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 capable of converting methane to a multi-carbon product comprising a heterologous nucleic acid encoding for a ketoacid decarboxylase (KDC), wherein the KDC has ketoacid decarboxylase activity and comprises an amino acid sequence having at least 90% sequence homology to SEQ ID NO: 8, wherein said methanotroph is capable of converting formaldehyde to pyruvate through a type I RuMP pathway or a type II serine pathway.
2. The genetically modified methanotroph of claim 1 , further comprising one or more nucleic acids encoding for a methane monooxygenase (MMO), methanol dehydrogenase (MDH), acteolactate synthase (AlsS), ketol-acid reductoisomerase (ilvC), or dihydroxy-acid dehydratase (ilvD).
3. The genetically modified methanotroph of claim 2 , wherein said one or more nucleic acids are heterologous.
4. The genetically modified methanotroph of claim 1 , wherein said multi-carbon product is isobutyraldehyde.
5. The genetically modified methanotroph of claim 1 , wherein said methanotroph is from the genus Methylobacter, Methylomicrobium, Methylomonas, Methylocaldum, Methylococcus, Methylosoma, Methylosarcina, Methylothermus, Methylohalobius, Methylogaea, Methylovulum, Crenothrix, Clonothrix, Methylosphaera, Methylocapsa, Methylocella, Methylosinus, Methylocystis , or Methyloacidophilum.
6. The genetically modified methanotroph of claim 5 , wherein said methanotroph is from the genus Methylococcus.
7. The genetically modified methanotroph of claim 6 , wherein said methanotroph is from the species Methylococcus capsulatus.
8. The genetically modified methanotroph of claim 1 , wherein the methanotroph comprises a nucleic acid sequence encoding for a KDC and a promoter, wherein said promoter is active in a methanotroph.
9. The genetically modified methanotroph of claim 8 , wherein said promoter is constitutively expressed.
10. The genetically modified methanotroph of claim 8 , wherein said promoter is inducible.