The manufacturing method of medium chain fatty acid using a (beta)-ketoacyl- ACP synthase

[Problem] To provide a method for producing a medium-chain fatty acid using β-ketoacyl-ACP synthase， or a lipid having said fatty acid as a constituent thereof， and to also provide a gene， a protein， and a transformant used in said method. [Solution] A method for producing a medium-chain fatty acid or a lipid having said fatty acid as a constituent thereof， said method comprising obtaining a transformant by introducing， to a host， a gene that codes a protein (A) or (B)， and extracting a medium-chain fatty acid or a lipid having said fatty acid as a constituent thereof from the obtained transformant. A gene， a protein， and a transformant used in said method. (A) A protein comprising an amino acid sequence represented by SEQ ID NO: 1; (B) A protein comprising an amino acid sequence that is at least 90% identical to said amino acid sequence represented by SEQ ID NO: 1， and exhibiting β-ketoacyl-ACP synthase activity specific to a medium-chain acyl-ACP [Problem] To provide a method for producing a medium-chain fatty acid using β-ketoacyl-ACP synthase， or a lipid having said fatty acid as a constituent thereof， and to also provide a gene， a protein， and a transformant used in said method. [Solution] A method for producing a medium-chain fatty acid or a lipid having said fatty acid as a constituent thereof， said method comprising obtaining a transformant by introducing， to a host， a gene that codes a protein (A) or (B)， and extracting a medium-chain fatty acid or a lipid having said fatty acid as a constituent thereof from the obtained transformant. A gene， a protein， and a transformant used in said method. (A) A protein comprising an amino acid sequence represented by SEQ ID NO: 1; (B) A protein comprising an amino acid sequence that is at least 90% identical to said amino acid sequence represented by SEQ ID NO: 1， and exhibiting β-ketoacyl-ACP synthase activity specific to a medium-chain acyl-ACP