Fatty acid synthase alpha subunit; part of the pki gene cluster that mediates the biosynthesis of 2,4-dihydroxy-3-methyl-6-(2-oxoundecyl)benzaldehyde. The first step in the pathway is the generation of the decanoyl starter unit by the FAS composed of subunits pkiB and pkiC, which is then transferred directly from the FAS to the SAT domain of the non-reducing polyketide synthase pkiA. PkiA condenses the decanoyyl starter unit with 4 malonyl-CoA units and performs one methylation step to yield 2,4-dihydroxy-3-methyl-6-(2-oxoundecyl)benzaldehyde