A method for enhancing the acetic acid fermentation ability of an acetic acid bacterium belonging to the genus Acetobacter or the genus Gluconacetobacter, wherein the function of one or two proteins which are encoded by the genes involved in the quorum-sensing system in the acetic acid bacterium belonging to the genus Acetobacter or the genus Gluconacetobacter is reduced or deleted,
- wherein the gene involved in the quorum-sensing system is a gene encoding:
- (A) a protein consisting of the amino acid sequence of SEQ ID NO:
- 2;
- or
- (B) a protein which consists of an amino acid sequence having at least 90% or more identity to the amino acid sequence of SEQ ID NO:
- 2, and which has the activity of an acyl homoserine lactone synthase,
- or a gene encoding:
- (A) a protein consisting of the amino acid sequence of SEQ ID NO:
- 3;
- or
- (B) a protein which consists of an amino acid sequence having at least 90% or more identity to the amino acid sequence of SEQ ID NO:
- 3, and which has the function as an acyl homoserine lactone receptor-type transcription factor.