Methods and microorganisms for the fermentation of methane to multi-carbon compounds
Genetically modified microorganisms that have the ability to convert carbon substrates into chemical products such as isobutanol are disclosed. For example, genetically modified methanotrophs that are capable of generating isobutanol at high titers from a methane source are disclosed. Methods of making these genetically modified microorganisms and methods of using them are also disclosed.
1. A genetically modified microorganism capable of converting a C 1 carbon to a multicarbon product, the microorganism comprising: (a) a gene encoding an acetolactate synthase comprising an amino acid sequence that is at least 90% identical to SEQ ID NO: 2; (b) a gene encoding a ketol-acid reductoisomerase comprising an amino acid sequence that is at least 90% identical to SEQ ID NO: 4; (c) a gene encoding a dihydroxy-acid dehydratase comprising an amino acid sequence that is at least 90% identical to SEQ ID NO: 8; and (d) a gene encoding a 2-keto acid decarboxylase comprising an amino acid sequence that is at least 90% identical to SEQ ID NO: 12; wherein at least one of the gene(s) is under the control of a rare earth metal switch.
2. The genetically modified microorganism of claim 1 , further comprising a gene encoding an alcohol dehydrogenase comprising an amino acid sequence that is at least 90% identical to any one of SEQ ID NOs: 14, 16, 18, 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 43, 45, 47, 49, 51, and 53.
3. The genetically modified microorganism of claim 1 , wherein the genetically modified microorganism is a methanotroph.
4. The genetically modified microorganism of claim 3 , wherein the methanotroph is a Methylococcus.
5. The genetically modified microorganism of claim 1 , wherein one or more of the gene(s) is heterologous to the microorganism.
6. The genetically modified microorganism of claim 1 , wherein at least one of the gene(s) is overexpressed.
7. The genetically modified microorganism of claim 1 , comprising multiple copies of at least one of the gene(s).
8. The genetically modified microorganism of claim 1 , wherein the rare earth metal switch is a lanthanum switch.
9. The genetically modified microorganism of claim 1 , further comprising a sugar permease gene.
10. A method of making the genetically modified microorganism of claim 1 , comprising contacting a microorganism with: a polynucleotide encoding the acetolactate synthase; a polynucleotide encoding the ketol-acid reductoisomerase; a polynucleotide encoding the dihydroxy-acid dehydratase; and/or a polynucleotide encoding the 2-keto acid decarboxylase.
11. A method of making the genetically modified microorganism of claim 9 , comprising contacting a microorganism with a polynucleotide encoding a sugar permease.
12. A method of making an aldehyde from a C 1 carbon comprising:
(a) contacting a C 1 carbon with the genetically modified microorganism of claim 1 comprising a gene encoding a 2-keto acid decarboxylase comprising an amino acid sequence that is at least 90% identical to SEQ ID NO:12; and
(b) growing the genetically modified microorganism to produce the aldehyde.
13. A method of making a useful product comprising:
(a) contacting the genetically modified microorganism of claim 1 with a C1 carbon substrate; and
(b) growing the genetically modified microorganism to produce the useful product, wherein the useful product comprises 2-acetolactate; 2,3-butanediol (2,3-BDO); diacetyl; 2,3-dihydroxy-2-methylbutanoic acid; 2,3-dihydroxyisovalerate; amino acids; ketoisovalerate; isobutyraldehyde; isobutyrate; methyl methacrylate (MMA); isovaleraldehyde; isovalerate; isopentanol; isoamyl acetate; pentadecanoic acid; isobutene; and/or p-xylene.
14. The genetically modified microorganism of claim 1 , the microorganism comprising genes encoding: an acetolactate synthase comprising an amino acid sequence that is at least 90% identical to SEQ ID NO: 2; a ketol-acid reductoisomerase comprising an amino acid sequence that is at least 90% identical to SEQ ID NO: 4; a dihydroxy-acid dehydratase comprising an amino acid sequence that is at least 90% identical to SEQ ID NO: 8; a first 2-keto acid decarboxylase comprising an amino acid sequence that is at least 90% identical to SEQ ID NO: 10; and a second 2-keto acid decarboxylase comprising an amino acid sequence that is at least 90% identical to SEQ ID NO: 12.
15. The genetically modified microorganism of claim 14 , wherein: the acetolactate synthase comprises an amino acid sequence that is at least 95% identical to SEQ ID NO: 2; the ketol-acid reductoisomerase comprises an amino acid sequence that is at least 95% identical to SEQ ID NO: 4; the dihydroxy-acid dehydratase comprises an amino acid sequence that is at least 95% identical to SEQ ID NO: 8; the first 2-keto acid decarboxylase comprises an amino acid sequence that is at least 95% identical to SEQ ID NO: 10; and the second 2-keto acid decarboxylase comprises an amino acid sequence that is at least 95% identical to SEQ ID NO: 12.
16. The genetically modified microorganism of claim 14 , wherein: the acetolactate synthase comprises the amino acid sequence of SEQ ID NO: 2 or one that differs therefrom by up to 25 conservative substitutions; the ketol-acid reductoisomerase comprises the amino acid sequence of SEQ ID NO: 4 or one that differs therefrom by up to 25 conservative substitutions; the dihydroxy-acid dehydratase comprises the amino acid sequence of SEQ ID NO: 8 or one that differs therefrom by up to 25 conservative substitutions; the first 2-keto acid decarboxylase comprises the amino acid sequence of SEQ ID NO: 10 or one that differs therefrom by up to 25 conservative substitutions; and the second 2-keto acid decarboxylase comprises the amino acid sequence of SEQ ID NO: 12 or one that differs therefrom by up to 25 conservative substitutions.
17. The genetically modified microorganism of claim 14 , wherein: the acetolactate synthase comprises the amino acid sequence of SEQ ID NO: 2 or one that differs therefrom by up to 10 conservative substitutions; the ketol-acid reductoisomerase comprises the amino acid sequence of SEQ ID NO: 4 or one that differs therefrom by up to 10 conservative substitutions; the dihydroxy-acid dehydratase comprises the amino acid sequence of SEQ ID NO: 8 or one that differs therefrom by up to 10 conservative substitutions; the first 2-keto acid decarboxylase comprises the amino acid sequence of SEQ ID NO: 10 or one that differs therefrom by up to 10 conservative substitutions; and the second 2-keto acid decarboxylase comprises the amino acid sequence of SEQ ID NO: 12 or one that differs therefrom by up to 10 conservative substitutions.
18. The genetically modified microorganism of claim 14 , wherein: the acetolactate synthase comprises the amino acid sequence of SEQ ID NO: 2; the ketol-acid reductoisomerase comprises the amino acid sequence of SEQ ID NO: 4; the dihydroxy-acid dehydratase comprises the amino acid sequence of SEQ ID NO: 8; the first 2-keto acid decarboxylase comprises the amino acid sequence of SEQ ID NO: 10; and the second 2-keto acid decarboxylase comprises the amino acid sequence of SEQ ID NO: 12.