Engineered thioesterase mutants and methods of using same to produce fatty acids

A method for generating a thioesterase mutant comprising:

• selecting a heterologous thioesterase for mutation based at least in part on a desired end product that is produced by the heterologous thioesterase;
• identifying amino acids on the heterologous thioesterase that form an interacting surface with E. coli AcpP, are involved in stabilizing the interaction, and are suitable for mutation;
• mutagenizing the identified amino acids of the heterologous thioesterase by introducing substitutions into a nucleic acid comprising the heterologous thioesterase nucleotide sequence;
• and
• expressing the nucleic acid comprising the mutated heterologous thioesterase nucleotide sequence in a bacterial cell to produce a heterologous thioesterase mutant,
• wherein the heterologous thioesterase mutant comprises an amino acid sequence that is at least 90% identical to an amino acid sequence selected from the group consisting of SEQ ID NOs 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 43, and
• wherein the bacterial cell expressing the heterologous thioesterase mutant has an improved medium-chain fatty acid titer production compared to a bacterial cell expressing a wildtype heterologous thioesterase nucleotide sequence.