POLYHYDROXYALKANOATE PRODUCTION AND RELATED PROCESSES
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Abstract
Embodiments of the invention relate generally to processes for the production and processing of polyhydroxyalkanoates (PHA) from carbon sources. In several embodiments, PHAs are produced at high efficiencies from carbon-containing gases through the utilization of a regenerative polymerization system.
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Citations
40 Claims
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1-18. -18. (canceled)
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19. A process for producing polyhydroxyalkanoate (PHA) by a culture of microorganisms, the process comprising:
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(a) providing a culture of two or more strains of microorganisms comprising a first strain of methanotrophic microorganisms capable of metabolizing methane to synthesize PHA and a second strain of microorganisms capable of metabolizing a PHA-reduced biomass to synthesize PHA; (b) providing a culture medium comprising at least one nutrient, methane, and a PHA-reduced biomass; (c) exposing said culture to said culture medium; (d) subjecting said culture to a growth period causing said first strain to use said methane to reproduce and said second strain to use said PHA-reduced biomass to reproduce; and (e) subjecting said grown culture to a polymerization period by reducing the concentration of at least one of said nutrients thereby causing said first strain to use said methane to synthesize PHA and said second strain to use said PHA-reduced biomass to synthesize PHA. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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34. A process for polyhydroxyalkanoate (PHA) production by a culture of microorganisms, the process comprising:
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(a) fermenting a culture of at least two strains of microorganisms comprising a culture medium, a first strain of microorganism capable of metabolizing a carbon-containing gas, a second strain of microorganism capable of metabolizing a reduced biomass, and at least one nutrient; (b) exposing said fermenting culture of microorganisms to an excess supply of carbon-containing gas throughout said fermentation step; (c) subjecting said fermenting culture of microorganisms to a growth period causing said culture of fermenting microorganisms to reproduce; (d) subjecting said fermenting culture of microorganisms to a polymerization period by reducing the concentration of at least one of said nutrients thereby causing said reproduced culture capable of synthesizing PHA to synthesize PHA; (e) repeatedly cycling said culture of microorganisms between said growth period and said polymerization period until the desired quantity of intracellular PHA is produced by those microorganisms capable of producing PHA thereby producing a PHA-containing biomass; (f) removing a portion of said microorganisms following step (e) to harvest said PHA to create a reduced biomass; (g) returning said reduced biomass produced in step (f) to the culture of step (a), wherein reducing the concentration of said one or more nutrients in step (c) and supplying an excess quantity of carbon-containing gas further causes said first and second strain of microorganism to synthesize PHA from said carbon-containing gas and said reduced biomass respectively; and (h) repeating steps (a)-(h) at least two times, to increase the yield of PHA produced using only said carbon containing gas and said reduced biomass as a carbon source. - View Dependent Claims (35, 36, 37, 38, 39, 40)
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Specification