of NA and octanoic acid (OA) or (c) 2:1 mixtures of 10-undecenoic acid with either NA or OA were determined by analyzing the oligomers prepared by partial pyrolysis of these copolymers using FAM mass spectrometry. the sequence distributions in these copolyesters followed Bernoullian statistics, indicating that they were random copolymers

brominated copolyesters were produced by Pseudomonas oleovorans grown with mixtures of an ω-bromoalkanoic acid and either nonanoic acid or octanoic acid. The mole percent of brominated units in these copolymers varied from 2% to 37% depending on the nonbrominated carbon substrate and on the ratio of the two comonomers. The mole fractions of brominated units in the PHAs obtained from mixtures of OA and an ω-bromoalkanoic acid were lower than those in the PHAs obtained from mixtures of NA, but the molecular weights of the PHAs were essentially the same regardless of carbon sources used

Analyse des copolyesters obtenus par culture de Pseudomonas oleovorans sur l'acide nonanoique ou un melange acide nonanoique/acide octanoique. Les copolymeres contiennent essentiellement des motifs β-hydroxyheptanoate et β-hydroxynonoate

UCRL-260 1 UncYas sif ied C h e m i s t r y Distribution UNIVERSITY O F CALIFORNIA Radiation L a b o r a t o r y C o n t r a c t No. W -7405 eng-48 J, R. Quayle, R, C. F d l e r , A , A, S e n s o n and M. Calvin Mayp 1954 B e r k e l e y , California