Required for the synthesis of N-butanoyl-L-homoserine lactone (BHL), an autoinducer molecule which binds to AhyR. a fatty acyl-[ACP] + S-adenosyl-L-methionine = an N-acyl-L-homoserine lactone + H(+) + holo-[ACP] + S-methyl-5'-thioadenosine Belongs to the autoinducer synthase family.