Bacteria and method for synthesizing fatty acids
There is provided a recombinant bacterium comprising at least one overexpressed acyl-ACP thioesterase gene, and wherein at least one gene from the tricarboxylic acid cycle or glycolysis or both is inactivated. There is also provided a method for producing fatty acids, said method comprising culturing bacteria comprising at least one overexpressed acyl-ACP thioesterase gene in a growth medium in a container having walls; allowing said bacteria to secrete fatty acids; and collecting said fatty acids. Acid supplementation is also shown to increase productivity.
1. A recombinant microorganism comprising at least one overexpressed hybrid acyl-ACP thioesterase, and wherein i) at least one protein from the tricarboxylic acid cycle is reduced, or ii) at least one protein from glycolysis pathway is reduced, or both i) and ii) are reduced.
2. The microorganism of claim 1 , wherein said at least one protein from the tricarboxylic acid cycle is selected from the group consisting of aconitase, isocitrate dehydrogenase, α-ketoglutarate dehydrogenase, succinyl-coA synthetase, succinic dehydrogenase, fumarase, malate dehydrogenase, and citrate synthase.
3. The microorganism of claim 1 , wherein said at least one protein from the tricarboxylic acid cycle is succinyl-CoA synthetase.
4. The microorganism of claim 1 , further comprising at least one further modification selected from the group consisting of i) overexpressed malonyl coenzyme A-acyl carrier protein transacylase, ii) overexpressed transhydrogenase, iii) moderately overexpressed acetyl-CoA carboxylase, iv) overexpressed NAD kinase and v) reduced activity of endogenous fatty acyl-CoA synthetase.
5. The microorganism of claim 4 , wherein said transhydrogenase is a soluble pyridine nucleotide transhydrogenase.
6. A microorganism comprising an overexpressed hybrid acyl-ACP thioesterase comprising amino acids 1-40 or 397-419 of the acyl-ACP thioesterase from Ricinus communis (SEQ ID NO 13) or a 90% homolog thereof that is operably coupled to the carboxyl or amino region of a second thioesterase from another species.
7. A microorganism comprising an overexpressed hybrid acyl-ACP thioesterase comprising a 95% homolog to:
i) amino acid 1 to amino acid 40 of SEQ ID NO 13, or
ii) amino acid 397 to amino acid 419 of SEQ ID NO 13, or
iii) both i) and ii),
operably fused to the remainder of an acyl-ACP thioesterase of another species.
8. A gene encoding the hybrid thioesterase comprising a 90-100% homolog of amino acid 1 to amino acid 40 of SEQ ID NO. 13 operably fused to the amino region of a second thioesterase.