Trans-enoyl reductase; part of the gene cluster that mediates the biosynthesis of cordypyrones A and B, 2 pyrones that show modest activities against pathogenic bacteria including methicillin-resistant Staphylococcus aureus (MRSA), Mycobacterium tuberculosis and Bacillus cereus (PubMed:34548637). The HR-PKS milA catalyzes the formation of cordypyrones A via condensation of one acetate with 10 malonate units (PubMed:34548637). Since milA lacks an enoyl reductase domain, the 2 beta-keto processing domains DH and KR of milA collaborate with the trans-enoyl reductase milB to catalyze the different levels of reduction (PubMed:34548637). The cytochrome P450 monooxygenase milC then hydroxylates the C-22 of cordypyrones A to yield cordypyrones B (PubMed:34548637). acetyl-CoA + 3 AH2 + 18 H(+) + 10 malonyl-CoA + 8 NADPH = 3 A + 10 CO2 + 11 CoA + cordypyrone A + 8 H2O + 8 NADP(+) Secondary metabolite biosynthesis. Monomer. Belongs to the zinc-containing alcohol dehydrogenase family.