Involved in the biosynthesis of methyl-branched alkylpyrones (PubMed:23615910). Pks11 catalyzes the extension of medium- and long-chain aliphatic acyl-CoA substrates by using malonyl-CoA and methylmalonyl-CoA as extender molecules to synthesize polyketide products (PubMed:12941968, PubMed:23615910). Palmitoyl-CoA or a similar long chain fatty acid derivative is the likely substrate in vivo (PubMed:23615910). 2 H(+) + hexadecanoyl-CoA + malonyl-CoA + methylmalonyl-CoA = 4-hydroxy-5-methyl-6-pentadecylpyran-2-one + 2 CO2 + 3 CoA 2 H(+) + malonyl-CoA + methylmalonyl-CoA + octadecanoyl-CoA = 4-hydroxy-5-methyl-6-heptadecylpyran-2-one + 2 CO2 + 3 CoA 2 H(+) + hexanoyl-CoA + 2 malonyl-CoA = 4-hydroxy-6-pentylpyran-2-one + 2 CO2 + 3 CoA dodecanoyl-CoA + 2 H(+) + 2 malonyl-CoA = 4-hydroxy-6-undecylpyran-2-one + 2 CO2 + 3 CoA dodecanoyl-CoA + 3 H(+) + 3 malonyl-CoA = 4-hydroxy-6-(2-oxotridecyl)pyran-2-one + 3 CO2 + 4 CoA Lipid metabolism; fatty acid biosynthesis. Homodimer. Belongs to the thiolase-like superfamily. Chalcone/stilbene synthases family.