Biological production of multi-carbon compounds from methane
Multi-carbon compounds such as ethanol, n-butanol, sec-butanol, isobutanol, tert-butanol, fatty (or aliphatic long chain) alcohols, fatty acid methyl esters, 2,3-butanediol and the like, are important industrial commodity chemicals with a variety of applications. The present invention provides metabolically engineered host microorganisms which metabolize methane (CH 4 ) as their sole carbon source to produce multi-carbon compounds for use in fuels (e.g., bio-fuel, bio-diesel) and bio-based chemicals. Furthermore, use of the metabolically engineered host microorganisms of the invention (which utilize methane as the sole carbon source) mitigate current industry practices and methods of producing multi-carbon compounds from petroleum or petroleum-derived feedstocks, and ameliorate much of the ongoing depletion of arable food source “farmland” currently being diverted to grow bio-fuel feedstocks, and as such, improve the environmental footprint of future bio-fuel, bio-diesel and bio-based chemical compositions.
1. A genetically modified methanotroph that is capable of producing 2,3-butanediol from methane (CH 4 ), the genetically modified methanotroph comprising exogenous polynucleotides encoding acetolactate synthase and 2,3-butanediol dehydrogenase, wherein the acetolactate synthase has acetolactate synthase activity and comprises an amino acid sequence having at least 90% sequence homology to SEQ ID NO:2, and the 2,3-butanediol dehydrogenase has 2,3-butanediol dehydrogenase activity and comprises an amino acid sequence having at least 90% sequence homology to SEQ ID NO: 157, wherein said methanotroph is capable of converting methane to pyruvate through an endogenous type I RuMP pathway or a type II serine pathway.
2. The genetically modified methanotroph of claim 1 , wherein said methanotroph is Methylobacter, Methylomicrobium, Methylomonas, Methylocaldum, Methylococcus, Methylosoma, Methylosarcina, Methylothermus, Methylohalobius, Methylogaea, Methylovulum, Crenothrix, Clonothrix, Methylosphaera, Methylocapsa, Methylocella, Methylosinus, Methylocystis , or Methyloacidophilum.
3. The genetically modified microorganism of claim 2 , wherein said methanotroph is Methylococcus.
4. The genetically modified microorganism of claim 3 , wherein said Methylococcus is Methylococcus capsulatus.
5. A method of producing 2,3-butanediol from methane comprising:
(a) contacting a methanotroph with methane,
(b) growing said methanotroph under suitable growth conditions to produce said 2,3-butanediol,
wherein said methanotroph is capable of converting methane to pyruvate through an endogenous type I RuMP pathway or a type II serine pathway and comprises exogenous polynucleotides encoding acetolactate synthase and 2,3-butanediol dehydrogenase, wherein the acetolactate synthase has acetolactate synthase activity and comprises an amino acid sequence having at least 90% sequence homology to SEQ ID NO:2, and the 2,3-butanediol dehydrogenase has 2,3-butanediol dehydrogenase activity and comprises an amino acid sequence having at least 90% sequence homology to SEQ ID NO: 157.
6. The method of claim 5 , wherein said methanotroph is Methylobacter, Methylomicrobium, Methylomonas, Methylocaldum, Methylococcus, Methylosoma, Methylosarcina, Methylothermus, Methylohalobius, Methylogaea, Methylovulum, Crenothrix, Clonothrix, Methylosphaera, Methylocapsa, Methylocella, Methylosinus, Methylocystis , or Methyloacidophilum.
7. The method of claim 5 , further comprising isolating and purifying said 2,3-butanediol.
8. The method of claim 6 , wherein said methanotroph is Methylococcus.
9. The method of claim 8 , wherein said Methylococcus is Methylococcus capsulatus.