Polyhydroxyalkanoate production methods and materials and microorganisms used in same
Embodiments of the invention relate generally to methods to generate microorganisms and/or microorganism cultures that exhibit the ability to produce polyhydroxyalkanoates (PHA) from carbon sources at high efficiencies. In several embodiments, preferential expression of, or preferential growth of microorganisms utilizing certain metabolic pathways, enables the high efficiency PHA production from carbon-containing gases or materials. Several embodiments relate to the microorganism cultures, and/or microorganisms isolated therefrom.
1. A culture of methanotrophic microorganisms characterized by:
(a) lack of the genetic material encoding soluble methane monooxygenase (sMMO), failure to transcribe DNA encoding sMMO or translate mRNA encoding sMMO, and/or failure to produce a functional sMMO enzyme;
(b) having the genetic material encoding the ethylmalonyl-CoA pathway, transcribing DNA encoding the ethylmalonyl-CoA pathway, and translating mRNA encoding the ethylmalonyl-CoA pathway; and
(c) the capability of producing polyhydroxyalkanoate (PHA) at intracellular PHA concentrations with a ratio of PHA to non-PHA biomass exceeding 3:1 on a dry weight basis.
2. The culture of claim 1 , consisting essentially of microorganisms characterized by:
(a) lack of the genetic material encoding soluble methane monooxygenase (sMMO), failure to transcribe DNA encoding sMMO or translate mRNA encoding sMMO, and/or failure to produce a functional sMMO enzyme;
(b) having the genetic material encoding the ethylmalonyl-CoA pathway, transcribing DNA encoding the ethylmalonyl-CoA pathway, and translating mRNA encoding the ethylmalonyl-CoA pathway; and
(c) the capability of producing polyhydroxyalkanoate (PHA) at intracellular PHA concentrations with a ratio of PHA to non-PHA biomass exceeding 3:1 on a dry weight basis.
3. A composition comprising isolated microorganisms from the culture of claim 1 .
4. The culture of claim 1 , wherein said culture comprises microorganisms from a genus selected from a group consisting of: Methylosinus, Methylocystis, Methylococcus, Methylobacterium , and Pseudomonas.
5. The culture of claim 1 , wherein said methanotrophic microorganisms exhibit particulate methane monooxygenase activity in the presence of copper ion concentrations between 0.001 micromolar and 1000 micromolar.
6. The culture of claim 1 , wherein said methanotrophic microorganisms exhibit ethylmalonyl-CoA pathway activity in the presence of copper concentrations between 0.001 micromolar and 1000 micromolar.
7. The culture of claim 1 , wherein said characteristics of said microorganisms are obtained due to mutation, genetically-engineered mutation, and/or selection-pressure-induced mutation.