Acetyl-CoA acetyltransferase; part of the first module of ergosterol biosynthesis pathway that includes the early steps of the pathway, conserved across all eukaryotes, and which results in the formation of mevalonate from acetyl-coenzyme A (acetyl-CoA). Erg10B catalyzes the formation of acetoacetyl-CoA from acetyl-CoA. The first module starts with the action of the cytosolic acetyl-CoA acetyltransferase erg10B that catalyzes the formation of acetoacetyl-CoA. The hydroxymethylglutaryl-CoA synthases erg13A and erg13B then condense acetyl-CoA with acetoacetyl-CoA to form HMG-CoA. The rate-limiting step of the early module is the reduction to mevalonate by the 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductases hmg1 and hmg2. Mevalonate is also a precursor for the extracellular siderophore triacetylfusarinine C (TAFC) (Probable)