Medium chain length polyhydroxyalkanoate polymer and method of making same
AssigneeQueen's University at Kingston
InventorsXuan Jiang, Zhiyong Sun, Juliana Ramsay, Bruce A. Ramsay
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Abstract
A method is provided for producing medium chain length poly(3-hydroxyalkanoate) (MCL-PHA) with a selected ratio of monomers. A method of controlling the ratio of monomers in MCL-PHA is also provided which includes fermenting naturally occurring microorganisms with a fatty acid substrate, a food source and an additive. The methods provided do not sacrifice cell growth and maintenance and provide high yields of MCL-PHAs. MCL-PHAs are provided that are copolymers of Cn and Cn−2 monomers, where (n is 6-18).
Claims38
A method of making MCL-PHA polymer, comprising:
- providing MCL-PHA-producing microbial cells in a medium suitable for microbial growth, the medium comprising:
- a substrate that is structurally related to MCL-PHA;
- a carbon source that is not structurally related to MCL-PHA;
- and
- a β-oxidation pathway inhibitor;
- and
- allowing microbial cell growth to occur in the medium wherein the microbial cells synthesize MCL-PHA polymer;
- wherein the MCL-PHA polymer is a homopolymer or a copolymer that has a selected ratio of comonomers that differs from that obtained in the absence of the β-oxidation pathway inhibitor;
- wherein microbial cell growth and MCL-PHA copolymer production take place in a carbon-limited fed-batch or a carbon-limited continuous fermentation process.
Polyhydroxyalkanoate polymer comprising a Cn monomer that has n carbons, wherein n is 6, 7, 8, 9, or 11 to 18, and
- wherein when n is 6, 7, 9, or 11, the polymer is at least about 85 mol % or higher Cn, monomer,
- wherein when n is 8, the polymer is at least about 97 mol % or higher Cn, monomer, and
- wherein when n is 12 to 18, the polymer is at least about 70 mol % or higher Cn monomer.
A method of making MCL-PHA polymer, comprising:
- providing MCL-PHA-producing microbial cells in a medium suitable for microbial growth, the medium comprising:
- a substrate that is structurally related to MCL-PHA;
- a carbon source that is not structurally related to MCL-PHA;
- and
- a β-oxidation pathway inhibitor;
- and
- allowing microbial cell growth to occur in the medium wherein the microbial cells synthesize MCL-PHA polymer;
- wherein the MCL-PHA polymer is a homopolymer or a copolymer that has a selected ratio of comonomers that differs from that obtained in the absence of the β-oxidation pathway inhibitor;
- wherein the molar ratio of substrate:carbon source is between about 1 and about 1.5 when glucose is the carbon source.
Dependencies are inferred from the claim text.