The accumulation of poly(3-hydroxyalkanoates) in Rhodobacter sphaeroides

In recent years industrial interest has been focussed on the evaluation of poly(3-hydroxyalkanoates) (PHA) as potentially biodegradable plastics for a wide range of technical applications. Studies have been carried out in order to optimize growth and culture conditions for the intracellular formation of PHA in the phototrophic, purple, non-sulfur bacterium Rhodobacter sphaeroides. Its potential to produce polyesters other than poly(3-hydroxybutyrate) (PHB) was investigated. On an industrial scale, the use of photosynthetic bacteria could harness sunlight as an energy source for the production of these materials. R. sphaeroides was grown anaerobically in the light on different carbon sources. Under nitrogenlimiting conditions a PHA content of up to 60 to 70% of the cellular dry weight was detected. In all of the cases studied, the storage polymer contained approximately 98 mol% of 3-hydroxybutyrate (HB) and 2 mol% 3-hydroxyvalerate (HV) monomer units. Decreasing light intensities did not stimulate PHA formation. Compared to Rhodospirillum rubrum (another member of the family of Rhodospirillaceae), R. sphaeroides showed a limited flexibility in its ability to form PHA with varying monomer unit compositions.

[1]  R. Gross,et al.  Plastics from bacteria and for bacteria: poly(beta-hydroxyalkanoates) as natural, biocompatible, and biodegradable polyesters. , 1990, Advances in biochemical engineering/biotechnology.

[2]  R. Lenz,et al.  Production of unsaturated polyesters by Pseudomonas oleovorans. , 1990, International journal of biological macromolecules.

[3]  R. Gross,et al.  The biosynthesis and characterization of poly(β-hydroxyalkanoates) produced by Pseudomonas oleovorans , 1989 .

[4]  M. Doudoroff,et al.  Role of Poly-β-Hydroxybutyric Acid in the Assimilation of Organic Carbon by Bacteria , 1959, Nature.

[5]  R. Bachofen,et al.  Aspects of growth and hydrogen production of the photosynthetic bacterium Rhodospirillum rubrum in continuous culture , 1982 .

[6]  P A Holmes,et al.  Applications of PHB - a microbially produced biodegradable thermoplastic , 1985 .

[7]  R. Gross,et al.  Ability of the phototrophic bacterium Rhodospirillum rubrum to produce various poly (beta-hydroxyalkanoates): potential sources for biodegradable polyesters. , 1989, International journal of biological macromolecules.

[8]  B. Haddock.  Microbial energetics. , 1980, Philosophical transactions of the Royal Society of London. Series B, Biological sciences.

[9]  R. Gross,et al.  Pseudomonas oleovorans as a Source of Poly(β-Hydroxyalkanoates) for Potential Applications as Biodegradable Polyesters , 1988, Applied and environmental microbiology.

[10]  R. Capon,et al.  Poly-3-hydroxyalkanoates from marine and freshwater cyanobacteria , 1983 .

[11]  E. Dawes,et al.  The role and regulation of energy reserve polymers in micro-organisms. , 1973, Advances in microbial physiology.

[12]  D. Byrom,et al.  Polymer synthesis by microorganisms: technology and economics , 1987 .

[13]  J. Shively.  Inclusion bodies of prokaryotes. , 1974, Annual review of microbiology.