Amino acid-producing microorganisms and methods of making and using

1. A method of synthesizing methionine, the method comprising culturing a methanotrophic recombinant Methylomicrobium buryatense comprising nucleic acids encoding inactivated endogenous proteins of pyruvate formate lyase, lactate dehydrogenase, and phosphate acetyltransferase, in a culture medium under conditions sufficient to produce methionine, in a culture medium comprising:

(a) methane, methanol, sugars, glycerol, or a combination thereof; and

(b) a source of sulfur.

2. The method of claim 1 , further comprising harvesting methionine synthesized by the methanotrophic recombinant Methylomicrobium buryatense.

3. The method of claim 2 , further comprising adding the harvested methionine to an animal feed or food product.

4. The method of claim 1 , wherein the methanotrophic recombinant Methylomicrobium buryatense further comprises:

heterologous nucleic acid encoding at least one protein selected from the group consisting of: pyruvate carboxylase, phosphoenolpyruvate carboxylase, aspartate transaminase, aspartate kinase, homoserine dehydrogenase, and methionine transporter; and/or

at least one additional inactivated endogenous protein selected from the group consisting of: methionine adenosyl transferase, diaminopimelate decarboxylase, starch synthase, oxaloacetate dehydrogenase, malic enzyme, sucrose phosphate synthase, and ectoine synthase.

5. The method of claim 1 , wherein the methanotrophic recombinant Methylomicrobium buryatense further comprises:

heterologous nucleic acid encoding one or more of protein selected from the group consisting of: formaldehyde dehydrogenase, formate dehydrogenase, aspartokinase, aspartate-semialdehyde dehydrogenase, homoserine dehydrogenase, and methionine synthase;

a heterologous nucleic acid that encodes a glucose transporter;

a heterologous nucleic acid encoding a homoserine O-acetyltransferase; and/or

a heterologous nucleic acid encoding methionine adenosyl transferase.

6. The method of claim 4 , wherein the pyruvate carboxylase is from C. glutamicum.

7. The method of claim 4 , wherein the phosphoenolpyruvate carboxylase is from Synechococcus sp. or M. thermoautotrophicus.

8. The method of claim 1 , wherein the methanotrophic recombinant Methylomicrobium buryatense is a recombinant Methylomicrobium buryatense 5G.

9. The method of claim 1 , wherein at least one of the inactivated endogenous proteins is a result of a deletion in an endogenous gene encoding the endogenous protein.

10. The method of claim 1 , wherein at least one of the inactivated endogenous proteins is a result of a point mutation in an endogenous gene encoding the endogenous protein.

11. The method of claim 4 , wherein the aspartate kinase is a feedback-resistant aspartate kinase.

12. The method of claim 1 , wherein the culture medium comprises methanol or methane.

13. The method of claim 1 , wherein the culture medium comprises methanol as the only carbon source.

14. The method of claim 1 , wherein the culture medium comprises glucose and methanol.

15. The method of claim 4 , wherein the pyruvate carboxylase is a feedback-resistant pyruvate carboxylase.

16. The method of claim 1 , wherein the culturing is performed under anaerobic conditions.

17. The method of claim 1 , wherein the source of sulfur is selected from the group of: ammonium sulfate, sodium sulfate, magnesium sulfate, potassium sulfate, ammonium thiosulfate, methanethiol, and dimethylthiol.

18. The method of claim 1 , wherein the methanotrophic recombinant Methylomicrobium buryatense further comprises inactivated endogenous diaminopimelate decarboxylase protein.

19. The method of claim 1 , wherein the methanotrophic recombinant bacterial Methylomicrobium buryatense further comprises:

heterologous nucleic acid encoding phosphoenolpyruvate carboxylase protein;

heterologous nucleic acid encoding feedback-resistant form of aspartate kinase protein; and

inactivated endogenous diaminopimelate decarboxylase protein.